Power System Analysis - Taylor & Francis Group

Marcel Dekker Inc New York bull Basel

Power SystemAnalysis

Short-Circuit Load Flow and Harmonics

J C DasAmec Inc

Atlanta Georgia

ISBN 0-8247-0737-0

This book is printed on acid-free paper

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Marcel Dekker Inc

270 Madison Avenue New York NY 10016tel 212-696-9000 fax 212-685-4540

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Neither this book nor any part may be reproduced or transmitted in any form or by any

means electronic or mechanical including photocopying microfilming and recording or byany information storage and retrieval system without permission in writing from the pub-lisher

Current printing (last digit)

10 9 8 7 6 5 4 3 2 1

PRINTED IN THE UNITED STATES OF AMERICA

POWER ENGINEERING

Series Editor

H Lee WillisABB Inc

Raleigh North Carolina

Advisory Editor

Muhammad H RashidUniversity of West Florida

Pensacola Florida

1 Power Distribution Planning Reference Book H Lee Willis2 Transmission Network Protection Theory and Practice Y G Paithankar3 Electrical Insulation in Power Systems N H Malik A A Al-Arainy and M I

Qureshi4 Electrical Power Equipment Maintenance and Testing Paul Gill5 Protective Relaying Principles and Applications Second Edition J Lewis

Blackburn6 Understanding Electric Utilities and De-Regulation Lorrin Philipson and H Lee

Willis7 Electrical Power Cable Engineering William A Thue8 Electric Systems Dynamics and Stability with Artificial Intelligence Applications

James A Momoh and Mohamed E El-Hawary9 Insulation Coordination for Power Systems Andrew R Hileman10 Distributed Power Generation Planning and Evaluation H Lee Willis and

Walter G Scott11 Electric Power System Applications of Optimization James A Momoh12 Aging Power Delivery Infrastructures H Lee Willis Gregory V Welch and

Randall R Schrieber13 Restructured Electrical Power Systems Operation Trading and Volatility

Mohammad Shahidehpour and Muwaffaq Alomoush14 Electric Power Distribution Reliability Richard E Brown15 Computer-Aided Power System Analysis Ramasamy Natarajan16 Power System Analysis Short-Circuit Load Flow and Harmonics J C Das17 Power Transformers Principles and Applications John J Winders Jr18 Spatial Electric Load Forecasting Second Edition Revised and Expanded H

Lee Willis19 Dielectrics in Electric Fields Gorur G Raju

ADDITIONAL VOLUMES IN PREPARATION

Protection Devices and Systems for High-Voltage Applications Vladimir Gure-vich

Series Introduction

Power engineering is the oldest and most traditional of the various areas withinelectrical engineering yet no other facet of modern technology is currently under-going a more dramatic revolution in both technology and industry structure Butnone of these changes alter the basic complexity of electric power system behavioror reduce the challenge that power system engineers have always faced in designingan economical system that operates as intended and shuts down in a safe and non-catastrophic mode when something fails unexpectedly In fact many of the ongoingchanges in the power industrymdashderegulation reduced budgets and staffing levelsand increasing public and regulatory demand for reliability among themmdashmakethese challenges all the more difficult to overcome

Therefore I am particularly delighted to see this latest addition to the PowerEngineering series J C Dasrsquos Power System Analysis Short-Circuit Load Flow andHarmonics provides comprehensive coverage of both theory and practice in thefundamental areas of power system analysis including power flow short-circuitcomputations harmonics machine modeling equipment ratings reactive powercontrol and optimization It also includes an excellent review of the standard matrixmathematics and computation methods of power system analysis in a readily-usableformat

Of particular note this book discusses both ANSIIEEE and IEC methodsguidelines and procedures for applications and ratings Over the past few years mywork as Vice President of Technology and Strategy for ABBrsquos global consultingorganization has given me an appreciation that the IEC and ANSI standards arenot so much in conflict as they are slightly different but equally valid approaches topower engineering There is much to be learned from each and from the study of thedifferences between them

As the editor of the Power Engineering series I am proud to include PowerSystem Analysis among this important group of books Like all the volumes in the

Power Engineering series this book provides modern power technology in a contextof proven practical application It is useful as a reference book as well as for self-study and advanced classroom use The series includes books covering the entire fieldof power engineering in all its specialties and subgenres all aimed at providingpracticing power engineers with the knowledge and techniques they need to meetthe electric industryrsquos challenges in the 21st century

H Lee Willis

iv Series Introduction

Preface

Power system analysis is fundamental in the planning design and operating stagesand its importance cannot be overstated This book covers the commonly requiredshort-circuit load flow and harmonic analyses Practical and theoretical aspectshave been harmoniously combined Although there is the inevitable computer simu-lation a feel for the procedures and methodology is also provided through examplesand problems Power System Analysis Short-Circuit Load Flow and Harmonicsshould be a valuable addition to the power system literature for practicing engineersthose in continuing education and college students

Short-circuit analyses are included in chapters on rating structures of breakerscurrent interruption in ac circuits calculations according to the IEC and ANSIIEEE methods and calculations of short-circuit currents in dc systems

The load flow analyses cover reactive power flow and control optimizationtechniques and introduction to FACT controllers three-phase load flow and opti-mal power flow

The effect of harmonics on power systems is a dynamic and evolving field(harmonic effects can be experienced at a distance from their source) The bookderives and compiles ample data of practical interest with the emphasis on harmonicpower flow and harmonic filter design Generation effects limits and mitigation ofharmonics are discussed including active and passive filters and new harmonicmitigating topologies

The models of major electrical equipmentmdashie transformers generatorsmotors transmission lines and power cablesmdashare described in detail Matrix tech-niques and symmetrical component transformation form the basis of the analysesThere are many examples and problems The references and bibliographies point tofurther reading and analyses Most of the analyses are in the steady state butreferences to transient behavior are included where appropriate

A basic knowledge of per unit system electrical circuits and machinery andmatrices required although an overview of matrix techniques is provided inAppendix A The style of writing is appropriate for the upper-undergraduate leveland some sections are at graduate-course level

Power Systems Analysis is a result of my long experience as a practicing powersystem engineer in a variety of industries power plants and nuclear facilities Itsunique feature is applications of power system analyses to real-world problems

I thank ANSIIEEE for permission to quote from the relevant ANSIIEEEstandards The IEEE disclaims any responsibility or liability resulting from theplacement and use in the described manner I am also grateful to the InternationalElectrotechnical Commission (IEC) for permission to use material from the interna-tional standards IEC 60660-1 (1997) and IEC 60909 (1988) All extracts are copy-right IEC Geneva Switzerland All rights reserved Further information on the IECits international standards and its role is available at wwwiecch IEC takes noresponsibility for and will not assume liability from the readerrsquos misinterpretationof the referenced material due to its placement and context in this publication Thematerial is reproduced or rewritten with their permission

Finally I thank the staff of Marcel Dekker Inc and special thanks to AnnPulido for her help in the production of this book

J C Das

vi Preface

Contents

Series Introduction iiiPreface v

1 Short-Circuit Currents and Symmetrical Components 1

11 Nature of Short-Circuit Currents 212 Symmetrical Components 513 Eigenvalues and Eigenvectors 814 Symmetrical Component Transformation 915 Clarke Component Transformation 1516 Characteristics of Symmetrical Components 1617 Sequence Impedance of Network Components 2018 Computer Models of Sequence Networks 35

2 Unsymmetrical Fault Calculations 39

21 Line-to-Ground Fault 4022 Line-to-Line Fault 4223 Double Line-to-Ground Fault 4324 Three-Phase Fault 4525 Phase Shift in Three-Phase Transformers 4626 Unsymmetrical Fault Calculations 5327 System Grounding and Sequence Components 6128 Open Conductor Faults 64

viii Contents

3 Matrix Methods for Network Solutions 72

31 Network Models 7332 Bus Admittance Matrix 7333 Bus Impedance Matrix 7834 Loop Admittance and Impedance Matrices 8135 Graph Theory 8236 Bus Admittance and Impedance Matrices by Graph Approach 8637 Algorithms for Construction of Bus Impedance Matrix 8938 Short-Circuit Calculations with Bus Impedance Matrix 10339 Solution of Large Network Equations 113

4 Current Interruption in AC Networks 116

41 Rheostatic Breaker 11742 Current-Zero Breaker 11843 Transient Recovery Voltage 12044 The Terminal Fault 12545 The Short-Line Fault 12746 Interruption of Low Inductive Currents 12747 Interruption of Capacitive Currents 13048 Prestrikes in Breakers 13349 Overvoltages on Energizing High-Voltage Lines 134410 Out-of-Phase Closing 136411 Resistance Switching 137412 Failure Modes of Circuit Breakers 139

5 Application and Ratings of Circuit Breakers and Fuses According

to ANSI Standards 145

51 Total and Symmetrical Current Rating Basis 14552 Asymmetrical Ratings 14753 Voltage Range Factor K 14854 Capabilities for Ground Faults 14855 ClosingndashLatchingndashCarrying Interrupting Capabilities 14956 Short-Time Current Carrying Capability 15357 Service Capability Duty Requirements and Reclosing

Capability 15358 Capacitance Current Switching 15559 Line Closing Switching Surge Factor 160510 Out-of-Phase Switching Current Rating 162511 Transient Recovery Voltage 163512 Low-Voltage Circuit Breakers 168513 Fuses 173

6 Short-Circuit of Synchronous and Induction Machines 179

61 Reactances of a Synchronous Machine 18062 Saturation of Reactances 182

Contents ix

63 Time Constants of Synchronous Machines 18364 Synchronous Machine Behavior on Terminal Short-Circuit 18365 Circuit Equations of Unit Machines 19466 Parkrsquos Transformation 19867 Parkrsquos Voltage Equation 20268 Circuit Model of Synchronous Machines 20369 Calculation Procedure and Examples 204610 Short-Circuit of an Induction Motor 214

7 Short-Circuit Calculations According to ANSI Standards 219

71 Types of Calculations 21972 Impedance Multiplying Factors 22073 Rotating Machines Model 22274 Types and Severity of System Short-Circuits 22275 Calculation Methods 22376 Network Reduction 23177 Breaker Duty Calculations 23378 High XR Ratios (DC Time Constant Greater than 45ms) 23379 Calculation Procedure 235710 Examples of Calculations 236711 Thirty-Cycle Short-Circuit Currents 261712 Dynamic Simulation 262

8 Short-Circuit Calculations According to IEC Standards 267

81 Conceptual and Analytical Differences 26782 Prefault Voltage 27183 Far-From-Generator Faults 27184 Near-to-Generator Faults 27585 Influence of Motors 28186 Comparison with ANSI Calculation Procedures 28387 Examples of Calculations and Comparison with ANSI

Methods 285

9 Calculations of Short-Circuit Currents in DC Systems 302

91 DC Short-Circuit Current Sources 30392 Calculation Procedures 30493 Short-Circuit of a Lead Acid Battery 30694 DC Motor and Generators 31295 Short-Circuit Current of a Rectifier 31896 Short-Circuit of a Charged Capacitor 32497 Total Short-Circuit Current 32598 DC Circuit Breakers 326

10 Load Flow Over Power Transmission Lines 328

101 Power in AC Circuits 329

102 Power Flow in a Nodal Branch 331103 ABCD Constants 334104 Transmission Line Models 336105 Tuned Power Line 345106 Ferranti Effect 346107 Symmetrical Line at No Load 347108 Illustrative Examples 349109 Circle Diagrams 3521010 System Variables in Load Flow 356

11 Load Flow Methods Part I 360

111 Modeling a Two-Winding Transformer 361112 Load Flow Bus Types 366113 Gauss and GaussndashSeidel Y-Matrix Methods 367114 Convergence in Jacobi-Type Methods 377115 GaussndashSeidel Z-Matrix Method 383116 Conversion of Y to Z Matrix 384

12 Load Flow Methods Part II 391

121 Function with One Variable 391122 Simultaneous Equations 393123 Rectangular Form of NewtonndashRaphson Method of Load

Flow 395124 Polar Form of Jacobian Matrix 397125 Simplifications of NewtonndashRaphson Method 405126 Decoupled NewtonndashRaphson Method 408127 Fast Decoupled Load Flow 408128 Model of a Phase-Shifting Transformer 411129 DC Models 4131210 Load Models 4151211 Impact Loads and Motor Starting 4221212 Practical Load Flow Studies 424

13 Reactive Power Flow and Control 435

131 Voltage Instability 436132 Reactive Power Compensation 442133 Reactive Power Control Devices 447134 Some Examples of Reactive Power Flow 460135 FACTS 467

14 Three-Phase and Distribution System Load Flow 478

141 Phase Co-Ordinate Method 479142 Three-Phase Models 481

x Contents

143 Distribution System Load Flow 491

15 Optimization Techniques 500

151 Functions of One Variable 501152 Concave and Convex Functions 502153 Taylorrsquos Theorem 503154 Lagrangian Method Constrained Optimization 505155 Multiple Equality Constraints 507156 Optimal Load Sharing Between Generators 508157 Inequality Constraints 510158 KuhnndashTucker Theorem 511159 Search Methods 5121510 Gradient Methods 5141511 Linear ProgrammingmdashSimplex Method 5161512 Quadratic Programming 5211513 Dynamic Programming 5211514 Integer Programming 523

16 Optimal Power Flow 525

161 Optimal Power Flow 525162 Decoupling Real and Reactive OPF 527163 Solution Methods of OPF 528164 Generation Scheduling Considering Transmission Losses 528165 Steepest Gradient Method 536166 OPF Using Newtonrsquos Method 539167 Successive Quadratic Programming 545168 Successive Linear Programming 545169 Interior Point Methods and Variants 5471610 Security and Environmental Constrained OPF 551

