SETTING AND COORDINATION OF OVERCURRENT RELAY IN

DISTRIBUTION SYSTEM

ABDUL HADI BIN ISMAIL

Submitted to the Faculty of Electrical Engineering

in partial fulfillment of the requirement for the degree of

Bachelor in Electrical Engineering (Power)

Faculty of Electrical Engineering

Universiti Teknologi Malaysia

MAY 2008

ii

iii

Dedicated, in thankful appreciation for support, encouragement and understandings

to:

My beloved mother Halijah Bte Ibrahim and father Ismail Bin Awang;

my brother and sister Norhasanah, Ahmad Tarmizi, Mohd Lotfi, Khairul Anwar

and Muhammad Naim;

also my beloved friend Ridhuan, Aidil, Rushdi, Afizan, Mohd Al-amin, Azizi and

Noor Izyawati Ibrahim

and all person contribute to this project.

iv

ACKNOWLEDGEMENT

First of all I would like to take this opportunity to express my sincere to Hjh

Faridah bt Hussin for his numerous invaluable advice, comments, guidance and

persistence encouragement throughout the course of this project.

My sincere appreciation also goes to Encik Hashim b Ahmad Turki (Branch

Manager, TNBD Langkawi) for his idea and advice to complete this project.

I would also like to thank our Advance Power Lab Technician, Puan Norlela for her

co-operations, guidance and helps in this project.

My appreciation also goes to my family who has been so tolerant and supports me

all these years. Thanks for their encouragement, love and emotional supports that they had

given to me.

Nevertheless, my great appreciation dedicated to my friends and those whom

involve directly or indirectly with this project. There is no such meaningful word

than...Thank You So Much.

v

ABSTRACT

This project mainly focuses on studies of protection relay in power distribution

system. Relay that used in this project is inverse definite minimum time relay (IDMT)

and its have a widely application in distribution system. The reliability of power system

can be increased by proper setting and coordination of the relays in power distribution

system. The characteristic of relay is analyzed to find out the operating condition and

setting of the relay. A case study of power distribution system in Universiti Teknologi

Malaysia is analyzed and simulated using SKM Power Tools software to find out the

setting and coordination of a relay. Using relay coordination concept that are discussed

in this project, the operating time of relay for distribution system can be analyzed and

developed.

vi

ABSTRAK

Projek ini memfokuskan mengenai geganti perlindungan yang digunakan di

dalam sistem pengagihan. Geganti yang digunakan dalam projek ini adalah geganti

masa minimum tertentu songsang yang banyak diaplikasikan di dalam sistem

pengagihan. Keboleharapan di dalam sistem kuasa juga boleh ditingkatkan oleh

pengesetan dan koordinasi yang betul dalam sistem pengagihan kuasa elektrik. Ciri-ciri

geganti telah dianalisis untuk mendapatkan pengesetan dan keadaan operasi geganti

tersebut. Sistem pengagihan Universiti Teknologi Malaysia digunakan sebagai kajian

untuk dianalisis dan simulasi menggunakan perisian SKM Power Tools untuk

mendapatkan pegesetan dan koordinasi geganti aruslebih. Berdasarkan konsep

koordinasi untuk geganti aruslebih yang dibincangkan dalam projek ini, masa operasi

bagi geganti aruslebih di dalam sistem pengagihan dapat dihasilkan dan dianalisis.

vii

TABLE OF CONTENT

CHAPTER TITLE PAGE

DECLARATION OF THESIS ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENT vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF SYMBOLS xii

