Power System Thesis

Modelling the Absorbence of the Rural

Distribution Network for Connection of

Embedded Generators

Diploma Thesis

by

Robert Schmaranz

University of Edinburgh Department of Electronics and Electrical Engineering

Edinburgh, United Kingdom May 2000

Submitted to Technical University Graz

Institute of Electric Power Systems Graz, Austria

Preface 1

“Modelling the Absorbence of the Rural Distribution Network for Connection of EGs” Robert Schmaranz

Preface

This project was performed at the University of Edinburgh, Department of Electronics and Electrical Engineering, and submitted to the Technical University Graz, Institute of Electric Power Systems. This work is intended to be my final thesis for diploma at the Technical University Graz. I would like to thank Dr. Robin Wallace, my project supervisor at the University of Edinburgh, for the proposal of the topic, the discussions and his help encouragement and professionalism during the course of the project. Thanks also go to Dr. Gary Conner for his invaluable advice and information provided with regard to the work I carried out, Gareth Harrison for the help he gave me when learning the VC++ programming language and the whole Energy System Group for their aid when writing the report. Many thanks also go to Professor Lothar Fickert at the Technical University Graz, Institute of Electric Power Systems, for his help during the application process and encouragement in the beginning of the project. A final word of thanks goes out to my dearest friends and family back home for their never-ending encouragement and support. The work shall be dedicated to my family and my girlfriend Hanni. Robert Schmaranz Edinburgh, 15 May 2000

Abstract 2


Abstract

Electricity is being demanded at an ever increasing rate by modern society. Due to the depletion of fossil fuel energy sources to generate electricity this increasing demand must be met by some other means. Government initiatives and the privatisation of the electricity supply industry in recent years has encouraged the development of wind farms, mini-hydro schemes and industrial Combined Heat and Power (CHP) generating plants which are embedded in the electricity distribution network. The operation of these embedded generators may improve or adversely effect the quality or stability of the electricity supplied to costumers. Each embedded generation scheme must be assessed for its technical feasibility as many of the plants may propose to connect in remote areas where the grid system is already weak. Due to the shear number of proposed schemes there is a need for a hierarchical rule-base which could identify, at an early stage in development, any problems that would be encountered by the connection. The effects an embedded generator has on the distribution system can be determined by different computer simulations.

This report explains the basics of embedded generation, the problems an embedded generator has on the rural distribution network and describes the construction of circle diagrams for a short- and long-transmission line, to determine the absorbence of the grid. With the developed knowledge a program in Microsoft Visual C++ Version 6.0 is written to visualise the obtained results.

The Visual C++ simulation shows an universal power circle diagram for a short-transmission line similar to the power circle diagram of a synchronous machine. It obtains an active and reactive power area for the receiving end and an area for the receiving- and sending-end voltage. The program additionally calculates the sending-end values for the active, reactive and complex power, the power factor, the phase angle, the current and the load angle. Keywords: circle diagram, embedded generation, grid absorbence, power flow, voltage

violation

Table of Contents 3


Table of Contents

1 INTRODUCTION .......................................................................................................8

1.1 General Background..................................................................................................8 1.2 Worldwide Energy Reserves – Forecast....................................................................9 1.3 Worldwide Energy Consumption – Forecast ..........................................................10 1.4 Situation in the United Kingdom.............................................................................11 1.5 The Future of Distributed Generation in the United Kingdom ...............................13 1.6 Scope of this Project ................................................................................................14

2 EMBEDDED GENERATION..................................................................................15

2.1 Basics.......................................................................................................................15 2.2 The Electricity Supply System ................................................................................15 2.3 Types of Embedded Generation ..............................................................................17

2.3.1 Combined Heat and Power Schemes.................................................................17 2.3.2 Mini-Hydro Schemes.........................................................................................17 2.3.3 Wind Power .......................................................................................................17 2.3.4 Others ................................................................................................................18

2.4 Advantages of Embedded Generators .....................................................................19 2.5 Legislation in the United Kingdom .........................................................................20 2.6 Types of Generators ................................................................................................21

2.6.1 The Synchronous Generator ..............................................................................21 2.6.2 The Induction Generator....................................................................................22 2.6.3 Fault Contribution .............................................................................................24 2.6.4 Choice of Generator ..........................................................................................24

2.7 Solid-State Power Convertors .................................................................................25 2.8 Effects of Embedded Generators on Weak Rural Grids..........................................26

2.8.1 Load Flow and Losses .......................................................................................26 2.8.2 Power Quality ....................................................................................................29 2.8.3 Fault Levels .......................................................................................................29 2.8.4 Steady-State and Transient Stability..................................................................30 2.8.5 Voltage Variations.............................................................................................30

2.9 Protection Considerations........................................................................................32 2.9.1 Generator Protection..........................................................................................32 2.9.2 Loss of Main Protection ....................................................................................32 2.9.3 G59/1 Protection................................................................................................33

Table of Contents 4


3 POWER FLOW AND ABSORBENCE...................................................................34

3.1 The Per-Unit System ...............................................................................................34 3.2 Reactive Power ........................................................................................................35 3.3 The Four-Terminal Network ...................................................................................37 3.4 The Short-Transmission Line ..................................................................................40

3.4.1 Power Transfer of a Short-Transmission Line ..................................................40 3.4.2 The Circle Diagram for Z = X (R = 0) ..............................................................43 3.4.3 The Receiving-End Power Circle Diagram of a Short-Transmission Line .......46 3.4.4 The Universal Power Circle Diagram of a Short-Transmission Line ...............51

3.5 The Long-Transmission Line ..................................................................................55 3.5.1 Transmission Line Constants ............................................................................55 3.5.2 The Receiving-End Power Circle Diagram of a Long-Transmission Line .......57 3.5.3 The Universal Power Circle Diagram of a Long-Transmission Line................59

3.6 The Use of Power Circle Diagrams.........................................................................61 3.7 Comparison between Long- and Short-Transmission Lines ...................................62

4 DEVELOPMENT OF SIMULATION PACKAGE ...............................................64

4.1 The Programming Language ...................................................................................64 4.2 The Microsoft Visual C++ Environment.................................................................64 4.3 Flow Chart of ‘Universal Power Circle Diagram’ (UPCD) ....................................66 4.4 Starting UPCD.........................................................................................................67 4.5 The Main Menu Screen ...........................................................................................67

4.5.1 The ‘File’ Menu.................................................................................................68 4.5.2 The ‘View’ Menu ..............................................................................................69 4.5.3 The ‘Start’ Menu ...............................................................................................69 4.5.4 The ‘Help’ Menu ...............................................................................................70 4.5.5 The ‘Zoom In’ and ‘Zoom Out’ Button ............................................................70 4.5.6 The ‘Constant Receiving Power Circle’ Button................................................71 4.5.7 The ‘Constant Power Factor’ Button.................................................................72 4.5.8 The ‘Print Screen’ Button..................................................................................72

4.6 The View Window ..................................................................................................73 4.7 Error Estimation ......................................................................................................76

5 CASE STUDIES ........................................................................................................77

5.1 System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 250 kVA ..................................77 5.2 System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 500 kVA ..................................79 5.3 System fault level: 3.98 MVA, Vgrid: 400 V, Sgrid: 500 kVA ..................................80 5.4 System fault level: 67 MVA, Vgrid: 3.3 kV, Sgrid: 6.5 MVA....................................81

Table of Contents 5


6 DISCUSSION AND CONCLUSION.......................................................................83

6.1 Overview .................................................................................................................83 6.2 Problems Encountered.............................................................................................83 6.3 Conclusion and Future Work...................................................................................84

7 LIST OF FIGURES...................................................................................................85

8 REFERENCES ..........................................................................................................87

9 BIBLIOGRAPHY......................................................................................................89

10 APPENDIX ................................................................................................................90

10.1 Class Calculation .....................................................................................................90 10.2 Class Circle DiagramDoc ........................................................................................94 10.3 Class Circle DiagramView ....................................................................................100 10.4 Class Draw Axis ....................................................................................................112 10.5 Class Input Dialog .................................................................................................119 10.6 Class MainFrm ......................................................................................................130 10.7 Class P1Out ...........................................................................................................133 10.8 Class PowerFactor Dialog .....................................................................................136 10.9 Class PrintScreenDlg Dialog.................................................................................139 10.10 Class Sconstant Dialog ........................................................................................141 10.11 Resource.h ...........................................................................................................144

Glossary 6


Glossary

ac............................. alternating current

ACSR......................Aluminium Conductor Steel Reinforcement

AVC........................Automatic Voltage Control

AVR........................Automatic Voltage Regulator

CEGB .....................Central Electricity Generating Board

CHP ........................Combined Heat and Power

dc ............................direct current

DG1 .........................Distributed Generation/Generator – a conceptual term based on the fact that an integrated electricity system with centralised generation can operate with Embedded Generation (EG) which tends to be situated closer to demand consumers (such as industrial sites with their own on-site generation). This term is used as a less specific (with regard to connection voltage) version of EG.

EG1 .........................Embedded Generation/Generator – refers to generation which is connected to a distribution network rather than the transmission system and which is not usually centrally-despatched.

EU...........................European Union

GTO........................Gate-Turn-Off Thyristor

IDMT...................... Inverse Definite Minimum Time

IGBT....................... Insulated-Gate Bipolar Transistor

LDC .......................Line Drop Compensation schemes

LOM .......................Loss Of Main

LV...........................Low Voltage (230 V / 400 V in United Kingdom)

MV..........................Medium Voltage (11 kV – 132 kV in United Kingdom)

HV ..........................High Voltage (above 132 kV in United Kingdom)

NFFO......................Non-Fossil Fuel Obligation (England and Wales)

NGC........................National Grid Company 1 definition taken from [5]

Glossary 7


PES .........................Public Electricity Supplier

pf.............................power factor

PWM.......................Pulse Width Modulation

REC ........................Regional Electricity Company

ROCOF...................Rate-Of-Change Of Frequency (df/dt)

SDI..........................Single Document Interface

SRO ........................Scottish Renewable Order

UK ..........................United Kingdom

UPCD .....................Universal Power Circle Diagram

There are some important differences between the United Kingdom (UK) and the Austrian system for circuit notation which are explained below:

• To represent an inductance the following symbols are used: Austria: a black box UK: a coil-symbol In this thesis the coil-symbol indicates an inductance.

• The reference arrow in voltage circuits: Austria: The arrow points from the higher level (dc: plus) to the lower level

(dc: minus, ac: ground) of voltage. Therefore, it indicates the voltage drop. UK: The arrow points from the lower level (dc: minus, ac: ground) to the higher

level (dc: plus) of voltage. Therefore, it indicates the voltage rise. In this thesis the arrow indicates the voltage drop.

Introduction 8


1 Introduction

1.1 General Background

Increasing environmental concern since the beginning of the decade has promoted considerable interest in the improvement of energy efficiency, the reduction of pollution, and the development of non-fossil-fuel and renewable energy generating schemes. Liberalisation of the electricity supply industries in many industrialised countries has resulted in the market-driven dispatch of privately-owned generating plants of capacity ranging from a few hundred kW up to 600 MW. Because such plant cannot be centrally constrained and since it can be connected to national electricity systems at distribution voltage, it is termed Embedded Generation (EG). System expansion in recent years in the United Kingdom has largely been met by the installation of privately-owned EG plant (mainly fast-access gas-turbine plant) which makes a significant contribution to total capacity.

Many European Union (EU) member states actively encourage renewable energy development by providing enhanced tariffs for energy produced from non-fossil fuel sources or by subsidy of investment in renewable energy plant. Among the truly renewable energy sources, wind and hydro power offer the greatest natural potential and the technologies are mature, proven and market-ready. Wind turbines offer economy of scale and commercially viable expansion tends to take the form of multi-machine wind farms, with unit capacities below 500 kW. Water turbines do not offer the same economy of scale and in many industrialised countries much of the large-scale hydro schemes were developed many years ago, requiring considerable government-led investment that will never again take place on the same scale, but there is considerable private interest in small and mini-hydro power stations [22].

Introduction 9


1.2 Worldwide Energy Reserves – Forecast

Figure 1-1 shows the worldwide consumption of crude oil, natural gas, coal and the ‘static range’ of secure reserves in the years 1970, 1980, 1990 and 1997. ‘Static range’ defines the temporal range for unchangeable production in the year specified and on the assumption of no further prospecting.

production of crude oil

production of natural gas

data in years for unchangeable consumption

mio. t oil-equivalent

production of coal

Figure 1-1: Range of the worldwide crude oil-, natural gas- and coal-reserves2

It is noted that the discovery of new resources in the last two decades has increased at a rate higher than consumption. The secured crude oil and natural gas reserves for 1970 were only for 36 and 42 years respectively. Twenty-seven years later, in 1997, the static range was 41 and 64 years respectively. It can be assumed that there will be the discovery and development of considerable new resources in the future, and thereby no decrease in the static range of fossil fuel. Another factor to be considered is that of political instability, as a

2 Data source: [1]

Introduction 10


considerable part of the natural gas and crude oil reserves lies in potential crisis regions [3].

1.3 Worldwide Energy Consumption – Forecast

Figure 1-2 shows the worldwide consumption of primary energy until 2050 in three different scenarios predicted by the World Energy Council (WEC) and the International Institutes for Applied Systems Analysis (IIASA).

1990A AB BC C

2020 2050

7%6% 6% 6%

12% 14%

4%

24%

24%

25%20%

15% 21%

11%

34%

28%30%

26%

32%

20%

19%

19%

24%

24%

27%

19%

23%

27%18%

16%

17%

21%

22%

22%

39%

renewables

14,2

19,8

24,8

11,4

13,615,4

Giga Tons Oil Equivalent [GTOE]

A ...’high growth’B ...’middle course’C ...’ecologically driven’

9,0

natural gascrude oil nuclear power

Figure 1-2: Evolution of the world energy consumption 1990, 2020 and 20503

Case A (‘high growth’) addresses key development in energy supply. It varies principally in the future to envisage coal on the one side, and nuclear and renewables, on the other. Dominance of oil and gas is perpetuated to the end of the 21st century. After 2020 rapid technological change in nuclear and renewable energy technologies will result in a phaseout of fossil fuels for economic reasons rather than due to resource scarcity. 3 Data source: [29]

Introduction 11


Course B (‘middle course’) incorporates more modest estimates of economic growth and technological development, and the demise of trade barriers and expansion of new arrangements facilitating international exchange. Compared with the Case A and C scenario, it is more ‘pragmatic’, which is its main appeal.

Case C (‘ecologically driven’) is the most challenging. It is optimistic about technology and geopolitics, but unlike Case A, it assumes unprecedented progressive international cooperation focused explicitly on environmental protection and international equity. In Case C, nuclear energy is at a crossroad. In this case there is a reduction of carbon emissions in 2100 to 2 Gigatonnes of Carbon per year, one-third of today’s level [29].

World population is expected to double by the middle of the 21st century and economic development will continue. According to the scenarios of the forecast, this results in a 1.5 to 3 fold increase in world economic output by 2020 and a 3 to 5 fold increase by 2050. The average percentage increase of renewables for all three scenarios will be about 50% between 1990 and 2020 and about 220% between 1990 and 2050.

1.4 Situation in the United Kingdom

In 1919 there were some 570 separate electricity undertakings in the UK operating 430 generating stations. There was no national transmission system and so the generators were connected directly to distribution networks serving their local area. The 132 kV National Grid was then built which allowed larger, more efficient generating stations to be used and electricity to be transmitted to remote loads. After nationalisation in 1948 the power system was developed using very large central power stations feeding a 275 kV or 400 kV supergrid which provided the bulk supplies to the distribution networks.

The Energy Act of 1983 contained an obligation on the area electricity boards to purchase power from independent generators, but this legislation failed to stimulate the wide scale development of EG [10].

In 1990, UK’s Central Electricity Generating Board (CEGB) was privatised as part of the restructuring of the electrical supply industry. This privatisation established conditions which are likely to be more favourable, although the commercial and administrative arrangements for EG in the new electricity market are complex and still being developed. The economic benefits of promoting competition between the resulting companies have been well documented, but attention must also be paid to the effects on the technical and operational aspects of such a change.

Previously, the nationalised industry was effectively a monopolistic structure in which the CEGB sold electricity to the 12 area distribution boards who each supplied a particular defined geographical area. Under this structure the CEGB had control of both the

Introduction 12


generation and the transmission system. Within the new structure, the ownership and operation of the 400 kV and 275 kV transmission system was transferred to the newly formed National Grid Company (NGC), with generation going to National Power, PowerGen and Nuclear Electric, with exception of 2100 MW of hydroelectric pumped storage capacity which remained within NGC. Since privatisation, an additional 46 generation licences have been issued to 22 independent generators. NGC was given the remit to ‘develop and maintain an efficient, coordinated and economical transmission system and to facilitate competition in the generation of electricity’. Local distribution remained with the 12 area distribution boards, now known as Regional Electricity Companies (REC), to which NGC supplies power.

The key features of this structure are that power is traded through an open commodity market known as the Pool, and that generators have no assurance of market share, but have to compete for business [14].

There has been a gradual increase in the amount of commissioned capacity of CHP and renewable energy schemes throughout the country in recent years. Figure 1-3 shows that the capacity of DG is about 3 GW, and this represents approximately 5% of the peak demand in the UK.

Figure 1-3: The recent growth of DG (installed capacity/MW) in the UK4

4 Data source: [4]

Introduction 13


The CHP schemes in Figure 1-3 tend to be less than 1 MW sites (83% of CHP sites were less than 1 MW in 1998) although the 5% of sites which were above 10 MW generate 79% of the total electricity. If we assume that the sites above 10 MW are not DG, then about 822 MW (21% of total) is DG. The remaining 3107 MW would then be transmission-connected.

The renewable plant is generally contracted under the Non-Fossil Fuel Obligation (NFFO) and the Scottish Renewable Order (SRO) and does not include large hydro or pumped storage stations. The growth in renewable project development is driven by government announcements of NFFO orders.

Large hydro plant, of which the majority is located in Scotland, are also defined as DG [5]. Large hydro is defined as plant belonging to companies with an aggregate hydro capacity of more than 5 MW and the data used in Figure 1-3 exclude pumped storage schemes [4].

1.5 The Future of Distributed Generation in the United

Kingdom

European initiatives, UK Government Renewable Orders NFFO 1-5, SRO 1-3, and revisions to energy trading arrangement will increase significantly the European and UK capacity of embedded and renewable generators. The renewed interest in EG has been stimulated by a number of technical, commercial and environmental factors. These include the high overall thermal efficiencies possible with CHP and the Government’s commitment to new renewable energy sources such as landfill gas and wind power. Permission for the construction of overhead circuits is difficult to obtain in certain areas and so the use of diesel or small gas turbine generators is being considered for reinforcement of the local distribution network.

There will be a large expansion of EG-capacity in the UK, if the Government is to meet its targets of:

• Renewable energy providing 10% of UK’s electricity supplies by 2010, and • Having 10 GW of CHP capacity contributing to the demand.

This is approximately a 3 to 4 times increase in unconstrained capacity to be added in the next 10 years and most of the new plant will be connected within the distribution network. More significantly, the capacity of renewable energy generating plants that are likely to be connected to the weak, remote parts of the distribution network is forecast to rise by over 12 times. Since none of this new plant will be centrally constrained or dispatched, and its presence will cause wide variations in rural load flow, there is real concern in the RECs about the effects on the distribution system of this amount of embedded renewable

Introduction 14


generation. Government aspirations will only be met if access is maximised by research into the ability of the distribution system to absorb and better integrate this rapidly increasing capacity of EGs.

Looking further into the future, the increased use of fuel cells, micro-CHP using Stirling engines and photovoltaic devices integrated into the fabric of buildings may all be anticipated as possible sources of power for EGs [10].

1.6 Scope of this Project

Embedded unconstrained renewable and CHP generating plant (EGs) at remote locations in the rural distribution system nearly always results in unacceptable voltage violations – both when the plant is in and out of service. The extent of this violation is determined by the net reversal of load flow, which varies with time of day and seasonally, because the availability of the energy resource and local load each vary to different chronological patterns.

To ensure that the distribution system will absorb the exported power within a statutory voltage envelope RECs include in the EG connection cost the reinforcement of those areas of the distribution system at which violation would occur. In many cases the attribution of these costs to new projects render them unfeasible and curtails the development of many otherwise suitable sites.

The aim of this project is to develop a body of knowledge and software that will readily establish the absorbence of the rural distribution network at a proposed point of connection. This will not be a single capacity but an area of active and reactive power within which the EG can operate without the net export leading to voltage violation.

Embedded Generation 15


2 Embedded Generation

2.1 Basics

The supply of electricity to the distribution network by most EGs is determined either by the heat demand and internal load of a CHP scheme or by the energy available from a renewable energy source. Thus the power output of CHP schemes may be described as ‘heat lead’ while renewable energy schemes may be considered to be ‘source led’.

Small generators are not subject to central dispatch by the NGC and so do not respond directly to the national electricity demand. However, some generators may respond to system loading conditions indirectly through pricing signals received via tariffs or other charging mechanisms. Although a small number of generators have been installed specifically to support the distribution system, most schemes are operating independently of the loading and voltage conditions on the local network. Wind turbines and some micro-hydro plants use induction generators with no direct control over reactive power flow while even CHP plant with synchronous generators may either use rather simple excitation equipment or choose to run at unity power factor in order to minimise charges for reactive power. Even those types of plants which technically can respond to distribution network conditions may be quite inflexible for commercial or contractual reasons.

At present most EG is viewed as a source of energy, rather than generation capacity, and the rules governing its connection reflect this. In the future, as the quantity of EG continues to increase it may be necessary to integrate its operation much more closely with that of the distribution network and to recognise its contribution to the capacity of the power system. Although technically this is quite feasible, the required commercial and institutional arrangements are not yet in place [10].

2.2 The Electricity Supply System

There are two ways generators can feed into the electricity supply system:

• At the level of the high voltage transmission network, i.e. into the National Grid. This is what all large generators do and it is known as centralised generation.

• At the level of the lower voltage distribution network, i.e. directly into the Regional Electricity Companies (RECs) network. This is known as Embedded Generation.



A diagrammatic representation of the UK electricity supply industry is shown below (Figure 2-1). All wind farms and most other renewable projects are embedded generators. EG can bring a number of advantages over centralised generation, but the extent of the advantage depends on where the EG is located in the network.

Large Generator

Electricity Pool

Large Generator

REC/PES REC/PESREC/PES REC/PES REC/PES Embedded Generator

NGC TransmissionNetwork

REC DistributionNetwork

= Electricity meter Figure 2-1: UK electricity supply industry

Basically, EGs deliver electricity to consumers in a more direct way than centralised generators. The electricity is generated in closer proximity to the user, reducing the distance over which the electricity has to travel and therefore reducing electrical losses. The electricity is also delivered either at or closer to the correct voltage for distribution. The electrical output from centralised generators has to be transformed up to a high voltage, transmitted, and then transformed back down to the lower voltage.

Many problems can occur when renewable-energy generators are installed at the remote extremities of power systems due both to the characteristics of the generators and the weakness of the electricity network. There can be variations and reversals in load flow causing electrical power transmission to exceed system thermal capacities, unacceptable voltage regulation, increased fault levels and loss of stability.

To accept safely the power produced by new renewable energy generators it is frequently necessary to up-grade and reinforce the existing electricity distribution system. This is an expensive process that can jeopardise the economic feasibility of many new seemingly attractive renewable energy schemes [22].



2.3 Types of Embedded Generation

2.3.1 Combined Heat and Power Schemes

Many large industrial sites utilise CHP schemes. Steam is used to run a turbine and generate electricity for the site. The steam leaves the turbine at a temperature that makes it useful for heating the site or delivery to any processes that require heat. Some industrial processes produce steam as a by-product and this makes this type of scheme a very viable alternative to buying in electricity. In the past most of these schemes operated in isolation but now with the change of legislation they can be embedded into the rest of the electricity network. Excess power generated can be sold to the local distribution company increasing profitability. Most of these types of plant use synchronous generators so that they can operate in isolation.

2.3.2 Mini-Hydro Schemes

The total installed hydro-electrical capacity in the world is currently close to 650 GW, meeting approximately 18.5% of global electricity demand. The World Council estimates that the world-wide growth of small-hydro capacity (general defined as less than 10 MW) between 1990-2020 will be 12%, rising to a predicted total capacity of 65 GW, with greatest investment in newly-industrialised or less-developed countries [22].

In the UK most potential large-scale hydro schemes have being exploited. In Scotland hydro-generated electricity accounts for 40% of electricity capacity. The development of small scale hydro generators has increased in the UK with the change of legislation and the obligation to renewable energy sources. Now, previously unviable schemes can be developed as an EG. Within the UK, the total small-scale accessible and practicable resource by 2005 is estimated to reach 3.9 TWh/yr (including existing sites) with 80% of the unexploited resources in Scotland [19].

2.3.3 Wind Power

Wind power is a form of EG that is being actively encouraged by most developed countries. These countries have committed to generate electricity through renewable means and using wind power is one viable alternative energy source. There are two schools of thought as to the best forms of wind energy:

• Single generators which have a large diameter blade and a medium generating capacity. Because of their large size they are not considered as EG and in some cases



they form the main source of generating especially on Island communities. Most large wind generators were developed from research and usually exist in prototype form. Their experimental status makes them unreliable and there is usually difficulty in obtaining spare parts [19].

• Wind farms, which are the most common type of wind generation, contain a number of small generators in one area. The size of each individual generator may be small but the aggregate capacity can be large. Wind farms are becoming increasingly more widespread and the technology is becoming standardised and reliable. The large number at any one site means that some turbines can be switched off for repairs without having any major effects. These farms are normally placed in remote rural areas and are connected into the local distribution network.