17 Harmonics Generation 554

171 Harmonics and Sequence Components 556172 Increase in Nonlinear Loads 557173 Harmonic Factor 557174 Three-Phase Windings in Electrical Machines 557175 Tooth Ripples in Electrical Machines 559176 Synchronous Generators 560177 Transformers 560178 Saturation of Current Transformers 564179 Shunt Capacitors 5651710 Subharmonic Frequencies 5651711 Static Power Converters 5661712 Switch-Mode Power (SMP) Supplies 5811713 Arc Furnaces 5821714 Cycloconverters 584

Contents xi

1715 Thyristor-Controlled Factor 5861716 Thyristor-Switched Capacitors 5881717 Pulse Width Modulation 5881718 Adjustable Speed Drives 5911719 Pulse Burst Modulation 5911720 Chopper Circuits and Electric Traction 5921721 Slip Frequency Recovery Schemes 5941722 Lighting Ballasts 5941723 Interharmonics 595

18 Effects of Harmonics 597

181 Rotating Machines 598182 Transformers 603183 Cables 607184 Capacitors 608185 Harmonic Resonance 609186 Voltage Notching 613187 EMI (Electromagnetic Interference) 613188 Overloading of Neutral 614189 Protective Relays and Meters 6151810 Circuit Breakers and Fuses 6151811 Telephone Influence Factor 616

19 Harmonic Analysis 619

191 Harmonic Analysis Methods 620192 Harmonic Modeling of System Components 626193 Load Models 630194 System Impedance 630195 Three-Phase Models 631196 Modeling of Networks 633197 Power Factor and Reactive Power 637198 Shunt Capacitor Bank Arrangements 640199 Study Cases 644

20 Harmonic Mitigation and Filters 664

201 Mitigation of Harmonics 664202 Band Pass Filters 665203 Practical Filter Design 668204 Relations in a ST Filter 678205 Filters for a Furnace Installation 681206 Filters for an Industrial Distribution System 683207 Secondary Resonance 684208 Filter Reactors 686209 Double-Tuned Filter 6872010 Damped Filters 689

xii Contents

2011 Design of a Second-Order High-Pass Filter 6932012 Zero Sequence Traps 6942013 Limitations of Passive Filters 6962014 Active Filters 6982015 Corrections in Time Domain 7012016 Corrections in the Frequency Domain 7022017 Instantaneous Reactive Power 7042018 Harmonic Mitigation at Source 706

Appendix A Matrix Methods 712

A1 Review Summary 712A2 Characteristics Roots Eigenvalues and Eigenvectors 716A3 Diagonalization of a Matrix 718A4 Linear Independence or Dependence of Vectors 719A5 Quadratic Form Expressed as a Product of Matrices 719A6 Derivatives of Scalar and Vector Functions 720A7 Inverse of a Matrix 721A8 Solution of Large Simultaneous Equations 725A9 Croutrsquos Transformation 727A10 Gaussian Elimination 729A11 ForwardndashBackward Substitution Method 730A12 LDU (Product Form Cascade or Choleski Form) 733

Appendix B Calculation of Line and Cable Constants 736

B1 AC Resistance 736B2 Inductance 736B3 Impedance Matrix 739B4 Three-Phase Line with Ground Conductors 739B5 Bundle Conductors 741B6 Carsonrsquos Formula 742B7 Capacitance of Lines 748B8 Cable Constants 751

Appendix C Transformers and Reactors 756

C1 Model of a Two-Winding Transformer 756C2 Transformer Polarity and Terminal Connections 761C3 Parallel Operation of Transformers 763C4 Autotransformers 765C5 Step-Voltage Regulators 770C6 Extended Models of Transformers 770C7 High-Frequency Models 776C8 Duality Models 776C9 GIC Models 779C10 Reactors 780

Contents xiii

Appendix D Sparsity and Optimal Ordering 784

D1 Optimal Ordering 784D2 Flow Graphs 785D3 Optimal Ordering Schemes 788

Appendix E Fourier Analysis 792

E1 Periodic Functions 792E2 Orthogonal Functions 792E3 Fourier Series and Coefficients 792E4 Odd Symmetry 795E5 Even Symmetry 795E6 Half-Wave Symmetry 796E7 Harmonic Spectrum 797E8 Complex Form of Fourier Series 799E9 Fourier Transform 800E10 Sampled Waveform Discrete Fourier Transform 803E11 Fast Fourier Transform 807

Appendix F Limitation of Harmonics 809

F1 Harmonic Current Limits 809F2 Voltage Quality 811F3 Commutation Notches 813F4 Interharmonics 816F5 Flicker 817

Appendix G Estimating Line Harmonics 819

G1 Waveform without Ripple Content 819G2 Waveform with Ripple Content 821G3 Phase Angle of Harmonics 827

Index 831

xiv Contents

Short-Circuit Currents andSymmetrical Components

Short-circuits occur in well-designed power systems and cause large decaying tran-sient currents generally much above the system load currents These result in dis-ruptive electrodynamic and thermal stresses that are potentially damaging Fire risksand explosions are inherent One tries to limit short-circuits to the faulty section ofthe electrical system by appropriate switching devices capable of operating undershort-circuit conditions without damage and isolating only the faulty section so thata fault is not escalated The faster the operation of sensing and switching devices thelower is the fault damage and the better is the chance of systems holding togetherwithout loss of synchronism

Short-circuits can be studied from the following angles

1 Calculation of short-circuit currents2 Interruption of short-circuit currents and rating structure of switching

devices3 Effects of short-circuit currents4 Limitation of short-circuit currents ie with current-limiting fuses and

fault current limiters5 Short-circuit withstand ratings of electrical equipment like transformers

reactors cables and conductors6 Transient stability of interconnected systems to remain in synchronism

until the faulty section of the power system is isolated

We will confine our discussions to the calculations of short-circuit currents and thebasis of short-circuit ratings of switching devices ie power circuit breakers andfuses As the main purpose of short-circuit calculations is to select and apply thesedevices properly it is meaningful for the calculations to be related to current inter-ruption phenomena and the rating structures of interrupting devices The objectivesof short-circuit calculations therefore can be summarized as follows

Determination of short-circuit duties on switching devices ie high- med-ium- and low-voltage circuit breakers and fuses

Calculation of short-circuit currents required for protective relaying and co-ordination of protective devices

Evaluations of adequacy of short-circuit withstand ratings of static equip-ment like cables conductors bus bars reactors and transformers

Calculations of fault voltage dips and their time-dependent recovery profiles

The type of short-circuit currents required for each of these objectives may not beimmediately clear but will unfold in the chapters to follow

In a three-phase system a fault may equally involve all three phases A boltedfault means as if three phases were connected together with links of zero impedanceprior to the fault ie the fault impedance itself is zero and the fault is limited by thesystem and machine impedances only Such a fault is called a symmetrical three-phase bolted fault or a solid fault Bolted three-phase faults are rather uncommonGenerally such faults give the maximum short-circuit currents and form the basis ofcalculations of short-circuit duties on switching devices

Faults involving one or more than one phase and ground are called unsym-metrical faults Under certain conditions the line-to-ground fault or double line-to-ground fault currents may exceed three-phase symmetrical fault currents discussedin the chapters to follow Unsymmetrical faults are more common as compared tothree-phase faults ie a support insulator on one of the phases on a transmissionline may start flashing to ground ultimately resulting in a single line-to-ground fault

Short-circuit calculations are thus the primary study whenever a new powersystem is designed or an expansion and upgrade of an existing system are planned

11 NATURE OF SHORT-CIRCUIT CURRENTS

The transient analysis of the short-circuit of a passive impedance connected to analternating current (ac) source gives an initial insight into the nature of the short-circuit currents Consider a sinusoidal time-invariant single-phase 60-Hz source ofpower Em sint connected to a single-phase short distribution line Z frac14 ethRthorn jLTHORNwhere Z is the complex impedance R and L are the resistance and inductance Em isthe peak source voltage and is the angular frequency frac142f f being the frequencyof the ac source For a balanced three-phase system a single-phase model is ade-quate as we will discuss further Let a short-circuit occur at the far end of the lineterminals As an ideal voltage source is considered ie zero Thevenin impedancethe short-circuit current is limited only by Z and its steady-state value is vectoriallygiven by Em=Z This assumes that the impedance Z does not change with flow of thelarge short-circuit current For simplification of empirical short-circuit calculationsthe impedances of static components like transmission lines cables reactors andtransformers are assumed to be time invariant Practically this is not true ie theflux densities and saturation characteristics of core materials in a transformer mayentirely change its leakage reactance Driven to saturation under high current flowdistorted waveforms and harmonics may be produced

Ignoring these effects and assuming that Z is time invariant during a short-circuit the transient and steady-state currents are given by the differential equationof the RndashL circuit with an applied sinusoidal voltage

2 Chapter 1

dtthorn Ri frac14 Em sinethtthorn THORN eth11THORN

where is the angle on the voltage wave at which the fault occurs The solution ofthis differential equation is given by

i frac14 Im sinethtthorn THORN Im sineth THORNeRt=L eth12THORNwhere Im is the maximum steady-state current given by Em=Z and the angle frac14 tan1ethLTHORN=R

In power systems L R A 100-MVA 085 power factor synchronous gen-erator may have an XR of 110 and a transformer of the same rating an XR of 45The XR ratios in low-voltage systems are of the order of 2ndash8 For present discus-sions assume a high XR ratio ie 90

If a short-circuit occurs at an instant t frac14 0 frac14 0 (ie when the voltage wave iscrossing through zero amplitude on the X-axis) the instantaneous value of the short-circuit current from Eq (12) is 2Im This is sometimes called the doubling effect

If a short-circuit occurs at an instant when the voltage wave peaks t frac14 0 frac14 =2 the second term in Eq (12) is zero and there is no transient component

These two situations are shown in Fig 1-1 (a) and (b)

Short-Circuit Currents and Symmetrical Components 3

Figure 1-1 (a) Terminal short-circuit of time-invariant impedance current waveforms with

maximum asymmetry (b) current waveform with no dc component

A simple explanation of the origin of the transient component is that in powersystems the inductive component of the impedance is high The current in such acircuit is at zero value when the voltage is at peak and for a fault at this instant nodirect current (dc) component is required to satisfy the physical law that the currentin an inductive circuit cannot change suddenly When the fault occurs at an instantwhen frac14 0 there has to be a transient current whose initial value is equal andopposite to the instantaneous value of the ac short-circuit current This transientcurrent the second term of Eq (12) can be called a dc component and it decays atan exponential rate Equation (12) can be simply written as

i frac14 Im sintthorn IdceRt=L eth13THORN

Where the initial value of Idc frac14 Im eth14THORNThe following inferences can be drawn from the above discussions

1 There are two distinct components of a short-circuit current (1) a non-decaying ac component or the steady-state component and (2) a decayingdc component at an exponential rate the initial magnitude of which is amaximum of the ac component and it depends on the time on the voltagewave at which the fault occurs

2 The decrement factor of a decaying exponential current can be defined asits value any time after a short-circuit expressed as a function of its initialmagnitude per unit Factor L=R can be termed the time constant Theexponential then becomes Idce

t=t 0 where t 0 frac14 L=R In this equationmaking t frac14 t 0 frac14 time constant will result in a decay of approximately623 from its initial magnitude ie the transitory current is reducedto a value of 0368 per unit after an elapsed time equal to the timeconstant as shown in Fig 1-2

3 The presence of a dc component makes the fault current wave-shapeenvelope asymmetrical about the zero line and axis of the wave Figure1-1(a) clearly shows the profile of an asymmetrical waveform The dccomponent always decays to zero in a short time Consider a modestX=R ratio of 15 say for a medium-voltage 138-kV system The dc com-ponent decays to 88 of its initial value in five cycles The higher is theX=R ratio the slower is the decay and the longer is the time for which the

4 Chapter 1

Figure 1-2 Time constant of dc-component decay

asymmetry in the total current will be sustained The stored energy can bethought to be expanded in I2R losses After the decay of the dc compo-nent only the symmetrical component of the short-circuit currentremains

4 Impedance is considered as time invariant in the above scenarioSynchronous generators and dynamic loads ie synchronous and induc-tion motors are the major sources of short-circuit currents The trappedflux in these rotating machines at the instant of short-circuit cannotchange suddenly and decays depending on machine time constantsThus the assumption of constant L is not valid for rotating machinesand decay in the ac component of the short-circuit current must also beconsidered

5 In a three-phase system the phases are time displaced from each other by120 electrical degrees If a fault occurs when the unidirectional compo-nent in phase a is zero the phase b component is positive and the phase ccomponent is equal in magnitude and negative Figure 1-3 shows a three-phase fault current waveform As the fault is symmetrical Ia thorn Ib thorn Ic iszero at any instant where Ia Ib and Ic are the short-circuit currents inphases a b and c respectively For a fault close to a synchronous gen-erator there is a 120-Hz current also which rapidly decays to zero Thisgives rise to the characteristic nonsinusoidal shape of three-phase short-circuit currents observed in test oscillograms The effect is insignificantand ignored in the short-circuit calculations This is further discussed inChapter 6

6 The load current has been ignored Generally this is true for empiricalshort-circuit calculations as the short-circuit current is much higher thanthe load current Sometimes the load current is a considerable percentageof the short-circuit current The load currents determine the effectivevoltages of the short-circuit sources prior to fault

The ac short-circuit current sources are synchronous machines ie turbogen-erators and salient pole generators asynchronous generators and synchronous andasynchronous motors Converter motor drives may contribute to short-circuit cur-rents when operating in the inverter or regenerative mode For extended duration ofshort-circuit currents the control and excitation systems generator voltage regula-tors and turbine governor characteristics affect the transient short-circuit process

The duration of a short-circuit current depends mainly on the speed of opera-tion of protective devices and on the interrupting time of the switching devices

12 SYMMETRICAL COMPONENTS

The method of symmetrical components has been widely used in the analysis ofunbalanced three-phase systems unsymmetrical short-circuit currents and rotatingelectrodynamic machinery The method was originally presented by CL Fortescuein 1918 and has been popular ever since