LIST OF APPENDICES xiii

1. INTRODUCTION 1.1 Problem Statement 1

1.2 Objectives 2

1.3 Scope of Work 2

1.4 Organization of The Thesis 4

2. POWER SYSTEM PROTECTION 2.1 Introduction 5

2.2 Protection for Power Distribution System 6

2.3 Protection Devices 6

2.3.1 Fuse 6

viii

2.3.2 Circuit Breaker 7

2.3.3 Relay 7

2.4 Relays 7

2.4.1 Induction Relays 8

2.4.2 Attracted-armature Relays 9

2.4.3 Moving coil Relays 10

2.4.4 Thermal Relays 11

2.4.5 Timing Relays 11

2.4.6 Static Relays 12

2.5 Requirements 13

2.6 Protective Relay Application in Electrical Network 13

2.7 Protective Relaying 14

2.7.1 Applications 14

2.7.2 System 15

2.7.3 Scheme 16

2.8 Relay Coordination Concept 17

2.8.1 Radial System 17

2.8.2 Ring System 17

2.9 Overcurrent relay 18

2.9.1 Overcurrent Protection 18

2.9.2 Overcurrent IDMT Type Relays 19

2.10 Overcurrent Schemes 19

2.10.1 Shortcomings 19

2.10.2 Overcurrent Relay in a Distribution System 20

2.11 Time-graded Overcurrent Protection 20

2.11.1 Settings 21

2.11.2 Time Multiplier Setting 21

ix

3 SOFTWARE 3.1 Introduction 23

3.2 SKM Power Tools for Windows 24

3.2.1 DAPPER 24

3.2.2 CAPTOR 26

3.3 SKM in Relays Coordination 26

3.3.1 Modeling 27

3.3.2 Simulation and Analysis 27

3.3.3 Coordination 27

3.3.4 Evaluation 28

4 RESULT AND DISCUSSION 4.1 Introduction 31

4.2 Result of Simulation for Zon 1 32

4.2.1 Result for Overcurrent Relay Setting in Zon 1 37

4.2.2 Different setting of Time Setting Multiplier 40

(TSM) in Zon 1

4.3 Result of Simulation for Zon 2 42

4.3.1 Result for Overcurrent Relay Setting in Zon 2 47

4.3.2 Different setting of Time Setting Multiplier 50

(TSM) in Zon 2

4.4 Discussion 53

5 CONCLUSION AND RECOMMENDATION 5.1 Conclusion 54

5.2 Recommendation 55

REFERENCES 56

APPENDICES 57

x

LIST OF TABLES

TABLE TITLE PAGE

4.1 Setting of overcurrent relay in Zon 1, UTM 37

4.2 Setting of overcurrent relay in Zon 1, UTM 40

(Different setting of TSM)

4.3 Setting of overcurrent relay in Zon 2, UTM 47

4.4 Setting of overcurrent relay in Zon 2, UTM 51

(Different setting of TSM)

xi

LIST OF FIGURES

FIGURE TITLE PAGE

1.1 Simple Circuits in Distribution System 2

1.2 Project Overview 3

2.1 Induction relays 9

2.2 Circuit of Time Graded Scheme 15

2.3 Relay coordination concepts for ring 18

System

2.4 Standard IDMT current-time characteristic 22

3.1 Component editor function 25

3.2 Relay adder, shifter, and calibration points 28

Function

3.3 Setting of IDMT overcurrent relay 29

3.4 Single Line Diagram of UTM 30

Power Distribution

4.1 Single line diagrams for Zon 1, UTM 32

4.2 Single line diagrams for Zon 1, UTM using 34

SKM Power Tools

4.3 Current-time graphs for Zon 1, UTM 35

4.4 Current-time graphs for different 36

Setting of TSM in Zon 1, UTM

xii

4.5 Single line diagram for Zon 2, UTM 42

4.6 Single line diagrams for Zon 2, UTM using 44

SKM Power Tools

4.7 Current-time graph for Zon 2, UTM 45

4.8 Current-time graphs for different 46

Setting of TSM in Zon 2, UTM

xiii

LIST OF SYMBOLS

T - Torque

a - Angles of induction relays (side A) b - Angles of induction relays (side B) Ia - current of induction relays (side A)

Ib - current of induction relays (side B)

T - Time operating relay

M - Multiple of setting

TSM - Time Setting Multiplier

PSM - Plug Setting Multiplier

ROT - Relay Operating Time

xiv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A CAPTOR TCC Report for Single 57

Line Zon 1, UTM

B CAPTOR TCC Report for Single Line Zon 1, 65

UTM (Different setting of TSM)

C CAPTOR TCC Report for Single 69

Line Zon 2, UTM

D CAPTOR TCC Report for Single Line Zon 2, 79

UTM (Different setting of TSM)

E Example of Demand Load Report from 83

DAPPER function

F Example of Short Circuit Report from 84

DAPPER function

CHAPTER 1

INTRODUCTION

1.1 PROBLEM STATEMENT

Power system for must have a reliable and efficient protection scheme. Once

fault occurred on the system, it must be isolated as quickly as possible. This action could

minimize the effects on system stability and damage to plant. Referring to figure 1.1,

when a fault occurred on the system, one of the relay should be operated. However,

sometimes the relay that should be operated due to the fault does not work properly

delay in operation or does not function at all. It might be due to the problems from the

setting of the relay. Therefore, relay should be set properly to make it will function

accordingly. So, related to the problem, the study will be focused to the setting and

coordination of the relays that used in distribution system.