2.3.4 Others

There has been much research into ways of harnessing renewable energy from different natural sources. Much of the research was carried out in 1970s, during the oil crises but now with the commitments to enhance development of renewable energy sources funds for research have been increased. These include:

• Geothermal energy Geothermal energy, in the broadest sense, is the natural heat of the earth. Temperatures in the earth rise with increasing depth. Geothermal energy may be relevant in those parts of the world where the heat of the earth’s core penetrates the cold crust and comes near to the surface [13].

• Ocean energy There are two different types of ocean energy: wave power and tidal power. Wave power uses small machines that can tap the power of the waves by bobbing up and down. Tidal power is similar in all essential respects to hydroelectric power. The difference is that tidal-electric power is obtained from the oscillatory flow of water in the filling and emptying of partially enclosed coastal basins during the semidiurnal rise and fall of the ocean tides [16].

• Photovoltaic energy This means converting the sun’s energy directly into electricity, using photovoltaic cells.

• Solar thermal energy To use solar power in an industrial way it is necessary to concentrate sunlight falling over a wide area with a large number of reflectors. This heat is used to produce steam and to drive a turbine which generates electricity.



2.4 Advantages of Embedded Generators

The commercial advantages of small generating plant arise from the benefits of being ‘embedded’ in distribution networks and the costs which it can avoid [5]:

• DG plant is not centrally-despatched by the NGC, can generate at will (self-dispatched) and is not liable for generation transmission charges;

• DG plant contracted to a supplier can reduce the suppliers liability for electrical losses in the transmission- and distribution-system as well as some charges for the use of the distribution network;

• DG can provide benefits to the network such as avoiding or deferring network reinforcement.

The DG’s are rarely, if ever, rewarded for most or all of these benefits. As more of these benefits are acknowledged and rewarded in the marketplace, DG will become more attractive to investors. DG has other advantages which all contribute to the growth in their development. For example [5]:

• the operating regime of CHP plant is governed by the heat and/or steam demand on-site and so it can run as and when it is required;

• construction timescales tend to be shorter than for transmission-connected generators;

• both CHP and renewables are promoted as part of the Government’s energy and environmental programmes.



2.5 Legislation in the United Kingdom

The statutory requirements for the operation of a private generating plant connected to the electricity supply network are set out in the Electricity Supply Regulation from 1988. The Energy Act (1983) permits any private person or company to use the electricity utility’s transmission and distribution networks to transmit energy [19].

In the Electricity Supply Industry there are extensive statutory requirements covering the transmission and distribution of electricity. These requirements include statutory obligations with respect to frequency, voltage, fault level, fault detection and protection. Before permission to connect an EG is given by the REC there is an established procedure that a design and application has to go through [2]:

• Notification: The REC has to be informed of a proposed project before advanced planning can proceed. An outline proposal has to be submitted to establish the feasibility of the project and to prepare costs.

• Technical Submission: Once preliminary notification has been approved a more detailed submission has to be made. Technical details of the scheme will be included and the REC will carry out a design study.

• Connection Quotation: When the details are agreed between REC and developer the REC makes a formal connection quotation. Planning permission and wayleaves must be obtained both for the connection to the grid and also the necessary buildings and structures.

• Connection, Supply and Meter Operator Agreements: These are drawn up between the PES and the EG-operator and include all the detailed aspects of the interface including protection, earthing and metering requirements. They also include details of charges for imported real and reactive energy.



2.6 Types of Generators

Once the output power and speed of the prime mover are determined, a fundamental choice that developers must make is whether to install synchronous or induction generators. The major differences between these two include method of excitation, operating efficiency and power factor, fault contribution and harmonic generation [6].

2.6.1 The Synchronous Generator

Synchronous generators are the traditional form of EGs. They are widely used and make up the bulk of EGs. They are called synchronous generators because they generate electricity only at synchronous speed. In the case of a generator acting in isolation this speed is set by the governor. When a synchronous generator is brought on-line it is first brought up to speed and then carefully synchronised. This is done by comparing frequency, voltage and phase. After the connection the frequency of the grid controls the speed of the generator.

In the steady-state a synchronous generator with a constant terminal voltage may be represented by the simplified diagram and the phasor diagram shown in Figure 2-2, where M is the mechanical prime mover, E is the voltage induced in the stator due to the rotating flux from the rotor, XS is the armature reaction, V is the voltage of the network, δ is the load angle, φ is the phase angle and cosφ the power factor.

M E

XS

V

I

E

VI

φ

δIXS

Figure 2-2: Small synchronous generator connected to the network and phasor diagram

It is common to find descriptions of how the governors of large generators may be set to maintain system frequency and the excitation system to control voltage. These considerations do not apply to a small generator connected to a utility distribution system. The generator has little control over its terminal voltage and none over the system frequency, which is fixed by the network. Therefore the governor is used to control the real power output of the unit and the excitation system determine the reactive power flow [10].



For the simple circuit of Figure 2-2 it may be shown that the generator output, per phase, of real and reactive power is given by:

δ⋅⋅

= sinX

VEPS

Equ. 2-1

S

2

S XVcos

XVEQ −δ⋅⋅

= Equ. 2-2

Recalling that both V and XS are constant and that δ is likely to be less than 30°, these simple equations illustrate how:

• The real power output (P) is controlled by the governor or the mechanical prime mover which determines the applied torque and hence the power angle (δ).

• The reactive power (Q) is controlled by the excitation system which varies the magnitude of the induced stator voltage (E).

A synchronous generator is excited by a dc-current applied by the field winding. In statically excited machines this dc is derived from the generator output by rectifying the ac and applying it to the rotor via slip rings. Modern brushless excitation systems use a permanent magnet exciter to supply this power. The armature of the exciter and the rectifier bridge are located on the rotor so power is transferred without the need of slip rings. This assists voltage build up at start but means that the generator will continue to provide fault current even with a short-circuit close to its terminals.

Synchronous generators are attractive as they can operate in a number of modes and allow independent control of real and reactive power flow. However, they need to be carefully synchronised to the grid and brushless excitation leads to complex rotor constructions which makes them expensive, although the large number of synchronous machines which are used in packaged standby diesel generating sets leads to economies of scale in their production [10].

2.6.2 The Induction Generator

Induction generators are simpler than synchronous generators, only the stator is excited. They are, in principle, motors with torque applied to the rotor shaft. Induction generators are becoming popular because of their simple construction, the fact that they do not need to be synchronised to the grid and their ability to introduce damping into the drive train of the generating set. They are commonly used in wind generators as they are able to absorb the fluctuating torque produced by the blades passing the tower. Small synchronous generators are not capable of providing adequate damping to control this torque. Small, high slip induction generators possess very good damping characteristics but it may be noted that, as



they increases in size, the transient response of induction generators to applied torque starts resemble that of synchronous machines [10].

The operation of an induction generator may be understood using the familiar induction motor equivalent circuit of Figure 2-3, where s is the slip, R1 is the stator resistance (stator copper loss), X1 is the stator reactance, Xm is the magnetising reactance, RC is the magnetising resistance (iron loss), X2’ is the rotor reactance referred to the stator and R2’ is the rotor resistance referred to the stator (rotor copper loss).

R1 R2’

R (1-s)/s2’V1 RC

Figure 2-3: Equivalent circuit of an induction machine

The usual simple analysis of this circuit leads to the torque/speed characteristic shown in Figure 2-4, where s is the slip, τ is the shaft torque, sM is the slip at τmax, -sM is the slip at τmin, ω is the shaft speed and ωs is the synchronous shaft speed.

ττmax

τmin

01 sM -sM0 -1 s

ωS 2ωSωno

load

normalgeneration

motoring generating

Figure 2-4: Torque/speed curve of an induction machine

Operating as a generator the slip is negative and the peak torque is larger than when the same machine is motoring. Variations in prime mover torque are absorbed by an increase



in rotor slip. Induction machines require magnetising current to create a magnetic field, thus an induction generator can not operate without a connected electricity supply unless it is separately excited. The field in the stator rotates at the same frequency as the grid and does not vary with torque applied or time. To produce active power the rotor rotates at above synchronous speed. The percentage difference between the speed of the rotor and the synchronous speed of the magnetic field of the stator is called the slip. The slip varies with the torque supplied by the prime mover. Unlike the synchronous machine the reactive power requirement of an induction machine remains constant and the power factor will vary from 0 to 0.9 leading and cannot be set like synchronous generators. The generator’s power factor will progressively decrease as the output power is reduced and falls off rapidly at light load.

Switching in of induction generators is simpler than of synchronous generators. The generator may be brought up to speed as a motor with the reactive and real power being supplied by the grid. Then the active supply to the prime mover can be switched, the prime mover accelerates above synchronous speed and the generator then supplies real power to the grid.

2.6.3 Fault Contribution

The initial fault contribution from an induction generator is likely to be lower than that from a synchronous generator of equivalent capacity. An induction generator cannot make a sustained contribution to a ‘close-up’ short-circuit in the system. Provided that the short- circuit causes the voltage on the stator to collapse, the rotating magnetic field will disappear and the machine will stop generating. Therefore the fault current of an induction machine is generally not relied on for the operation of any protective relays. The sub-transient fault current of a synchronous generator will contribute to the fault current of the network and may lead to overstressing of switchgear. In both cases the initial fault contribution may be estimated from the sub-transient reactance of the machines, with induction generators having a higher reactance than synchronous.

2.6.4 Choice of Generator

The choice of the type of machines to use for an EG is always left to the developer. Induction machines are usually cheaper than synchronous machines, they are simpler and more robust in construction, there is no apparent need for a governor or voltage regulator and synchronising and protection equipment is simpler and less expensive [24]. For these reasons induction machines are usually chosen initially provided that they can be magnetised from the grid. Developers may forget the possibility that they may have to



purchase the reactive power to magnetise their machine from the REC and this will be expensive.

In some cases the choice will be determined by the nature of the prime mover. The generators of wind turbines experience strong periodic torque pulsations as the blades pass the tower as well as those brought about by changes in wind speed. Synchronous machines have only limited damping and careful design is necessary to control even the cyclic torque variation in a reciprocating engine. For this reason induction machines are normally used for wind power generation and synchronous machines are used where the delivery of mechanical power from the prime mover has a much lower torque variance. Examples of these are:

• water turbines (mini-hydro schemes) • steam turbines (waste or landfill gas burning) • gas turbines (CHP schemes) • high speed diesel engines (CHP schemes)

It should be noted that induction generators could also be used with any of these prime movers. Ultimately the choice of machine for the EG will depend on the effect it has on the distribution network when it is connected and exporting real power [6].

2.7 Solid-State Power Convertors

High-power electronic devices are being used increasingly in various convertor configurations to interface EGs with the distribution network. The main advantage of these arrangements is that the speed of the generator is no longer directly linked to the network frequency.

The conventional circuit is that of Figure 2-5 which shows a current source, naturally commutated network side convertor. The generator side convertor may be a controlled or diode rectifier, but its operation has little effect on the distribution network.

generator M

primemover rectifier

current sourcenaturally commutated

convertor

transformer

grid

X

Figure 2-5: Variable speed convertor (using thyristors)

This arrangement is well proven and uses thyristors as switching devices. However, the power factor of the network side convertor is proportional to the dc link voltage which, on



weak networks, must be kept low. Also, significant harmonics currents are injected into the network and so filtering is likely to be required [10].

A more recent development is the voltage source, forced commutated convertor, shown in Figure 2-6. This uses either Insulated-Gate Bipolar Transistors (IGBTs) or Gate-Turn-Off thyristors (GTOs) as the switches.

generator M

primemover rectifier

voltage sourceforced commutated

convertor

transformer

grid

C

Figure 2-6: Variable speed convertor (using IGBTs)

This convertor can run at any desired power factor and, using fast switching in a Pulse Width Modulation (PWM) pattern, does not produce low-order harmonics. Although much more benign to the network, these convertors are at present rather expensive and rapid switching of the devices can lead to significant power losses [10].

2.8 Effects of Embedded Generators on Weak Rural Grids

Energy schemes with exploit renewable energy resources in particular have to be located where the source of primary energy is available. This may be in a geographically or electrically remote area, therefore the EG is often installed in areas where the grid system is weak. The presence of the EG can lead to real and reactive power flows in rather direction depending on the powers produced and absorbed locally, and this must be predicted carefully for all local loads [5]. The design, selection and application of EG plant requires to be assessed carefully to ensure satisfactory operation under all conditions, including the ability of the distribution grid to successfully integrate the generators presence.

2.8.1 Load Flow and Losses

Passive distribution networks were originally designed to deliver electricity from the main transmission system to remote consumers, with real and reactive power generally flowing towards the edge of the system in the direction of the voltage gradient. Particularly with single source radial distribution feeders, transformers along the feeders are tapped up to compensate for the voltage drop along the line under maximum loading to ensure that consumers at the remote end receive supplies within the statutory voltage limits. Due to the



remote location of renewable energy resources, many EGs are now connected to the remote ends of distribution networks at, or below 33kV, operating in parallel with the existing grid system. Integrating EGs to operate in parallel with the existing grid system produces an active distribution network with bi-directional power flows (depending on loading conditions), resulting in a change in losses and variations in voltage. This is illustrated in Figure 2-7 by considering the effects of increasing generator output power in a feeder with a fixed local load.

Local LoadP , QL LEmbedded

GeneratorP , QG G

33 kV

11 kV

400 V

Power transmittedP , QLine Line

AVC

Figure 2-7: Typical EG connection

There are five cases to be considered [22]:

1. If the output of the EG is zero, the local load is supplied by the grid (PLine = PL and QLine = QL).

2. If the active (or real) power PG [kW] and reactive (or imaginary) power QG [kVAr] produced by the EG is less than that required by the local load PL and QL, this reduces the real and reactive power PLine and QLine transmitted from the grid towards the generator (PLine = PL - PG and QLine = QL - QG) and reduces losses on the distribution system and voltage drop along the line.



3. If the generator output increases until the kW and kVAr generated just meets that demanded by the local load or load distributed along the line, losses in the line are zero and the voltage profile is virtually flat.

4. Where the active and reactive power produced exceed that consumed locally, but is less than twice the local load demand, the excesses are exported along the line towards the bulk supply point, causing an increase in losses and local voltage rise, but these will be comparable in magnitude with those of the voltage drops where the grid supplies the local load.

5. If the active and reactive power produced is more than twice the local load demand, the increase in load flow and losses may exceed the thermal limits of the line and the local voltage may exceed the statutory maximum.

The 11 kV or 33 kV circuit breakers within the supply authority boundary may have current- or impedance-operated protection relays set to protect the system for unidirectional power flow. Their operation may become ineffective or spurious as a result in the re-direction and changes to current flow in the system.

The transmission of additional real or reactive power – in either direction increases feeder losses. A large synchronous generator operated overexcited exports reactive power that exaggerates voltage rise and increases system losses. The presence of a large induction generator which requires to be magnetised from the grid will add to the system losses as reactive power is supplied to magnetise it, but a fortunate consequence is that absorbing reactive power at the remote end reduces voltage rise. If a large quantity of reactive power is carried, then the maximum real power that can be transmitted within the thermal limit of the line is reduced.

Larger sites such as multi-machine wind farms or large-hydro power stations are usually thermally limited by the capacity of the rural system, and the costs of upgrading substations and/or re-conductoring sections of line are most frequently attributed to the scheme proposed. Even if there are no problems brought about by thermal limits the next most prevalent limit occurs due to increased voltage variations [22].

It is conventional practice for the network voltage to be controlled by Automatic Voltage Control (AVC), such as auto-tap changing transformers, (negative reactance) Line Drop Compensation schemes (LDC) and AVC relays. The AVC voltage reference is usually on the second winding of the supply transformer, as shown in Figure 2-7. When the EG is exporting, reverse power flow through the transformer causes erroneous operation of the voltage sensing relay and tap-changing mechanism. Protection settings for the supply authority under- and over-voltage relays that are appropriate for the condition where the generator is out of service may cause the relays to operate and trip the authority circuit breakers when the generator is in service and loaded (or vice-versa). Time variant energy



sources (wind farms, wave-devices) without storage produce power and voltage variations. This is a serious problem because it causes the AVC equipment operating continually rather than occasionally, leading to increased wear and maintenance [11].

2.8.2 Power Quality

Embedded generation will influence the power quality of distribution networks. The usual causes of concern are transient network voltage disturbance, referred to as ‘flicker’ because of its effects on lighting, and harmonic distortion of the voltage waveform. Voltage flicker may be caused either by the connection and disconnection of generators or by transient torque pulsations from the prime mover being translated into network voltage variations. Harmonic distortion of the network voltage is generally caused by the power electronic interfaces which are being used increasingly for the connection of EGs, although directly connected generators may also have an effect.

Standards are in place to control the connection of loads likely to degrade the power quality of the distribution network, and these are also applied to EGs. Voltage flicker and harmonic voltage distortion tend to be most significant in rural distribution systems which have a low fault level and hence high source impedance. Surprisingly, the connection of rotating EGs may act to improve the power quality of the network by increasing the fault level and so reducing transient voltage variations [11].

2.8.3 Fault Levels

Where the electricity supply system is heavily reinforced the prospective three phase symmetrical short-circuit fault level of the grid is likely to exceed that contributed by the EG towards an intervening fault. In such circumstances it is the developers responsibility to ensure that their new switchgear is adequately fault rated for the total prospective (and future) grid fault current and the contribution from the generator.

A geographical effect of installing the EG at a remote point is that the system fault level decreases with increasing series impedance and the REC switchgear at the remote end may have a fault capacity below that resulting once the EG was connected. Where the supply grid is older or weaker the increases fault level due to the EG plant may cause the total fault level at points out in the system to exceed the supply authority switchgear short-circuit rating. If the short-circuit fault level at any point in the system exceeds the fault rating of the switchgear this will require the installation of new switchgear whose costs may be included in the costs of connecting the new EG.



It should be noted that while the REC may quote a fault level at the point of connection, they reserve the right to reinforce fully the network up to this point, and this future fault level may exceed existing values and must be taken into account.

Synchronous generators with permanent magnets or otherwise secure excitation supplies and low reactances contribute the highest short-circuit currents. Smaller EGs will have less impact on any limit imposed by system fault level or capacity, and will integrate more easily in remote areas. Installing the EG at a location closer to the primary substation will mean that the existing equipment is likely to have a higher fault capacity with a margin that would allow the connection of a larger EG. The likelihood of the EG exceeding the fault capacity is proportional to both EG capacity and distance from the primary substation [22].

2.8.4 Steady-State and Transient Stability

Steady-state and transient stability analysis is necessary to determine the ability of the embedded synchronous generator to remain synchronised following small disturbances in the grid system (e.g. gradual changes in load, excitation or prime mover input) and large disturbances (e.g. severe load changes, switching operations and electrical faults). During such disturbances there is a dynamic mismatch between mechanical power input to the generator and that absorbed to produce the electrical power accepted by the grid connection. This results in acceleration, dynamic change in shaft speed and rotor angle and possible loss of synchronism. The generator behaviour and overall stability depends on

• the fault type; • the electrical distance from disturbance; • the stored kinetic energy in the shaft system (directly rated to combined shaft inertia

of the shaft system) and eventually on • the response of the governor or AVR.

Distribution codes, Engineering Recommendations and Guidelines define the design, operational and protection requirements applied to EG schemes [22].

2.8.5 Voltage Variations

Many generators may be owned by organisations without any direct interest in power quality and its main control will therefore be through the connection agreement. One of the main concerns about the effect EG has on power quality in general is the steady-state voltage variation, which will be considered in Chapter 3 and 4. The EG capacity is normally limited by the maximum over-voltage created at any point in the REC distribution network, which is usually at the most remote point closest to the EG. Following rationalisation in 1995, the statutory voltage variation for LV-distribution



networks in the UK became +10/-6% of nominal 400/230 V. The variation at MV is only around ± 6% but the problems with voltage violation are most frequent and obvious at LV. These limits are in place to protect consumers and network equipment.

A remote EG that produces real (P) and reactive (Q) power (over-excited synchronous generator) causes a greater local voltage rise than it would at unity power factor (Q = 0). An EG that absorbs reactive power (under-excited synchronous generator or induction generator) will reduce local voltage rise.

The REC may accommodate the over-voltage at LV by tapping down the local transformer but this is unusual since when the EG trips or is shut down the voltage at the remote end of the line may fall back below the statutory minimum. Where there is AVC equipment within distribution substations, such as auto-tap changing transformers, the reverse load flow and voltage violations can cause over-frequent operation. This is particularly serious where renewable energy power production can vary widely and frequently.



2.9 Protection Considerations

The addition of rotating EG plant will raise the network fault level and change the X/R-ratio of the system as seen from the point of fault. In areas where the distribution system fault level is already high, careful calculations will be required to ensure that the fault ratings of existing switchgear and other equipment are not exceeded. If equipment ratings are exceeded then additional impedance, in the form of transformers or reactors, may be inserted in the connection to the generator, although this will increase voltage drops and may influence adversely transient stability [11].

2.9.1 Generator Protection

Current-operated relays are required to protect comprehensively the EG (depending on the capacity of the plant) including: Inverse Definite Minimum Time (IDMT) over-current, instantaneous high-set over-current, voltage-restrained over-current, instantaneous- or time-graded earth fault, differential protection and reverse power. Other generator protection such as over-speed and vibration detectors must be installed to protect the plant against mechanical failure together with devices that will detect winding, bearing, or coolant over-temperatures [22].

2.9.2 Loss of Main Protection

Distribution networks are normally designed to supply passive loads. To enhance supply reliability, it is common practice in the UK to provide auto-reclose circuit breakers. Should a fault occur, the protection will open the breaker for a limited period, then close it again. If the fault does not persist, supply will be restored. Otherwise the breaker will open again. There may be several reclosure operations before the protection deems the fault to be persistent.

The presence of EG in the utility network poses a problem for the auto-reclosure operation. There is the probability of an out-of-phase reclosure, onto what may now be an active network. To avoid this, the UK regulations for EG require the machine to be fitted with Loss Of Main (LOM) protection. The aim is to ensure that, should the generator and its load become isolated from the network as a result of fault clearance on the supply line, the ensuing auto-reclosure operation will not result in an out-of-phase reclosure. The generator should be disconnected to clear the way for safe auto-reclosure. It may then reconnected in the usual way.



In practice an EG is seldom – if ever – likely to develop exactly the active power demanded by the local load, and there will always be a net import (or export) of active power from (or to) the grid. On remote disconnection of the grid and loss of the synchronous reference supply, there is then a shortfall (or excess) of active power that causes shaft speed and frequency to decrease (or increase) before the governor acts, if possible, to maintain speed [27]. The standard technique for detection of LOM is to measure the Rate-Of-Change Of Frequency (df/dt) called ROCOF, that results from the load change of the loss of the grid connection. The basis of the method is that the island supplied by the EG is unlikely to have a generation/demand balance. The rate setting is typically 0.125 Hz/sec to minimise the risk of nuisance tripping caused by minor system frequency variations [12].

2.9.3 G59/1 Protection

The nature and extent of protection specified by Engineering Recommendation G59/1 is intended to protect the PES system and its connected consumers from the effect of the EG, including: preventing connection of the EG to an unhealthy or faulted rural grid; preventing EG from displacing voltage or frequency out with statutory limits and preventing the EG from continuing to back-feed part of the grid in the event that a remote fault had tripped the main grid supply. The minimum requirements of G59/1 include over- and under-voltage relays set to operate within the absolute limits on voltage of ± 10% of nominal 230 V (253-207 V), and over- and under-frequency relays to operate within +1/-6% of nominal 50 Hz (50.5-47 Hz). While the recommended total tripping time is 0.5 seconds, increasing times may be agreed with the REC. Neutral voltage displacement protection can be used to provide back-up to phase voltage failure and assist over-current protection that might not be sensitive to an over-current or earth fault remote in the distribution system. The above protection relays and LOM protection are voltage and frequency operated [22].

Power Flow and Absorbence 34


3 Power Flow and Absorbence

3.1 The Per-Unit System

In the analysis of power networks instead of using actual values or quantities it is usual to express them as fractions of reference quantities, such as rated or full-load values. These fractions are called per-unit (denoted by p.u.) and the p.u. value of any quantity is defined as shown below.

]unitsamethein[referenceorbasethe]unitanyin[valueactualthe.]u.p[valueactualthe =

Some authorities express the p.u. value as percentage. Although the use of p.u. values may at first sight seem a rather indirect method of expression, there are in fact great advantages; they are as follows [28]:

• The apparatus considered may vary widely in size; losses and volt drops will also vary considerably. For apparatus of the same general type the p.u. volt drops and losses are in the same order regardless of size.

• By the choice of appropriate voltage bases the solution of networks containing several transformers is facilitated. Since 1.0 per-unit is the same at any level – transformers may be represented by a single leakage reactance and no voltage ratio.

• Per-unit values lend themselves more readily to automatic computation.

• The use of 3 ’s in the three phase calculation is reduced.

For instance to a base of one minute, one second is 1/60 per-unit. To a base of one kilowatt a 60 W light bulb is rated 0.06 p.u., and a 100 W bulb 0.1 p.u..

All of per-unit analysis rests on the correct and consistent choice of a common base, and accurate conversion of circuit parameters into and out of that base. A minimum of four base quantities is required to completely define a per-unit system, these are: voltage, current, power and impedance. If two of them are set arbitrarily, then the other two are automatically fixed. For circuit analysis a base apparent power [VA] is chosen, and 1.0 p.u. voltage is prescribed throughout the circuit, so the base currents and base impedances are fully defined and a per-unit computation may be carried out [23].



Base apparent power [VA] bbb .VI [V] voltageBase [A]current Base S =×= Equ. 3-1

Base impedance [Ω] b

bbase I

V]A[currentBase]V[voltageBaseZ == Equ. 3-2

Per-unit impedance [p.u.] ][impedanceBase][impedanceActualZ .u.p Ω

Ω= Equ. 3-3

Per-unit current [p.u.] ]A[currentBase]A[currentActualI .u.p = Equ. 3-4

Per-unit voltage [p.u.] VActual voltage VBase voltage Vp u. .