Unbalance occurs in three-phase power systems due to faults single-phaseloads untransposed transmission lines or nonequilateral conductor spacings In athree-phase balanced system it is sufficient to determine the currents and vol-

tages in one phase and the currents and voltages in the other two phases aresimply phase displaced In an unbalanced system the simplicity of modeling athree-phase system as a single-phase system is not valid A convenient way ofanalyzing unbalanced operation is through symmetrical components The three-phase voltages and currents which may be unbalanced are transformed into three

6 Chapter 1

Figure 1-3 Asymmetries in phase currents in a three-phase short-circuit

sets of balanced voltages and currents called symmetrical components Theimpedances presented by various power system components ie transformersgenerators and transmission lines to symmetrical components are decoupledfrom each other resulting in independent networks for each component Theseform a balanced set This simplifies the calculations

Familiarity with electrical circuits and machine theory per unit system andmatrix techniques is required before proceeding with this book A review of thematrix techniques in power systems is included in Appendix A The notationsdescribed in this appendix for vectors and matrices are followed throughout thebook

The basic theory of symmetrical components can be stated as a mathematicalconcept A system of three coplanar vectors is completely defined by six parametersand the system can be said to possess six degrees of freedom A point in a straightline being constrained to lie on the line possesses but one degree of freedom and bythe same analogy a point in space has three degrees of freedom A coplanar vector isdefined by its terminal and length and therefore possesses two degrees of freedom Asystem of coplanar vectors having six degrees of freedom ie a three-phase unba-lanced current or voltage vectors can be represented by three symmetrical systems ofvectors each having two degrees of freedom In general a system of n numbers canbe resolved into n sets of component numbers each having n components ie a totalof n2 components Fortescue demonstrated that an unbalanced set on n phasors canbe resolved into n 1 balanced phase systems of different phase sequence and onezero sequence system in which all phasors are of equal magnitude and cophasial

Va frac14 Va1 thorn Va2 thorn Va3 thorn thorn Van

Vb frac14 Vb1 thorn Vb2 thorn Vb3 thorn thorn Vbn

Vn frac14 Vn1 thorn Vn2 thorn Vn3 thorn thorn Vnn

eth15THORN

where VaVb Vn are original n unbalanced voltage phasors Va1 Vb1 Vn1

are the first set of n balanced phasors at an angle of 2=n between them Va2Vb2 Vn2 are the second set of n balanced phasors at an angle 4=n and thefinal set VanVbn Vnn is the zero sequence set all phasors at neth2=nTHORN frac14 2 iecophasial

In a symmetrical three-phase balanced system the generators producebalanced voltages which are displaced from each other by 2=3 frac14 120 These vol-tages can be called positive sequence voltages If a vector operator a is defined whichrotates a unit vector through 120 in a counterclockwise direction thena frac14 05thorn j0866 a2 frac14 05 j0866 a3 frac14 1 1thorn a2 thorn a frac14 0 Considering a three-phase system Eq (15) reduce to

Va frac14 Va0 thorn Va1 thorn Va2

Vb frac14 Vb0 thorn Vb1 thorn Vb2

Vc frac14 Vc0 thorn Vc1 thorn Vc2

eth16THORN

We can define the set consisting of Va0 Vb0 and Vc0 as the zero sequence set the setVa1 Vb1 and Vc1 as the positive sequence set and the set Va2 Vb2 and Vc2 as thenegative sequence set of voltages The three original unbalanced voltage vectors giverise to nine voltage vectors which must have constraints of freedom and are not

totally independent By definition of positive sequence Va1 Vb1 and Vc1 should berelated as follows as in a normal balanced system

Vb1 frac14 a2Va1Vc1 frac14 aVa1

Note that Va1 phasor is taken as the reference vectorThe negative sequence set can be similarly defined but of opposite phase

sequence

Vb2 frac14 aVa2Vc2 frac14 a2Va2

Also Va0 frac14 Vb0 frac14 Vc0 With these relations defined Eq (16) can be written as

frac141 1 1

1 a2 a

1 a a2

eth17THORN

or in the abbreviated form

VVabc frac14 TTsVV012 eth18THORN

where TTs is the transformation matrix Its inverse will give the reverse transforma-tion

While this simple explanation may be adequate a better insight into the sym-metrical component theory can be gained through matrix concepts of similaritytransformation diagonalization eigenvalues and eigenvectors

The discussions to follow show that

Eigenvectors giving rise to symmetrical component transformation are thesame though the eigenvalues differ Thus these vectors are not unique

The Clarke component transformation is based on the same eigenvectorsbut different eigenvalues

The symmetrical component transformation does not uncouple an initiallyunbalanced three-phase system Prima facie this is a contradiction ofwhat we said earlier that the main advantage of symmetrical componentslies in decoupling unbalanced systems which could then be representedmuch akin to three-phase balanced systems We will explain what ismeant by this statement as we proceed

13 EIGENVALUES AND EIGENVECTORS

The concept of eigenvalues and eigenvectors is related to the derivation of symme-trical component transformation It can be briefly stated as follows

Consider an arbitrary square matrix AA If a relation exists so that

AA xx frac14 xx eth19THORNwhere is a scalar called an eigenvalue characteristic value or root of the matrix AAand xx is a vector called the eigenvector or characteristic vector of AA

Then there are n eigenvalues and corresponding n sets of eigenvectors asso-ciated with an arbitrary matrix AA of dimensions n n The eigenvalues are notnecessarily distinct and multiple roots occur

8 Chapter 1

Equation (19) can be written as

xxfrac12 frac14 0 eth110THORN

where I the is identity matrix Expanding

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

This represents a set of homogeneous linear equations Determinant jA I j mustbe zero as xx 6frac14 0

AA I frac14 0 eth112THORN

This can be expanded to yield an nth order algebraic equation

ann thorn an In 1thorn thorn a1thorn a0 frac14 0 ie

1 a1eth THORN 2 a2eth THORN n aneth THORN frac14 0eth113THORN

Equations (112) and (113) are called the characteristic equations of the matrix AAThe roots 1 2 3 n are the eigenvalues of matrix AA The eigenvector xxjcorresponding to j is found from Eq (110) See Appendix A for details and anexample

14 SYMMETRICAL COMPONENT TRANSFORMATION

Application of eigenvalues and eigenvectors to the decoupling of three-phase systemsis useful when we define similarity transformation This forms a diagonalizationtechnique and decoupling through symmetrical components

141 Similarity Transformation

Consider a system of linear equations

AA xx frac14 yy eth114THORNA transformation matrix CC can be introduced to relate the original vectors xx and yy tonew sets of vectors xxn and yyn so that

xx frac14 CC xxn

yy frac14 CC yyn

AA CC xxn frac14 CC yyn

CC1 AA CC xxn frac14 CC1 CC yyn

CC1 AA CC xxn frac14 yyn

This can be written as

AAn xxn frac14 yyn

AAn frac14 CC1 AA CCeth115THORN

AAn xxn frac14 yyn is distinct from AA xx frac14 yy The only restriction on choosing CC is that itshould be nonsingular Equation (115) is a set of linear equations derived fromthe original equations (114) and yet distinct from them

If CC is a nodal matrix MM corresponding to the coefficients of AA then

CC frac14 MM frac14 x1 x2 xnfrac12 eth116THORNwhere xxi are the eigenvectors of the matrix AA then

CC1 AA CC frac14 CC1 AA x1 x2 xnfrac12 CC1 AAx1 AAx2 AAxn

frac14 CC1 1x1 2x2 nxnfrac12

frac14 C1 x1 x2 xnfrac12

frac14 CC1 CC

frac14

eth117THORN

Thus CC1 AA CC is reduced to a diagonal matrix called a spectral matrix Its diagonalelements are the eigenvalues of the original matrix AA The new system of equations isan uncoupled system Equations (114) and (115) constitute a similarity transforma-tion of matrix AA The matrices AA and AAn have the same eigenvalues and are calledsimilar matrices The transformation matrix CC is nonsingular

142 Decoupling a Three-Phase Symmetrical System

Let us decouple a three-phase transmission line section where each phase has amutual coupling with respect to ground This is shown in Fig 1-4(a) An impedancematrix of the three-phase transmission line can be written as

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

where Zaa Zbb and Zcc are the self-impedances of the phases a b and c Zab is themutual impedance between phases a and b and Zba is the mutual impedance betweenphases b and a

Assume that the line is perfectly symmetrical This means all the mutual impe-dances ie Zab frac14 Zba frac14 M and all the self-impedances ie Zaa frac14 Zbb frac14 Zcc frac14 Zare equal This reduces the impedance matrix to

eth119THORN

It is required to decouple this system using symmetrical components First findthe eigenvalues

frac14 0 eth120THORN

The eigenvalues are

Figure 1-4 (a) Impedances in a three-phase transmission line with mutual coupling between

phases (b) resolution into symmetrical component impedances

frac14 Z thorn 2M

frac14 Z M

The eigenvectors can be found by making frac14 Z thorn 2M and then Z MSubstituting frac14 Z thorn 2M

Z ethZ thorn 2MTHORN M M

M Z ethZ thorn 2MTHORN M

M M Z ethZ thorn 2MTHORN

This can be reduced to

This give X1 frac14 X2 frac14 X3 frac14 any arbitrary constant k Thus one of the eigenvectors ofthe impedance matrix is

eth123THORN

It can be called the zero sequence eigenvector of the symmetrical component trans-formation matrix and can be written as

eth124THORN

Similarly for frac14 Z M

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

This gives the general relation X1 frac14 X2 frac14 X3 frac14 0 Any choice of X1X2X3 whichsatisfies this relation is a solution vector Some choices are shown below

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

where a is a unit vector operator which rotates by 120 in the counterclockwisedirection as defined before

Equation (127) is an important result and shows that for perfectly symme-trical systems the common eigenvectors are the same although the eigenvalues aredifferent in each system The Clarke component transformation (described in sec15) is based on this observation

The symmetrical component transformation is given by solution vectors

eth128THORN

A symmetrical component transformation matrix can therefore be written as

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

This is the same matrix as was arrived at in Eq (18) Its inverse is

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

For the transformation of currents we can write

IIabc frac14 TTsII012 eth131THORN

where IIabc the original currents in phases a b and c are transformed into zerosequence positive sequence and negative sequence currents II012 The original pha-sors are subscripted abc and the sequence components are subscripted 012 Similarlyfor transformation of voltages

Conversely

II012 frac14 TT1s

IIabc VV012 frac14 TT1s

VVabc eth133THORNThe transformation of impedance is not straightforward and is derived as follows

VVabc frac14 ZZabcIIabc

TTsVV012 frac14 ZZabc

TTsII012

VV012 frac14 TT1s

ZZabcTTsII012 frac14 ZZ012

eth134THORN

Therefore

ZZ012 frac14 TT1s

ZZabcTTs eth135THORN

ZZabc frac14 TTsZZ012

TT1s eth136THORN

Applying the impedance transformation to the original impedance matrix ofthe three-phase symmetrical transmission line in Eq (119) the transformed matrixis

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

frac14Z thorn 2M 0 0

0 Z M 0

0 0 Z M

eth137THORN

The original three-phase coupled system has been decoupled through symme-trical component transformation It is diagonal and all off-diagonal terms are zeromeaning that there is no coupling between the sequence components Decoupledpositive negative and zero sequence networks are shown in Fig 1-4(b)

143 Decoupling a Three-Phase Unsymmetrical System

Now consider that the original three-phase system is not completely balancedIgnoring the mutual impedances in Eq (118) let us assume unequal phase impe-dances Z1 Z2 and Z3 ie the impedance matrix is

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

The symmetrical component transformation is

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

Z1 thorn Z2 thorn Z3 Z1 thorn a2Z2 thorn aZ3 Z1 thorn aZ2 thorn aZ3

Z1 thorn aZ2 thorn aZ3 Z1 thorn Z2 thorn Z3 Z1 thorn a2Z2 thorn aZ3

Z1 thorn a2Z2 thorn aZ3 Z1 thorn aZ2 thorn aZ3 Z1 thorn Z2 thorn Z3

eth139THORN

The resulting matrix shows that the original unbalanced system is not decoupledIf we start with equal self-impedances and unequal mutual impedances or vice versathe resulting matrix is nonsymmetrical It is a minor problem today as nonreciprocalnetworks can be easily handled on digital computers Nevertheless the main appli-cation of symmetrical components is for the study of unsymmetrical faults Negativesequence relaying stability calculations and machine modeling are some otherexamples It is assumed that the system is perfectly symmetrical before an unbalancecondition occurs The asymmetry occurs only at the fault point The symmetricalportion of the network is considered to be isolated to which an unbalanced condi-tion is applied at the fault point In other words the unbalance part of the network

14 Chapter 1

can be thought to be connected to the balanced system at the point of faultPractically the power systems are not perfectly balanced and some asymmetryalways exists However the error introduced by ignoring this asymmetry is small(This may not be true for highly unbalanced systems and single-phase loads)

144 Power Invariance in Symmetrical Component Transformation

Symmetrical component transformation is power invariant The complex power in athree-phase circuit is given by

S frac14 VaIa thorn VbI

b thorn VcI

c frac14 VV 0

abcIIabc eth140THORN

where Ia is the complex conjugate of Ia This can be written as

S frac14 frac12 TTsVV012 TT

sII012 frac14 VV 0

012TT 0sTTsII012 eth141THORN

The product TTsTTs is given by (see Appendix A)

