Automatic Power Factor Improvement by Using PLC & SCADA

Department of Electrical and Electronic Engineering

Port City International University

NAME OF THE PROJECT

Automatic Power Factor Improvement by Using PLC & SCADA

Supervisor

Professor Ahmad HossainCo-ordinator, Department of CSIT, ECE & EEE.

PCIU.

Co-SupervisorAbrar Hussain

Lecturer, Department of EEE.PCIU.

Project Submitted by

Md.ID: 008-07-16

Md.ID: 008-07-04

Department of EEE.PCIU.

Low power factor occurs large copper losses, poor voltage regulation and reduce handling capacity of the system. At low power factor KVA rating of the equipment has to be made more, making the equipment larger and expensive [1]. Power factor improvement is important because at high, medium and low power factor the current distortion levels tends to fall into lowTHDI≤20%,medium(20%<THDI≤50%)and high(THDI >50%)respectively[2].For the low power quality high financial loss per incident occurs that are given below.

INTRODUCTION

This paper represents the most effective automatic power factor improvement by using static capacitors which will be controlled by a PLC with very low cost although many existing systems are present which are expensive and difficult to manufacture. In this study, many small rating capacitors are connected in parallel and a reference power factor is set as standard value into the PLC. Suitable number of static capacitors is automatically connected according to the instruction of the PLC to improve the power factor close to unity. Some tricks such as using resistors instead of potential transformer and using one of the most low cost PLC SIEMENS S7-200 CPU215 DC/DC/DC which also reduce programming complexity that make it most economical system than any other controlling system. Keywords : PLC SIEMENS S7-200 CPU215 DC/DC/DC, current transformer, comparator, relay, capacitor, Software Micro win v4.0 SP9, Win CC Flexible ( SCADA).

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Abstract

The low power factor is mainly due to the fact that most of the power loads are inductive and therefore, take lagging currents. So capacitors are connected parallel with the load for leading power. It draws current Ic which leads the supply voltage by 900 .The resulting line current I1 is the phasor sum of I and IC and it angle of lag is ᴓ2 as shown in Fig1(c).It is clear that ᴓ2 is less than ᴓ1 from phasor diagram. So that cosᴓ2 is greater than cosᴓ1 .So that power factor of the load is improved

POWER FACTOR IMPROVEMENT THEORY

Power factor improvement circuit and phasor diagram Fig1(c)

Benefits of Power Factor Correction. There are numerous benefits to be gained through power factor correction. These benefits range from reduced demand charges on your power system to increased load carrying capabilities in your existing circuits and overall reduced power system loses.

1. Avoid Power Factor Penalties

2. Reduced Demand Charges

3. Increased Load Carrying Capabilities in Existing Circuits

4. Improved Voltage

5. Reduced Power System Losses

OBJECTIVES

To develop an automatic Power system protection and control this system using PLC and SCADA.

To increase the efficiency of an industrial plant by incorporating the automation system which replaces the manual Protection of Power system protection unit system.

EQUIPMENTS

PLC SIEMENS S7 200 (CPU 215 DC/DC/DC)Programming Cable MPI cableSoftware Micro win v4.0 SP9Software USB to RS 232 driver v110.Win CC Flexible ( SCADA)Electromechanical Relay. Cable. Power supply (24 volts dc).Fan TC-K TypePR-4116( Universal Transmitter)CTWeidmuller WAS1 CMA 1/5/10A acEM-235Laurel TA210RMV5PC

SCADA

PLC S7 200 CPU 215 DC/DC/DC

MPI

EM 235

Analog Input Device

Digital Input Device

Digital Out put Device

Inductive Load

Capacitor Bank

Block Diagram

Start ConditionRecipe download?Temperature <80°C?Voltage 1Ø<250?Voltage 1Ø>120?

Operator Start command ?

Temperature >40°C?

FFFan Start

Temperature <35°C?

Over voltage >250V?

FFAlarm & Full system stop

Under voltage <100V?

Over Current >7A?

FFAlarm & Full system stop

PF =.96 & A=1?

FFCapacitor Bank 1 Start

Current >5A

FFLoad shading Start

PF =.98 & A=10?

Load shading time over

Flowchart

FFFF FFAlarm & Full system stopFan Stop Capacitor Bank 2 Start FFAlarm & Full system stop

Temperature >48°C?

FFAlarm & Full system stop

FFFF FFAlarm & Full system stop

Fan Stop Capacitor Bank 2 Start

Temperature >48°C?

FFAlarm & Full system stop

FFAlarm & Full system stop

1M 1L+ 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 2M 2L+ 1.0 1.1 M L+

1M 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 2M 1.0 1.1 1.2 1.3 1.4 1.5 M L+

CPU 214 EM 235AI 3*12BitsAQ 1*12Bits

RA A+ A- RB B+ B- RC C+ C- Vo Io L+ M

AC to DC

Pr4116

PR 4116

Input Supply Output

PR4116 14 11

UH

230 V AC

UA

+ -

CT

RS 485

SCADA

Voltage

MPI

Circuit Diagram

CT

TC K Type DC 24V EM 235 EM 235 EM 235

M

N

1 In our project, we have used only one level indicator but in future it will be more suitable in industrial

application if we use two level indicator and sensors of higher specifications. We also used this only single

phase but in future we will develop this project for three phase line.

2 Siemens S7 200 CPU 215 PLC & WinCC Flexible2008 we have used in our project but in future

3 we can develop our project with Advance PLC S7 1200 & S7 1500 PLC & SCADA TIA Portal system

which will be very useful in industrial application and others utility services like water supply gas supply

and power sector etc.

Future work

This paper shows an efficient technique to improve the power factor of a power system by an economical way. Static capacitors are invariably used for power factor improvement in factories or distribution line. But this paper presents a system that uses capacitors only when power factor is low otherwise they are cut off from line. Thus it not only improves the power

CONCLUSION