[ ][ ]

= Equ. 3-5

3.2 Reactive Power

The source of the simple circuit shown in Figure 3-1 is supplying active energy to the load in one direction only. At the same time an interchange of reactive energy is taking place between the source and the load of average value zero, but of peak value V.Isinφ. This latter quantity is known as the reactive power Q and the unit is Volt-Ampere reactive [VAr]. The interchange of energy between the source and the inductive and capacitive elements of the load (i.e. the magnetic and electric fields) takes place at twice the supply frequency. It is possible to think, therefore, of a power component P [Watt] of magnitude V.Icosφ and a reactive-power component Q [VAr] equal to V.Isinφ, where φ is the phase angle, i.e. the angle between I and V. It should be stressed, however, that the two quantities P and Q are physically quite different.

V Z=R+j Lω

I

φvφi

φ

V

I

Figure 3-1: Voltage source and load; phasor diagram

The quantity S [VA], known as the complex power, may be found by multiplying V by the complex conjugate of I or vice versa. The case when I lags V should be considered, and S=V*.I assumed.



Referring to Figure 3-1,

( ) φ−φ−φ−φφ− ⋅⋅=⋅⋅=⋅×⋅=⋅= jjjj eIVeIVeIeVI*VS iViV

jQPS −= Equ. 3-6

Next assume ( ) φφ−φφ−φ ⋅⋅=⋅⋅=⋅×⋅=⋅= jjjj eIVeIVeIeV*IVS iViV

jQPS += Equ. 3-7

Obviously both methods above give the correct magnitudes for P and Q but the sign of Q is different. The method used is arbitrarily decided and the convention to be adopted in this thesis is as follows:

The volt-ampere reactive absorbed by an inductive load shall be considered positive, and by a capacitive load negative; hence S=V.I*. This convention is also recommended by the International Electrotechnical Commission.

In a network the net energy is the sum of the various inductive and capacitive stored energies present. The net value of reactive power is the sum of the VArs absorbed by the various components present, taking due account of the sign. Lagging VArs can be considered as either being produced or absorbed in a circuit; a capacitive load can be though of as generating lagging VArs. Assuming that an inductive load is represented by R+jX and that the V.I* convention is used then an inductive load absorbs positive or lagging VArs and a capacitive load produces lagging VArs [28].

The magnitude of S, 22 QPS += , is the apparent power. The apparent power gives a

direct indication of heating and is used as a rating unit of power equipment.

φv

φi

φ

V

I

φ

P

QS

Figure 3-2: Phasor diagram and power triangle for an inductive load (lagging pf)



φvφi

φ

VI

φP

QS

Figure 3-3: Phasor diagram and power triangle for a capacitive load (leading pf)

The reactive power Q is positive when the phase angle φ (φ = φv - φi) between voltage and current is positive (i.e., when the load impedance is inductive, and I lags V) as shown in Figure 3-2. Q is negative when φ is negative (i.e., when load impedance is capacitive and I leads V) as shown in Figure 3-3 [17].

3.3 The Four-Terminal Network

A three-phase transmission line can be represented by a circuit consisting of two terminals where power enters the circuit and two terminals where power leaves the circuit. The circuit is said to be passive, linear and bilateral. It is passive because it contains no sources of electric energy, linear because the impedances of its elements are independent of the amount of current passing through them, and bilateral because the impedances are independent of the direction of the current. The most general network consisting of a pair of input terminals and a pair of output terminals has an impedance connected between each combination of two of its four terminals and is called a four-terminal network. Any linear, passive, and bilateral four-terminal network can be represented by either a T- or Π-circuit which is equivalent to it in so far as measurements at the input or output terminals are concerned. Such a T- or Π-circuit actually is a three-terminal network since one terminal is common to both the sending- and receiving-ends.

To find the relationships between sending- and receiving- end quantities of a four-terminal network, the voltage and current at the sending end of the unsymmetrical T-circuit of Figure 3-4 in terms of the voltage and current at the receiving end must be determined, since an unsymmetrical T is equivalent to the general four-terminal network for measurements made at the ends of the network with the assumption that the network is passive, linear and bilateral.



V S VR

Z 1

IS IR

Z 2

Y

Figure 3-4: Unsymmetrical T-circuit equivalent to a four terminal network

The current at the sending end is

( ) ( ) R2R2RRRS IZY1VYZIVYII ⋅⋅++⋅=⋅+⋅+= Equ. 3-8

The voltage at the sending end is

21R1RR12RR1S2RRS ZZYIZIVYZZIVZIZIVV ⋅⋅⋅+⋅+⋅⋅+⋅+=⋅+⋅+=

( ) ( ) R2121R1S IZZYZZVZY1V ⋅⋅⋅+++⋅⋅+= Equ. 3-9

The above equations are simplified in form by letting

1ZY1A ⋅+= 2121 ZZYZZB ⋅⋅++=

YC = 2ZY1D ⋅+= Equ. 3-10

Then Equation 3-9 becomes

RRS IBVAV ⋅+⋅= Equ. 3-11

and Equation 3-8 becomes

RRS IDVCI ⋅+⋅= Equ. 3-12

The matrix-form of these equations is

⎥⎦

⎤⎢⎣

⎡⎥⎦

⎤⎢⎣

⎡=⎥

⎦

⎤⎢⎣

⎡

R

R

S

S

IV

DCBA

IV

Equ. 3-13

Since the unsymmetrical T-circuit is valid for measuring the end conditions of any passive, linear, and bilateral four-terminal network Equation 3-13 is valid for any such network. The constants A, B, C and D are called the generalized circuit constants or the ABCD-constants of the network, and they can be evaluated for any such four-terminal network.



Solving the Equation 3-13 for VR and IR and using the known relationship AD - BC = 1 [18], we obtain

⎥⎦

⎤⎢⎣

⎡⎥⎦

⎤⎢⎣

⎡−

−=⎥

⎦

⎤⎢⎣

⎡

S

S

R

R

IV

ACBD

IV

Equ. 3-14

Usually the ABCD-constants are complex. An interpretation of each constant is found by examination of Equations 3-11 and 3-12.

By letting IR equal zero in Equation 3-11, it is seen that the constant A is the ratio of sending-end voltage to receiving-end voltage when the receiving end is open-circuited. The constant A is dimensionless since it is a ratio of two voltages. Unless the voltages are in phase, A is complex and its angle is the phase between the voltages.

If VR is equal zero in Equation 3-11, it is found that B is the ratio of voltage at the sending end to current at the receiving end with the receiving end short-circuited. Since it is a ratio of voltage to current, the constant B has the dimension of impedance and is specified in ohms.

Similarly, by letting IR equal zero in Equation 3-12, it is seen that the constant C is the ratio of current at the sending end to voltage at the receiving end with the receiving end open-circuited. Since it is a ratio of current to voltage, the constant C has the dimension of admittance and is specified in siemens.

If VR is equal zero in Equation 3-12, it is found that D is the ratio of sending-end current to receiving-end current with the receiving end short-circuited. The constant D is dimensionless since it is a ratio of two currents.

V S VR

IS IR

A B C D

Figure 3-5: Symbolic diagram representing a four-terminal network

A general four-terminal network is often indicated by a diagram similar to Figure 3-5, where a rectangle encloses the two pairs of terminals and letters symbolizing the generalized circuit constants are placed inside the rectangle [18].



3.4 The Short-Transmission Line

The classification of power transmission lines according to length depends upon what approximations are justified in treating the parameters of the line. Resistance, inductance, and capacitance are uniformly distributed along the line, and exact calculations of long lines must recognize this fact. For short lines, the total capacitive susceptance is negligible and may be omitted.

The parameters ABCD of a four-terminal network for a short-transmission line, as seen in Figure 3-6, become

⎥⎦

⎤⎢⎣

⎡θ∠=

=⎥⎦

⎤⎢⎣

⎡1ZZ01

DCBA

Equ. 3-15

3.4.1 Power Transfer of a Short-Transmission Line

The circuit shown in Figure 3-6 is very important as it represents the simplest electrical model for a synchronous generator (VS) feeding into a power system represented by a voltage source (VR). For this network the sign of power entering a boundary is assumed positive and leaving a boundary negative.

V S S∠δ V R R∠δ

Z ∠θ

I -∠ φ

SS SR

Figure 3-6: Power transfer of a short-transmission line

The determination of the voltages and currents in a network can obviously be achieved by means of complex notation, but in power systems usually active power (P) and reactive power (Q) are specified.

For the assumed direction of current

( )θ−δθ−δθ

δδ

−=⎟⎟⎠

⎞⎜⎜⎝

⎛ −=⎟⎟

⎠

⎞⎜⎜⎝

⎛ −= RS

RSjR)(jS

j

jR

jSRS e

ZV

eZ

VZe

eVeVZ

VVI Equ. 3-16



The complex power SS at the sending end is given by

⎟⎟⎠

⎞⎜⎜⎝

⎛ −⋅=⎟⎟

⎠

⎞⎜⎜⎝

⎛ −⋅=⋅−= θ−

δ−δ−δ

∗∗

j

jS

jRj

SSR

SSS ZeeVeV

eVZ

VVVIVS

SRS

θθ+δ−δ −⋅

= j2

S)(jRSS e

ZV

eZVV

S RS Equ. 3-17

Thus, the real and reactive power at the sending end are

( ) ( ) ( )θ⋅−θ+δ−δ⋅⋅

== cosZ

Vcos

ZVV

SReP2

SRS

RSSS Equ. 3-18

( ) ( ) ( )θ⋅−θ+δ−δ⋅⋅

== sinZ

Vsin

ZVV

SImQ2

SRS

RSSS Equ. 3-19

On the receiving end the complex power SR is given by

⎟⎟⎠

⎞⎜⎜⎝

⎛ −⋅=⎟⎟

⎠

⎞⎜⎜⎝

⎛ −⋅=⋅= θ−

δ−δ−δ

∗∗

j

jR

jSj

RRS

RRR ZeeVeV

eVZ

VVVIVS

RSR

θθ+δ−δ −⋅

= j2

R)(jSRR e

ZVe

ZVV

S SR Equ. 3-20

The real and reactive power at the receiving end are

( ) ( ) ( )θ⋅−θ+δ−δ⋅⋅

== cosZ

Vcos

ZVV

SReP2

RSR

SRRR Equ. 3-21

( ) ( ) ( )θ⋅−θ+δ−δ⋅⋅

== sinZ

Vsin

ZVV

SImQ2

RSR

SRRR Equ. 3-22

Power transmission lines have small resistance compared to the reactance. Assuming R = 0, θ = 90 (i.e. Z = X∠90°) and RS δ−δ=δ , the above equations become

( )δ⋅⋅

−= sinX

VVP RS

S Equ. 3-23

( )X

Vcos

XVV

Q2

SRSS −δ⋅

⋅= Equ. 3-24

( )δ⋅⋅

= sinX

VVP SR

R Equ. 3-25

( )X

VcosX

VVQ

2RSR

R −δ⋅⋅

= Equ. 3-26



Since R = 0, there are no transmission line losses and the real power sent equals the real power received.

From the above results, for a typical power system with small R/X ratio, the following important observations are made:

1. Equations 3-23 and 3-25 show that small changes in δS and δR will have a significant effect in the real power flow, while small changes in voltage magnitudes will not have appreciable effect on the real power flow. Therefore, the flow of real power on a transmission line is governed mainly by the angle difference of the terminal voltages (i.e., P12 ∝ sin δ), where δ = δS - δR. If VS leads VR , δ is positive and the real power flows from the sending to the receiving end. If VS lags VR , δ is negative and the real power flows from the receiving to the sending end.

2. Assuming R = 0, the theoretical maximum power (static transmission capacity) occurs when δ = 90° and the maximum power transfer is given by

XVV

P RSmax

⋅= Equ. 3-27

3. To maintain transient stability, the power system is usually operated with a small load angle δ. Also, from Equations 3-24 and 3-26 it is seen that the reactive power flow is determined by the magnitude difference of the two terminal voltages, (i.e.,

Q RS VV −∝ ).

4. For R = 0 and the assumed direction of current, voltage and power the sign of the receiving-end real power PR and the receiving-end reactive power QR is as follows:

• PR is positive (PR enters the grid) for 0° < δ < 90° • PR is negative (PR leaves the grid) for 0° > δ > -90° • PR is zero for δ = 0° • QR is negative (QR leaves the grid) for VS ≤ VR

• QR is negative (QR leaves the grid) for VS > VR and ( ) °<δ< 90V/Vcos SR-1

• QR is positive (QR enters the grid) for VS > VR and

( ) ( )SR-1

SR-1 V/VcosV/Vcos −>δ>

• QR is zero for VS = VR and δ = 0°



3.4.2 The Circle Diagram for Z = X (R = 0)

The operating conditions of a transmission circuit can be expressed in terms of many different quantities. There are, for example, the terminal voltages VS and VR, the currents IS and IR, the active powers PS and PR, the reactive powers QS and QR; there are also the power losses PL, and the load angle δ between the terminal voltages. If any three of these quantities are known, all the remainder may be determined [21].

A graphical analysis of the variation of the voltage, current, or power of a circuit, when some parameters or the circuit are changing, not only saves a great deal of time when the number of points to be calculated is great, but also serves to explain some of the results obtained. The locus of the end points of a phasor of voltage or current some place in a circuit is very often a circle when some parameters of the circuit are varied. Thus circles can often be plotted on a set of rectangular coordinates to show the variation of some quantity in a circuit in response to the variation of some other quantity. Such circle diagrams are very helpful in the design and operation of power systems.

As an introduction to the study of circle diagrams of a power circuit, the equivalent circuit of a short-transmission line, as shown in Figure 3-6, should be considered. It will be shown that for R = 0 (Z = X) and VR = constant the circle diagram is exactly the same as for the synchronous machine. The phasor diagram shown in Figure 3-7 is for the assumptions of Z = X, δ positive, φ positive and VS > VR.

δ φ

VR

I

VS

I.jX

Icosφ.jX

Isinφ.jX

Isinφ

Icosφ

φ

Figure 3-7: Phasor diagram of a synchronous machine and a short-transmission line with R = 0

respectively



The current I may be separated into real and reactive power (in- and out-of phase) components φcosI and φsinI . These components may be considered to induce separate

stator voltage drops jXcosI ⋅φ and jXsinI ⋅φ , as shown in Figure 3-7. This resolution is

also consistent with resolving the short sides of the triangle in which jXI ⋅ is hypotenuse.

From the triangle containing VS as hypotenuse the following voltage relationships emerge

( ) ( ) XcosIsinVS ⋅φ=δ

( ) ( )XsinV

cosI S δ=φ Equ. 3-28

( ) ( ) XsinIVcosV RS ⋅φ+=δ

( ) ( )X

VcosVsinI RS −δ

=φ Equ. 3-29

Multiplying each of the above active and reactive components of current by voltage gives the real and reactive electrical powers in terms of equivalent circuit parameters:

( ) ( )δ⋅⋅

=φ⋅= sinX

VVcosIVP SR

RR Equ. 3-30

( ) ( )X

VcosX

VVsinIVQ

2RSR

RR −δ⋅⋅

=φ⋅= Equ. 3-31

The x-direction of the phasor diagram VS.sin(δ) represents real power, and the y-direction of the phasor diagram VS.cos(δ)-VR represents reactive power. The voltage phasor diagram may be superimposed on the P-Q coordinate system to create the operating chart, provided that a common means of scaling the respective axes can be established. The origin of the P-Q plane must be located on the tip of VR such that δ = 0° and φ = 90° corresponds to zero power. To align the two graphical representations a common scale must be found which equates distance on a voltage plane with distance on a P-Q plane.

Since

( )δ⋅⋅

= sinX

VVP SR

R Equ. 3-32

when the system is operating at maximum power P = 1.0 p.u., VR = 1.0 p.u., and since sin δ = 1. From these conditions

.)u.p(X.)u.p(VS = Equ. 3-33

This equation defines the relationship between the scales in the voltage phasor diagram and the P-Q plane.



1.0

0.8

0.6

0.4

0.2

-1.0-0.8-0.6-0.4-0.21.0 0.8 0.6 0.4 0.2

Q [p.u.]

P [p.u.]

0.8

0.6

0.4

0.2

1.00.80.60.40.20.8 0.6 0.4 0.2 0

δpositive δnegative

1.25

V=const.

S1

(V=V

)S2

R

VS

VR

S=const

pf=const.

φ

(V<V

)S1

R

V=const.

S2

V=const.

S3

(V>V

)S3

R

1.01.0 Figure 3-8: Circle diagram for VR = constant and X = 1.25 p.u. (R = 0 p.u.)

Figure 3-8 shows the operating chart for a short-transmission line with the receiving-end voltage VR = constant, the sending-end voltage VS = variable, the resistance R = 0 p.u. and the inductive reactance X = 1.25 p.u.. This circle diagram is exactly the same as for the synchronous machine. Rotating VS round ± 90° from VR (which defines 1.0 p.u. voltage) to the horizontal sets the voltage scales. In this position setting VS = 1.25 p.u. defines maximum (1 p.u.) power. Projecting lines up from VS = 1.25 p.u. till they cross the P axis (drawn on the tip of VR) defines ± 1 p.u. power and the scale for the P and Q axes. The framework of the diagram is complete. At any operating point P,Q in the plane the per-unit values of P and Q now define VS and δ. Per-unit changes in VS and δ also define new P and Q and power factors. The diagram also shows constant sending-end voltage circles (VS1 < VR, VS2 = VR, VS3 > VR), a constant power circle (S = const.) and a constant power factor line (pf = const.) [23].



3.4.3 The Receiving-End Power Circle Diagram of a Short-

Transmission Line

At the next stage the equivalent circuit of a short-transmission line represented by a series impedance Z = R + jX between the sending and receiving ends of the circuit is considered, as shown in Figure 3-6. Figure 3-9 is the phasor diagram of the circuit and shows the sending-end voltage VR, which is the reference, and the voltage drops in the resistance and inductive reactance of the line, I.R and I.jX, respectively.

δ VR

I

VS

I.jX

I.sinφ

I.cosφφI.R

I.Ζ

Figure 3-9: Phasor diagram of a short-transmission line

For these assumptions it is also possible to draw a diagram with its coordinates real power on the horizontal axis and reactive power on the vertical axis. Each load at the receiving end is represented on the chart by a point determined by the real and reactive power of the load. This circle diagram is developed from the phasor diagram shown in Figure 3-10.

δ VR

I

VS

φ

I.Ζ

θ

n

k

Oθ−φ

Figure 3-10: Phasor diagram of a two-sources network

All the phasors except the current I on the diagram of Figure 3-10 are voltages. Since a diagram of real and reactive power is desired, all the quantities must be multiplied by current, and since power at the receiving end of the network should be obtained, it is



obvious to choose VR/Z as the multiplier. VR/Z has the dimensions of current, and the product of the voltage I.Z and the current VR/Z is VR.I, the volt-amperes at the receiving-end of the network.

VR is the reference phasor in Figure 3-10 and its phase angle is chosen at zero degree. The phasor VR/Z is displaced from the reference phasor by the angle -θ, since

θ−⋅=θ−∠=θ∠

°∠ jRRR eZ

VZ

VZ

0V Equ. 3-34

Therefore, multiplication of the phasor of voltage on the diagram of Figure 3-10 by VR/Z shifts all the phasors, and the whole diagram, through the angle -θ. The result is the power diagram of Figure 3-11.

δ

V IR

φ

n

k

O

θ−δ

real power

reactivepower

V VS R

ZVR

2

Z

θ

Figure 3-11: Receiving-end power diagram

For convenience, the origin of the coordinate system is placed at point O in the new diagram. Now VR.I lies at an angle -φ, or at an angle φ below the horizontal. Since VR.I intersects the horizontal axis at the origin at the angle by which the current lags the voltage, the horizontal component of VR.I is real power, and the vertical component is reactive power. The coordinate axes may be marked in watts and VArs.



In constructing Figure 3-11, current was taken as lagging the voltage at the load. Thus, the load is inductive, and on the diagram the VArs drawn by an inductive load, or flowing into an inductive load, are negative. In order to conform to the convention adopted in Chapter 3.2 (a positive sign indicates the lagging VArs taken by an inductive load), the diagram will rotate. The required alteration is the interchanging of points below and above the horizontal axis by rotating the whole diagram about the horizontal axis. To use the same direction of the P-axis as for the circle diagram of a synchronous machine (Figure 3-8), it is also necessary to change +P and –P by rotating the diagram on the vertical axis. Figure 3-12 is the result. Now the left side of the nO-line in the picture indicates positive load angle (+δ) and the right side negative load angle (-δ).

δ

| | | |V IR .

φ

n

k

O

θ−δ

+P

+Q

| | | |V VS . R

| |Z | |VR2

| |Z

θ

-Q

-P

δpositive δnegative

d

c

Figure 3-12: Receiving-end power diagram after rotation

Distances on Figure 3-12 are marked only as magnitudes since they do not have the same angular relation with the horizontal reference axis as the corresponding distances of Figure 3-11.



Now some points on the power diagram of Figure 3-12 for various loads should be

determined, with fixed values of SV and RV . First it is noticed that the point n is not

dependent on the current and will not change as long as RV and θ∠Z is constant. If RV

and Z is constant and the angle ( )RXarctan=θ is changing, then the point n will move

around a circle with the centre O between the points c and d. The point c indicates θ = 90°, which means R = 0 and the receiving-end power diagram is the same as the circle diagram for a synchronous machine developed in Chapter 3.4.1 (Figure 3-8). The point d indicates θ = 0°, which means X = 0. It is noted further that the distance from point n to point k is

constant for fixed values of SV , RV and Z . Therefore, as the distance from O to k

changes with changing load, the point k, since it must remain at a constant distance from the fixed point n, is constrained to move in a circle whose centre is at n. Thus all the points

representing loads on a network with fixed values of SV , RV and Z lie on the circle

determined by the values of the fixed voltages and the fixed impedance. If a different

voltage of SV is held constant with the same value for RV , the location of point n is

unchanged, but a new circle of radius nk is found.

The point n may be located by measuring ZV 2R from the origin at an angle of θ with

the horizontal. Greater accuracy is obtained if the point n is located by computing its horizontal and vertical coordinates. Examination of Figure 3-12 shows, for the receiving-end diagram,

ZVV

]VA[circleendreceivingaofRadius RS ⋅=− Equ. 3-35

Coordinates of the centre of a receiving-end circle (point n):

)cos(Z

V]watts[Horizontal

2R θ⋅−= Equ. 3-36

Vertical [VArs] )sin(Z

V 2R θ⋅−= Equ. 3-37

If the voltages used in the equations above are line-to-line voltages then the coordinates of the power diagram are three-phase quantities. If line-to-neutral voltages are used, the coordinates of the power diagram are per-phase quantities.

The angle δ between the sending- and the receiving-end voltages is called the load angle. As the load changes, the load angle changes. On the power diagram the load angle δ is

measured between the line ZV 2R and ZVV RS ⋅ .



If the receiving-end voltage is held constant and receiving-end circles are drawn for different values of sending-end voltages, the resulting circles are concentric because the location of the centre of the receiving-end power circles is independent of the sending-end voltage. A family of receiving-end circles is shown in Figure 3-13. The radial lines cutting the circles are spaced at 10° intervals so that the load angle can be read for any load. The load line marked in Figure 3-13 is convenient if the load changes in magnitude while its power factor remains constant. The angle between the load line through the origin and the horizontal axis is the phase angle (between IR and UR) whose cosine is the power factor of the load.

φ

n

O+P

+Q

θ

-Q

-P

load line

0°

-20°-10°

-30°

+10°

+20°

+30°

+40°

load angle | |VS1

| |VS4

| |VS3

| |VS2

| |V =constantR

Figure 3-13: Receiving-end power circle diagram for ⎟VR⎟ = constant and ⎟VS⎟ = variable

If the sending-end voltage is fixed, the receiving-end power circles for different receiving-end voltages are not concentric. The equations 3-35 to 3-37 show that the centres of the

circles are at different points for each value of RV , but the centres all lie on the same line



through the origin. The radii of the circles change also as RV changes [18]. In the same

way as developing the receiving-end power circle diagram it is also possible to construct the sending-end power circle diagram which is not shown in this thesis.

3.4.4 The Universal Power Circle Diagram of a Short-Transmission

Line

The power circle diagram described has several limitations, the most serious of which is that, although a series of concentric receiving-end circles can be drawn for a number of sending-end voltages, the resulting chart is valid for only the one receiving-end voltage for which it is constructed. If several receiving-end voltages are to be investigated a new receiving-end chart must be constructed for each new receiving-end voltage. If the latter course is followed, the resulting circles are not concentric for the receiving-end chart, and the load-angle lines are drawn from different centres for each circle. This limitation of the power circle diagram can be overcome by a modification of the coordinate system [7].

To take full advantage of the method, each distance on the modified circle diagram must be expressed as a ratio of the distance on the original diagram in volt-amperes to a selected

reference or base value of volt-ampere equal to ZV 2 , where Z is the impedance of the

circuit and V is called the reference or base voltage and is chosen arbitrarily. Usually V

is the nominal line-to-neutral or line-to-line voltage of the system depending on whether the coordinates of the power diagram being modified are per-phase or three-phase quantities. Dimensionless units result from the division of the quantities on the original

diagram by ZV 2 . The resulting quantities VVR and VVS are ratios of actual

voltage to the chosen base and are called per-unit receiving- and per-unit sending-end

voltages. If it is considered that SV and RV specify voltages in per-unit rather than in

volts, the Equations 3-35 to 3-37 become

RS VV.]u.p[circleendreceivingaofRadius ⋅=− Equ. 3-38

Coordinates of the centre of a receiving-end circle:

)cos(V.]u.p[Horizontal 2R θ⋅−= Equ. 3-39

)sin(V.]u.p[Vertical 2R θ⋅−= Equ. 3-40

Figure 3-14 shows the scaling of a universal power circle diagram with the reference

voltage .u.p1VV R == , the base volt-ampere .u.p1ZV 2R = and the sending-end



voltage VS rotating round ± 90° from VR. It is noticed that the P/Q- and the V-axis use the same scale in per-unit but a different origin of the axes. The point n, which is the origin of the V-axis, rotates for a changing angle θ on a circle with the centre OR, as explained in the previous chapter. The reason for the same scaling of both axes is the new volt-ampere base

.u.p1ZV 2R = . The diagram also shows three constant sending-end voltage circles

(VS1 = 1.0 p.u., VS2 = 1.3 p.u., VS3 = 1.6 p.u.), a constant power circle (S = const.) and a constant power factor line (pf = const.). Now it is possible to use this circle diagram in the same way as the circle diagram of a synchronous machine.