TT 0sTTs frac14 3

eth142THORN

S frac14 3V1I1 thorn 3V2I

2 thorn 3V0I

0 eth143THORN

This shows that complex power can be calculated from symmetrical components

15 CLARKE COMPONENT TRANSFORMATION

It has been already shown that for perfectly symmetrical systems the componenteigenvectors are the same but eigenvalues can be different The Clarke componenttransformation is defined as

frac141 1 0

ffiffiffi3

eth144THORN

Note that the eigenvalues satisfy the relations derived in Eq (127) and

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

The transformation matrices are

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabcTTc eth148THORN

ZZabc frac14 TTcZZ0

TT1c eth149THORN

The Clarke component expression for a perfectly symmetrical system is

frac14Z00 0 0

eth150THORN

The same philosophy of transformation can also be applied to systems withtwo or more three-phase circuits in parallel The Clarke component transformationis not much in use

16 CHARACTERISTICS OF SYMMETRICAL COMPONENTS

Matrix equations (132) and (133) are written in the expanded form

Va frac14 V0 thorn V1 thorn V2

Vb frac14 V0 thorn a2V1 thorn aV2

Vc frac14 V0 thorn aV1 thorn a2V2

eth151THORN

V0 frac141

3Va thorn Vb thorn Vceth THORN

V1 frac141

3Va thorn aVb thorn a2Vc

V2 frac14

3Va thorn a2Vb thorn aVc

eth152THORN

These relations are graphically represented in Fig 1-5 which clearly shows thatphase voltages Va Vb and Vc can be resolved into three voltages V0 V1 and V2defined as follows

V0 is the zero sequence voltage It is of equal magnitude in all the threephases and is cophasial

V1 is the system of balanced positive sequence voltages of the same phasesequence as the original unbalanced system of voltages It is of equalmagnitude in each phase but displaced by 120 the component ofphase b lagging the component of phase a by 120 and the componentof phase c leading the component of phase a by 120

16 Chapter 1

Figure 1-5 (a) (b) (c) and (d) Progressive resolution of voltage vectors into sequencecomponents

V2 is the system of balanced negative sequence voltages It is of equalmagnitude in each phase and there is a 120 phase displacement betweenthe voltages the component of phase c lagging the component of phase aand the component of phase b leading the component of phase a

Therefore the positive and negative sequence voltages (or currents) can bedefined as lsquolsquothe order in which the three phases attain a maximum valuersquorsquo For thepositive sequence the order is abca while for the negative sequence it is acba We canalso define positive and negative sequence by the order in which the phasors pass afixed point on the vector plot Note that the rotation is counterclockwise for all threesets of sequence components as was assumed for the original unbalanced vectors Fig1-5(d) Sometimes this is confused and negative sequence rotation is said to be thereverse of positive sequence The negative sequence vectors do not rotate in a directionopposite to the positive sequence vectors though the negative phase sequence isopposite to the positive phase sequence

Example 11

An unbalanced three-phase system has the following voltages

Va frac14 09 lt 0 per unitVb frac14 125 lt 280 per unitVc frac14 06 lt 110 per unit

The phase rotation is abc counterclockwise The unbalanced system is shownin Fig 1-6(a) Resolve into symmetrical components and sketch the sequence vol-tages

Using the symmetrical component transformation the resolution is shownin Fig 1-6(b) The reader can verify this as an exercise and then convert backfrom the calculated sequence vectors into original abc voltages graphically andanalytically

In a symmetrical system of three phases the resolution of voltages or currentsinto a system of zero positive and negative components is equivalent to threeseparate systems Sequence voltages act in isolation and produce zero positiveand negative sequence currents and the theorem of superposition applies The fol-lowing generalizations of symmetrical components can be made

1 In a three-phase unfaulted system in which all loads are balanced and inwhich generators produce positive sequence voltages only positivesequence currents flow resulting in balanced voltage drops of thesame sequence There are no negative sequence or zero sequence voltagedrops

2 In symmetrical systems the currents and voltages of different sequencesdo not affect each other ie positive sequence currents produce onlypositive sequence voltage drops By the same analogy the negativesequence currents produce only negative sequence drops and zerosequence currents produce only zero sequence drops

3 Negative and zero sequence currents are set up in circuits of unbalancedimpedances only ie a set of unbalanced impedances in a symmetricalsystem may be regarded as a source of negative and zero sequence cur-

18 Chapter 1

rent Positive sequence currents flowing in an unbalanced system producepositive negative and possibly zero sequence voltage drops The negativesequence currents flowing in an unbalanced system produce voltage dropsof all three sequences The same is true about zero sequence currents

4 In a three-phase three-wire system no zero sequence currents appear inthe line conductors This is so because I0 frac14 eth1=3THORNethIa thorn Ib thorn IcTHORN and there-fore there is no path for the zero sequence current to flow In a three-phase four-wire system with neutral return the neutral must carry out-of-balance current ie In frac14 ethIa thorn Ib thorn IcTHORN Therefore it follows thatIn frac14 3I0 At the grounded neutral of a three-phase wye system positiveand negative sequence voltages are zero The neutral voltage is equal tothe zero sequence voltage or product of zero sequence current and threetimes the neutral impedance Zn

5 From what has been said in point 4 above phase conductors emanatingfrom ungrounded wye or delta connected transformer windings cannothave zero sequence current In a delta winding zero sequence currents ifpresent set up circulating currents in the delta winding itself This isbecause the delta winding forms a closed path of low impedance forthe zero sequence currents each phase zero sequence voltage is absorbedby its own phase voltage drop and there are no zero sequence componentsat the terminals

Figure 1-6 (a) Unbalanced voltage vectors (b) resolution into symmetrical components

17 SEQUENCE IMPEDANCE OF NETWORK COMPONENTS

The impedance encountered by the symmetrical components depends on the type ofpower system equipment ie a generator a transformer or a transmission line Thesequence impedances are required for component modeling and analysis We derivedthe sequence impedances of a symmetrical coupled transmission line in Eq (137)Zero sequence impedance of overhead lines depends on the presence of ground wirestower footing resistance and grounding It may vary between two and six times thepositive sequence impedance The line capacitance of overhead lines is ignored inshort-circuit calculations Appendix B details three-phase matrix models of transmis-sion lines bundle conductors and cables and their transformation into symmetricalcomponents While estimating sequence impedances of power system components isone problem constructing the zero positive and negative sequence impedance net-works is the first step for unsymmetrical fault current calculations

171 Construction of Sequence Networks

A sequence network shows how the sequence currents if these are present will flowin a system Connections between sequence component networks are necessary toachieve this objective The sequence networks are constructed as viewed from thefault point which can be defined as the point at which the unbalance occurs in asystem ie a fault or load unbalance

The voltages for the sequence networks are taken as line-to-neutral voltagesThe only active network containing the voltage source is the positive sequence net-work Phase a voltage is taken as the reference voltage and the voltages of the othertwo phases are expressed with reference to phase a voltage as shown in Fig 1-5(d)

The sequence networks for positive negative and zero sequence will have perphase impedance values which may differ Normally the sequence impedance net-works are constructed on the basis of per unit values on a common MVA base and abase MVA of 100 is in common use For nonrotating equipment like transformersthe impedance to negative sequence currents will be the same as for positive sequencecurrents The impedance to negative sequence currents of rotating equipment will bedifferent from the positive sequence impedance and in general for all apparatusesthe impedance to zero sequence currents will be different from the positive or nega-tive sequence impedances For a study involving sequence components the sequenceimpedance data can be (1) calculated by using subroutine computer programs (2)obtained from manufacturersrsquo data (3) calculated by long-hand calculations or (4)estimated from tables in published references

The positive direction of current flow in each sequence network is outward atthe faulted or unbalance point This means that the sequence currents flow in thesame direction in all three sequence networks

Sequence networks are shown schematically in boxes in which the fault pointsfrom which the sequence currents flow outwards are marked as F1 F2 and F0 andthe neutral buses are designated as N1 N2 and N0 respectively for the positivenegative and zero sequence impedance networks Each network forms a two-portnetwork with Thevenin sequence voltages across sequence impedances Figure 1-7illustrates this basic formation Note the direction of currents The voltage across thesequence impedance rises from N to F As stated before only the positive sequence

20 Chapter 1

network has a voltage source which is the Thevenin equivalent With this conven-tion appropriate signs must be allocated to the sequence voltages

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

Based on the discussions so far we can graphically represent the sequence impe-dances of various system components

172 Transformers

The positive and negative sequence impedances of a transformer can be taken to beequal to its leakage impedance As the transformer is a static device the positive ornegative sequence impedances do not change with phase sequence of the appliedbalanced voltages The zero sequence impedance can however vary from an opencircuit to a low value depending on the transformer winding connection method ofneutral grounding and transformer construction ie core or shell type

We will briefly discuss the shell and core form of construction as it has a majorimpact on the zero sequence flux and impedance Referring to Fig 1-8(a) in a three-phase core-type transformer the sum of the fluxes in each phase in a given directionalong the cores is zero however the flux going up one limb must return through theother two ie the magnetic circuit of a phase is completed through the other twophases in parallel The magnetizing current per phase is that required for the coreand part of the yoke This means that in a three-phase core-type transformer themagnetizing current will be different in each phase Generally the cores are longcompared to yokes and the yokes are of greater cross-section The yoke reluctance is

Figure 1-7 Positive negative and zero sequence network representation

only a small fraction of the core and the variation of magnetizing current per phase isnot appreciable However consider now the zero sequence flux which will be direc-ted in one direction in each of the limbs The return path lies not through the corelimbs but through insulating medium and tank

In three separate single-phase transformers connected in three-phase config-uration or in shell-type three-phase transformers the magnetic circuits of each phaseare complete in themselves and do not interact Fig 1-8(b) Due to advantages inshort-circuit and transient voltage performance the shell form is used for largertransformers The variations in shell form have five- or seven-legged cores Briefly

22 Chapter 1

Figure 1-8 (a) Core form of three-phase transformer flux paths for phase and zero sequencecurrents (b) shell form of three-phase transformer

we can say that in a core type the windings surround the core and in the shell typethe core surrounds the windings

1721 DeltandashWye or WyendashDelta Transformer

In a deltandashwye transformer with the wye winding grounded zero sequence impe-dance will be approximately equal to positive or negative sequence impedanceviewed from the wye connection side Impedance to the flow of zero sequence cur-rents in the core-type transformers is lower as compared to the positive sequenceimpedance This is so because there is no return path for zero sequence exciting fluxin core type units except through insulating medium and tank a path of highreluctance In groups of three single-phase transformers or in three-phase shell-type transformers the zero sequence impedance is higher

The zero sequence network for a wyendashdelta transformer is constructed asshown in Fig 1-9(a) The grounding of the wye neutral allows the zero sequencecurrents to return through the neutral and circulate in the windings to the source ofunbalance Thus the circuit on the wye side is shown connected to the L side line Onthe delta side the circuit is open as no zero sequence currents appear in the linesthough these currents circulate in the delta windings to balance the ampere turns in

Figure 1-9 (a) Derivations of equivalent zero sequence circuit for a deltandashwye transformerwye neutral solidly grounded (b) zero sequence circuit of a deltandashwye transformer wye

neutral isolated

the wye windings The circuit is open on the H side line and the zero sequenceimpedance of the transformer seen from the high side is an open circuit If thewye winding neutral is left isolated Fig 1-9(b) the circuit will be open on bothsides presenting an infinite impedance

Three-phase current flow diagrams can be constructed based on the conventionthat current always flows to the unbalance and that the ampere turns in primarywindings must be balanced by the ampere turns in the secondary windings

1722 WyendashWye Transformer

In a wyendashwye connected transformer with both neutrals isolated no zero sequencecurrents can flow The zero sequence equivalent circuit is open on both sides andpresents an infinite impedance to the flow of zero sequence currents When one of theneutrals is grounded still no zero sequence currents can be transferred from thegrounded side to the ungrounded side With one neutral grounded there are nobalancing ampere turns in the ungrounded wye windings to enable current to flowin the grounded neutral windings Thus neither of the windings can carry a zerosequence current Both neutrals must be grounded for the transfer of zero sequencecurrents

A wyendashwye connected transformer with isolated neutrals is not used due to thephenomenon of the oscillating neutral This is discussed in Chapter 17 Due tosaturation in transformers and the flat-topped flux wave a peak emf is generatedwhich does not balance the applied sinusoidal voltage and generates a resultant third(and other) harmonics These distort the transformer voltages as the neutral oscil-lates at thrice the supply frequency a phenomenon called the lsquolsquooscillating neutralrsquorsquo Atertiary delta is added to circulate the third harmonic currents and stabilize theneutral It may also be designed as a load winding which may have a rated voltagedistinct from high- and low-voltage windings This is further discussed in Sec1725 When provided for zero sequence current circulation and harmonic suppres-sion the terminals of the tertiary connected delta winding may not be brought out ofthe transformer tank Sometimes core-type transformers are provided with five-limbcores to circulate the harmonic currents

1723 DeltandashDelta Transformer

In a deltandashdelta connection no zero currents will pass from one winding to anotherOn the transformer side the windings are shown connected to the reference busallowing the circulation of currents within the windings

1724 Zigzag Transformer

A zigzag transformer is often used to derive a neutral for grounding of a deltandashdeltaconnected system This is shown in Fig 1-10 Windings a1 and a2 are on the samelimb and have the same number of turns but are wound in the opposite directionThe zero sequence currents in the two windings on the same limb have cancelingampere turns Referring to Fig 1-10(b) the currents in the winding sections a1 and c2must be equal as these are in series By the same analogy all currents must be equalbalancing the mmfs in each leg

ia1 frac14 ia2 frac14 ib1 frac14 ib2 frac14 ic1 frac14 ic2

24 Chapter 1

The impedance to the zero sequence currents is that due to leakage flux of thewindings For positive or negative sequence currents neglecting magnetizing currentthe connection has infinite impedance Figure 1-10(a) shows the distribution of zerosequence current and its return path for a single line to ground fault on one of thephases The ground current divides equally through the zigzag transformer one-third of the current returns directly to the fault point and the remaining two-thirdsmust pass through two phases of the delta connected windings to return to the faultpoint Two phases and windings on the primary delta must carry current to balance