1.0

0.8

0.6

0.4

0.2

1.0 0.8 0.6 0.4 0.2

Q [p.u.]

P [p.u.]

δ posit

ive

δ negative

n

OR

θ

1.0

0.8

0.6

0.4

0.2

1.0 0.8 0.6 0.4 0.2

V [p.u.]

V [p.u.]

| |VR2

V =1.0 p.u.=const

S1S=const

pf=const.V =1.3 p.u.=const.

S2

V =1.6 p.u.=const.

S3

δ=+90°

δ=-90°

Figure 3-14: Scaling of the universal power circle diagram of a short-transmission line

If a receiving-end circle diagram according to the equations above for various per-unit

values of SV and a specified value of RV is constructed, the concentric circles shown in



Figure 3-15 with their centres at n and the origin of the coordinate system at OR are obtained.

If a larger value of RV is chosen and circles for the same values of RS VV ⋅ are drawn, a

new family of concentric circles having the same radii as those shown in Figure 3-15 and the same origin OR are obtained. The new circles must be drawn from a different centre

such as n’, as determined by the Equations 3-38 to 3-40 for the new value of RV . The

centre n’ lies on the same line through OR as the point n. Thus far this diagram is identical to the original diagram discussed except for the use of per-unit quantities.

n

OR

+P [p.u.]

+Q [p.u.]

θ

-Q [p.u.]

-P [p.u.]

n’

O R’

Figure 3-15: Universal power circle diagram of a short-transmission line

If the new set of circles with centres at n’ are drawn and the new diagram along the line nOR is moved so that n and n’ coincide without the diagram being rotated, both families of circles coincide.



The origin from which power measurements are made for the new value of RV is shifted

to O’R on the extension of the line nOR. The distance from the centre n to the origin is the square root of the sum of the squares of the horizontal and vertical coordinates given in Equations 3-39 and 3-40, which is

Distance n to OR [p.u.] = 2RV Equ. 3-41

The method can now be extended to any number of values of receiving-end voltages.

Measurement of power are made from a different origin for each value of RV . Positive

real power is read to the left of OR, positive reactive power is read upward from OR. Per-

unit values measured on the diagram and multiplied by ZV 2 give the three phase real

and reactive power respectively if V is the line-to-line base voltage from which the per-

unit voltages are determined [18].



3.5 The Long-Transmission Line

3.5.1 Transmission Line Constants

The exact solution of any transmission line and the one required for a high degree of accuracy must consider the fact that the parameters of the line are not lumped but are distributed uniformly throughout the length of the line. For this assumptions and for an equivalent Π-circuit the ABCD constants of long-transmission lines involve hyperbolic functions. These are [18]:

( ) ( )

( ) ( )⎥⎥⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢⎢⎢

⎣

⎡

⋅γθ−∠⋅γ

θ∠⋅γ⋅⋅γ=⎥

⎦

⎤⎢⎣

⎡

lcoshZ

lsinh

lsinhZlcosh

DCBA

CC

CC

Equ. 3-42

The term yzZZ CCC =θ∠= and is called the characteristic impedance of the line,

zy ⋅=γ and is called the propagation constant. The term lZz = and lYy = , where

Z is the total series impedance per phase of the line, Y is the total shunt impedance per

phase to neutral and l is the length of the line [18].

Povejsil and Johnson [26] have published a method of obtaining simpler equations. This method is based on the fact that the product of L and C is practically constant for overhead lines of stranded copper or Aluminium Conductor Steel Reinforcement (ACSR). Only the length of the line and the ratio of series resistance to inductive reactance need to be known to calculate the values for the ABCD constants.

If the product LC is identical for all lines, lγ at a given frequency is a function only of R/X

and the length of the line l, where R is the resistance of the line in ohms per mile and X is the inductive reactance of the line in ohms per mile, since

lzyl ⋅⋅=⋅γ Equ. 3-43

and in terms of L and C

( ) lL

Rj1LClCjLjRl 2 ⋅ω

+−⋅ω=⋅ω⋅ω+=⋅γ

lXRj1LCl 2 ⋅+−⋅ω=⋅γ Equ. 3-44



which is a function only of R/X and l, if LC is constant for all lines.

Povejsil and Johnson pointed out that an examination of a considerable number of lines

showed that the factor CL2 ⋅⋅ω was always between 2.05×10-3 and 2.07×10-3 for 60-cycle overhead lines of stranded copper and ACSR.

If the Equations 3-42 are solved for the assumptions above and if the ABCD constants are

expressed in per-unit of CZ , they become [18]:

⎟⎟⎠

⎞⎜⎜⎝

⎛+−⋅⋅⋅= −

XRj1l1006.2cosh.]u.p[A 3

C3

XRj1l1006.2sinh.]u.p[B θ∠

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+−⋅⋅⋅= − Equ. 3-45

C3

XRj1l1006.2sinh.]u.p[C θ−∠

⎥⎥⎦

⎤

⎢⎢⎣

⎡⎟⎟⎠

⎞⎜⎜⎝

⎛+−⋅⋅⋅= −

A.]u.p[D =

The angle Cθ associated with the characteristic impedance is also a function of R/X, since

CjLjR

yzZC ω

ω+== Equ. 3-46

( )2

90RLtanZZ1

CC−ω

∠=−

Equ. 3-47

and

⎟⎠⎞

⎜⎝⎛⋅−=θ −

XRtan

21 1

C Equ. 3-48

With Cθ expressed in terms of R/X, the ABCD constants in per-unit given in

Equations 3-45 are functions only of the ratio R/X and the length of the line l.



3.5.2 The Receiving-End Power Circle Diagram of a Long-

Transmission Line

The basics of circle diagrams were already explained in Chapter 3.4.2. The next stage is to develop the power circle diagram for a long-transmission line and to determine the differences between the short- and the long-transmission line diagram.

In order to draw the phasor diagram, the two constants A and B should be:

α∠= AA

CBB θ∠= Equ. 3-49

The constant C is not required in the development of circle diagrams, and D is only for diagrams drawn in terms of sending-end power. Figure 3-16 is the phasor diagram of a four-terminal network with the receiving-end voltage VR as reference. The phasor AVR leads VR by the angle α. If the current IR is lagging VR by an angle φR the phasor BIR leads VR by the angle (θC - φR). The sending-end voltage VS is the sum of AVR and BIR.

δ

VR

IR

VS

φR

BIR

θC

n

k

Oθ −C φRAVR

α

Figure 3-16: Phasor diagram of a four-terminal network

Since a diagram of real and reactive power is desired, it is necessary to multiply all the quantities by current. The multiplier will be VR/B, which has the dimension of current. This results, similar to the diagram of a short-transmission line, in a displacement from the reference phasor VR by the angle -θC, since

CjRC

R

C

R eB

VB

VB

0V θ−⋅=θ−∠=θ∠

°∠ Equ. 3-50



In order to conform to the convention adopted in Chapter 3.2 the diagram will rotate on the horizontal and the vertical axis. The result is shown in Figure 3-17.

δ

| | | |V IR . R

n

k

O

θ −C δ

+P

+Q

| | | |V VS . R

|Β|

| |VR2

|Β|

-Q

-Pd

c

θC

θC-α

|Α|.| |VR2

|Β|

φR

Figure 3-17: Receiving-end power diagram of a long-transmission line

The point n may be located by measuring BVA 2R⋅ from the origin at an angle of

(θC - α) with the horizontal. Greater accuracy is obtained if the point n is located by computing its horizontal and vertical coordinates. Examination of Figure 3-17 shows, for the receiving-end diagram,

BVV

]VA[circleendreceivingaofRadius RS ⋅=− Equ. 3-51




)cos(VBA

]watts[Horizontal C2

R α−θ⋅⋅−= Equ. 3-52

Vertical [VArs] )sin(VBA

C2

R α−θ⋅⋅−= Equ. 3-53

To determine P and Q the following equations, as seen in Figure 3-17, can be used:

( ) ( )α−θ⋅

−δ−θ⋅

= C

2R

CRS

R cosB

VAcos

BVV

P Equ. 3-54

( ) ( )α−θ⋅

−δ−θ⋅

= C

2R

CRS

R sinB

VAsin

BVV

Q Equ. 3-55

The differences between the circle diagram of a long-transmission line and a short-transmission line are as followed:

• The four-terminal network constant B and its angle θC is used instead of the impedance Z and its angle θ.

• A long-transmission line has a new phasor labelled AVR. This phasor leads the reference voltage VR by the angle α. The complex addition of this phasor and the phasor BIR results in the sending-end voltage VS.

3.5.3 The Universal Power Circle Diagram of a Long-Transmission

Line

In this case dimensionless units result from the division of the quantities on the original

diagram by the reference base BV 2 instead of ZV 2 , where B is the generalized

circuit constant and V is the reference voltage and is chosen arbitrarily. If it is considered

that SV and RV already specify voltages in per unit, the following formulas are obtained:

RS VV.]u.p[circleendreceivingaofRadius ⋅=− Equ. 3-56


)cos(VA.]u.p[Horizontal C2

R α−θ⋅⋅−= Equ. 3-57

)sin(VA.]u.p[Vertical C2

R α−θ⋅⋅−= Equ. 3-58



Figure 3-18 shows the scaling of a universal power circle diagram for a long-transmission

line with the reference voltage .u.p1VV R == , the base volt-ampere .u.p1BV 2R =

and the sending-end voltage VS rotating round ± 90° from VR.

1.0

0.8

0.6

0.4

0.2

1.0 0.8 0.6 0.4 0.2

Q [p.u.]

P [p.u.] OR

| |VR2

θC θC-α

|Α|.| |VR2

1.0V [p.u.]

n

0.8

0.6

0.4

0.2

1.0 0.8 0.6 0.4 0.2V [p.u.]

δ=+90°

δ=-90°

V =1.3 p.u.=const.

S

V =0.85 p.u.=const.

S

V = p.u.=const.

S V =1.0R

Figure 3-18: Scaling of the universal power circle diagram of a long-transmission line

The distance from the centre n to the origin is the square root of the sum of the squares of the horizontal and vertical coordinates given in Equations 3-57 and 3-58, which is

Distance n to OR [p.u.] 2RVA ⋅= Equ. 3-59



3.6 The Use of Power Circle Diagrams

Once the circle diagrams have been drawn for a transmission line or any four-terminal network, a great deal of information can be obtained very quickly. Some useful information is the voltage that must be maintained at the sending end for a specified load and voltage at the receiving end. It is assumed that Figure 3-19 is the receiving-end power

diagram for the value of RV which must be maintained at the load or at the primary

terminals of a transformer supplying the load. If the load varies in amount while its power factor remains the same, a load line is drawn through the origin at an angle with the horizontal axis equal to the phase angle of the load. The horizontal coordinate of the point where the load line intersects a circle of constant sending-end voltage is the power at the load for the sending-end voltage of the circle intersected. In this manner information for plotting sending-end voltage versus power at the load for a given load voltage and power factor is obtained rapidly.

φ

n

O+P

+Q

θ

-Q

-P

load line

0°

-20°-10°

10°

20°

load angle

| |VS2

| |VS1

| |V =const.R

a

b

Figure 3-19: The use of the power circle diagrams



Another problem readily solved with the circle diagram is the determination of the amount of reactive power that must be supplied by synchronous condensers at a load in order to increase the power factor, to reduce the amount of voltage regulation, or to maintain constant voltage at the receiving end for a given sending-end voltage. For instance, the circle diagram of Figure 3-19 may represent the conditions on a transmission line whose receiving-end voltage is to remain constant at the value for which the diagram is drawn, and it may be desirable to operate the line at unity power factor. If the coordinates of the point a on the load line are the kW and kVArs of the load, the inductive kVArs of the load represented by the vertical line ab must be supplied by a synchronous condenser or static capacitors. The line supplies only the real power represented by Ob, and the voltage at the

sending end must be slightly greater than 2SV .

Both the sending-end and receiving-end circle diagrams may be needed for the solution of a problem. For instance, both diagrams are needed to find the sending-end power for a given receiving-end load. If the load and load voltage are known and the receiving-end power diagram is available for this load voltage, the voltage at the sending end and the torque angle may be read. Then, on a sending-end diagram drawn for the sending-end voltage found from the receiving-end diagram, the sending-end power may be read at the same torque angle and receiving-end voltage. This is an example of an torque angle measured from the reference line of a diagram being required to find corresponding points on the two diagrams [18].

3.7 Comparison between Long- and Short-Transmission

Lines

In the previous chapters the construction of power circle diagrams of long- and short-transmission lines were explained. This chapter examines the differences in results between these models.

Figure 3-20 shows the absolute percentage difference for the receiving-end power calculation of a short-transmission line model compared with the accurate values of a long-transmission line model in four cases. In these cases the values of the sending-end voltage, the load angle and the R/X-ratio of the line are varied. The calculations use the formulas and four-terminal network constants A, B, C and D developed in Chapter 3.4 and 3.5.



Figure 3-20: Absolute percentage difference of a short-transmission line model compared with a long-transmission line model

All four cases show that the percentage error of a short-transmission line model for the receiving-end power calculation for a line shorter than 100 miles is below one percent and a line shorter than 200 miles below three percent. For longer distances the error increases rapidly.

As the distance for the connection of EGs to the grid will always be under 100 miles, the percentage error will always be smaller than one percent. Therefore, the simulation package for universal power circle diagrams of EGs in the next chapter is developed for the short-transmission line model. This circle diagram has the advantages of being easier to calculate and to draw than the long-transmission one.

Development of Simulation Package 64


4 Development of Simulation Package

4.1 The Programming Language

The basic code for this simulation is written in the C++ programming language, which is an offspring of the C high level language. With Windows now being the standard PC operating system, C++ is a standard Windows application development language.

The key concept in C++ is the class. Classes provide data hiding, guaranteed initialisation of data, implicit type conversion of user-defined types, user-controlled memory management, dynamic typing, and mechanisms for overloading parameters [20].

The software developed in this thesis does not take advantage of all the resources that C++ can offer, as the basic task of this program is to automate the drawing of circle diagrams on a computer screen. Therefore the program uses C++ graphic utilities rather than complex C++ structures.

4.2 The Microsoft Visual C++ Environment

Successful software, in addition to performing its basic function, should be user friendly. This is one of the reasons why the software utilised in the environment of the Microsoft Visual C++ Version 6.0 programming language instead of a command prompt based environment such as DOS.

A fundamental feature of the windows environment is multi-tasking which is the ability for several applications to run simultaneously. When an application is running, an application window is visible which acts as the user interface, all the other functionality is hidden from the view.

Another important feature is that windows programs are device independent. This means that, instead of setting up the device parameter for each program individually, the windows interface supplies an uniform set of instructions for interfacing with the necessary devices. This makes it easier to change device parameters and use applications on different computers as there is no need for device information to be programmed individually.



There are several different parts of a windows application that must be integrated. This is carried out by using a so called ‘Workspace’. This ‘Workspace’ brings together all the necessary parts of the written programme:

• Header files The header files include declarations for the functions, variables and library header files. These files have the extension ‘.h’.

• Source files The source files include the different functions which are required in the program. These functions can be split into several different files to make them easier to handle. All source files have the extension ‘.cpp’.

• Resource files The resource files contain the code used to create the graphics windows that form the user interface. These files are developed through the resource editor and are given the extension ‘.rc’.



4.3 Flow Chart of ‘Universal Power Circle Diagram’ (UPCD)

Once all of the information required by UPCD has been entered by the user, or is loaded from an existing file, the program calculates the base power and base voltage. After the diagram has been drawn, the user has the choice between different features of the program. This is shown in the flow chart of Figure 4-1.

Figure 4-1: Flow chart of UPCD

Start

Keyboard input

Calculation ofbase-power and

base-voltage

Draw graphicsand

output text-values

End

New fileOpen existing file

Data input

Save data

End program

Recalculate

Newoutput values

Draw power-factor or

power-circle

Zoom

Calculation of the values for the current mouse-

position

Redraw

Select file



4.4 Starting UPCD

One of the advantages of Microsoft Visual C++ is that it automatically creates an ‘executable’ of the program. This file includes all the resources necessary to run as an independent Windows application. The executable of this program, the Microsoft Visual C++ source code and the Word file of this thesis is located on the compact disk included with the thesis.

Figure 4-2: The UPCD icon

UPCD will start automatically after the compact disc is put into the compact disc drive or by positioning the mouse pointer over the UPCD-icon and double-clicking the left mouse button. The icon of the ‘executable’ file is shown in Figure 4-2. The software has been written so that at any point during operation it is possible to exit from UPCD.

4.5 The Main Menu Screen

With a windows application the usual format is a main window displaying results and containing a menu-bar from which various commands can be activated. In this program a Single Document Interface (SDI) is used, which allows only one open ‘document frame window’ at any time. This main window and one drop-down menu is shown in Figure 4-3.

Figure 4-3: The main window and one drop down menu



The user-interface mechanism is common to most Windows applications. That is, each application window contains an icon on the corner to minimize, maximise or close the window. Other icons include ‘New Document’, ‘Open File’, ‘Save File’, ‘About‘ dialog box and an icon called ‘Start’ to run UPCD. All of these commands are also available in the pop-up menus which are explained in the chapters following.

The main frame has five additional buttons: ‘Zoom In’, ‘Zoom Out’, ‘Constant Receiving Power Circle’, ‘Constant Power Factor’ and ‘Print Screen’. Each of these buttons opens a dialog box which are also described in the next chapters.

Further, the main window contains a vertical and a horizontal scroll bar and the mouse being used in a similar manner as in any other windows application.

4.5.1 The ‘File’ Menu

Below are listed the options on the drop-down menu ‘File’:

• New This option deletes all the data present. The screen will be cleared and the emblem of the University of Edinburgh will be shown.

• Open This option opens a dialog box and allows the user to choose and open an already existing file with the extension ‘.cir’.

• Save If the current document already has a name, this option will save all values without opening a dialog box. For an untitled document the procedure will be the same as for the ‘Save As’ option in this menu.

• Save As If the data is to be used again, it must be saved. Upon saving data, the user will encounter a dialog box. It allows the user to select a directory and enter a name for the file which has the predefined extension ‘.cir’.

• Exit This option is used to quit the program. If not previously saved, the current data will be lost.



4.5.2 The ‘View’ Menu

The options listed in the drop-down menu ‘View’ are:

• Toolbar The user can hide or show the toolbar by clicking on this icon.

• Status Bar The user can hide or show the status bar by clicking on this icon.

4.5.3 The ‘Start’ Menu

The only option in this menu is ‘Run UPCD’. This option starts the program by opening the System Parameters dialog box as shown in Figure 4-4.

Figure 4-4: The System Parameters dialog box



There are five areas within this dialog box:

1. Grid and base voltage: The user must enter the voltage of the grid in kilovolts. Depending on whether the nominal line-to-neutral or line-to-line voltage is entered the coordinates of the power diagram are per-phase or three-phase quantities. This voltage entered is automatically the base voltage for the per-unit calculations.

Only one of the next four areas can be selected at any time, depending on the data available. This is achieved by clicking on the radio button on the left hand side of each section:

2. Resistance and inductive reactance in ohms. 3. Impedance and its angle in ohms and degrees respectively. 4. Prospective short circuit current in amperes and the X/R ratio. 5. System fault level in mega volt-amperes and the X/R ratio.

When a number is entered in one of these edit boxes, all the other values are automatically calculated and updated. The number entered is additionally checked for errors.

Pressing the OK-button confirms the data, calculates the values necessary and draws the universal power circle diagram. To close the System Parameter dialog box without any further calculations or circle diagram drawing the user must press the Cancel-button.

4.5.4 The ‘Help’ Menu

The ‘About UPCD’ command is used to display the name of the program, the version number of this copy, the copyright notice, and the email address for software support.

4.5.5 The ‘Zoom In’ and ‘Zoom Out’ Button

These two buttons allow the user to zoom in or out of a specific area on the screen. The range of the zoom is from 100% to 600% in six equal steps.



4.5.6 The ‘Constant Receiving Power Circle’ Button

This button opens the Power Circle dialog box as shown in Figure 4-5. It is possible to enter up to three receiving-end complex power circles in mega volt-amperes.

Figure 4-5: The Power Circle dialog box

On clicking the OK-button, an error-checking of the values entered will be carried out automatically and the circles will be drawn. By clicking the Cancel-button the screen will not be updated with the new values entered. To delete a circle the user must enter the value zero in the corresponding edit box.



4.5.7 The ‘Constant Power Factor’ Button

The Power Factor dialog box opens after clicking the Constant Power Factor button. Here

the user can enter the power factor between 0 and 1. Confirmation of the input is via the

OK-button, cancellation or deleting already drawn lines is via the Cancel-button.

Figure 4-6: The Power Factor dialog box

4.5.8 The ‘Print Screen’ Button

This button opens a dialog box which explains in three steps a method by which the current

diagram and the output-values displayed may be printed.

Figure 4-7: The Print Screen dialog box



4.6 The View Window

After the values in the System Parameters dialog box are confirmed the program begins to calculate and draw the universal power circle diagram for a short-transmission line as developed in Chapter 3.4. It is important to remember that all the drawings on the screen are receiving-end values, except of the sending-end voltage VS. Figure 4-8 shows the circle diagram for the input values of the System Parameters dialog box from Figure 4-4.

Figure 4-8: The universal power circle diagram – screen output

The diagram shows the receiving-end power area with its two axes P and Q in per-unit form and the voltage area V in per-unit form. The four half-circles drawn are constant sending-end voltages with the values 0.8 p.u., 0.94 p.u., 1.1 p.u. and 1.2 p.u.. The two red half-circles, 1.1 p.u. and 0.94 p.u. respectively, indicate the maximum voltage variation of +10% and –6%. The half-circles start at the left-hand-side with a load angle of +90° and end at the right-hand-side with a load angle of –90°.

The text-values printed on the right border of the window describe the current position of the mouse in the diagram. For the receiving end, these values are: the voltage VR, the active power PR, the reactive power QR, the complex power SR, the power factor cos(φR) and the phase angle φR. There are no sending-end values (except VS) drawn in the diagram



but for each receiving-end point on the screen it is possible to calculate the sending-end values which are printed as text below the receiving-end output values. These are: the voltage VS, the active power PS, the reactive power QS, the complex power SS, the power factor cos(φS) and the phase angle φS. The text output also includes the load angle δ and the current IR. The receiving-end current and the sending-end current have a phase difference of 180 degrees, according to the conventions set out in Chapter 3.4.1. The sum of the two phase angles shown on the screen is not exactly 180 degrees. The difference is the load angle, which is the angle between the sending-end and the receiving-end voltage. As the mouse moves all of these output-values are calculated for the actual position of the mouse and automatically updated on the screen.

Figure 4-9 shows the same diagram as Figure 4-8 with an additional constant receiving-end power circle of 45.0 MVA and a zoom-factor of 300%.

Figure 4-9: Circle diagram with marked point P1 and constant power circle SR

The user can mark a point in the diagram labelled with ‘P1’ by pressing the left mouse-button. The corresponding values for this point are shown in the upper right area of the screen. The line from zero power to P1 indicates I.Z in per-unit and also a constant receiving-end power factor line. The line from zero voltage to P1 indicates the sending-end voltage in per-unit and a constant load angle line. The distance between the origins of the



power axis and the voltage axis is always the receiving-end voltage, which is the base voltage for every calculation and therefore one per-unit. Pressing the right mouse button at any time deletes the point marked and all output-values shown.

Figure 4-10: Circle diagram with power factor lines and the Power Factor dialog box

Figure 4-10 shows the last drawing-feature of the program, the receiving-end power factor lines. In this example a power factor of 0.9 is chosen and entered in the Power Factor dialog box. The program draws the lines for all four quadrants and labels them.



4.7 Error Estimation

In this section the different sources of error are discussed and a total percentage error for a calculation estimated. The program contains two error-sources which have to be considered:

1. Use of the short- instead of the long-transmission line model: This error was already explained and calculated in Chapter 3.7. It was shown that the error for a short-transmission line model with a line-length below 100 miles is smaller than one percent. The distance for the connection of EGs to the grid will always be smaller than 100 miles. Therefore, this estimation assumes a maximum error of one percent.

2. Screen resolution: When drawing the power- and the voltage-axes on the screen, pixels are used. Thus, all the values have to be rounded to conform to the screen pixelation and a rounding error occurs. When calculating the output-values for the current mouse position, the position of the according pixel is used. As the screen resolution is not infinite, these values will jump from pixel to pixel, depending on the zoom-factor. A comparison between the output-values of the program and Excel-based calculations with the formulas developed in Chapter 3.4.1 shows, that the maximum error will be up to two percent.

To calculate the total maximum error, the values of the two errors explained must be summed. Therefore, the absolute total maximum error is estimated to be three percent. To keep the error as small as possible it is important to zoom into the specific area, thus minimizing pixelation rounding errors.

Case Studies 77


5 Case Studies

5.1 System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 250 kVA

In this case a 400 V generator connected to the grid via a short-transmission line with a fault level of 1.99 MVA is studied. The grid is as always on the receiving end and the generator on the sending end of the transmission line. Figure 5-1 shows the universal power circle diagram for this scenario with a receiving-end power circle of 250 kVA, which is assumed to be full output from the generator at the receiving end . The X/R-ratio of the transmission line is 10.

Figure 5-1: System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 250 kVA - screen output

The area within which the EG can operate without the net export leading to voltage violation or exceeding the 250 kVA receiving-end power circle (full generator output at the receiving end) has four boundaries which are coloured green:

1. The top boundary is the red 1.1 p.u. sending-end voltage circle. 2. The right-hand side boundary for a generator is the Q-axis (P equals zero). 3. The bottom boundary is the red 0.94 p.u. sending-end voltage circle. 4. The left-hand side boundary is the 250 kVA receiving-end power circle.

Case Studies 78


The green painted boundary is for the benefit of the report only and is not drawn by UPCD. One corner of this boundary is marked and labelled with ‘P1’. The corresponding values are shown on the upper right corner of the screen. It can be seen that the sending-end voltage has been calculated as 440 V, the maximum allowed over-voltage. What this shows is that a generator overexcited producing 250 kVA at the receiving end with a receiving-end power factor of 0.65 lagging will cause a voltage violation. However, the same generation operated at rated receiving-end power factor of 0.8 lagging will produce a sending-end voltage within the 1.1 p.u. envelope.

The values shown on the lower right corner of Figure 5-1 are related to the current mouse position, which is indicated in the picture with an arrow. In this case it is the point with the maximum active power which could be produced by the generator. The reactive power received is zero, consequently the receiving-end power factor is unity and the current is in phase with the receiving-end voltage.

The difference between the sending-end real power and the receiving-end real power are the real power losses of the line, which are equal to RI2 × . The difference between the sending- and receiving-end reactive power are the reactive power line ‘losses’, which are equal to XI2 × . The sum of the absolute values of the receiving-end phase angle, the sending-end phase angle and the load angle is exactly 180 degrees. This convention was adopted in Chapter 3.4.1, where power or current leaving a boundary was signed negative and entering a boundary positive.

Case Studies 79



This case studies an induction generator with the receiving-end values of 500 kVA complex power and 0.9 power factor leading and compares it with a synchronous machine with the receiving-end values of 500 kVA and 0.8 power factor lagging. The generators are connected to a 400 V grid with a 1.99 MVA system fault level. The X/R-ratio is assumed to be 10. Figure 5-2 shows the according screen output of UPCD.

Figure 5-2: System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 500 kVA – screen output

The point labelled with ‘P1’ is the induction generator with the receiving-end power factor of 0.9 leading. The corresponding values are shown on the upper right corner of the screen. The values on the lower right corner indicate the current mouse position on the screen, which is the operating point of the overexcited synchronous machine. An arrow points to the according position in Figure 5-2.

As seen, the induction machine operates at this point with a sending-end voltage drop of –5.5 percent, which is within the voltage limitation. The synchronous machine, exporting 500 kVA receiving-end power at a 0.8 lagging receiving-end power factor, has a sending-end voltage rise of +18.3 percent, which exceeds the voltage limitation by +8.3 percent and

Case Studies 80


is therefore not acceptable. To operate within the voltage limitation, the synchronous generator has to decrease the receiving-end complex power or to increase the receiving-end power factor. The green coloured boundaries indicates once more the area within which the generators are allowed to operate and is not drawn by UPCD.


This case uses the same assumptions as the case in Chapter 5.2. The only difference is the simulation of the reinforcement of the grid by halving the line impedance, which results in a doubled system fault level.

Figure 5-3: System fault level: 3.98 MVA, Vgrid: 400 V, Sgrid: 500 kVA – screen output

As before, the upper values indicate the induction machine, labelled in the picture with ‘P1’, and the lower values the synchronous machine, indicated with an arrow. For these assumptions both machines are with its operation points within the voltage limits, which is shown in Figure 5-3. The voltage drop of the induction generator is, compared with the latter case, reduced by 36 percent and the voltage rise of the synchronous generator by 48 percent.

Case Studies 81


5.4 System fault level: 67 MVA, Vgrid: 3.3 kV, Sgrid: 6.5 MVA

This case studies a 3.3 kV generator connected to the grid with a fault level of 67 MVA. The generator should be operate to produce an sending-end apparent power of 6.5 MVA at a sending-end power factor of 0.8 leading.

As explained, it is not possible to draw sending-end power values in the receiving-end area, but it is possible to calculate all sending-end values for every single point on the receiving-end diagram. Therefore, to find the sending-end point a 6.5 MVA receiving-end power circle and a 0.8 lagging receiving-end power factor line is drawn. The receiving-end point for these assumptions is found where the power circle crosses the lagging power factor line. Now it is possible to search for the sending-end point by moving the mouse around the area of the receiving-end point. Figure 5-4 shows the circle diagram for this generator with the 6.5 MVA receiving-end power circle and the 0.8 receiving-end power factor lines.

Figure 5-4: System fault level: 67 MVA, Vgrid: 3.3 kV, Sgrid: 6.5 MVA – screen output

The upper right output-values in the picture indicate the P/Q-values for the point P1 and therefore the values for 6.5 MVA sending-end power and a sending-end power factor of 0.8 leading. The lower values indicate the point for the same assumptions at the receiving-

Case Studies 82


end. This point is slightly above P1 where the power circle intersects the power factor line, as seen in Figure 5-4, and is indicated in the picture with an arrow.

The figure also shows that for a constant receiving-end power circle of 6.5 MVA the over-voltage limit will never be exceeded. In this case there are only three boundaries (drawn green), within which the EG can operate without the net export leading to voltage violation or exceeding the 6.5 MVA (assumed full generator output at the receiving end) receiving-end power circle:

1. The left-hand side boundary is the 6.5 MVA receiving-end power circle. 2. The right-hand side boundary for the generator is the Q-axis (P equals zero). 3. The bottom boundary is the red 0.94 p.u. sending-end voltage circle.

The green boundary is, as explained before, for the benefit of the report only and not drawn by UPCD.

Discussion and Conclusion 83


6 Discussion and Conclusion

6.1 Overview

This chapter finishes the diploma thesis with a discussion on the problems encountered, possible improvements to the software, a conclusion and a recommendation for future work.

6.2 Problems Encountered

During the development of this project, many problems were experienced and solved. As some problems were more difficult to solve than others within the time constrained, they have yet to be corrected.

While running the program, the circle diagrams drawn could disappear and UPCD will not start drawing them again. The user must close the program and restart it. However, the error could not be consistently recreated. This error was observed to occur after copious use of the scroll bars and the left mouse button respectively. In both cases the program has to redraw the whole area. The problem is suspected to be a computer memory limitation. Improper memory allocation may occur, thus causing a reduction in available memory. The program code needs to be thoroughly examined to determine if this is the reason, and solved to make the program more robust.

Another problem occurs when entering decimal numbers in the ‘Input’ dialog box. When any numeric value is entered in one of the edit-boxes, all the other values in this dialog box are calculated and updated automatically. Entry of a decimal point following a number is not registered as it is not a numeric value. A decimal point must therefore be entered once the numeric value is in place. For example, if the user wants to enter the number 29.5, he must first enter the value 295 and add the decimal point afterwards.

The last problem is the resolution of the screen. This program works best with a resolution of 1024 by 768 pixels. It is also possible to use UPCD with a resolution higher than that. In this case all the drawings are further left than before and the output-values are not at the right border of the screen. The program can not be used for a resolution smaller than 1024 by 768 as the output-values will no longer be on the screen. To avoid this problem, it would be necessary to rewrite all drawing-commands in the source code by using a different graphics mapping-code.

Discussion and Conclusion 84


6.3 Conclusion and Future Work

This thesis explains the basics of embedded generation and the problems an EG has within a rural distribution network. Further, the background, mathematical theories, development of a methodology, software implementation and testing of power circle diagrams for short- and long-transmission lines were explained. It was shown that it is possible to visualize the absorbence of the rural distribution grid at a proposed point of connection by using universal power circle diagrams. The result was not a single point (a best or worst case) but an area of active and reactive power within which the EG can operate without the net export leading to voltage violation.

The Visual C++ simulation shows an universal power circle diagram for a short-transmission line. It contains an area for active and reactive power at the receiving end and an area for the receiving- and sending-end voltage. Additionally, the program calculates and outputs all receiving- and sending-end values.

Through the use of this software a great deal of knowledge regarding absorbence of the grid can be attained more efficiently than through manual ‘pen and paper’ calculations. The main advantages of this program are the ability to visualise this area, to simply and rapidly change systems parameters and to automatically calculate and output the receiving- and sending-end values for every single point in the diagram. As far as known, there is no equivalent package on the market that tests and visualize the absorbence of the grid.

UPCD can be used to test induction as well as synchronous generators at the same proposed point of connection. It is also possible to test the effects of system reinforcement by changing the system fault level.

UPCD shows, that the voltage rise is proportional to the apparent power of the generator and to the inductive reactance of the grid, inversely proportional to the system fault level and also affected by the power factor. For a small load angle the magnitude difference of the two terminal voltages is proportional to the reactive power flow which is proportional to the sending-end voltage and therefore to the machine excitation and the power factor control.

The maximum total on-screen error has been estimated as not exceeding three percent. As UPCD is intended to be a fast initial feasibility tool for an EG-connection, this error is acceptable.

A recommendation for further work is to connect UPCD to an EG- and local load-simulation to examine the time-variation of the active and reactive power of the generator and the load and therefore the time-variation of the voltage. This can be used to assess the duration of the voltage-violation.

List of Figures 85


7 List of Figures

Figure 1-1: Range of the worldwide crude oil-, natural gas- and coal-reserves....................9

Figure 1-2: Evolution of the world energy consumption 1990, 2020 and 2050..................10

Figure 1-3: The recent growth of DG (installed capacity/MW) in the UK .........................12

Figure 2-1: UK electricity supply industry..........................................................................16

Figure 2-2: Small synchronous generator connected to the network and phasor diagram..21

Figure 2-3: Equivalent circuit of an induction machine ......................................................23

Figure 2-4: Torque/speed curve of an induction machine...................................................23

Figure 2-5: Variable speed convertor (using thyristors)......................................................25

Figure 2-6: Variable speed convertor (using IGBTs)..........................................................26

Figure 2-7: Typical EG connection .....................................................................................27

Figure 3-1: Voltage source and load; phasor diagram.........................................................35

Figure 3-2: Phasor diagram and power triangle for an inductive load (lagging pf) ............36

Figure 3-3: Phasor diagram and power triangle for a capacitive load (leading pf) .............37

Figure 3-4: Unsymmetrical T-circuit equivalent to a four terminal network ......................38

Figure 3-5: Symbolic diagram representing a four-terminal network.................................39

Figure 3-6: Power transfer of a short-transmission line .....................................................40

Figure 3-7: Phasor diagram of a synchronous machine and a short-transmission line with R

= 0 respectively....................................................................................................................43

Figure 3-8: Circle diagram for VR = constant and X = 1.25 p.u. (R = 0 p.u.) .....................45

Figure 3-9: Phasor diagram of a short-transmission line.....................................................46

Figure 3-10: Phasor diagram of a two-sources network......................................................46

Figure 3-11: Receiving-end power diagram........................................................................47

Figure 3-12: Receiving-end power diagram after rotation ..................................................48

Figure 3-13: Receiving-end power circle diagram for ⎟VR⎟ = constant and ⎟VS⎟ = variable

.............................................................................................................................................50

Figure 3-14: Scaling of the universal power circle diagram of a short-transmission line...52

Figure 3-15: Universal power circle diagram of a short-transmission line .........................53

Figure 3-16: Phasor diagram of a four-terminal network....................................................57

Figure 3-17: Receiving-end power diagram of a long-transmission line ............................58

Figure 3-18: Scaling of the universal power circle diagram of a long-transmission line....60

List of Figures 86


Figure 3-19: The use of the power circle diagrams .............................................................61

Figure 3-20: Absolute percentage difference of a short-transmission line model compared

with a long-transmission line model....................................................................................63

Figure 4-1: Flow chart of UPCD .........................................................................................66

Figure 4-2: The UPCD icon ................................................................................................67

Figure 4-3: The main window and one drop down menu....................................................67

Figure 4-4: The System Parameters dialog box...................................................................69

Figure 4-5: The Power Circle dialog box ............................................................................71

Figure 4-6: The Power Factor dialog box............................................................................72

Figure 4-7: The Print Screen dialog box .............................................................................72

Figure 4-8: The universal power circle diagram – screen output ........................................73

Figure 4-9: Circle diagram with marked point P1 and constant power circle SR................74

Figure 4-10: Circle diagram with power factor lines and the Power Factor dialog box .....75

Figure 5-1: System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 250 kVA - screen output...77

Figure 5-2: System fault level: 1.99 MVA, Vgrid: 400 V, Sgrid: 500 kVA – screen output ..79

Figure 5-3: System fault level: 3.98 MVA, Vgrid: 400 V, Sgrid: 500 kVA – screen output ..80

Figure 5-4: System fault level: 67 MVA, Vgrid: 3.3 kV, Sgrid: 6.5 MVA – screen output ...81

References 87


8 References

[1] British Petroleum (http://www.bp.com/bpstats/)

[2] British Wind Energy Association Factsheet 14: ‘Generating Electricity into the UK Electricity System’; web site: http//www.bea.com/fs14elec.htm

[3] Cerveny, M.: ‘Overheadfolien Energie 1999’; Energieverwertungsagentur (E.V.A.), Austria, 1999 (in German)

[4] Department of Trade and Industry: ‘Digest of United Kingdom Energy Statistics 1999’, United Kingdom, 2000

[5] Energy Technology Support Unit (ETSU): ‘Increasing Levels of Distributed Generation and its Effects an Electricity Networks’; 1998

[6] Gillespie, A.W.: ‘Simulation of Remote Embedded Generation’; BEng Hons Project Report HSP 1281, Department of Electrical Engineering, University of Edinburgh, May 1997

[7] Goodrich, R.D. Jr.: ‘A Universal Power Circle Diagram’; Trans. AIEE, Vol. 70, pp. 2042 - 2049, 1951

[8] Harrison, G.P.: ‘Ancillary Services in the UK Electricity Supply Industry’; BEng Hons Dissertation Report HD 1196, Department of Electrical Engineering, University of Edinburgh, May 1997

[9] Hughes, E.: ‘Electrical Technology’; Longman Group, 1970, 4th ed., pp. 288-329

[10] Jenkins, N.: ‘Embedded Generation, Tutorial – Part I’; Power Engineering Journal, pp. 145-150, June 1995, 9, (3)

[11] Jenkins, N.: ‘Embedded Generation, Tutorial - Part II’; Power Engineering Journal, pp. 233-239, October 1996

[12] Kane, P.J.O.; Fox, B. and Morrow, D.J.: ‘Impact of embedded generation on emergency reserve’; IEE Proceedings Generation Transmission Distribution, Vol. 146, No. 2, pp. 159-163, March 1999

[13] Kenward, M.: ’Potential Energy – An Analysis of World Energy Technology’; Cambridge University Press, Cambridge, 1976

[14] Luckett, Martin: ‘Have vars, can travel’; IEE REVIEW, pp.207-210, 1999

[15] Povejsil, D.J. and Johnson, A. A.: ’A Per-unit Interpretation of Transmission Line Constants’; Trans. AIEE, Vol. 70, pp. 194 - 200, 1951

References 88


[16] Ruedisili, L.C. and Firebaugh M. W.: ‘Perspectives on Energy - Issues, Ideas, and Environmental Dilemmas’; Oxford University Press Inc., London, 1975

[17] Saadat, H.: ‘Power System Analysis’; Milwaukee School of Engineering, 1999

[18] Stevenson, W.D. Jr.: ‘Elements of Power System Analysis’; McGraw-Hill Publishing Company Ltd., London, 1955

[19] Stinson, J.F.: ‘Simulation of Loss of Main, Detection and Protection’; BEng Honours Project Report HSP 1284, Department of Electrical Engineering, University of Edinburgh, May 1997

[20] Stroustrup, B.: ‘The C++ Programming Language’; Addison-Wesley Publishing Company, 1991

[21] Waddicor, H.: ‘The Principles of Electric Power Transmission’; Chapman and Hall Ltd., London, 1964

[22] Wallace, A.R.: ‘Integration of embedded generation plant into electricity supply networks’; Energy System Group, Departments of Electronics and Electrical Engineering, University of Edinburgh, UK

[23] Wallace, A.R.: ‘Power Systems – 3th Year Notes’; Departments of Electronics and Electrical Engineering, University of Edinburgh, UK, 1999

[24] Wallace, A.R. and Stapleton, S.A.: ‘Operation and protection of Embedded Generation Schemes’; Departments of Electronics and Electrical Engineering, University of Edinburgh, UK, 1997

[25] Wallace, A.R. and Whittington, H.W.: ‘Power Systems and Machines – 4th Year Notes’; Departments of Electronics and Electrical Engineering, University of Edinburgh, UK, 1996

[26] Ward, C.: ’Technical Requirements for a Reactive Service’; IEE Colloquium on Economic provision of reactive power for system voltage control, pp. 2/1-4, 1996

[27] Warnock, G.J.: ‘Simulation of Loss of Grid Connection to an Embedded Generator’; BEng Hons Project Report HSP 1373, Department of Electrical Engineering, University of Edinburgh, May 1998

[28] Weedy, B.M.: ‘Electric Power Systems’; Department of Electrical Engineering, The University of Southampton, Third Edition, 1989

[29] World Energy Council (WEC), International Institutes for Applied Systems Analysis (IIASA): ‘Globally in Energy Perspectives 1998’; Austria, 1999

(http://www.iiasa.ac.at/cgi-bin/book_dyn/bookcnt.py)

Bibliography 89


9 Bibliography

[1] Fickert, L.: ‘Elektrische Energieübertragung’; Institute for Electronic Power System, University of Graz, Austria, 1998 (in German)

[2] Fickert, L.: ‘Elektrische Energieerzeugung’; Institute for Electronic Power System, University of Graz, Austria, 1998 (in German)

[3] Gurewich, O. and Gurewich N.: ‘Teach Yourself Visual C++ 4 in 21 Days’; First Edition, Sams Publishing, USA, 1996

[4] Kruglinski, D.J.: ‘Inside Visual C++’; Microsoft Press, Washington, 1997

[5] Sams Publishing: ‘Sams teach Yourself C++ in 21 Days’; Third Edition, USA, February 1999

[6] Schildt, H.: ‘Teach Yourself C++, Third Edition’; Osborne/The McGraw-Hill Companies, USA, 1998

Appendix 90


10 Appendix

The following chapters include the source code of the different Microsoft Visual C++ classes of UPCD. Each class is split up into its header- and source-file.

10.1 Class Calculation

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Calculations.h: interface for the CCalculations class. // This class calculates the output-values for the circle diagram ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class CCircleDiagramDoc; class CCalculations public: float P_DRAWFACTOR; float V_DRAWFACTOR; float BasePower; float BaseVoltage; float FaultLevel; float Reactance; float PCSS; float Resistance; float Voltage; float XRratio; float Angle; float Impedance; float ImpedanceCalc; float AngleCalc; int zoom; int IndicationCheckBox; // indicates which checkbox is pressed, 1 for checkBoxRX, // 2 for checkBoxZ, 3 for checkBoxPSCC and 4 for checkBoxFault void SetDocPointer (CCircleDiagramDoc*); void DoCalculation(); CCalculations(); virtual ~CCalculations(); protected: CCircleDiagramDoc *pDoc; ;

Appendix 91


// Calculations.cpp: implementation of the CCalculations class. // This class calculates the output-values for the circle diagram ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "Calculations.h" #include "Input.h" #include "Circle DiagramDoc.h" #include <complex> #include <math.h> #include <stdio.h> #define __STD_COMPLEX using namespace std; #ifdef _DEBUG #undef THIS_FILE static char THIS_FILE[]=__FILE__; #define new DEBUG_NEW #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// CCalculations::CCalculations() CCalculations::~CCalculations() // Copies pointer to Circle DiagramDoc void CCalculations::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr; // This function calculates all values for the output in the Input-Dialog-Box // and the variables P_DRAWFACTOR and V_DRAWFACTOR void CCalculations::DoCalculation() double pi = 3.1415926535; // Get data from document BaseVoltage = pDoc->BaseVoltage; FaultLevel = pDoc->FaultLevel; Reactance = pDoc->Reactance; PCSS = pDoc->PCSS; Resistance = pDoc->Resistance; Voltage = pDoc->Voltage; XRratio = pDoc->XRratio; Angle = pDoc->Angle; Impedance = pDoc->Impedance; IndicationCheckBox = pDoc->IndicationCheckBox; zoom = pDoc->zoom; // Calculates the impedance and its angle for four different input-cases switch (IndicationCheckBox) // R and X are available case 1:

Appendix 92


ImpedanceCalc = sqrt(Resistance*Resistance+Reactance*Reactance); AngleCalc = atan(Reactance/Resistance); pDoc->Impedance = ImpedanceCalc; pDoc->Angle = AngleCalc*180/pi; pDoc->PCSS = ((Voltage/sqrt(3))/ImpedanceCalc)*1000; //PSCC in Ampere pDoc->XRratio = (Reactance/Resistance); pDoc->FaultLevel = (Voltage*Voltage/ImpedanceCalc); break; // Z and the angle of Z are available case 2: ImpedanceCalc = Impedance; AngleCalc = Angle*pi/180; pDoc->Resistance = (ImpedanceCalc*cos(AngleCalc)); pDoc->Reactance = (ImpedanceCalc*sin(AngleCalc)); pDoc->Impedance = ImpedanceCalc; pDoc->Angle = AngleCalc*180/pi; pDoc->PCSS = ((Voltage/sqrt(3))/ImpedanceCalc)*1000; pDoc->XRratio = (tan(AngleCalc)); pDoc->FaultLevel = (Voltage*Voltage/ImpedanceCalc); break; // PSCC and the X/R-ratio are available case 3: ImpedanceCalc = ((Voltage/sqrt(3))/(PCSS/1000)); // kV/kA = V/A = ohm AngleCalc = atan(XRratio); pDoc->Resistance = (ImpedanceCalc*cos(AngleCalc)); pDoc->Reactance = (ImpedanceCalc*sin(AngleCalc)); pDoc->Impedance = ImpedanceCalc; pDoc->Angle = AngleCalc*180/pi; pDoc->FaultLevel = (Voltage*Voltage/ImpedanceCalc); break; // The system fault level and the X/R-ratio are available case 4: ImpedanceCalc = (Voltage*Voltage/FaultLevel); // kV*kV/MVA = V/A = ohm AngleCalc = atan(XRratio); pDoc->Resistance = (ImpedanceCalc*cos(AngleCalc)); pDoc->Reactance = (ImpedanceCalc*sin(AngleCalc)); pDoc->Impedance = ImpedanceCalc; pDoc->Angle = AngleCalc*180/pi; pDoc->PCSS = ((Voltage/sqrt(3))/ImpedanceCalc)*1000; break; default: break; // Calculating of the base power and saving in document BasePower = BaseVoltage*BaseVoltage/ImpedanceCalc; // kV*kV/ohm = MVAbase pDoc->BasePower = BasePower;

Appendix 93


// Saving of the calculated angle in document pDoc->AngleCalc=AngleCalc; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Calculating of the P_DRAWFACTOR and V_DRAWFACTOR. These factors are used // for the scaling on the screen. It is the BasePower or BaseVoltage dividet // through 200, where 200 is the length of one half of the axis and is // equivalent to 1p.u.Therefore P_DRAWFACTOR indicates the power per pixel and // V_DRAWFACTOR the voltage per pixel. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// P_DRAWFACTOR = BasePower/(200); pDoc->P_DRAWFACTOR = P_DRAWFACTOR; V_DRAWFACTOR = BaseVoltage/(201); pDoc->V_DRAWFACTOR = V_DRAWFACTOR;

Appendix 94


10.2 Class Circle DiagramDoc

// Circle DiagramDoc.h : interface of the CCircleDiagramDoc class // This class sets the default-values and stores all Input-datas ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include <complex> using namespace std; class CCircleDiagramDoc : public CDocument protected: // create from serialization only CCircleDiagramDoc(); DECLARE_DYNCREATE(CCircleDiagramDoc) // Attributes public: // Operations public: void DeleteContents(); // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(CCircleDiagramDoc) public: virtual BOOL OnNewDocument(); virtual void Serialize(CArchive& ar); //AFX_VIRTUAL // Implementation public: BOOLEAN SwitchSave; BOOLEAN StartSwitch; BOOLEAN MarkDelete; BOOLEAN MarkSwitch; BOOLEAN PFSwitch; CString SaveP1Iout; CPoint DevicePosition; int Mark_y; int Mark_x; int zoom; int YVoltage; int XVoltage; int IndicationCheckBox; double Sradius; double Sradius2; double Sradius3; complex <double> IComplex; float SendingVoltage; float MarkZoom; float PowerFactor; float AngleCalc; float P_DRAWFACTOR; float V_DRAWFACTOR; float BasePower; float BaseVoltage;

Appendix 95


float FaultLevel; float Reactance; float PCSS; float Resistance; float Voltage; float XRratio; float Angle; float Impedance; CString P1Iout; CString P1AngleSendOut; CString P1PFSendout; CString P1Ssout; CString P1Qsout; CString P1Psout; CString P1LAngleout; CString P1Vout; CString P1AngleOut; CString P1PFout; CString P1Pout; CString P1Qout; CString P1Sout; CString P1VrOut; CString SaveP1AngleSendOut; CString SaveP1PFSendout; CString SaveP1Ssout; CString SaveP1Qsout; CString SaveP1Psout; CString SaveP1LAngleout; CString SaveP1Vout; CString SaveP1AngleOut; CString SaveP1PFout; CString SaveP1Pout; CString SaveP1Qout; CString SaveP1Sout; CString SaveP1VrOut; virtual ~CCircleDiagramDoc(); #ifdef _DEBUG virtual void AssertValid() const; virtual void Dump(CDumpContext& dc) const; #endif protected: // Generated message map functions protected: //AFX_MSG(CCircleDiagramDoc) //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 96