Figure 1-10 (a) Current distribution in a deltandashdelta system with zigzag grounding trans-former for a single line-to-ground fault (b) zigzag transformer winding connections

the ampere turns of the secondary winding currents Fig 1-10(b) An impedance canbe added between the artificially derived neutral and ground to limit the ground faultcurrent

Table 1-1 shows the sequence equivalent circuits of three-phase two-windingtransformers When the transformer neutral is grounded through an impedance Zn aterm 3Zn appears in the equivalent circuit We have already proved that In frac14 3I0The zero sequence impedance of the high- and low-voltage windings are shown asZH and ZL respectively The transformer impedance ZT frac14 ZH thorn ZL on a per unitbasis This impedance is specified by the manufacturer as a percentage impedance ontransformer MVA base based on OA (natural liquid cooled for liquid immersedtransformers) or AA (natural air cooled without forced ventilation for dry-typetransformers) rating of the transformer For example a 138ndash138 kV transformermay be rated as follows

40 MVA OA ratings at 55C rise448 MVA OA rating at 65C rise60 MVA FA (forced air ie fan cooled) rating at first stage of fan cooling

65C rise75 MVA FA second-stage fan cooling 65C rise

These ratings are normally applicable for an ambient temperature of 40Cwith an average of 30C over a period of 24 h The percentage impedance will benormally specified on a 40-MVA or possibly a 448-MVA base

The difference between the zero sequence impedance circuits of wyendashwye con-nected shell- and core-form transformers in Table 1-1 is noteworthy Connections 8and 9 are for a core-type transformer and connections 7 and 10 are for a shell-typetransformer The impedance ZM accounts for magnetic coupling between the phasesof a core-type transformer

1725 Three-Winding Transformers

The theory of linear networks can be extended to apply to multiwinding transfor-mers A linear network having n terminals requires 1

2 nethnthorn 1THORN quantities to specify itcompletely for a given frequency and emf Figure 1-11 shows the wye equivalentcircuit of a three-winding transformer One method to obtain the necessary data is todesignate the pairs of terminals as 1 2 n All the terminals are then short-circuited except terminal one and a suitable emf is applied across it The currentflowing in each pair of terminals is measured This is repeated for all the terminalsFor a three-winding transformer

ZH frac14 1

2ZHM thorn ZHL ZMLeth THORN

ZM frac14 1

2ZML thorn ZHM ZHLeth THORN

ZL frac14 1

2ZHL thorn ZML ZHMeth THORN

eth155THORN

where ZHM frac14 leakage impedance between the H and X windings as measured on theH winding with M winding short-circuited and L winding open circuited ZHL frac14leakage impedance between the H and L windings as measured on the H winding

26 Chapter 1

Table 1-1 Equivalent Positive Negative and Zero Sequence Circuits for Two-WindingTransformers

with L winding short-circuited and M winding open circuited ZML frac14 leakage impe-dance between the M and L windings as measured on the M winding with L windingshort-circuited and H winding open circuited

frac14 1=2

We also see that

ZHL frac14 ZH thorn ZL

ZHM frac14 ZH thorn ZM

ZML frac14 ZM thorn ZL

eth156THORN

Table 1-2 shows the equivalent sequence circuits of a three-winding transformer

173 Static Load

Consider a static three-phase load connected in a wye configuration with the neutralgrounded through an impedance Zn Each phase impedance is Z The sequencetransformation is

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

Figure 1-11 Wye-equivalent circuit of a three-winding transformer

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

This shows that the load can be resolved into sequence impedance circuits This resultcan also be arrived at by merely observing the symmetrical nature of the circuit

Table 1-2 Equivalent Positive Negative and Zero Sequence Circuits for Three-Winding

Transformers

174 Synchronous Machines

Negative and zero sequence impedances are specified for synchronous machines bythe manufacturers on the basis of the test results The negative sequence impedanceis measured with the machine driven at rated speed and the field windings short-circuited A balanced negative sequence voltage is applied and the measurementstaken The zero sequence impedance is measured by driving the machine at ratedspeed field windings short-circuited all three-phases in series and a single-phasevoltage applied to circulate a single-phase current The zero sequence impedance ofgenerators is low while the negative sequence impedance is approximately given by

X 00d thorn X 00

2eth160THORN

where X 00d and X 00

q are the direct axis and quadrature axis subtransient reactancesAn explanation of this averaging is that the negative sequence in the stator results ina double-frequency negative component in the field (Chapter 18 provides furtherexplanation) The negative sequence flux component in the air gap may be consid-ered to alternate between poles and interpolar gap respectively

The following expressions can be written for the terminal voltages of a wyeconnected synchronous generator neutral grounded through an impedance Zn

Va frac14d

dtLaf cos If LaaIa LabIb LacIcfrac12 IaRa thorn Vn

Vb frac14d

dtLbf cos 120eth THORNIf LbaIa LbbIb LbcIcfrac12 IaRb thorn Vn

Vc frac14d

dtLcf cos 240eth THORNIf LcaIa LcbIb LccIcfrac12 IaRc thorn Vn

eth161THORN

The first term is the generator internal voltage due to field linkages and Laf denotesthe field inductance with respect to phase A of stator windings and If is the fieldcurrent These internal voltages are displaced by 120 and may be termed Ea Eband Ec The voltages due to armature reaction given by the self-inductance of aphase ie Laa and its mutual inductance with respect to other phases ie Lab andLac and the IRa drop is subtracted from the generator internal voltage and theneutral voltage is added to obtain the line terminal voltage Va

For a symmetrical machine

Laf frac14 Lbf frac14 Lcf frac14 Lf

Ra frac14 Rb frac14 Rc frac14 R

Laa frac14 Lbb frac14 Lcc frac14 L

Lab frac14 Lbc frac14 Lca frac14 L 0

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

Transform using symmetrical components

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

L0 frac14 Lthorn 2L 0

L1 frac14L2 frac14 L L 0 eth165THORN

The equation may thus be written as

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

The equivalent circuit is shown in Fig 1-12 This can be compared with thestatic three-phase load equivalents Even for a cylindrical rotor machine theassumption Z1 frac14 Z2 is not strictly valid The resulting generator impedance matrixis nonsymmetrical

Figure 1-12 Sequence components of a synchronous generator impedances

Example 12

Figure 1-13(a) shows a single line diagram with three generators three transmissionlines six transformers and three buses It is required to construct positive negativeand zero sequence networks looking from the fault point marked F Ignore the loadcurrents

The positive sequence network is shown in Fig 1-13(b) There are three gen-erators in the system and their positive sequence impedances are clearly marked in

32 Chapter 1

Fig 1-13(b) The generator impedances are returned to a common bus TheThevenin voltage at the fault point is shown to be equal to the generator voltageswhich are all equal This has to be so as all load currents are neglected ie all theshunt elements representing loads are open-circuited Therefore the voltage magni-tudes and phase angles of all three generators must be equal When load flow is

Figure 1-13 (a) A single line diagram of a distribution system (b) (c) and (d) positive

negative and zero sequence networks of the distribution system in (a)

considered generation voltages will differ in magnitude and phase and the voltagevector at the chosen fault point prior to the fault can be calculated based on loadflow We have discussed that the load currents are normally ignored in short-circuitcalculations Fault duties of switching devices are calculated based on rated systemvoltage rather than the actual voltage which varies with load flow This is generallytrue unless the prefault voltage at the fault point remains continuously above orbelow the rated voltage

Figure 1-13(c) shows the negative sequence network Note the similarity withthe positive sequence network with respect to interconnection of various systemcomponents

Figure 1-13(d) shows zero sequence impedance network This is based on thetransformer zero sequence networks shown in Table 1-1 The neutral impedance ismultiplied by a factor of three

Each of these networks can be reduced to a single impedance using elementarynetwork transformations Referring to Fig 1-14 wye-to-delta and delta-to-wyeimpedance transformations are given by

Delta to wye

Z1 frac14Z12Z31

Z12 thorn Z23 thorn Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

and from wye to delta

Z12 frac14Z1Z2 thorn Z2Z3 thorn Z3Z1

eth168THORN

34 Chapter 1

Figure 1-14 Wyendashdelta and deltandashwye transformation of impedances

18 COMPUTER MODELS OF SEQUENCE NETWORKS

Referring to the zero sequence impedance network of Fig 1-13(d) a number ofdiscontinuities occur in the network depending on transformer winding connectionsand system grounding These disconnections are at nodes marked T U M and NThese make a node disappear in the zero sequence network while it exists in themodels of positive and negative sequence networks The integrity of the nodes shouldbe maintained in all the sequence networks for computer modeling Figure 1-15shows how this discontinuity can be resolved

Figure 1-15(a) shows a deltandashwye transformer wye side neutral groundedthrough an impedance Zn connected between buses numbered 1 and 2 Its zerosequence network when viewed from the bus 1 side is an open circuit

Two possible solutions in computer modeling are shown in Fig 1-15(b) and (c)In Fig 1-15(b) a fictitious bus R is created The positive sequence impedance circuitis modified by dividing the transformer positive sequence impedance into two parts

Figure 1-15 (a) Representation of a deltandashwye transformer (b) and (c) zero and positive

and negative sequence network representation maintaining integrity of nodes

ZTL for the low-voltage winding and ZTH for the high-voltage winding An infiniteimpedance between the junction point of these impedances to the fictitious bus R isconnected In computer calculations this infinite impedance will be simulated by alarge value ie 999thorn j9999 on a per unit basis

The zero sequence network is treated in a similar manner ie the zerosequence impedance is split between the windings and the equivalent groundingresistor 3RN is connected between the junction point and the fictitious bus R

Figure 1-15( c) shows another approach to the creation a fictitious bus R topreserve the integrity of nodes in the sequence networks For the positive sequencenetwork a large impedance is connected between bus 2 and bus R while for the zerosequence network an impedance equal to Z0TH thorn 3RN is connected between bus 2and bus R

This chapter provides the basic concepts The discussions of symmetrical com-ponents construction of sequence networks and fault current calculations are car-ried over to Chapter 2

Problems

1 A short transmission line of inductance 005 H and resistance 1 ohm issuddenly short-circuited at the receiving end while the source voltage is480 eth ffiffiffi

2p THORN sin eth2ftthorn 30THORN At what instant of the short-circuit will the dc

offset be zero At what instant will the dc offset be a maximum2 Figure 1-1 shows a nondecaying ac component of the fault current

Explain why this is not correct for a fault close to a generator3 Explain similarity transformation How is it related to the diagonaliza-

tion of a matrix4 Find the eigenvalues of the matrix

5 A power system is shown in Fig 1-P1 Assume that loads do not con-tribute to the short-circuit currents Convert to a common 100 MVAbase and form sequence impedance networks Redraw zero sequencenetwork to eliminate discontinuities

6 Three unequal load resistances of 10 20 and 20 ohms are connected indelta 10 ohms between lines a and b 20 ohms between lines b and c and200 ohms between lines c and a The power supply is a balanced three-phase system of 480 V rms between the lines Find symmetrical compo-nents of line currents and delta currents

7 In Fig 1-10 the zigzag transformer is replaced with a wyendashdelta con-nected transformer Show the distribution of the fault current for a phase-to-ground fault on one of the phases

8 Resistances of 6 6 and 5 ohms are connected in a wye configurationacross a balanced three-phase supply system of line-to-line voltage of480V rms (Fig 1-P2) The wye point of the load (neutral) is notgrounded Calculate the neutral voltage with respect to ground usingsymmetrical components and Clarkersquos componentsrsquo transformation

36 Chapter 1

9 Based on the derivation of symmetrical component theory presented inthis chapter can another transformation system be conceived

10 Write equations for a symmetrical three-phase fault in a three-phase wye-connected system with balanced impedances in each line

11 The load currents are generally neglected in short-circuit calculations Dothese have any effect on the dc component asymmetry (1) Increase it(2)Decrease it (3) have no effect Explain

12 Write a 500 word synopsis on symmetrical components without usingequations or figures

13 Figure 1-9(a) shows the zero sequence current flow for a deltandashwye trans-former with the wye neutral grounded Construct a similar diagram for athree-winding transformer wyendashwye connected with tertiary delta andboth wye neutrals solidly grounded

14 Convert the sequence impedance networks of Example 12 to single impe-dances as seen from the fault point Use the following numerical valueson a per unit basis (all on a common MVA base) Neglect resistances

Generators G1 G2 and G3 Z1 frac14 015 Z2 frac14 018 Z0 frac14 008 Zn (neu-tral grounding impedanceTHORN frac14 020

Transmission lines L1 L2 and L3 Z1 frac14 02 Z2 frac14 02Transformers T1 T2 T3 T4 T5 and T6 Z1 frac14 Z2 frac14 010 transformer

T1Z0 frac14 01015 Repeat problem 14 for a fault at the terminals of generator G2

Figure 1-P1 Power system with impedance data for Problem 5

Figure 1-P2 Network for Problem 8

BIBLIOGRAPHY

1 CF Wagner RD Evans Symmetrical Components New York McGraw-Hill 19332 E Clarke Circuit Analysis of Alternating Current Power Systems vol 1 New York

Wiley 19433 JO Bird Electrical Circuit Theory and Technology Oxford UK Butterworth

Heinemann 1997

4 GW Stagg A Abiad Computer Methods in Power Systems Analysis New YorkMcGraw-Hill 1968

5 WE Lewis DG Pryce The Application of Matrix Theory to Electrical EngineeringLondon EampFN Spon 1965 ch 6

6 LJ Myatt Symmetrical Components Oxford UK Pergamon Press 19687 CA Worth (ed) J amp P Transformer Book 11th ed London Butterworth 19838 Westinghouse Electric Transmission and Distribution Handbook 4th Edition

Westinghouse Electric Corp East Pittsburgh PA 19649 AE Fitzgerald C Kingsley A Kusko Electric Machinery 3rd ed New York McGraw-

Hill 1971

10 MS Chen WE Dillon Power SystemModeling Proceedings of IEEE Vol 62 July 1974pp 901ndash915

11 CL Fortescu Method of Symmetrical Coordinates Applied to the Solution of Polyphase

Networks AIEE Vol 37 1918 pp 1027ndash1140

38 Chapter 1

References

1 Short-Circuit Currents and SymmetricalComponents

1 CF Wagner RD Evans Symmetrical Components New YorkMcGraw-Hill 1933

2 E Clarke Circuit Analysis of Alternating Current PowerSystems vol 1 New York Wiley 1943

3 JO Bird Electrical Circuit Theory and TechnologyOxford UK Butterworth Heinemann 1997

4 GW Stagg A Abiad Computer Methods in Power SystemsAnalysis New York McGraw-Hill 1968

5 WE Lewis DG Pryce The Application of Matrix Theory toElectrical Engineering London EampFN Spon 1965 ch 6

6 LJ Myatt Symmetrical Components Oxford UK PergamonPress 1968

7 CA Worth (ed) J amp P Transformer Book 11th edLondon Butterworth 1983

8 Westinghouse Electric Transmission and DistributionHandbook 4th Edition Westinghouse Electric Corp EastPittsburgh PA 1964

9 AE Fitzgerald C Kingsley A Kusko Electric Machinery3rd ed New York McGrawHill 1971

10 MS Chen WE Dillon Power SystemModeling Proceedingsof IEEE Vol 62 July 1974 pp 901ndash915

11 CL Fortescu Method of Symmetrical Coordinates Appliedto the Solution of Polyphase Networks AIEE Vol 37 1918pp 1027ndash1140

2 Unsymmetrical Fault Calculations

1 WD Stevenson Elements of Power System Analysis 4th edNew York McGraw-Hill 1982

2 CA Gross Power System Analysis New York John Wiley1979

3 GO Calabrase Symmetrical Components Applied to ElectricPower Networks New York Ronald Press Group 1959

4 JL Blackburn Symmetrical Components for Power SystemsEngineering New York Marcel Dekker 1993

5 DR Smith Digital Simulation of Simultaneous UnbalancesInvolving Open and Faulted Conductors IEEE Trans PAS Vol89 No 8 1970 pp 1826ndash1835

1 Transformer Connections (Including Auto-transformerConnections) General Electric Publication no GET-2HPittsfield MA 1967

2 ANSIIEEE General Requirements of Liquid ImmersedDistribution Power and Regulating Transformers StandardC571200-1987

3 ANSI Terminal Markings and Connections for Distributionand Power Transformers Standard C571270-1978

4 Electrical Transmission and Distribution Reference Book4th ed Westinghouse Electric Corp East Pittsburgh PA1964

3 Matrix Methods for Network Solutions

1 PM Anderson Analysis of Faulted Power Systems IowaState Press Ames IA 1973

2 HE Brown Solution of Large Networks by Matrix MethodsNew York John Wiley 1975

3 GW Stagg AH El-Abiad Computer Methods in Power SystemsAnalysis New York McGraw-Hill 1968 ch 3

4 HE Brown CE Parson Short-circuit Studies of LargeSystems by the Impedance Matrix Method Proc PICA 1967 pp335-346

5 GL Kusic Computer-Aided Power Systems Analysis NewJersey Prentice-Hall 1986

4 Current Interruption in AC Networks

1 K Ragaller Current Interruption in High VoltageNetworks New York Plenum Press 1978

2 A Braun A Eidinger E Rouss Interruption ofShort-Circuit Currents in High-Voltage AC Networks BrownBoveri Review vol 66 Baden April 1979

3 IEC High-Voltage Alternating Current Circuit Breakers1987 Standard 60056

4 A Greenwood Electrical Transients in Power Systems NewYork Wiley Interscience 1991

5 H Toda Y Ozaki I Miwa Development of 800-kV GasInsulated Switchgear IEEE Trans PD 7 316ndash322 1992

6 CIGRE Working Group 13-02 Switching Overvoltages in EHVand UHV Systems with Special Reference to Closing andReclosing Transmission Lines Electra 70ndash122 1973

5 Application and Ratings of CircuitBreakers and Fuses According to ANSIStandards

1 ANSI Application Guide for High-Voltage CircuitBreakers 1961 Standard C37010

2 ANSIIEEE Application Guide for AC High-Voltage CircuitBreakers Rated on a Symmetrical Current Basis 1999(revision of 1979) Standard C37010

3 ANSI Rating Structure for AC High-Voltage CircuitBreakers Rated on a Symmetrical Current Basis 1999(revision of 1979) Standard C3704

4 ANSIIEEE Guide for Calculation of Fault Currents forApplication of AC HighVoltage Circuit Breakers Rated on aTotal Current Basis 1979 Standard C375

5 ANSI AC High-Voltage Circuit Breakers Rated on aSymmetrical Current Basismdash Preferred Ratings and RelatedCapabilities 2000 (revision of 1987) Standard C3706

6 ANSIIEEE Application Guide for Capacitance CurrentSwitching for AC HighVoltage Circuit Breakers Rated on aSymmetrical Current Basis 1979 Standard C37012 7ANSIIEEE Test Procedure for AC High-Voltage CircuitBreakers Rated on a Symmetrical Current Basis 1999Standard C3709 8 IEEE Application Guide for TRV for ACHigh-Voltage Circuit Breakers Rated on a SymmetricalCurrent Basis Switchgear Committee of IEEE PowerEngineering Society 1994 Report PC37011 9 IEEEApplying Low-Voltage Circuit Breakers Used in Industrialand Commercial Power Systems 1997 Standard 1015 10ANSIIEEE Standard for Low-Voltage AC Power CircuitBreakers in Enclosures 1995 Standard C3713 11 NEMAMolded Case Circuit Breakers and Molded Case Switches1993 Standard AB1 12 Molded Case Circuit Breakers andCircuit-Breaker Enclosures 1991 Standard 489 13 IECLow-voltage Switchgear and Control Gear ndash Part 2 CircuitBreakers 1995 Standard 947-2 14 NEMA High-VoltageFuses 1981 Standard SG2 15 IEEE IEEE Standard Testsfor High-Voltage Fuses Distribution Enclosed Single-PoleAir Swiches Fuse Disconnecting Switches and Accessories1994 Standard C3741 16 ANSI American National StandardSpecifications for Distribution Cutouts and Fuse Links1996 Standard C3742 17 ANSI American National StandardSpecifications for Power Fuses and Fuse Disconnect Switches1987 (revision of 1981) Standard C3746 18 ANSIAmerican National Standard Specifications for Distribution

Fuse Disconnecting Switches Fuse Supports andCurrent-Limiting Fuses 1981 Standard C3747

6 Short-Circuit of Synchronous andInduction Machines

1 B Adkins The General Theory of Electrical MachinesLondon Chapman and Hall 1964

2 C Concordia Synchronous Machines New York John Wiley1951

3 PM Anderson Analysis of Faulted Power Systems AmesIA Iowa State University Press 1973 ch 6

7 Short-Circuit Calculations According toANSI Standards

1 IEC Short-Circuit Calculations in Three-Phase ACSystems 1988 Standard 909

2 VDE Calculations of Short-Circuit Currents inThree-Phase Systems 1971 and 1975 Standard 0102 Parts11171 and 21175

Table 7-P1 Impedance Data (Problems 5 and 6)

Equipment identification Impedance data

138-kV utilityrsquos source 3600 MVA X=R frac14 20

Generator 138-kV 45-MVA 085 pF 2-pole subtransientsaturated reactance frac14 117 X=R frac14 100 transient saturatedfrac14 168 synchronous frac14 205 on generator MVA base constantexcitation three-phase subtransient and transient timeconstants equal to 0016 and 046 s respectively armaturetime constant frac14 018 s

Induction motor M1 132-kV 5000-hp 2-pole locked rotorreactance frac14 167 X=R frac14 55

Synchronous motor M2 138-kV 10000-hp 4-pole X 00 d frac1420 X=R frac14 38

Motor group 4-kV 200ndash1000 hp 4-pole induction motorslocked rotor reactance frac14 17 consider an average X=R frac14 15total installed kVA frac14 8000

Transformer T1 3050-MVA 138ndash138 kV Z frac14 10 X=R frac14 25datandashwye secondary neutral resistance grounded

Transformers T2 and T3 5000-kVA 138ndash416 kV Z frac14 55X=R frac14 11 transformer taps are set to provide 5 secondaryvoltage boost

Reactor 03 ohms X=R frac14 100

Cable C1 0002thorn j0018 ohms

Cables C2 and C3 0055thorn j0053 ohms 3 ANSIIEEEApplication Guide for AC High-Voltage Circuit BreakersRated on a Symmetrical Current Basis 1999 (revision of1979 standard) Standard C37010 4 IEEE IEEE RecommendedPractice for Electrical Power Distribution for IndustrialPlants 1993 Standard 141 5 ANSIIEEE Standard for

Low-Voltage AC Power Circuit Breakers in Enclosures 1997Standard C3713 6 WC Huening Jr Interpretation of NewAmerican Standards for Power Circuit Breaker ApplicationsIEEE Trans Industry Applications IA-18 85-92 7 IEEEStandard for AC High-Voltage Generator Breakers Rated onSymmetrical Current Basis 1997 Standard C37-013 8 IMCanay L Warren Interrupting Sudden AsymmetricShort-Circuit Currents Without Zero Transition BrownBoveri Review 56 484-493 1969 9 IM Canay Comparison ofGenerator Circuit Breaker Stresses in Test Laboratory andReal Service Condition IEEE Trans Power Delivery 16415-421 2001 10 The Aluminum Association AluminumElectrical Conductor Handbook Second Edition WashingtonDC 1982 11 NFPA (National Fire Protection Association)National Electric Code 12 JC Das Limitations of FaultCurrent Limiters for Expansion of Electrical DistrubtionSystems IEEE Trans Industry Applications 33 1073-10821997 13 DG Fink and JM Carroll (Editors) StandardHandbook for Electrical Engineers 10 th Edition New YorkMcGraw-Hill 1968 (see section 4 Table 4-8)

8 Short-Circuit Calculations According toIEC Standards

1 IEC Short-Circuit Current Evaluation in Three-Phase ACSystems 1st ed 1988 Publication 909

2 Revision of IEC 909 (1988) Short-Circuit Calculationin Three-Phase AC Systems IEC 1993 Preliminary Draft 73Sec 56

3 IEC Data for Short-Circuit Calculations in Accordancewith IEC 909 (1988) 1st ed 1992 Technical Report 909-2

4 IEC High Voltage Alternating-Current Circuit Breakers4th ed 1987 Standard 56

5 JC Das Short-circuit calculationsndashANSIIEEE amp IECmethods similarities and differences Proceedings of 8thInternational Symposium on Short-Circuit Currents in PowerSystems Brussels 1998

Figure 8-P2 System configuration for Problems 4 and 5

9 Calculations of Short-Circuit Currentsin DC Systems

1 General Electric Company GE Industrial Power SystemData Book Schenectady NY 1978

2 ANSIIEEE Standard for Low-Voltage DC Power CircuitBreakers Used in Enclosures 1979 Standard C3714

3 IEC Short-Circuit Currents in DC AuxiliaryInstallations in Power Plants and Substations 1997Standard 61660-1

4 IEEE DC Auxiliary Power Systems for GeneratingStations 1992 Standard 946

5 AIEE Committee Report Maximum Short-Circuit Current ofDC Motors and Generators Transient Characteristics of DCMotors and Generators AIEE Trans 69146ndash149 1950

6 AT McClinton EL Brancato R Panoff MaximumShort-Circuit Current of DC Motors and GeneratorsTransient Characteristics of DC Motors and Generators AIEETrans 681100ndash1106 1949

7 AG Darling TM Linville Rate of Rise of Short-CircuitCurrent of DC Motors and Generators AIEE Trans 71314ndash3251952

10 Load Flow Over Power Transmission Lines

1 OI Elgered Electrical Energy System Theory AnIntroduction New York McGraw-Hill 1971

2 WA Blackwell LL Grigsby Introductory Network TheoryBoston MA PWS Engineering 1985

3 Transmission Line Reference Bookmdash345 kV and Above PaloAlto CA EPRI 1975

4 EHV Transmission IEEE Trans 1966 (special issue) No6 PAS-85-1966 pp 555-700

5 Westinghouse Electric Corporation ElectricalTransmission and Distribution Reference Book 4th ed EastPittsburgh PA 1964

6 EW Kimberk Direct Current Transmission vol 1 NewYork John Wiley 1971

7 B Stott Review of Load-flaw Calculation MethodsProceedings IEEE Vol 62 No 7 July 1974

11 Load Flow Methods Part I

1 RB Shipley Introduction to Matrices and Power SystemsNew York John Wiley 1976

2 J Arrillaga JCP Arnold BJ Harker Computer Modelingof Electrical Power Systems New York John Wiley 1983

3 GW Stagg AH El-Abiad Computer Methods in Power SystemAnalysis New York McGraw-Hill 1968

4 FJ Hubert DR Hayes A Rapid Digital Computer Solutionfor Power System Netword Load Flow IEEE Trans PAS90934ndash940 1971

5 HE Brown GK Carter HH Happ CE Person Power FlowSolution by Impedance Iterative Methods IEEE Trans PAS 21-10 1963

7 MA Laughton Decomposition Techniques in Power SystemsNetwork Load Flow Analysis Using the Nodal ImpedanceMatrix Proc IEE 1968 115

12 Load Flow Methods Part II

1 RJ Brown WF Tinney Digitial Solution of Large PowerNetworks Trans AIEE PAS 76 347ndash355 1957

2 WF Tinney CE Hart Power Flow Solution by NewtonrsquosMethod Trans IEEE PAS 86 1449ndash1456 1967

3 B Stott O Alsac Fast Decoupled Load Flow Trans IEEEPAS 93 859ndash869 1974

4 NM Peterson WS Meyer Automatic Adjustment ofTransformer and Phase-Shifter Taps in the Newton PowerFlow Trans IEEE 90 103ndash108 1971