// Circle DiagramDoc.cpp : implementation of the CCircleDiagramDoc class // This class sets the default-values and stores all Input-datas ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "Input.h" #include "Circle DiagramDoc.h" #include "Calculations.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramDoc ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// IMPLEMENT_DYNCREATE(CCircleDiagramDoc, CDocument) BEGIN_MESSAGE_MAP(CCircleDiagramDoc, CDocument) //AFX_MSG_MAP(CCircleDiagramDoc) //AFX_MSG_MAP END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramDoc construction/destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// CCircleDiagramDoc::CCircleDiagramDoc() // TODO: add one-time construction code here CCircleDiagramDoc::~CCircleDiagramDoc() BOOL CCircleDiagramDoc::OnNewDocument() if (!CDocument::OnNewDocument()) return FALSE; // TODO: add reinitialization code here // (SDI documents will reuse this document) return TRUE; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramDoc serialization ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // This function stores and restores all datas from the document void CCircleDiagramDoc::Serialize(CArchive& ar) double RealCurrent,ImagCurrent; if (ar.IsStoring()) RealCurrent = real(IComplex); ImagCurrent = imag(IComplex);

Appendix 97


// TODO: add storing code here ar << Angle; ar << AngleCalc; ar << BasePower; ar << BaseVoltage; ar << DevicePosition; ar << FaultLevel; ar << RealCurrent; ar << ImagCurrent; ar << Impedance; ar << IndicationCheckBox; ar << Mark_x; ar << Mark_y; ar << MarkDelete; ar << MarkSwitch; ar << MarkZoom; ar << P1Iout; ar << P1AngleSendOut; ar << P1PFSendout; ar << P1Ssout; ar << P1Qsout; ar << P1Psout; ar << P1LAngleout; ar << P1Vout; ar << P1AngleOut; ar << P1PFout; ar << P1Pout; ar << P1Qout; ar << P1Sout; ar << P1VrOut; ar << P_DRAWFACTOR; ar << PCSS; ar << PFSwitch; ar << PowerFactor; ar << Reactance; ar << Resistance; ar << SaveP1AngleSendOut; ar << SaveP1PFSendout; ar << SaveP1Ssout; ar << SaveP1Qsout; ar << SaveP1Psout; ar << SaveP1LAngleout; ar << SaveP1Vout; ar << SaveP1AngleOut; ar << SaveP1PFout; ar << SaveP1Pout; ar << SaveP1Qout; ar << SaveP1Sout; ar << SaveP1VrOut; ar << SaveP1Iout; ar << SendingVoltage; ar << Sradius; ar << Sradius2; ar << Sradius3; ar << StartSwitch; ar << V_DRAWFACTOR; ar << Voltage; ar << XRratio; ar << XVoltage; ar << YVoltage; ar << zoom;

Appendix 98


else // TODO: add loading code here ar >> Angle; ar >> AngleCalc; ar >> BasePower; ar >> BaseVoltage; ar >> DevicePosition; ar >> FaultLevel; ar >> RealCurrent; ar >> ImagCurrent; ar >> Impedance; ar >> IndicationCheckBox; ar >> Mark_x; ar >> Mark_y; ar >> MarkDelete; ar >> MarkSwitch; ar >> MarkZoom; ar >> P1Iout; ar >> P1AngleSendOut; ar >> P1PFSendout; ar >> P1Ssout; ar >> P1Qsout; ar >> P1Psout; ar >> P1LAngleout; ar >> P1Vout; ar >> P1AngleOut; ar >> P1PFout; ar >> P1Pout; ar >> P1Qout; ar >> P1Sout; ar >> P1VrOut; ar >> P_DRAWFACTOR; ar >> PCSS; ar >> PFSwitch; ar >> PowerFactor; ar >> Reactance; ar >> Resistance; ar >> SaveP1AngleSendOut; ar >> SaveP1PFSendout; ar >> SaveP1Ssout; ar >> SaveP1Qsout; ar >> SaveP1Psout; ar >> SaveP1LAngleout; ar >> SaveP1Vout; ar >> SaveP1AngleOut; ar >> SaveP1PFout; ar >> SaveP1Pout; ar >> SaveP1Qout; ar >> SaveP1Sout; ar >> SaveP1VrOut; ar >> SaveP1Iout; ar >> SendingVoltage; ar >> Sradius; ar >> Sradius2; ar >> Sradius3; ar >> StartSwitch; ar >> V_DRAWFACTOR; ar >> Voltage; ar >> XRratio; ar >> XVoltage; ar >> YVoltage;

Appendix 99


ar >> zoom; IComplex = complex<double>(RealCurrent,ImagCurrent); SwitchSave = FALSE; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramDoc diagnostics ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #ifdef _DEBUG void CCircleDiagramDoc::AssertValid() const CDocument::AssertValid(); void CCircleDiagramDoc::Dump(CDumpContext& dc) const CDocument::Dump(dc); #endif //_DEBUG ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramDoc commands ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // This function is called to set the default values for the input-variables void CCircleDiagramDoc::DeleteContents() BaseVoltage = (float) 0.4; Voltage = (float) 0.4; Resistance = (float) 0.0080003; Reactance = (float) 0.080003; XRratio = 10; Impedance = (float) 0.080402; Angle = (float) 84.2894; FaultLevel = (float) 1.99; PCSS = (float) 2872.32; zoom=1; PowerFactor=0; Sradius = 0; Sradius2 = 0; Sradius3 = 0; P_DRAWFACTOR=0; V_DRAWFACTOR=0; PFSwitch = FALSE; MarkSwitch = FALSE; MarkDelete = FALSE;

Appendix 100


10.3 Class Circle DiagramView

// Circle DiagramView.h : interface of the CCircleDiagramView class // This class is the main-drawing-class for all drawings on the screen ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class CCircleDiagramView : public CScrollView protected: // create from serialization only CCircleDiagramView(); DECLARE_DYNCREATE(CCircleDiagramView) // Attributes public: CCircleDiagramDoc* GetDocument(); // Operations public: // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(CCircleDiagramView) public: virtual void OnDraw(CDC* pDC); // overridden to draw this view virtual BOOL PreCreateWindow(CREATESTRUCT& cs); protected: virtual void OnInitialUpdate(); // called first time after construct //AFX_VIRTUAL // Implementation public: CDC* pDC; void CallInitialUpdate(); void CallDrawUpdate(); virtual ~CCircleDiagramView(); #ifdef _DEBUG virtual void AssertValid() const; virtual void Dump(CDumpContext& dc) const; #endif protected: // Generated message map functions protected: //AFX_MSG(CCircleDiagramView) afx_msg void OnZoomin(); afx_msg void OnZoomout(); afx_msg void OnStart(); afx_msg void OnSconstant(); afx_msg void OnMouseMove(UINT nFlags, CPoint point); afx_msg void OnPowerFactor(); afx_msg void OnLButtonUp(UINT nFlags, CPoint point); afx_msg void OnRButtonDown(UINT nFlags, CPoint point); afx_msg void OnPrintScreen(); afx_msg void OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar); afx_msg void OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar); //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 101


// Circle DiagramView.cpp : implementation of the CCircleDiagramView class // This class is the main-drawing-class for all drawings on the screen ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "DrawAxis.h" #include "Input.h" #include "Calculations.h" #include "afxwin.h" #include "Sconstant.h" #include "PowerFactor.h" #include "P1Out.h" #include "Circle DiagramDoc.h" #include "Circle DiagramView.h" #include "PrintScreenDlg.h" #include <complex> #include <stdlib.h> #include <math.h> using namespace std; #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramView ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// IMPLEMENT_DYNCREATE(CCircleDiagramView, CScrollView) BEGIN_MESSAGE_MAP(CCircleDiagramView, CScrollView) //AFX_MSG_MAP(CCircleDiagramView) ON_BN_CLICKED(IDC_ZOOMIN, OnZoomin) ON_BN_CLICKED(IDC_ZOOMOUT, OnZoomout) ON_COMMAND(ID_START, OnStart) ON_BN_CLICKED(IDC_SCONSTANT, OnSconstant) ON_WM_MOUSEMOVE() ON_BN_CLICKED(IDC_PowerFactor, OnPowerFactor) ON_WM_LBUTTONUP() ON_WM_RBUTTONDOWN() ON_BN_CLICKED(IDC_PrintScreen, OnPrintScreen) ON_WM_VSCROLL() ON_WM_HSCROLL() //AFX_MSG_MAP // Standard printing commands ON_COMMAND(ID_FILE_PRINT, CScrollView::OnFilePrint) ON_COMMAND(ID_FILE_PRINT_DIRECT, CScrollView::OnFilePrint) ON_COMMAND(ID_FILE_PRINT_PREVIEW, CScrollView::OnFilePrintPreview) END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramView construction/destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// CCircleDiagramView::CCircleDiagramView() // TODO: add construction code here CCircleDiagramView::~CCircleDiagramView()

Appendix 102


BOOL CCircleDiagramView::PreCreateWindow(CREATESTRUCT& cs) // TODO: Modify the Window class or styles here by modifying // the CREATESTRUCT cs return CScrollView::PreCreateWindow(cs); ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramView drawing ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // This funktion calles the different drawing-functions from the class DrawAxis. // It is called every time when the screen needs to be updated. void CCircleDiagramView::OnDraw(CDC* pDC) CCircleDiagramDoc* pDoc = GetDocument(); ASSERT_VALID(pDoc); // TODO: add draw code for native data here if (pDoc->StartSwitch) DrawAxis AxisV; AxisV.SetDocPointer(GetDocument()); AxisV.pDCPointer(pDC); AxisV.DrawPQaxis(pDoc->zoom); double radius = 201*1.1; // 200 pixel equals 1 per-unit CString circleName = "1.1 p.u."; int Red = 255; AxisV.DrawCircles(pDoc->zoom, radius, circleName, Red); radius = 201*0.94; circleName = "0.94 p.u."; Red = 255; AxisV.DrawCircles(pDoc->zoom, radius, circleName, Red); radius = 201*0.8; circleName = "0.8 p.u."; int Black = 0; AxisV.DrawCircles(pDoc->zoom, radius, circleName, Black); radius = 201*1.2; circleName = "1.2 p.u."; Black = 0; AxisV.DrawCircles(pDoc->zoom, radius, circleName, Black); AxisV.DrawSCircle(pDoc->zoom, pDoc->Sradius/pDoc->P_DRAWFACTOR); AxisV.DrawSCircle(pDoc->zoom, pDoc->Sradius2/pDoc->P_DRAWFACTOR); AxisV.DrawSCircle(pDoc->zoom, pDoc->Sradius3/pDoc->P_DRAWFACTOR); AxisV.DrawPowerFactorLine(pDoc->zoom); AxisV.DrawMark(pDoc->zoom); pDoc->MarkSwitch = FALSE; CDC* pdc; pdc = GetDC(); P1Out NameP1Out; NameP1Out.SetDocPointer(pDoc); NameP1Out.ScreenOutP1(pdc);

Appendix 103


// This function is called in the beginning of the program (initialisation) // and if a new document is opened void CCircleDiagramView::OnInitialUpdate() CScrollView::OnInitialUpdate(); // Calculates the total size of the view CSize sizeTotal (3000,2000); CSize sizePage (sizeTotal.cx / 10, sizeTotal.cy / 10); CSize sizeLine (sizeTotal.cx / 50, sizeTotal.cy / 50); SetScrollSizes (MM_TEXT, sizeTotal, sizePage, sizeLine); // Initialisation of the screen position in the beginning int P1=1100, P2=750; CPoint POINT1 (P1, P2); ScrollToPosition (POINT1); CCircleDiagramDoc* pDoc = GetDocument(); if(pDoc->SwitchSave) pDoc->StartSwitch = FALSE; // Draw Bitmap on the screen CPaintDC dc(this); HBITMAP hbitmap= ::LoadBitmap(AfxGetApp()->m_hInstance,MAKEINTRESOURCE(IDB_BITMAP1)); HDC hMemDC = ::CreateCompatibleDC(NULL); SelectObject(hMemDC,hbitmap); ::StretchBlt(dc.m_hDC,300,130,400,400,hMemDC,0,0,375,379,SRCCOPY); DeleteDC(hMemDC); DeleteObject(hbitmap); else pDoc->SwitchSave = TRUE; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramView diagnostics ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #ifdef _DEBUG void CCircleDiagramView::AssertValid() const CScrollView::AssertValid(); void CCircleDiagramView::Dump(CDumpContext& dc) const CScrollView::Dump(dc); CCircleDiagramDoc* CCircleDiagramView::GetDocument() // non-debug version is inline ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CCircleDiagramDoc))); return (CCircleDiagramDoc*)m_pDocument; #endif //_DEBUG ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CCircleDiagramView message handlers ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // This function is called when the button 'ZOOM IN' is pressed void CCircleDiagramView::OnZoomin()

Appendix 104


// TODO: Add your control notification handler code here CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch && pDoc->zoom<33) pDoc->zoom=pDoc->zoom*2; CCircleDiagramDoc* pDoc = GetDocument(); pDoc->MarkZoom = pDoc->MarkZoom*2; pDoc->MarkSwitch = FALSE; CScrollView::OnInitialUpdate(); // This function is called when the button 'ZOOM OUT' is pressed void CCircleDiagramView::OnZoomout() // TODO: Add your control notification handler code here CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->zoom>1) pDoc->zoom=pDoc->zoom/2; pDoc->MarkZoom = pDoc->MarkZoom/2; pDoc->MarkSwitch = FALSE; CScrollView::OnInitialUpdate(); // This function is called when the button 'S' (Start) is pressed void CCircleDiagramView::OnStart() // TODO: Add your command handler code here CScrollView::OnInitialUpdate(); // DeleteContents is called before Input-Box to initialise all variables CCircleDiagramDoc* pDoc = GetDocument(); pDoc->DeleteContents(); pDoc->StartSwitch=FALSE; // Initialisation of Sradius pDoc->Sradius=0; // Initialisation of Point1 pDoc->MarkDelete = FALSE; // Call Input-DialogBox Input InputDlg; InputDlg.SetDocPointer(GetDocument()); InputDlg.SetViewPointer(this); InputDlg.DoModal(); // Call DoCalculation CCalculations CalcDlg; CalcDlg.SetDocPointer(GetDocument()); CalcDlg.DoCalculation(); // This function is called from the OnCancel-function (class Input) after // the Button 'Cancel' on the Input-Dlg-Box is pressed. It calles OnIntitialUpdate // to show the Bitmap Emblem void CCircleDiagramView::CallInitialUpdate() CCircleDiagramDoc* pDoc = GetDocument(); pDoc->StartSwitch=FALSE; OnInitialUpdate();

Appendix 105


// This function is called from the OnOK-function (class Input) after the Button 'OK' // on the Input-Dlg-Box is pressed. It calles OnIntitialUpdate to draw the diagram void CCircleDiagramView::CallDrawUpdate() CCircleDiagramDoc* pDoc = GetDocument(); pDoc->StartSwitch=TRUE; pDoc->zoom=1; CScrollView::OnInitialUpdate(); // This function is called when the button 'constant receiving power circle' is pressed void CCircleDiagramView::OnSconstant() // TODO: Add your control notification handler code here //Call Sconstant-DialogBox CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch) Sconstant SConstDlg; SConstDlg.SetDocPointer(GetDocument()); SConstDlg.DoModal(); CScrollView::OnInitialUpdate(); // This function is called when the mouse is moved. It calculates the values // of P, Q, V, I, the power factor, the load and the phase angles according // to the x anc y position of the mouse void CCircleDiagramView::OnMouseMove(UINT nFlags, CPoint point) // TODO: Add your message handler code here and/or call default //general initialisations double pi = 3.1415926535; CPoint POINT1; POINT1 = GetDeviceScrollPosition( ); CDC* pdc; pdc = GetDC(); CCircleDiagramDoc* pDoc = GetDocument(); //start calculation and output if (pDoc->StartSwitch) ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Output of the RECEIVING-END values ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// int xOutput = 345; pdc->TextOut(800,xOutput," "); pdc->TextOut(800,xOutput,"Receiving-end values:"); ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Vr: convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// CString VrOut; VrOut.Format ("Vr: %.3f kV",pDoc->Voltage); pdc->TextOut(800,xOutput + 20," "); pdc->TextOut(800,xOutput + 20,VrOut);

Appendix 106


pDoc->P1VrOut = VrOut; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Pr, Qr and Sr: Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PQ initialisations int x_PQaxis_zero, y_PQaxis_zero; float MousePcalc, MouseQcalc, Scalc; float P_DRAWFACTOR = pDoc->P_DRAWFACTOR/pDoc->zoom; CString Pout, Qout, Sout; // Calculation of the x and y coordinates for P and Q // The point (0,0) is in the crossing of the two axis P and Q x_PQaxis_zero = (point.x-(1500-POINT1.x))*(-1); y_PQaxis_zero = (point.y-(1000-POINT1.y))*(-1); // Calclation of the actual P and Q values MousePcalc = (P_DRAWFACTOR) * x_PQaxis_zero; MouseQcalc = (P_DRAWFACTOR) * y_PQaxis_zero; Scalc = (float) (sqrt(MousePcalc*MousePcalc + MouseQcalc*MouseQcalc)); // Conversion and output of the P and Q values on the screen Pout.Format ("Pr: %.3f MW",MousePcalc); pdc->TextOut(800,xOutput + 35," "); pdc->TextOut(800,xOutput + 35,Pout); pDoc->P1Pout = Pout; Qout.Format ("Qr: %.3f Mvar",MouseQcalc); pdc->TextOut(800,xOutput + 50," "); pdc->TextOut(800,xOutput + 50,Qout); pDoc->P1Qout = Qout; Sout.Format ("Sr: %.3f MVA",Scalc); pdc->TextOut(800,xOutput + 65," "); pdc->TextOut(800,xOutput + 65,Sout); pDoc->P1Sout = Sout; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Output of the SENDING-END values ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// pdc->TextOut(800,xOutput+130," "); pdc->TextOut(800,xOutput+130,"Sending-end values:"); ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Voltage (sending end): Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // V initialisations int x_Vaxis_zero, y_Vaxis_zero; float MouseVcalc, Vaxis_zero; float V_DRAWFACTOR = pDoc->V_DRAWFACTOR/pDoc->zoom; CString Vout; // Calculation of the x and y coordinates for V // The point (0,0) is in the crossing of the V axis x_Vaxis_zero = (point.x-(pDoc->XVoltage-POINT1.x)); y_Vaxis_zero = (point.y-(pDoc->YVoltage-POINT1.y)); Vaxis_zero = (float) sqrt(x_Vaxis_zero*x_Vaxis_zero+y_Vaxis_zero*y_Vaxis_zero); // Calclation of the actual V value MouseVcalc = (V_DRAWFACTOR) * Vaxis_zero; pDoc->SendingVoltage = MouseVcalc; // Conversion and output of the V value on the screen Vout.Format ("Vs: %.3f kV",MouseVcalc);

Appendix 107


pdc->TextOut(800,xOutput+150," "); pdc->TextOut(800,xOutput+150,Vout); pDoc->P1Vout = Vout; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Load angle: Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Load angle initialisations double Angle, Angle1; CString LAngleout; float LoadAngle; // Calclation of the load angle float AngleCalc = (float) (pDoc->AngleCalc*180/pi); Angle = (double) (atan2(-y_Vaxis_zero,-x_Vaxis_zero)); Angle1 = (double)(Angle*(180/pi)); LoadAngle = (float) (AngleCalc - Angle1); if (180<LoadAngle) LoadAngle=LoadAngle-360; // Conversion and output of the load angle value on the screen LAngleout.Format ("Load angle: %.2f degree",LoadAngle); pdc->TextOut(800,xOutput+260," "); pdc->TextOut(800,xOutput+260,LAngleout); pDoc->P1LAngleout = LAngleout; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Current (flowing from the send. to the rec. end): Calculate, convert and output //// Ir = -Is because of short transmission line ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //Current initialisations complex <double> VrComplex, VsComplex, ZComplex; CString Iout; VrComplex = complex<double>(pDoc->Voltage*1000,0); double RealSendingVoltage = pDoc->SendingVoltage * cos(LoadAngle*pi/180)*1000; double ImagSendingVoltage = pDoc->SendingVoltage * sin(LoadAngle*pi/180)*1000; VsComplex = complex<double>(RealSendingVoltage,ImagSendingVoltage); ZComplex = complex<double>(pDoc->Resistance,pDoc->Reactance); pDoc->IComplex = (VsComplex - VrComplex)/ZComplex; ///I in Ampere // Conversion and output of the current on the screen Iout.Format ("Current: %.1f A",(double) (abs(pDoc->IComplex)/sqrt(3))); pdc->TextOut(800,xOutput+275," "); pdc->TextOut(800,xOutput+275,Iout); pDoc->P1Iout = Iout; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Ps, Qs and Ss (sending end): Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Ps and Qs initialisations float SP1, SP2, SPangle, SendingRealPower; float SQ1, SQ2, SQangle, SendingReactivePower; float SendingComplexPower; CString Psout, Qsout, Ssout; // Calculation of Ps, Qs and Ss SP1 = (float) (MouseVcalc * pDoc->BaseVoltage)/pDoc->Impedance; SPangle = (float) (cos(LoadAngle*pi/180+pDoc->AngleCalc)); SP2 = (float) ((MouseVcalc*MouseVcalc/pDoc->Impedance)*cos(pDoc->AngleCalc)); SendingRealPower = SP1*SPangle - SP2;

Appendix 108


SQ1 = SP1; SQangle = (float) (sin(LoadAngle*pi/180+pDoc->AngleCalc)); SQ2 = (float) ((MouseVcalc*MouseVcalc/pDoc->Impedance)*sin(pDoc->AngleCalc)); SendingReactivePower = SQ1*SQangle - SQ2;

SendingComplexPower = (float)(sqrt(SendingRealPower*SendingRealPower + SendingReactivePower*SendingReactivePower));

// Conversion and output of the Ps,Qs and Ss values on the screen Psout.Format ("Ps: %.3f MW",SendingRealPower); Qsout.Format ("Qs: %.3f MVar",SendingReactivePower); Ssout.Format ("Ss: %.3f MVA",SendingComplexPower); pdc->TextOut(800,xOutput+165," "); pdc->TextOut(800,xOutput+165,Psout); pDoc->P1Psout = Psout; pdc->TextOut(800,xOutput+180," "); pdc->TextOut(800,xOutput+180,Qsout); pDoc->P1Qsout = Qsout; pdc->TextOut(800,xOutput+195," "); pdc->TextOut(800,xOutput+195,Ssout); pDoc->P1Ssout = Ssout; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Phase angle and power factor (receiving end): Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PF initialisations double AnglePF, PF; CString PFout, AngleOut; // Calculation of the power factor PF = MousePcalc/Scalc; AnglePF = (double) ((acos (PF))*180/pi); // in degree // Conversion and output on the screen if (MouseQcalc>=0) if (PF < 0) PF = PF * (-1); PFout.Format ("Power factor: %.2f lagging",PF); pdc->TextOut(800,xOutput + 80," "); pdc->TextOut(800,xOutput + 80,PFout); pDoc->P1PFout = PFout; AngleOut.Format ("Phase angle: %.2f degree",AnglePF); pdc->TextOut(800,xOutput + 95," "); pdc->TextOut(800,xOutput + 95,AngleOut); pDoc->P1AngleOut = AngleOut; else if (MouseQcalc<0) if (PF < 0) PF = PF * (-1); AnglePF = -AnglePF; PFout.Format ("Power factor: %.2f leading",PF); pdc->TextOut(800,xOutput + 80," "); pdc->TextOut(800,xOutput + 80,PFout); pDoc->P1PFout = PFout; AngleOut.Format ("Phase angle: %.2f degree",AnglePF); pdc->TextOut(800,xOutput + 95," "); pdc->TextOut(800,xOutput + 95,AngleOut); pDoc->P1AngleOut = AngleOut;

Appendix 109


////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// //// Phase angle and power factor (sending end): Calculate, convert and output ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PF initialisations double AnglePFsend, PFsend; CString PFSendout, AngleSendOut; // Calculation of the power factor angle PFsend = SendingRealPower/SendingComplexPower; AnglePFsend = (double) ((acos (PFsend))*180/pi); // in degree // Conversion and output on the screen if (SendingReactivePower >= 0) if (PFsend < 0) PFsend = PFsend * (-1); PFSendout.Format ("Power factor: %.2f lagging",PFsend); pdc->TextOut(800,xOutput+210," "); pdc->TextOut(800,xOutput+210,PFSendout); pDoc->P1PFSendout = PFSendout; AngleSendOut.Format ("Phase angle: %.2f degree",AnglePFsend); pdc->TextOut(800,xOutput+225," "); pdc->TextOut(800,xOutput+225,AngleSendOut); pDoc->P1AngleSendOut = AngleSendOut; else if (SendingReactivePower < 0) if (PFsend < 0) PFsend = PFsend * (-1); AnglePFsend = -AnglePFsend; PFSendout.Format ("Power factor: %.2f leading",PFsend); pdc->TextOut(800,xOutput+210," "); pdc->TextOut(800,xOutput+210,PFSendout); pDoc->P1PFSendout = PFSendout; AngleSendOut.Format ("Phase angle: %.2f degree",AnglePFsend); pdc->TextOut(800,xOutput+225," "); pdc->TextOut(800,xOutput+225,AngleSendOut); pDoc->P1AngleSendOut = AngleSendOut; CScrollView::OnMouseMove(nFlags, point); // This function is called when the button 'constant power factor' is pressed void CCircleDiagramView::OnPowerFactor() // TODO: Add your control notification handler code here // Call Sconstant-DialogBox CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch) PowerFactor NFactor; NFactor.SetDocPointer(GetDocument()); NFactor.DoModal(); CScrollView::OnInitialUpdate();

Appendix 110


// This function is called when the left mouse button is pressed void CCircleDiagramView::OnLButtonUp(UINT nFlags, CPoint point) // TODO: Add your message handler code here and/or call default CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch) pDoc->MarkSwitch = TRUE; // for zooming if a Mark (P1) is on screen; indicates if // a new mark is selected or zoom with old mark. pDoc->MarkDelete = TRUE; // indicates that the rigth mouse button was pressed -> // CLEAR SCREEN pDoc->DevicePosition = GetDeviceScrollPosition( ); pDoc->Mark_x = point.x; pDoc->Mark_y = point.y; P1Out NameP1Out; NameP1Out.SetDocPointer(pDoc); NameP1Out.SaveValues(); CScrollView::OnInitialUpdate(); CScrollView::OnLButtonUp(nFlags, point); // This function is called when the right mouse button is pressed -> CLEAR P1 void CCircleDiagramView::OnRButtonDown(UINT nFlags, CPoint point) // TODO: Add your message handler code here and/or call default CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch) CCircleDiagramDoc* pDoc = GetDocument(); pDoc->MarkDelete = FALSE; CScrollView::OnInitialUpdate(); CScrollView::OnRButtonDown(nFlags, point); // This function is called when the 'PrintScreen' button is pressed void CCircleDiagramView::OnPrintScreen() // TODO: Add your control notification handler code here //Call PrintDlg-DialogBox PrintScreenDlg NPrintScreen; NPrintScreen.DoModal(); CCircleDiagramDoc* pDoc = GetDocument(); if (pDoc->StartSwitch) CScrollView::OnInitialUpdate(); // This function updates the screen if vertical scroll-bar is used void CCircleDiagramView::OnVScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) // TODO: Add your message handler code here and/or call default CScrollView::OnInitialUpdate(); CScrollView::OnVScroll(nSBCode, nPos, pScrollBar);

Appendix 111


// This function updates the screen if horizontal scroll-bar is used void CCircleDiagramView::OnHScroll(UINT nSBCode, UINT nPos, CScrollBar* pScrollBar) // TODO: Add your message handler code here and/or call default CScrollView::OnInitialUpdate(); CScrollView::OnHScroll(nSBCode, nPos, pScrollBar);

Appendix 112


10.4 Class Draw Axis

// DrawAxis.h: interface for the DrawAxis class. // This class is called from the class CCircleDiagramView. It // calculates and draws the axis, the circles and the poer factor line ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class CCircleDiagramDoc; class DrawAxis public: int y; int x; int yV; int xV; float BasePower; void SetDocPointer(CCircleDiagramDoc*); void pDCPointer(CDC*); void DrawPowerFactorLine(int zoom); void DrawMark(int zoom); void DrawPQaxis(int zoom); void DrawCircles(int zoom, double radius, CString circleName,int Colour); void DrawSCircle(int zoom, double radius); DrawAxis(); virtual ~DrawAxis(); protected: CCircleDiagramDoc *pDoc; CDC *pDC; ;

Appendix 113


// DrawAxis.cpp: implementation of the DrawAxis class. // This class is called from the class CCircleDiagramView. It // calculates and draws the axis, the circles and the poer factor line ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "DrawAxis.h" #include "MainFrm.h" #include "Circle DiagramDoc.h" #include <afxwin.h> #include <math.h> #ifdef _DEBUG #undef THIS_FILE static char THIS_FILE[]=__FILE__; #define new DEBUG_NEW #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// DrawAxis::DrawAxis() DrawAxis::~DrawAxis() // Copies pointer to CircleDiagramDoc void DrawAxis::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr; // Copies pointer to pDC void DrawAxis::pDCPointer(CDC* pDCPointer) pDC = pDCPointer; // Draws the PQ-axis and the V-axis and scales them void DrawAxis::DrawPQaxis(int zoom) ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////// PQ axis ///////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Initialisation of the origin x=1500; y=1000; CPen newPen(PS_DASHDOTDOT,2,(COLORREF) 0); pDC->SelectObject(&newPen); pDC->MoveTo(x-215*zoom,y); pDC->LineTo(x+215*zoom,y); // Draw x-coordinate pDC->MoveTo(x-215*zoom,y); pDC->LineTo(x-207*zoom,y-4*zoom); // Draw left arrow pDC->MoveTo(x-215*zoom,y); pDC->LineTo(x-207*zoom,y+4*zoom); pDC->MoveTo(x+215*zoom,y); pDC->LineTo(x+207*zoom,y-4*zoom); // Draw right arrow pDC->MoveTo(x+215*zoom,y); pDC->LineTo(x+207*zoom,y+4*zoom); pDC->MoveTo(x,y-215*zoom); pDC->LineTo(x,y+215*zoom); // Draw y-coordinate pDC->MoveTo(x,y-215*zoom); pDC->LineTo(x-4*zoom,y-207*zoom); // Draw top arrow

Appendix 114


pDC->MoveTo(x,y-215*zoom); pDC->LineTo(x+4*zoom,y-207*zoom); pDC->MoveTo(x,y+215*zoom); pDC->LineTo(x-4*zoom,y+207*zoom); // Draw bottom arrow pDC->MoveTo(x,y+215*zoom); pDC->LineTo(x+4*zoom,y+207*zoom); pDC->SelectStockObject(BLACK_PEN); // Scale P/Q axis CString axis_value; CFont Text_Achse; Text_Achse.CreatePointFont(70*zoom, "Arial", pDC); CFont* pOldFont = pDC->SelectObject(&Text_Achse); pDC->SetBkMode(TRANSPARENT); pDC->TextOut(x-250*zoom,y-6*zoom,"P [p.u.]"); pDC->TextOut(x-16*zoom,y-228*zoom,"Q [p.u.]"); pDC->TextOut(x-7*zoom,y,"0"); for (int i = 40; i<240; i=i+40) if (i==40) axis_value = "0.2"; if (i==80) axis_value = "0.4"; if (i==120) axis_value = "0.6"; if (i==160) axis_value = "0.8"; if (i==200) axis_value = "1.0"; pDC->MoveTo(x-3*zoom,y-i*zoom); pDC->LineTo(x+3*zoom,y-i*zoom); pDC->TextOut(x-17*zoom,y-(i+5)*zoom,axis_value); pDC->MoveTo(x-i*zoom,y-3*zoom); pDC->LineTo(x-i*zoom,y+3*zoom); pDC->TextOut(x-(i+6)*zoom,y+2*zoom,axis_value); for ( i = 40; i<240; i=i+40) if (i==40) axis_value = "-0.2"; if (i==80) axis_value = "-0.4"; if (i==120) axis_value = "-0.6"; if (i==160) axis_value = "-0.8"; if (i==200) axis_value = "-1.0"; pDC->MoveTo(x-3*zoom,y+i*zoom); pDC->LineTo(x+3*zoom,y+i*zoom); pDC->TextOut(x-20*zoom,y+(i-5)*zoom,axis_value); pDC->MoveTo(x+i*zoom,y-3*zoom); pDC->LineTo(x+i*zoom,y+3*zoom); pDC->TextOut(x+(i-9)*zoom,y+2*zoom,axis_value); ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// ///////////////////////// V axis ///////////////////////// ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// double pi = 3.1415926535; // Calculate the new coordinates of the V-origin double xAbstandVAchse = 201*cos(pDoc->AngleCalc); double yAbstandVAchse = 201*sin(pDoc->AngleCalc); xV = x+(int)xAbstandVAchse*zoom; pDoc->XVoltage = xV; yV = y+(int)yAbstandVAchse*zoom; pDoc->YVoltage = yV; pDC->SelectObject(&newPen); pDC->MoveTo(xV-215*zoom,yV); pDC->LineTo(xV+215*zoom,yV); // Draw x-coordinate pDC->MoveTo(xV-215*zoom,yV); pDC->LineTo(xV-207*zoom,yV-4*zoom); // Draw left arrow

Appendix 115


pDC->MoveTo(xV-215*zoom,yV); pDC->LineTo(xV-207*zoom,yV+4*zoom); pDC->MoveTo(xV+215*zoom,yV); pDC->LineTo(xV+207*zoom,yV-4*zoom); // Draw right arrow pDC->MoveTo(xV+215*zoom,yV); pDC->LineTo(xV+207*zoom,yV+4*zoom); pDC->MoveTo(xV,yV-215*zoom); pDC->LineTo(xV,yV+215*zoom); // Draw y-coordinate pDC->MoveTo(xV,yV-215*zoom); pDC->LineTo(xV-4*zoom,yV-207*zoom); // Draw top arrow pDC->MoveTo(xV,yV-215*zoom); pDC->LineTo(xV+4*zoom,yV-207*zoom); pDC->MoveTo(xV,yV+215*zoom); pDC->LineTo(xV-4*zoom,yV+207*zoom); // Draw bottom arrow pDC->MoveTo(xV,yV+215*zoom); pDC->LineTo(xV+4*zoom,yV+207*zoom); pDC->SelectStockObject(BLACK_PEN); pDC->TextOut(xV-250*zoom,yV-6*zoom,"V [p.u.]"); pDC->TextOut(xV-16*zoom,yV-228*zoom,"V [p.u.]"); // Scale V Axis pDC->TextOut(xV-7*zoom,yV,"0"); for ( i = 40; i<240; i=i+40) if (i==40) axis_value = "0.2"; if (i==80) axis_value = "0.4"; if (i==120) axis_value = "0.6"; if (i==160) axis_value = "0.8"; if (i==200) axis_value = "1.0"; pDC->MoveTo(xV-3*zoom,yV+i*zoom); pDC->LineTo(xV+3*zoom,yV+i*zoom); pDC->TextOut(xV-17*zoom,yV+(i-5)*zoom,axis_value); pDC->MoveTo(xV-3*zoom,yV-i*zoom); pDC->LineTo(xV+3*zoom,yV-i*zoom); pDC->TextOut(xV-17*zoom,yV-(i+5)*zoom,axis_value); pDC->MoveTo(xV+i*zoom,yV-3*zoom); pDC->LineTo(xV+i*zoom,yV+3*zoom); pDC->TextOut(xV+(i-6)*zoom,yV+2*zoom,axis_value); pDC->MoveTo(xV-i*zoom,yV-3*zoom); pDC->LineTo(xV-i*zoom,yV+3*zoom); pDC->TextOut(xV-(i+6)*zoom,yV+2*zoom,axis_value); // Draws the constant Vr-circles void DrawAxis::DrawCircles(int zoom, double radius, CString circleName, int Colour) CPen newPen(PS_SOLID,1,RGB(Colour,0,0)); pDC->SelectObject(&newPen); int i; int xcircle1, ycircle1,xcircle2, ycircle2; double pi = 3.1415926535; double circle[2][181]; double angle; // The angle StoreAngle is (90-theta); theta=artan(X/R) double StoreAngle = (double) (90-(pDoc->AngleCalc)*180/pi); // Calculates and stores datas of the circle in array 'circle' for (i = 0; i<181; i++) angle = (i-StoreAngle)*pi/180; // The angle is counting from i-90+theta // to i+90-theta circle[0][i] = radius*cos(angle)*zoom; circle[1][i] = radius*sin(angle)*zoom; // Draw circle int DrawVar = 1; if (Colour == 0) DrawVar = 2; // For black circles draw intercepted lines if (Colour == 255) DrawVar = 1; // For red circles draw normal lines

Appendix 116


for (i = 1; i<181; i=i+DrawVar) xcircle1 = (int) circle[0][i-1]; ycircle1 = (int) circle[1][i-1]; xcircle2 = (int) circle[0][i]; ycircle2 = (int) circle[1][i]; pDC->MoveTo(xV-xcircle1,yV-ycircle1); pDC->LineTo(xV-xcircle2,yV-ycircle2); // Text circle int intradius = (int) radius; pDC->SetTextColor (RGB(Colour,0,0)); pDC->TextOut(xV+50*zoom,yV-(intradius+2)*zoom,circleName); pDC->SetTextColor (RGB(0,0,0)); // Draws the constant receiving S-circle void DrawAxis::DrawSCircle(int zoom, double radius) int i; int xcircle1, ycircle1,xcircle2, ycircle2; double pi = 3.1415926535; double circle[2][361]; double angle; CString TextCircle; CPen newPen(PS_SOLID,1,RGB(0,0,0)); pDC->SelectObject(&newPen); // Calculates and stores datas of circle in array circle for (i = 0; i<361; i++) angle = i*pi/180; circle[0][i] = radius*cos(angle)*zoom; circle[1][i] = radius*sin(angle)*zoom; // Draw circle for (i = 1; i<361; i=i+2) xcircle1 = (int) circle[0][i-1]; ycircle1 = (int) circle[1][i-1]; xcircle2 = (int) circle[0][i]; ycircle2 = (int) circle[1][i]; pDC->MoveTo(x-xcircle1,y-ycircle1); pDC->LineTo(x-xcircle2,y-ycircle2); // TextOut if (radius>0) TextCircle.Format ("Sr = %.2f MVA",radius*pDoc->P_DRAWFACTOR); pDC->TextOut((int) (x-circle[0][135]+5*zoom),(int)(y-circle[1][135]),TextCircle); // Draws the constant power factor lines void DrawAxis::DrawPowerFactorLine(int zoom) if (pDoc->PFSwitch) // Initialisation int PFx, PFy;

Appendix 117


float PFangle; double pi = 3.1415926535; CPen newPen(PS_SOLID,1,RGB(0,0,0)); pDC->SelectObject(&newPen); // Calculation for power factor lagging (P and Q positive) PFangle = (float) (acos (pDoc->PowerFactor)); //in radiant PFx = (int) (200* cos(PFangle) * zoom); PFy = (int) (200* sin(PFangle) * zoom); // Draw power factor line pDC->MoveTo(x,y); pDC->LineTo(x-PFx,y-PFy); // Text pf; conversion and output of the pf value pDC->SetTextColor (RGB(0,0,0)); int intPowerFactor = (int)pDoc->PowerFactor; CString PFname; PFname.Format ("pf lagging: %.2f",pDoc->PowerFactor); pDC->TextOut(x-PFx-35*zoom,y-PFy-15*zoom,PFname); // Calculation for power factor lagging (P negative, Q positive) PFx = (int) (-200* cos(PFangle) * zoom); PFy = (int) (200* sin(PFangle) * zoom); // Draw power factor line pDC->MoveTo(x,y); pDC->LineTo(x-PFx,y-PFy); // Text pf; conversion and output of the pf value PFname.Format ("pf lagging: %.2f",pDoc->PowerFactor); pDC->TextOut(x-PFx-35*zoom,y-PFy-15*zoom,PFname); // Calculation for power factor leading (P positive and Q negative) PFangle = (float) (acos (pDoc->PowerFactor)); //in radiant PFx = (int) (200* cos(PFangle) * zoom); PFy = (int) (-200* sin(PFangle) * zoom); // Draw power factor line pDC->MoveTo(x,y); pDC->LineTo(x-PFx,y-PFy); // Text pf; conversion and output of the pf value pDC->SetTextColor (RGB(0,0,0)); intPowerFactor = (int)pDoc->PowerFactor; PFname.Format ("pf leading: %.2f",pDoc->PowerFactor); pDC->TextOut(x-PFx-35*zoom,y-PFy+zoom,PFname); // Calculation for power factor leading (P and Q negative) PFx = (int) (-200* cos(PFangle) * zoom); PFy = (int) (-200* sin(PFangle) * zoom); // Draw power factor line pDC->MoveTo(x,y); pDC->LineTo(x-PFx,y-PFy); // Text pf; conversion and output of the pf value PFname.Format ("pf leading: %.2f",pDoc->PowerFactor); pDC->TextOut(x-PFx-35*zoom,y-PFy+zoom,PFname);

Appendix 118


// Draws the Vs and Vr arrows if left mouse button was pressed void DrawAxis::DrawMark(int zoom) if(pDoc->MarkDelete) int Mark_x,Mark_y; if (pDoc->MarkSwitch) Mark_x = (x-(pDoc->DevicePosition.x + pDoc->Mark_x)); Mark_y = (y-(pDoc->DevicePosition.y + pDoc->Mark_y)); pDoc->MarkZoom = 1; else Mark_x = (int) ((x-(pDoc->DevicePosition.x + pDoc->Mark_x))*pDoc->MarkZoom); Mark_y = (int) ((y-(pDoc->DevicePosition.y + pDoc->Mark_y))*pDoc->MarkZoom); pDC->TextOut(x-Mark_x-6*zoom,y-Mark_y-10*zoom,"P1"); pDC->MoveTo(x,y); pDC->LineTo(x-Mark_x,y-Mark_y); pDC->MoveTo(xV,yV); pDC->LineTo(x-Mark_x,y-Mark_y);

Appendix 119


10.5 Class Input Dialog

class CCircleDiagramDoc; class CCircleDiagramView; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Input dialog // Class for the Input-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class Input : public CDialog // Construction public: int IndicationCheckBox; // tells which checkbox is pressed, is 1 for checkBoxRX, // 2 for checkBoxZ, 3 for checkBoxPSCC and 4 for checkBoxFault void SetDocPointer(CCircleDiagramDoc*); void SetViewPointer(CCircleDiagramView*); Input(CWnd* pParent = NULL); // standard constructor // Dialog Data //AFX_DATA(Input) enum IDD = IDD_INPUT ; float m_BaseVoltage; float m_FaultLevel; float m_Reactance; float m_PCSS; float m_Resistance; float m_Voltage; float m_XRratio1; float m_Angle; float m_Impedance; float m_XRratio2; BOOL m_CheckRX; BOOL m_CheckZ; BOOL m_CheckPSCC; BOOL m_CheckFault; //AFX_DATA // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(Input) protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support //AFX_VIRTUAL // Implementation protected: CCircleDiagramDoc *pDoc; CCircleDiagramView *pView; // Generated message map functions //AFX_MSG(Input) virtual BOOL OnInitDialog(); virtual void OnOK(); virtual void OnCancel(); afx_msg void OnChangeVoltage(); afx_msg void OnCheckRx(); afx_msg void OnCheckZ(); afx_msg void OnCheckPscc(); afx_msg void OnCHECKFault();

Appendix 120


afx_msg void OnChangeResistance(); afx_msg void OnChangeReactance(); afx_msg void OnChangeImpedance(); afx_msg void OnChangeAngle(); afx_msg void OnChangePscc(); afx_msg void OnChangeXRratio1(); afx_msg void OnChangeXRratio2(); afx_msg void OnChangeFaultlevel(); //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 121


// Input.cpp : implementation file // Class for the Input-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "Input.h" #include "Circle DiagramDoc.h" #include "Circle DiagramView.h" #include "Calculations.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Input dialog ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// Input::Input(CWnd* pParent /*=NULL*/) : CDialog(Input::IDD, pParent) //AFX_DATA_INIT(Input) m_BaseVoltage = 0.0f; m_FaultLevel = 0.0f; m_Reactance = 0.0f; m_PCSS = 0.0f; m_Resistance = 0.0f; m_Voltage = 0.0f; m_XRratio1 = 0.0f; m_Angle = 0.0f; m_Impedance = 0.0f; m_XRratio2 = 0.0f; m_CheckFault = FALSE; m_CheckPSCC = FALSE; m_CheckRX = FALSE; m_CheckZ = FALSE; //AFX_DATA_INIT void Input::DoDataExchange(CDataExchange* pDX) CDialog::DoDataExchange(pDX); //AFX_DATA_MAP(Input) DDX_Text(pDX, IDC_BASEVOLTAGE, m_BaseVoltage); DDX_Text(pDX, IDC_FAULTLEVEL, m_FaultLevel); DDX_Text(pDX, IDC_Reactance, m_Reactance); DDX_Text(pDX, IDC_PSCC, m_PCSS); DDV_MinMaxFloat(pDX, m_PCSS, 0.f, 1.e+006f); DDX_Text(pDX, IDC_RESISTANCE, m_Resistance); DDX_Text(pDX, IDC_VOLTAGE, m_Voltage); DDV_MinMaxFloat(pDX, m_Voltage, 0.f, 1000.f); DDX_Text(pDX, IDC_XRratio1, m_XRratio1); DDX_Text(pDX, IDC_Angle, m_Angle); DDV_MinMaxFloat(pDX, m_Angle, 0.f, 90.f); DDX_Text(pDX, IDC_Impedance, m_Impedance); DDX_Text(pDX, IDC_XRratio2, m_XRratio2); DDX_Check(pDX, IDC_CHECK_RX, m_CheckRX); DDX_Check(pDX, IDC_CHECK_Z, m_CheckZ); DDX_Check(pDX, IDC_CHECK_PSCC, m_CheckPSCC); DDX_Check(pDX, IDC_CHECK_Fault, m_CheckFault); //AFX_DATA_MAP

Appendix 122


BEGIN_MESSAGE_MAP(Input, CDialog) //AFX_MSG_MAP(Input) ON_EN_CHANGE(IDC_VOLTAGE, OnChangeVoltage) ON_BN_CLICKED(IDC_CHECK_RX, OnCheckRx) ON_BN_CLICKED(IDC_CHECK_Z, OnCheckZ) ON_BN_CLICKED(IDC_CHECK_PSCC, OnCheckPscc) ON_BN_CLICKED(IDC_CHECK_Fault, OnCHECKFault) ON_EN_CHANGE(IDC_RESISTANCE, OnChangeResistance) ON_EN_CHANGE(IDC_Reactance, OnChangeReactance) ON_EN_CHANGE(IDC_Impedance, OnChangeImpedance) ON_EN_CHANGE(IDC_Angle, OnChangeAngle) ON_EN_CHANGE(IDC_PSCC, OnChangePscc) ON_EN_CHANGE(IDC_XRratio1, OnChangeXRratio1) ON_EN_CHANGE(IDC_XRratio2, OnChangeXRratio2) ON_EN_CHANGE(IDC_FAULTLEVEL, OnChangeFaultlevel) //AFX_MSG_MAP END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Input message handlers ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Copies pointer to CircleDiagramDoc void Input::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr; // Copies pointer to CircleDiagramView void Input::SetViewPointer(CCircleDiagramView *ViewPtr) pView = ViewPtr; // Initialisation of the Input-Dialog-Box-values BOOL Input::OnInitDialog() CDialog::OnInitDialog(); // TODO: Add extra initialization here // Get data from document or set data default m_BaseVoltage = pDoc->BaseVoltage; m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_Voltage = pDoc->Voltage; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_Impedance = pDoc->Impedance; m_XRratio2 = pDoc->XRratio; // Initialise all edit-windows GetDlgItem(IDC_BASEVOLTAGE)->EnableWindow(FALSE); GetDlgItem(IDC_RESISTANCE)->EnableWindow(TRUE); GetDlgItem(IDC_Reactance)->EnableWindow(TRUE); GetDlgItem(IDC_Impedance)->EnableWindow(FALSE); GetDlgItem(IDC_Angle)->EnableWindow(FALSE); GetDlgItem(IDC_PSCC)->EnableWindow(FALSE); GetDlgItem(IDC_XRratio1)->EnableWindow(FALSE); GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(FALSE); GetDlgItem(IDC_XRratio2)->EnableWindow(FALSE); // Initialise check boxes

Appendix 123


m_CheckRX = TRUE; m_CheckZ = FALSE; m_CheckPSCC = FALSE; m_CheckFault = FALSE; // Initialise IndicationCheckBox IndicationCheckBox = 1; UpdateData(FALSE); return TRUE; // return TRUE unless you set the focus to a control // EXCEPTION: OCX Property Pages should return FALSE // This function is executed if the 'OK'-button on the Input-Dialog-Box is // pressed. Saves datas and calles CallDrawUpdate. void Input::OnOK() // TODO: Add extra validation here UpdateData(TRUE); pDoc->BaseVoltage = m_BaseVoltage; pDoc->FaultLevel = m_FaultLevel; pDoc->Reactance = m_Reactance; pDoc->PCSS = m_PCSS; pDoc->Resistance = m_Resistance; pDoc->Voltage = m_Voltage; if (m_CheckPSCC == TRUE) pDoc->XRratio = m_XRratio1; pDoc->Angle = m_Angle; pDoc->Impedance = m_Impedance; if (m_CheckFault == TRUE) pDoc->XRratio = m_XRratio2; pDoc->IndicationCheckBox = IndicationCheckBox; CDialog::OnOK(); pView->CallDrawUpdate(); // This function is executed if the 'Cancel'-button on the Input-Dialog-Box is // pressed. It calles CallInitialUpdate. void Input::OnCancel() // TODO: Add extra cleanup here CDialog::OnCancel(); pView->CallInitialUpdate(); // This function is called if the value in the voltage edit-box is changed void Input::OnChangeVoltage() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); m_BaseVoltage = m_Voltage; pDoc->Voltage = m_Voltage; if (IndicationCheckBox == 1) pDoc->IndicationCheckBox = IndicationCheckBox;

Appendix 124


pDoc->Resistance = m_Resistance; pDoc->Reactance = m_Reactance; if (IndicationCheckBox == 2) pDoc->IndicationCheckBox = IndicationCheckBox; pDoc->Impedance = m_Impedance; pDoc->Angle = m_Angle; if (IndicationCheckBox == 3) pDoc->IndicationCheckBox = IndicationCheckBox; pDoc->PCSS = m_PCSS; pDoc->XRratio = m_XRratio1; if (IndicationCheckBox == 4) pDoc->IndicationCheckBox = IndicationCheckBox; pDoc->FaultLevel = m_FaultLevel; pDoc->XRratio = m_XRratio2; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_Reactance = pDoc->Reactance; m_FaultLevel = pDoc->FaultLevel; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_Impedance = pDoc->Impedance; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is executed if check-box 'RX' is marked. void Input::OnCheckRx() // TODO: Add your control notification handler code here UpdateData (TRUE); // Fetches datas from the dialog box if (m_CheckRX==TRUE) m_Resistance = pDoc->Resistance; GetDlgItem(IDC_RESISTANCE)->EnableWindow(TRUE); m_Reactance = pDoc->Reactance; GetDlgItem(IDC_Reactance)->EnableWindow(TRUE); m_Impedance = pDoc->Impedance; GetDlgItem(IDC_Impedance)->EnableWindow(FALSE); m_Angle = pDoc->Angle; GetDlgItem(IDC_Angle)->EnableWindow(FALSE); m_PCSS = pDoc->PCSS; GetDlgItem(IDC_PSCC)->EnableWindow(FALSE); m_XRratio1 = pDoc->XRratio; GetDlgItem(IDC_XRratio1)->EnableWindow(FALSE); m_FaultLevel = pDoc->FaultLevel; GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(FALSE); m_XRratio2 = pDoc->XRratio; GetDlgItem(IDC_XRratio2)->EnableWindow(FALSE); m_CheckZ = FALSE; m_CheckPSCC = FALSE; m_CheckFault = FALSE; IndicationCheckBox = 1; else