5 MH Kent WR Schmus FA McCrackin LM Wheeler DynamcModeling of Loads in Stability Studies Trans IEEE PAS139ndash146 1969

6 EPRI Load Modeling for Power Flow and TransientStabililty Computer Studies 1987 Report EL-5003

7 NEMA Large Machines-Induction Motors Standard MG1 Part20 1993

8 JC Das Effects of Momentary Voltage Dips on theOperation of Induction and Synchronous Motors Trans IEEEInd Application Society 26 711ndash718 1990

9 JC Das Characteristics and Starting of LargeSynchronous Motors IEEE IampCPS Tech Conf Sparks 1ndash91999

Figure 12-P1 A three-bus system for Problems 2 3 5 6and 7

13 Reactive Power Flow and Control

1 ANSI Voltage Rating for electrical Power Systems andEquipments (60 Hz) 1988 Standard C841

2 NEMA Large Machines-Induction Motors 1993 StandardMG1-Part 20

3 P Kessel R Glavitsch Estimating Voltage Stability of aPower System Trans IEEE PWRD 1 346-352 1986

4 TJE Miller Reactive Power Control in Electrical PowerSystems New York 1982

5 IEEE Committee Report Var Management-Problem andControl Trans IEEE PAS 103 2108-2116 1984

6 ANSI American National Standard Requirements forCylindrical Rotor Synchronous Generators 1977 StandardC5013

7 CIGRE WG 30-01 Task Force No2 In IA Erinmez edStatic Var Compensators 1986

8 TMKay PW Sauer RD Shultz RA Smith EHV and UHV LineLoadability Dependent on Var Supply Capability Trans IEEEPAS 101 3586-3575 1982

9 NG Hingorani Flexiable AC Transmission IEEE Spectrumpp 40ndash45 1993

10 C Schauder M Gernhard E Stacey T Lemak L Gyugi TWCease A Edris Development of a 100 Mvar Static Condenserfor Voltage Control of Transmission Systems Trans IEEEPWRD 10 1486ndash1993 1995

3 Three-Phase and Distribution SystemLoad Flow

1 L Roy Generalized Polyphase Fault Analysis ProgramCalculation of Cross Country Faults Proc IEE (Part B)126(10) 995ndash1000 1979

2 MA Loughton The Analysis of Unbalanced PolyphaseNetworks by the Method of Phase Coordinates Part 1 SystemRepresentation in Phase Frame Reference Proc IEE 115(8)1163ndash1172 1968

3 MA Loughton The Analysis of Unbalanced PolyphaseNetworks by the Method of Phase Coordinates Part 2 SystemFault Analysis Proc IEE 1165(5) 857ndash865 1969

4 M Chen and WE Dillon Power System Modeling Proc IEEEPAS 62 901ndash915 1974

5 G Kron Tensor Analysis of networks London McDonald1965

6 HL Willis H Tram MV Engel L Finley L FinleySelecting and Applying Distribution Optimization MethodsIEEE Comp Applic Power 9(1) 12ndash17 1996

7 WH Kersting and DL Medive An Application of LadderNetwork to the Solution of Three-Phase Radial Load FlowProblems IEEE PES Winter Meeting New York 1976

8 BR Williams and David G Walden Distribution AutomationStrategy for the Future IEEE Comp Applic Power 7(3)16ndash21 1994

9 JJ Grainger SH Lee Optimum Size and Location of ShuntCapacitors for Reduction of Losses on Distribution FeedersIEEE Trans PAS 100 3 1105ndash1118 1981

10 SH Lee JJ Gaines Optimum Placement of Fixed andSwithced Capacitors of Primary Distribution Feeders IEEETrans PAS 100 345ndash352 1981

11 SK Chan Distribution System Automation PhDDissertation University of Texas at Arlington 1982

Figure 14-14 Three-stage flow chart of dynamic programming

15 Optimization Techniques

1 PE Gill W Murray MH Wright Practical OptimizationNew York Academic Press 1984

2 DG Lulenberger Linear and Non-Linear ProgrammingReading MA Addison Wesley 1984

3 RJ Vanderbei Linear Programming Foundations andExtensions 2 nd Edition Boston Kluwar 2001

4 R Fletcher MJD Powell A rapidly Convergent DescentMethod for Minimization Comp J 5(2) 163ndash168 1962

5 R Fletcher CM Reeves Function Minimization byConjugate Gradients Comp J 7(2) 149ndash153 1964

6 GB Dantzig Linear Programming and ExtensionsPrinceton NJ Princeton University Press 1963

7 E Yaahedi HMZ E1-Din Considerations in ApplyingOptimal Power Flow to Power System Operation IEEE TransPAS 4(2) 694ndash703 1989

16 Optimal Power Flow

11 SN Talukdar TC Giras A Fast and Robust VariableMetric Method for Optimal Power Flows IEEE Trans PAS101(2) 415ndash420 1982

12 RC Burchett HH Happ KA Wirgau Large Scale OptimalPower Flow IEEE Trans PAS 101 (10) 3722ndash3732 1982

13 B Sttot JL Marinho Linear Programming for PowerSystem Network Security Applications IEEE PAS 98 837ndash8481979

14 DS Kirschen HP Van Meeten MWVoltage Control in aLinear Programming Based Optimal Load Flow IEEE TransPower Sys 3 782ndash790 May 1988

15 N Karmarkar A new Polynomial-Time Algorithm forLinear Programming Combinatorica 4(4) 373ndash395 1984

16 PE Gill W Murray MA Saunders JA Tomlin MH WrightOn Projected Newton Barrier Methods for Linear Programmingand an Equivalence to Karmarkarrsquos Projective Method 36183ndash209 1986

17 PE Gill On Projected Newton Barrier Methods for LinearProgramming and an Equivalence to Karmarkarrsquos ProtectiveMethod Math Program 36 183ndash209 1986

18 MJ Todd BP Burrell An Extension of KarmarkarrsquosAlgorithm for Linear Programming Using Dual VariablesAlgorithmica 1 409ndash424 1986

19 RE Marsten Implementation of Dual Affine Interior PointAlgorithm for Linear Programming ORSA Computing1287ndash297 1989

20 IJ Lustig RE Marsen NDF Shanno IP Methods for LinearProgramming Computational State of Art Technical ReportComputational Optimization Center School of Industrial andSystem Engineering Georgia Institute of TechnologyAtlanta Georgia 1992

21 RDC Monteiro I Adler Interior Path FollowingPrimal-Dual Algorithms Part 1 Linear Programming PartII Convex Quadratic Programming Math Program 44 27ndash661989

22 B Stott O Alsac AJ Monticelli Security Analysis andOptimization Proc IEEE 75(2) 1623ndash1644 1987

23 AJ Monticelli MVF Pereira S Granville SecurityConstrained Optimal Power Flow with Post-ContingencyCorrective Rescheduling IEEE Trans Power Sys 2(1)175ndash182 1987

24 RC Burchett HH Happ DR Vierath QuadraticallyConvergent Optimal Power Flow PAS 103 3267ndash3275 1984

25 AM Sasson Optimal Power Flow Solution using theHessian Matrix IEEE Trans PAS 92 31ndash41 1973

26 IJ Lustig Feasibility Issues in an Interior PointMethod for Linear Programming Math Program 49 145ndash1621991

27 IEEE Power Engineering Society IEEE TutorialCoursendashOptimal Power Flow Solution TechniquesRequirements and ChallengesndashIEEE Document Number 96TP111-0 1996

28 JF Benders Partitioning for Solving Mixed VariableProgramming Problems Numerische Mathematik 4 283ndash2521962

29 SN Talukdar VC Ramesh A Multi-Agent Technique forContingency Constrained Optimal Power Flows IEEE TransPower Sys 9(2) 885ndash861 May 1994

30 I Adler An Implementation of Karmarkarrsquos Algorithm forSolving Linear Programming Problems Math Program 44297ndash335 1989

31 IEEE Committee Report IEEE Reliability Test SystemIEEE Trans PAS PAS-98 2047ndash2054 1979

33 JA Momoh Application of Quadratic Interior PointAlgorithm to Optimal Power Flow EPRI Final Report RP2473-36 II 1992

17 Harmonics Generation

1 IEEE IEEE Recommended Practices and Requirements forHarmonic Control in Power Systems 1992 Standard 519

2 IEEE Working Group on Power System Harmonics PowerSystem Harmonics An Overview IEEE Trans On PowerApparatus and Systems PAS 102 2455ndash2459 1983

3 BR Pelly Thyristor Phase-Controlled Converters andCycloconverters Operation Control and Performation NewYork John Wiley 1971

4 H Flick Excitation of Sub-synchronous TorsionalOscillations in Turbine Generator Sets by a Current-SourceConverter Siemens Power Engineering IV (2) 83ndash86 1982

5 R Arthur RA Sanhan Neutral Currents in Three-Phase WyeSystems Square D Company WI 0104ED9501R896 August1996

6 R Yacamini Power System HarmonicsPart4mdashInterharmonics Power Eng J 10 (4) 185ndash 93 1996

7 CEIIEC 1000-2-11990 Electromagnetic CompatibilityPart 2 Environment Sect 1 Description of theEnvironmentmdashElectromagnetic Environment for Low-FrequencyConducted Disturbances and Signalling in Public PowerSupply Systems First Edition 1990-05 IEC Standard

18 Effects of Harmonics

1 IEEE A report prepared by Load Characteristics TaskForce The Effects of Power System Harmonics on PowerSystem Equipment and Loads IEEE Trans PAS 104 255525611985

2 IEEE Working group J5 of the Rotating MachineryProtection Subcommittee Power System Relaying CommitteeThe Impact of Large Steel Mill Loads on Power GeneratingUnits IEEE Trans Power Deliv 15 24-30 2000

3 NEMA Motors and Generators Parts 30 and 31 1993Standard MG-1

4 ANSI Synchronous Generators Synchronous Motors andSynchronous Machines in General 1995 Standard C501

5 ANSI American Standard Requirements for CylindricalRotor Synchronous Generators 1965 Standard C5013

6 MD Ross JW Batchelor Operation ofNon-Salient-Pole-Type Generators Supplying a Rectifier LoadAIEE Trans 62 667-670 1943

7 AH Bonnett Available Insulation Systems for PWMInverter-Fed Motors IEEE Ind Applic Mag 4 15-26 1998

8 JC Das RH Osman Grounding of AC and DC Low-Voltage andMedium-Voltage Drive Systems IEEE Trans Ind Appl 34205-216 1998

9 JM Bentley PJ Link Evaluation of Motor Power Cablesfor PWM AC Drives IEEE Trans Ind Appl 33 342-358 1997

10 ANSIIEEE Recommended Practice for EstablishingTransformer Capability when supplying Non-sinusoidal LoadCurrents 1986 (Revises 1992) Standard C57110

11 UL Dry type General Purpose and Power Transformers1990 Standard UL1561

12 UL Transformers Distribution Dry Type-Over 600 V1990 Standard UL 1562

13 JH Neher MHMcGrath The Calculation of the TemperatureRise and Load Capability of Cable Systems AIEE Trans Oct1957

14 A Harnandani Calculations of Cable Ampacities

Including the Effects of Harmonics IEEE Ind Appl Mag 442-51 1998

15 IEEE IEEE Guide for Application of Shunt PowerCapacitors 1992 Standard 1036

16 NFPA National Electric Code 1999 NFPA 70

17 IEEE IEEE Recommended Practice and Requirements forHarmonic Control in Electrical Sytems 1992 Standard 519

Table 18-8 Balanced IT Guidelines for ConverterInstallation Tie Lines

Category Description IT

I Levels unlikely to cause interference Up to 10000

II Levels that might cause interference 10000ndash50000

III Levels that probably will cause interference gt50000

19 Harmonic Analysis

1 IEEE Task Force on Harmonic Modeling and SimulationModeling and Simulation of Propagation of Harmonics inElectrical Power Systems-Part I Concepts Models andSimulation Techniques IEEE Trans Power Deliv 11 452-4651996

2 IEEE Task Force on Harmonic Modeling and SimulationModeling and Simulation of Propagation of Harmonics inElectrical Power Systems-Part II Sample Systems andExamples IEEE Trans Power Deliv 11 466-474 1996

3 C Hatziadoniu GD Galanos Interaction Between the ACVoltages and Dc Current in Weak ACDC InterconnectionsIEEE Trans Power Deliv 3 1297-1304 1988

4 D Xia GT Heydt Harmonic Power Flow StudiesPart-1-Formulation and Solution IEEE Trans PAS 1011257-1265 1982

5 D Xia GT Heydt Harmonic Power Flow Studies-Part IIImplementation and Practical Applications IEEE Trans PAS101 1266-1270 1982

6 AA Mohmoud RD Shultz A Method of Analyzing HarmonicDistribution in AC Power Systems IEEE Trans PAS 1011815-1824 1982

7 J Arrillaga DA Bradley PS Bodger Power SystemHarmonics New York John Wiley 1985

8 J Arrillaga BC Smith NR Watson AR Wood Power SystemHarmonic Analysis West Sussex England John Wiley 1997

9 EPRI HVDC-AC System Interaction for AC Harmonics EPRIReport 1 72-73 1983

10 CIGRE Working Group 36-05 Harmonic CharacteristicParameters Methods of Study Estimating of Existing Valuesin the Network Electra 35-54 1977

11 EW Kimbark Direct Current Transmission New York JohnWiley 1971

12 M Valcarcel JG Mayordomo Harmonic Power Flow forUnbalance Systems IEEE Trans Power Deliv 8 2052-20591993

13 T Hiyama MSAA Hammam TH Ortmeyer Distribution System

Modeling with Distributed Harmonic Sources IEEE TransPower Deliv 4 1297-1304 1989