Appendix 125


GetDlgItem(IDC_RESISTANCE)->EnableWindow(FALSE); GetDlgItem(IDC_Reactance)->EnableWindow(FALSE); UpdateData (FALSE); // This function is executed if check-box 'Z' is marked. void Input::OnCheckZ() // TODO: Add your control notification handler code here UpdateData (TRUE); // Fetches datas from the dialog box if (m_CheckZ==TRUE) m_Resistance = pDoc->Resistance; GetDlgItem(IDC_RESISTANCE)->EnableWindow(FALSE); m_Reactance = pDoc->Reactance; GetDlgItem(IDC_Reactance)->EnableWindow(FALSE); m_Impedance = pDoc->Impedance; GetDlgItem(IDC_Impedance)->EnableWindow(TRUE); m_Angle = pDoc->Angle; GetDlgItem(IDC_Angle)->EnableWindow(TRUE); m_PCSS = pDoc->PCSS; GetDlgItem(IDC_PSCC)->EnableWindow(FALSE); m_XRratio1 = pDoc->XRratio; GetDlgItem(IDC_XRratio1)->EnableWindow(FALSE); m_FaultLevel = pDoc->FaultLevel; GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(FALSE); m_XRratio2 = pDoc->XRratio; GetDlgItem(IDC_XRratio2)->EnableWindow(FALSE); m_CheckRX = FALSE; m_CheckPSCC = FALSE; m_CheckFault = FALSE; IndicationCheckBox = 2; else GetDlgItem(IDC_Impedance)->EnableWindow(FALSE); GetDlgItem(IDC_Angle)->EnableWindow(FALSE); UpdateData (FALSE); // This function is executed if check-box 'PSCC' is marked. void Input::OnCheckPscc() // TODO: Add your control notification handler code here UpdateData (TRUE); // Fetches datas from the dialog box if (m_CheckPSCC == TRUE) m_Resistance = pDoc->Resistance; GetDlgItem(IDC_RESISTANCE)->EnableWindow(FALSE); m_Reactance = pDoc->Reactance; GetDlgItem(IDC_Reactance)->EnableWindow(FALSE); m_Impedance = pDoc->Impedance; GetDlgItem(IDC_Impedance)->EnableWindow(FALSE); m_Angle = pDoc->Angle; GetDlgItem(IDC_Angle)->EnableWindow(FALSE); m_PCSS = pDoc->PCSS; GetDlgItem(IDC_PSCC)->EnableWindow(TRUE); m_XRratio1 = pDoc->XRratio; GetDlgItem(IDC_XRratio1)->EnableWindow(TRUE); m_FaultLevel = pDoc->FaultLevel; GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(FALSE); m_XRratio2 = pDoc->XRratio; GetDlgItem(IDC_XRratio2)->EnableWindow(FALSE); m_CheckRX = FALSE; m_CheckZ = FALSE; m_CheckFault = FALSE; IndicationCheckBox = 3; else GetDlgItem(IDC_PSCC)->EnableWindow(FALSE); GetDlgItem(IDC_XRratio1)->EnableWindow(FALSE);

Appendix 126


UpdateData (FALSE); // This function is executed if check box 'Fault' is marked. void Input::OnCHECKFault() // TODO: Add your control notification handler code here UpdateData (TRUE); // Fetches datas from the dialog box if (m_CheckFault == TRUE) m_Resistance = pDoc->Resistance; GetDlgItem(IDC_RESISTANCE)->EnableWindow(FALSE); m_Reactance = pDoc->Reactance; GetDlgItem(IDC_Reactance)->EnableWindow(FALSE); m_Impedance = pDoc->Impedance; GetDlgItem(IDC_Impedance)->EnableWindow(FALSE); m_Angle = pDoc->Angle; GetDlgItem(IDC_Angle)->EnableWindow(FALSE); m_PCSS = pDoc->PCSS; GetDlgItem(IDC_PSCC)->EnableWindow(FALSE); m_XRratio1 = pDoc->XRratio; GetDlgItem(IDC_XRratio1)->EnableWindow(FALSE); m_FaultLevel = pDoc->FaultLevel; GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(TRUE); m_XRratio2 = pDoc->XRratio; GetDlgItem(IDC_XRratio2)->EnableWindow(TRUE); m_CheckRX = FALSE; m_CheckZ = FALSE; m_CheckPSCC = FALSE; IndicationCheckBox = 4; else GetDlgItem(IDC_FAULTLEVEL)->EnableWindow(FALSE); GetDlgItem(IDC_XRratio2)->EnableWindow(FALSE); UpdateData (FALSE); // This function is called if the value in the 'Resistance' edit-box is changed void Input::OnChangeResistance() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->Resistance = m_Resistance; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_Impedance = pDoc->Impedance; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'Reactance' edit-box is changed void Input::OnChangeReactance()

Appendix 127


// TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->Reactance = m_Reactance; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_Impedance = pDoc->Impedance; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'Impedance' edit-box is changed void Input::OnChangeImpedance() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->Impedance = m_Impedance; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'Z angle' edit-box is changed void Input::OnChangeAngle() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE);

Appendix 128


pDoc->Angle = m_Angle; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_Impedance = pDoc->Impedance; m_XRratio1 = pDoc->XRratio; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'PSCC' edit-box is changed void Input::OnChangePscc() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->PCSS = m_PCSS; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_Resistance = pDoc->Resistance; m_Impedance = pDoc->Impedance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'XRratio1' edit-box is changed void Input::OnChangeXRratio1() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->XRratio = m_XRratio1; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance;

Appendix 129


m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_Impedance = pDoc->Impedance; m_Angle = pDoc->Angle; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE); // This function is called if the value in the 'XRratio2' edit-box is changed void Input::OnChangeXRratio2() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->XRratio = m_XRratio2; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_FaultLevel = pDoc->FaultLevel; m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_Impedance = pDoc->Impedance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; UpdateData(FALSE); // This function is called if the value in the 'Fault level' edit-box is changed void Input::OnChangeFaultlevel() // TODO: If this is a RICHEDIT control, the control will not // send this notification unless you override the CDialog::OnInitDialog() // function and call CRichEditCtrl().SetEventMask() // with the ENM_CHANGE flag ORed into the mask. // TODO: Add your control notification handler code here UpdateData(TRUE); pDoc->FaultLevel = m_FaultLevel; pDoc->IndicationCheckBox = IndicationCheckBox; CCalculations CalcDlg; CalcDlg.SetDocPointer(pDoc); CalcDlg.DoCalculation(); m_Reactance = pDoc->Reactance; m_PCSS = pDoc->PCSS; m_Resistance = pDoc->Resistance; m_Impedance = pDoc->Impedance; m_XRratio1 = pDoc->XRratio; m_Angle = pDoc->Angle; m_XRratio2 = pDoc->XRratio; UpdateData(FALSE);

Appendix 130


10.6 Class MainFrm

// MainFrm.h : interface of the CMainFrame class // This file contains the frame class CMainFrame, which is derived from // CFrameWnd and controls all SDI frame features. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class CMainFrame : public CFrameWnd protected: // create from serialization only CMainFrame(); DECLARE_DYNCREATE(CMainFrame) // Attributes public: // Operations public: // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(CMainFrame) public: virtual BOOL PreCreateWindow(CREATESTRUCT& cs); //AFX_VIRTUAL // Implementation public: virtual ~CMainFrame(); #ifdef _DEBUG virtual void AssertValid() const; virtual void Dump(CDumpContext& dc) const; #endif protected: // control bar embedded members CStatusBar m_wndStatusBar; CToolBar m_wndToolBar; CReBar m_wndReBar; CDialogBar m_wndDlgBar; // Generated message map functions protected: //AFX_MSG(CMainFrame) afx_msg int OnCreate(LPCREATESTRUCT lpCreateStruct); //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 131


// MainFrm.cpp : implementation of the CMainFrame class // This file contains the frame class CMainFrame, which is derived from // CFrameWnd and controls all SDI frame features. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "Input.h" #include "MainFrm.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CMainFrame ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// IMPLEMENT_DYNCREATE(CMainFrame, CFrameWnd) BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd) //AFX_MSG_MAP(CMainFrame) ON_WM_CREATE() ON_WM_MOUSEMOVE() //AFX_MSG_MAP END_MESSAGE_MAP() static UINT indicators[] = ID_SEPARATOR, // status line indicator ID_INDICATOR_CAPS, ID_INDICATOR_NUM, ID_INDICATOR_SCRL, ; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CMainFrame construction/destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// CMainFrame::CMainFrame() // TODO: add member initialization code here CMainFrame::~CMainFrame() int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct) if (CFrameWnd::OnCreate(lpCreateStruct) == -1) return -1; if (!m_wndToolBar.CreateEx(this) || !m_wndToolBar.LoadToolBar(IDR_MAINFRAME)) TRACE0("Failed to create toolbar\n"); return -1; // fail to create if (!m_wndDlgBar.Create(this, IDR_MAINFRAME, CBRS_ALIGN_TOP, AFX_IDW_DIALOGBAR)) TRACE0("Failed to create dialogbar\n");

Appendix 132


return -1; // fail to create if (!m_wndReBar.Create(this) || !m_wndReBar.AddBar(&m_wndToolBar) || !m_wndReBar.AddBar(&m_wndDlgBar)) TRACE0("Failed to create rebar\n"); return -1; // fail to create if (!m_wndStatusBar.Create(this) || !m_wndStatusBar.SetIndicators(indicators, sizeof(indicators)/sizeof(UINT))) TRACE0("Failed to create status bar\n"); return -1; // fail to create // TODO: Remove this if you don't want tool tips m_wndToolBar.SetBarStyle(m_wndToolBar.GetBarStyle() | CBRS_TOOLTIPS | CBRS_FLYBY); return 0; BOOL CMainFrame::PreCreateWindow(CREATESTRUCT& cs) if( !CFrameWnd::PreCreateWindow(cs) ) return FALSE; // TODO: Modify the Window class or styles here by modifying // the CREATESTRUCT cs // Size the window to the screen size and center it cs.cy = ::GetSystemMetrics(SM_CYSCREEN); cs.cx = ::GetSystemMetrics(SM_CXSCREEN); cs.y = ((cs.cy ) - cs.cy) / 2; cs.x = ((cs.cx ) - cs.cx) / 2; return TRUE; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CMainFrame diagnostics ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #ifdef _DEBUG void CMainFrame::AssertValid() const CFrameWnd::AssertValid(); void CMainFrame::Dump(CDumpContext& dc) const CFrameWnd::Dump(dc); #endif //_DEBUG ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // CMainFrame message handlers //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Appendix 133


10.7 Class P1Out

// P1Out.h: interface for the P1Out class. // This class is responsible for the output of the calculated datas // on the screen after the left mouse button was pressed ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class CCircleDiagramDoc; class P1Out public: void SaveValues(); void SetDocPointer(CCircleDiagramDoc*); void ScreenOutP1(CDC* pDC); P1Out(); virtual ~P1Out(); protected: CCircleDiagramDoc *pDoc; ;

Appendix 134


// P1Out.cpp: implementation of the P1Out class. // This class is responsible for the output of the calculated datas // on the screen after the left mouse button was pressed ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "P1Out.h" #include "Circle DiagramDoc.h" #ifdef _DEBUG #undef THIS_FILE static char THIS_FILE[]=__FILE__; #define new DEBUG_NEW #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Construction/Destruction ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// P1Out::P1Out() P1Out::~P1Out() // Copies pointer to CircleDiagramDoc void P1Out::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr; // Saves the values if mouse button is pressed void P1Out::SaveValues() pDoc->SaveP1AngleSendOut = pDoc->P1AngleSendOut; pDoc->SaveP1PFSendout = pDoc->P1PFSendout; pDoc->SaveP1Ssout = pDoc->P1Ssout ; pDoc->SaveP1Qsout = pDoc->P1Qsout; pDoc->SaveP1Psout = pDoc->P1Psout; pDoc->SaveP1LAngleout = pDoc->P1LAngleout; pDoc->SaveP1Vout = pDoc->P1Vout ; pDoc->SaveP1AngleOut = pDoc->P1AngleOut; pDoc->SaveP1PFout = pDoc->P1PFout; pDoc->SaveP1Pout = pDoc->P1Pout ; pDoc->SaveP1Qout = pDoc->P1Qout; pDoc->SaveP1Sout = pDoc->P1Sout ; pDoc->SaveP1VrOut = pDoc->P1VrOut; pDoc->SaveP1Iout = pDoc->P1Iout; // Output of the Mark (P1) values on the screen void P1Out::ScreenOutP1(CDC* pDC) if(pDoc->MarkDelete) int xOutput = 15; pDC->TextOut(1500 + 800,xOutput," "); pDC->TextOut(800,xOutput,"P1 - receiving-end values:"); pDC->TextOut(800,xOutput + 20," "); pDC->TextOut(800,xOutput + 20,pDoc->SaveP1VrOut);

Appendix 135


pDC->TextOut(800,xOutput + 35," "); pDC->TextOut(800,xOutput + 35,pDoc->SaveP1Pout); pDC->TextOut(800,xOutput + 50," "); pDC->TextOut(800,xOutput + 50,pDoc->SaveP1Qout); pDC->TextOut(800,xOutput + 65," "); pDC->TextOut(800,xOutput + 65,pDoc->SaveP1Sout); pDC->TextOut(800,xOutput + 80," "); pDC->TextOut(800,xOutput + 80,pDoc->SaveP1PFout); pDC->TextOut(800,xOutput + 95," "); pDC->TextOut(800,xOutput + 95,pDoc->SaveP1AngleOut); pDC->TextOut(800,xOutput+130," "); pDC->TextOut(800,xOutput+130,"P1 - sending-end values:"); pDC->TextOut(800,xOutput+150," "); pDC->TextOut(800,xOutput+150,pDoc->SaveP1Vout); pDC->TextOut(800,xOutput+260," "); pDC->TextOut(800,xOutput+260,pDoc->SaveP1LAngleout); pDC->TextOut(800,xOutput+165," "); pDC->TextOut(800,xOutput+165,pDoc->SaveP1Psout); pDC->TextOut(800,xOutput+180," "); pDC->TextOut(800,xOutput+180,pDoc->SaveP1Qsout); pDC->TextOut(800,xOutput+195," "); pDC->TextOut(800,xOutput+195,pDoc->SaveP1Ssout); pDC->TextOut(800,xOutput+210," "); pDC->TextOut(800,xOutput+210,pDoc->SaveP1PFSendout); pDC->TextOut(800,xOutput+225," "); pDC->TextOut(800,xOutput+225,pDoc->SaveP1AngleSendOut); pDC->TextOut(800,xOutput+210," "); pDC->TextOut(800,xOutput+210,pDoc->SaveP1PFSendout); pDC->TextOut(800,xOutput+225," "); pDC->TextOut(800,xOutput+225,pDoc->SaveP1AngleSendOut); pDC->TextOut(800,xOutput+275," "); pDC->TextOut(800,xOutput+275,pDoc->SaveP1Iout);

Appendix 136


10.8 Class PowerFactor Dialog

class CCircleDiagramDoc; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PowerFactor dialog // Class for the PowerFactor-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class PowerFactor : public CDialog // Construction public: PowerFactor(CWnd* pParent = NULL); // standard constructor void SetDocPointer(CCircleDiagramDoc*); // Dialog Data //AFX_DATA(PowerFactor) enum IDD = IDD_POWERFACTOR ; float m_PowerFactor; //AFX_DATA // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(PowerFactor) protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support //AFX_VIRTUAL // Implementation protected: CCircleDiagramDoc *pDoc; // Generated message map functions //AFX_MSG(PowerFactor) virtual BOOL OnInitDialog(); virtual void OnOK(); virtual void OnCancel(); //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 137


// PowerFactor.cpp : implementation file // Class for the PowerFactor-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "PowerFactor.h" #include "Circle DiagramDoc.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PowerFactor dialog ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// PowerFactor::PowerFactor(CWnd* pParent /*=NULL*/) : CDialog(PowerFactor::IDD, pParent) //AFX_DATA_INIT(PowerFactor) m_PowerFactor = 0.0f; //AFX_DATA_INIT void PowerFactor::DoDataExchange(CDataExchange* pDX) CDialog::DoDataExchange(pDX); //AFX_DATA_MAP(PowerFactor) DDX_Text(pDX, IDC_PowerFactor, m_PowerFactor); DDV_MinMaxFloat(pDX, m_PowerFactor, 0.f, 1.f); //AFX_DATA_MAP BEGIN_MESSAGE_MAP(PowerFactor, CDialog) //AFX_MSG_MAP(PowerFactor) //AFX_MSG_MAP END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PowerFactor message handlers ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Initialisation of the DialogBox BOOL PowerFactor::OnInitDialog() CDialog::OnInitDialog(); // TODO: Add extra initialization here pDoc->PFSwitch = TRUE; return TRUE; // return TRUE unless you set the focus to a control // EXCEPTION: OCX Property Pages should return FALSE // Copies pointer to Circle DiagramDoc void PowerFactor::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr;

Appendix 138


// This function is called if the 'OK'-button of this dialog-box is pressed void PowerFactor::OnOK() // TODO: Add extra validation here UpdateData(TRUE); pDoc->PowerFactor = m_PowerFactor; CDialog::OnOK(); // This function is called if the 'Cancel'-button of this dialog-box is pressed void PowerFactor::OnCancel() // TODO: Add extra cleanup here pDoc->PFSwitch = FALSE; CDialog::OnCancel();

Appendix 139


10.9 Class PrintScreenDlg Dialog

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PrintScreenDlg dialog ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class PrintScreenDlg : public CDialog // Construction public: PrintScreenDlg(CWnd* pParent = NULL); // standard constructor // Dialog Data //AFX_DATA(PrintScreenDlg) enum IDD = IDD_PrintDlg ; // NOTE: the ClassWizard will add data members here //AFX_DATA // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(PrintScreenDlg) protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support //AFX_VIRTUAL // Implementation protected: // Generated message map functions //AFX_MSG(PrintScreenDlg) // NOTE: the ClassWizard will add member functions here //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 140


// PrintScreenDlg.cpp : implementation file ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "PrintScreenDlg.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PrintScreenDlg dialog ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// PrintScreenDlg::PrintScreenDlg(CWnd* pParent /*=NULL*/) : CDialog(PrintScreenDlg::IDD, pParent) //AFX_DATA_INIT(PrintScreenDlg) // NOTE: the ClassWizard will add member initialization here //AFX_DATA_INIT void PrintScreenDlg::DoDataExchange(CDataExchange* pDX) CDialog::DoDataExchange(pDX); //AFX_DATA_MAP(PrintScreenDlg) // NOTE: the ClassWizard will add DDX and DDV calls here //AFX_DATA_MAP BEGIN_MESSAGE_MAP(PrintScreenDlg, CDialog) //AFX_MSG_MAP(PrintScreenDlg) // NOTE: the ClassWizard will add message map macros here //AFX_MSG_MAP END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // PrintScreenDlg message handlers //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Appendix 141


10.10 Class Sconstant Dialog

class CCircleDiagramDoc; ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Sconstant dialog // Class for the Sconstant-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// class Sconstant : public CDialog // Construction public: Sconstant(CWnd* pParent = NULL); // standard constructor void SetDocPointer(CCircleDiagramDoc*); // Dialog Data //AFX_DATA(Sconstant) enum IDD = IDD_SCONSTANT ; double m_RadiusSCircle; double m_RadiusSCircle2; double m_RadiusSCircle3; //AFX_DATA // Overrides // ClassWizard generated virtual function overrides //AFX_VIRTUAL(Sconstant) protected: virtual void DoDataExchange(CDataExchange* pDX); // DDX/DDV support //AFX_VIRTUAL // Implementation protected: CCircleDiagramDoc *pDoc; // Generated message map functions //AFX_MSG(Sconstant) virtual void OnOK(); virtual BOOL OnInitDialog(); //AFX_MSG DECLARE_MESSAGE_MAP() ;

Appendix 142


// Sconstant.cpp : implementation file // Class for the Sconstant-Dlg-Box ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #include "stdafx.h" #include "Circle Diagram.h" #include "Sconstant.h" #include "Circle DiagramDoc.h" #ifdef _DEBUG #define new DEBUG_NEW #undef THIS_FILE static char THIS_FILE[] = __FILE__; #endif ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Sconstant dialog ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// Sconstant::Sconstant(CWnd* pParent /*=NULL*/) : CDialog(Sconstant::IDD, pParent) //AFX_DATA_INIT(Sconstant) m_RadiusSCircle = 0.0; m_RadiusSCircle2 = 0.0; m_RadiusSCircle3 = 0.0; //AFX_DATA_INIT void Sconstant::DoDataExchange(CDataExchange* pDX) CDialog::DoDataExchange(pDX); //AFX_DATA_MAP(Sconstant) DDX_Text(pDX, IDC_RadiusSCircle, m_RadiusSCircle); DDV_MinMaxDouble(pDX, m_RadiusSCircle, 0., 1000.); DDX_Text(pDX, IDC_RadiusSCircle2, m_RadiusSCircle2); DDV_MinMaxDouble(pDX, m_RadiusSCircle2, 0., 1000.); DDX_Text(pDX, IDC_RadiusSCircle3, m_RadiusSCircle3); DDV_MinMaxDouble(pDX, m_RadiusSCircle3, 0., 1000.); //AFX_DATA_MAP BEGIN_MESSAGE_MAP(Sconstant, CDialog) //AFX_MSG_MAP(Sconstant) //AFX_MSG_MAP END_MESSAGE_MAP() ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Sconstant message handlers ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Copies pointer to Circle DiagramDoc void Sconstant::SetDocPointer(CCircleDiagramDoc *DocPtr) pDoc = DocPtr; // This function is called if the 'OK'-button of this dialog-box is pressed void Sconstant::OnOK() // TODO: Add extra validation here UpdateData(TRUE); pDoc->Sradius = m_RadiusSCircle;

Appendix 143


pDoc->Sradius2 = m_RadiusSCircle2; pDoc->Sradius3 = m_RadiusSCircle3; CDialog::OnOK(); BOOL Sconstant::OnInitDialog() CDialog::OnInitDialog(); // TODO: Add extra initialization here m_RadiusSCircle = pDoc->Sradius; m_RadiusSCircle2 = pDoc->Sradius2; m_RadiusSCircle3 = pDoc->Sradius3; UpdateData(FALSE); return TRUE; // return TRUE unless you set the focus to a control // EXCEPTION: OCX Property Pages should return FALSE

Appendix 144


10.11 Resource.h

// Microsoft Developer Studio generated include file. // Used by Circle Diagram.rc ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #define IDD_ABOUTBOX 100 #define IDR_MAINFRAME 128 #define IDR_CIRCLETYPE 129 #define IDD_DIALOG1 130 #define IDD_INPUT 130 #define IDB_BITMAP1 132 #define IDD_SCONSTANT 135 #define IDD_PrintDlg 138 #define IDB_EA 146 #define IDB_ESG 149 #define IDB_ESG_klein 151 #define IDB_EA_klein 155 #define IDC_EDIT1 1000 #define IDC_PSCC 1000 #define IDC_PowerFactor 1000 #define IDC_EDIT2 1001 #define IDC_VOLTAGE 1001 #define IDC_RadiusSCircle 1001 #define IDC_PrintScreen 1001 #define IDC_EDIT3 1002 #define IDC_FAULTLEVEL 1002 #define IDC_RadiusSCircle2 1002 #define IDC_EDIT4 003 #define IDC_INDUCTANCE 1003 #define IDC_Reactance 1003 #define IDC_RadiusSCircle3 1003 #define IDC_EDIT5 1004 #define IDC_RESISTANCE 1004 #define IDC_EDIT6 1005 #define IDC_BASEVOLTAGE 1005 #define IDC_EDIT7 1006 #define IDC_XRratio 1006 #define IDC_ZOOMIN 1006 #define IDC_XRratio1 1006 #define IDC_ZOOMOUT 1007 #define IDC_XRratio2 1007 #define IDC_START 1008 #define IDC_Angle 1008 #define IDC_Impedance 1009 #define IDC_SCONSTANT 1009 #define IDC_SENDINGSCONST 1010 #define IDC_CHECK_RX 1015 #define IDC_CHECK_Z 1016 #define IDC_CHECK_Fault 1017 #define IDC_CHECK_PSCC 1018 #define IDC_PFlagging 1019 #define IDC_PFleading 1020 #define ID_BUTTON32773 32773 #define ID_BUTTON32779 32779 #define ID_START 32781 ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Next default values for new objects ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #ifdef APSTUDIO_INVOKED #ifndef APSTUDIO_READONLY_SYMBOLS #define _APS_3D_CONTROLS 1

Appendix 145


#define _APS_NEXT_RESOURCE_VALUE 156 #define _APS_NEXT_COMMAND_VALUE 32782 #define _APS_NEXT_CONTROL_VALUE 1025 #define _APS_NEXT_SYMED_VALUE 101 #endif #endif

Power System Thesis

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