14 MFMcGranaghan RC Dugan WL Sponsler DigitalSimulation of Distribution System Frequency-ResponseCharacteristics IEEE Trans PAS 100 1362-1369 1981

15 MF Akram TH Ortmeyer JA Svoboda An Improved HarmonicModeling Technique for Transmission Network IEEE TransPower Deliv 9 1510-1516 1994

16 IEEE IEEE Recommended Practice and Requirements forHarmonic Control in Electrical Systems 1992 Standard 519

17 ANSIIEEE Guide for Protection of Shunt CapacitorBanks 1980 Standard C3799

20 Harmonic Mitigation and Filters

4 J Zaborszky JW Rittenhouse Fundamental Aspects of SomeSwitching Overvoltages in Power Systems IEEE Trans PAS1727-1734 1982

6 JD Anisworth Filters Damping Circuits and ReactiveVoltamperes in HVDC Converters in High Voltage DirectCurrent Converters and Systems London Macdonald 1965

7 JC Das Analysis and Control of Harmonic Currents UsingPassive Filters TAPPI Proceedings Atlanta Conference1075-1089 1999

8 H Akagi Trends in Active Power Line Conditioners IEEETrans Power Electron 9 263268 1994

9 WM Grady MJ Samotyi AH Noyola Survey of Active LineConditioning Methodologies IEEE Trans Power Deliv 51536-1541 1990

10 H Akagi New Trends in Active Filters for PowerConditioning IEEE Trans Ind Appl 32 1312-1322 1996

11 A Cavallini GCMontanarion Compensation Strategies forShunt Active Filter Control IEEE Trans Power Electron 9587-593 1994

12 CV Nunez-Noriega GG Karady Five Step-Low FrequencySwitching Active Filter for Network Harmonic Compensationin Substations IEEE Trans Power Deliv 14 12981303 1999

13 H Akagi A Nabe The p-q Theory in Three-Phase SystemsUnder Non-Sinusoidal Conditions ETEP 3 27-30 1993

14 JS Lai FZ Peng Multilevel Converters-A New Breed ofPower Converters IEEE Trans Ind Appl 32 509-517 1996

15 T Tanaka N Koshio H Akagi A Nabae Reducing SupplyCurrent Harmonics IEEE Ind Appl Mag 4 31-35 1998

Figure 20-25 (Continued)

Appendix A Matrix Methods

1 PL Corbeiller Matrix Analysis of Electrical NetworksCambridge MA Harvard University Press 1950

2 WE Lewis DG Pryce The Application of Matrix Theory toElectrical Engineering London EampF N Spon 1965

3 HE Brown Solution of Large Networks by Matrix MethodsNew York Wiley Interscience 1975

4 SA Stignant Matrix and Tensor Analysis in ElectricalNetwork Theory London Macdonald 1964

5 RB Shipley Introduction to Matrices and Power SystemsNew York Wiley 1976

Appendix B Calculation of Line and CableConstants

1 DG Fink (Ed) Standard Handbook for ElectricalEngineers 10th ed New York McGraw-Hill 1969

2 Croft Carr Watt American Electricianrsquos Handbook 9thed New York McGraw-Hill 1970

3 Central Station Engineers Electrical Transmission andDistribution Reference Book 4th ed East Pittsburgh PAWestinghouse Corp 1964

4 The Aluminum Association Aluminum Conductor Handbook2nd ed Washington DC 1982

5 PM Anderson Analysis of Faulted Systems Ames IA IowaState University Press 1973

Table B-1 Typical Values for Dielectric Constants of CableInsulation

Type of insulation Permittivity ()

Polyvinyl chloride (PVC) 35ndash80

Ethyelene-propylene insulation (EP) 28ndash35

Polyethylene insulation 23

Cross-linked polyethylene 23ndash60

Impregnated paper 33ndash37

Appendix C Transformers and Reactors

1 ANSI Terminal Markings and Connections for Distributionand Power Transformers 1978 (Revised 1992) StandardC571270

2 IEEE Standard Requirements Terminology and Test Codefor Step-Voltage Regulators 1999 Standard C5715

3 CE Lin JB Wei CL Huang CJ Huang A NewMethod forRepresentation of Hysteresis Loops IEEE Trans Power Deliv4 413-419 1989

4 CanadianAmerican EMTP User Group ATP RuleBookPortland Oregon 1987-1992

5 JD Green CA Gross Non-Linear Modeling of TransformersIEEE Trans Ind Appl 24 434-438 1988

6 WJ McNutt TJ Blalock RA Hinton Response ofTransformer Windings to System Transient Voltages IEEETrans PAS 9457-467 1974

7 PTM Vaessen Transformer Model for High FrequenciesIEEE Trans Power Deliv 3 1761-1768 1988

8 T Adielson et al Resonant Overvoltages in EHVTransformers-Modeling and Application IEEE Trans PAS 1003563-3572 1981

9 X Chen SS Venkta A Three-Phase Three-Winding Core-TypeTransformer Model for Low-Frequency Transient Studies IEEETrans PD 12 775-782 1997

10 A Narang RH Brierley Topology Based Magnetic Modelfor Steady State and Transient Studies for Three-Phase CoreType Transformers IEEE Trans PS 9 13371349 1994

11 S Lu Y Liu JDR Ree Harmonics Generated from a DCBiased Transformer IEEE Trans PD 8 725-731 1993

12 JC Das WF Robertson J Twiss Duplex Reactor for LargeCogeneration Distribution System-An Old ConceptReinvestigated TAPPI Engineering Conference Nashville637-648 1991

Appendix D Sparsity and Optimal Ordering

1 N Sato WF Tinney Technique for Exploiting the Sparsityof the Network Admittance Matrix IEEE Trans PAS 82944-950 1963

2 WF Tinney JW Walker Direct Solutions of Sparse NetworkEquations by Optimally Ordered Triangular FactorizationIEEE Proc 55 1801-1809 1967

3 AH El-Abiad (Ed) Solution of Network Problems bySparsity Techniques Chapter 1 Proceedings of the ArabSchool of Science and Technology Kuwait 1983 Distributedby McGraw Hill New York

Figure D-4 (Continued)

Appendix F Limitation of Harmonics

2 IEC Electromagnetic Compatibility-Part 3Limits-Section 2 Limits for Harmonic Current Emission(Equipment Input Current 16A Per Phase) 1995 Standard61000-3-2

1 IEC Electromagnetic Compatibility Part 3 LimitsSection 3 Limitations of Voltage Fluctuations and Flickerin Low-Voltage Supply Systems for Equipment with RatedCurrent E` 16 A Geneva 1994 Standard 61000-3-3

2 IEC Electromagnetic Compatibility Part 4 Section 7General Guide on Harmonic and Interharmonic Measurementsand Instrumentation for Power Supply Systems and EquipmentConnected Thereto Geneva 2001 Standard 61000-4-7

3 IEEE IEEE Interharmonic Task Force Working DocumentIH0101 2000

4 SR Mendis MT Bishop JF Witte Investigation of VoltageFlicker in Electric Arc Furnace Power Systems IEEE Ind Mag2 28-34 1996

Appendix G Estimating Line Harmonics

1 AD Graham ET Schonholzer Line Harmonics of Converterswith DC-Motor Loads IEEE Trans Ind Appl 19 84-93 1983

2 JC Read The Calculation of Rectifier and InverterPerformance Characteristics JIEE UK 495-509 1945

3 M Grlsquotzbach R Redmann Line Current Harmonics ofVSI-Fed Adjustable-Speed Drives IEEE Trans Ind Appl 36683-690 2000

Table G-1 Harmonic Spectrum of a Voltage Source or

Pulse-Width Modulated ASD (Adjustable Speed Drive)

Harmonic order Magnitude Phase angle

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

Short-Circuit Currents and Symmetrical Components

References

Marcel Dekker Inc New York bull Basel

Power SystemAnalysis

Short-Circuit Load Flow and Harmonics

J C DasAmec Inc

Atlanta Georgia

ISBN 0-8247-0737-0

Headquarters

Marcel Dekker Inc

Marcel Dekker AG

World Wide Web

httpwwwdekkercom

10 9 8 7 6 5 4 3 2 1

POWER ENGINEERING

Series Editor

H Lee WillisABB Inc

Advisory Editor

Pensacola Florida

Series Introduction

H Lee Willis

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

ISBN 0-8247-0737-0

Headquarters

Marcel Dekker Inc

Marcel Dekker AG

World Wide Web

httpwwwdekkercom

10 9 8 7 6 5 4 3 2 1

POWER ENGINEERING

Series Editor

H Lee WillisABB Inc

Advisory Editor

Pensacola Florida

Series Introduction

H Lee Willis

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

POWER ENGINEERING

Series Editor

H Lee WillisABB Inc

Advisory Editor

Pensacola Florida

Series Introduction

H Lee Willis

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Series Introduction

H Lee Willis

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

H Lee Willis

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Preface

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

J C Das

vi Preface

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Contents

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

viii Contents

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Contents ix

Methods 285

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

x Contents

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Contents xi

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

xii Contents

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Contents xiii

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Index 831

xiv Contents

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

2 Chapter 1

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

4 Chapter 1

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

6 Chapter 1

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

eth15THORN

eth16THORN

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

sequence

frac141 1 1

1 a2 a

1 a a2

eth17THORN

8 Chapter 1

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

a11 a12 a13 a1n

a21 a22 a23 a2n

an1 an2 an3 ann

frac14

eth111THORN

xx frac14 CC xxn

yy frac14 CC yyn

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

AAn xxn frac14 yyn

frac14 CC1 CC

frac14

eth117THORN

Zaa Zab Zac

Zba Zbb Zbc

Zca Zcb Zcc

eth118THORN

10 Chapter 1

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

eth119THORN

The eigenvalues are

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

frac14 Z thorn 2M

frac14 Z M

eth123THORN

eth124THORN

Z ethZ MTHORN M M

M Z ethZ MTHORN M

M M Z ethZ MTHORN

which gives

frac141

0ffiffiffi3

ffiffiffi3

eth127THORN

12 Chapter 1

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

eth128THORN

TTs frac141 1 1

1 a2 a

1 a a2

eth129THORN

TT1s frac14 1

1 a a2

1 a2 a

eth130THORN

Conversely

II012 frac14 TT1s

TTsII012

VV012 frac14 TT1s

eth134THORN

Therefore

ZZ012 frac14 TT1s

TT1s eth136THORN

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

ZZ012 frac141

1 a a2

1 a2 a

1 a a2

0 Z M 0

0 0 Z M

eth137THORN

ZZabc frac14Z1 0 0

0 Z2 0

0 0 Z3

eth138THORN

ZZ012 frac141

1 a a2

1 a2 a

Z1 0 0

0 Z2 0

0 0 Z3

1 a2 a

1 a a2

frac14 1

eth139THORN

14 Chapter 1

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

b thorn VcI

c frac14 VV 0

sII012 frac14 VV 0

TT 0sTTs frac14 3

eth142THORN

2 thorn 3V0I

0 eth143THORN

frac141 1 0

ffiffiffi3

eth144THORN

frac1413

0 1ffiffiffi3

p 1ffiffiffi3

eth145THORN

TTc frac141 1 0

1 1=2ffiffiffi3

eth146THORN

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

TT1c frac14

1=3 1=3 1=3

2=3 1=3 1=3

0 1=ffiffiffi3

p 1=ffiffiffi3

eth147THORN

and as before

ZZ0 frac14 TT1c

ZZabc frac14 TTcZZ0

TT1c eth149THORN

frac14Z00 0 0

eth150THORN

eth151THORN

V0 frac141

V1 frac141

V2 frac14

eth152THORN

16 Chapter 1

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Example 11

18 Chapter 1

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

20 Chapter 1

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

V1 frac14 Va I1Z1

V2 frac14 I2Z2

V0 frac14 I0Z0

eth153THORN

or in matrix form

frac140

Z1 0 0

0 Z2 0

0 0 Z3

eth154THORN

172 Transformers

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

22 Chapter 1

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

neutral isolated

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

24 Chapter 1

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

ZH frac14 1

ZM frac14 1

ZL frac14 1

eth155THORN

26 Chapter 1

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

frac14 1=2

We also see that

eth156THORN

173 Static Load

frac14Z 0 0

frac14 Ts

frac14Z 0 0

eth157THORN

frac14 T1s

thorn T1s

eth158THORN

28 Chapter 1

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

frac14Z 0 0

frac14

Z thorn 3Zn 0 0

eth159THORN

Transformers

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

X 00d thorn X 00

2eth160THORN

Va frac14d

Vb frac14d

Vc frac14d

eth161THORN

eth162THORN

frac14Ea

L L 0 L 0

L 0 L L 0

L 0 L 0 L

eth163THORN

30 Chapter 1

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

frac14 Ts

L L 0 L 0

L 0 L L 0

L 0 L 0 L

frac14E0

L0 0 0

0 L1 0

0 0 L2

eth164THORN

frac140

Z0 thorn 3Zn 0 0

0 Z1 0

0 0 Z2

eth166THORN

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Example 12

32 Chapter 1

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Delta to wye

Z1 frac14Z12Z31

Z2 frac14Z12Z23

Z3 frac14Z23Z31

eth167THORN

eth168THORN

34 Chapter 1

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Problems

36 Chapter 1

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

BIBLIOGRAPHY

Heinemann 1997

Hill 1971

38 Chapter 1

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

1 1000 0

3 31 160

5 607 178

7 412 172

9 07 158

11 385 165

13 774 177

14 03 53

15 041 135

17 32 32

18 03 228

19 154 179

21 032 110

23 18 38

25 13 49

29 12 95

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

31 07 222

Cover and Prelims

Series Introduction

Preface

Contents

References

Power System Analysis - Taylor & Francis Group

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