2

Figure 1.1 Simple Circuits in Distribution System

1.2 OBJECTIVES

The main objective is to study how to setting the relay on the distribution

network, under various fault location. Secondly is to improve the reliability and

efficiency of power distribution by using optimum relay coordination. This project

focused on the application of relay in a power distribution system.

1.3 SCOPE OF WORK

Research will be focused on relay setting and coordination in power distribution

system. It involves in studying the characteristic of the relay, specification and function

of the relay in power distribution system. Then, analyze the different setting of relay and

the coordination using suitable software. For simulation, the single line diagram will be

used to analyze the real system in distribution. From the analysis, the setting and

11kV 250MVA

A B C

F

3

coordination of relay in distribution system will be developed. Figure 1.2 shows the

Project Overview of this project.

Figure 1.2 Project Overview

Background

knowledge of fault, relay and

distribution network

Single line diagram from TNB

for simulation

Relay setting, coordination, and

characteristics

Analyze and compare the

simulation result to make conclusion

Repeat simulation with different setting and coordination of

relay

Computer simulation using suitable software

4

1.4 ORGANIZATION OF THE THESIS

This thesis consists of five chapters. Each chapter will discuss the details about

the particular topic. First chapter covers the introduction of the project and scope of

work. This chapter highlights the overview of the project title and work flow of

methodology.

The second chapter describes the theory and technical literature. This topic

covered all the protection that used in distribution power system. The different types of

relay also discussed in this topic. This project focuses more on inverse definite minimum

times relay (IDMT) and the coordination concept in distribution system.

The software that used in setting and coordination of overcurrent relay was

present in the third chapter. Two main functions from SKM Power Tools software

namely, Distribution Analysis for Power Planning Evaluation and Reporting (DAPPER)

and Computer Aided Plotting for Time Overcurrent Reporting (CAPTOR) were

discussed in this chapter.

In the chapter four, presents the results of the study along with the discussions of

results. The result from simulation give the setting and coordination of overcurrent relay

in distribution system.

Finally, a conclusion and future recommendation of this project is present in

chapter five. Appendices sections are included to assist in further understanding on the

subject of this project.

CHAPTER 2

POWER SYSTEM PROTECTION

2.1 INTRODUCTION

Protection system for power system has been developed to minimize the damage

and to make sure supply in safe condition, continuously and economically. Relay is one

of the most important components in protection system. There is several kind of relay

that each kind has own characteristic. A relay is device that makes a measurement or

receives a signal that causes it to operate and to effect the operation of other equipment.

It responds abnormal conditions in faulty section of the system with the minimum

interruption of supply. The advantages of isolating a system fault as quickly as possible

include safety for personnel and public, minimizing damage to plant and minimizing

effects on system stability.

6

2.2 PROTECTION FOR POWER DISTRIBUTION SYSTEM

The distribution system need a protection to minimize the damage and to ensure

supply is reliable and economically. Protection systems distinguish between the

protections against overload currents, effect of short circuit current and excessive

temperature rise. Protective system should provide reliability, selectivity, speed,

economy and stability in power system.

2.3 PROTECTION DEVICES

There are three-protection device used in distribution system:

1. Fuse

2. Circuit breaker

3. Relay

2.3.1 Fuse

The fuse is a preliminary protective device. As the power capacity and voltage of

electrical installations increase and their switching circuits become complicated, fuse

protection become inadequate. This leads to the development of protective gears based

on special, automatic device relays that are called protective relaying.

7

2.3.2 Circuit breaker

A circuit breaker is a device that is not designed for frequent operation, but is

capable of making and breaking all currents including fault currents up to its relative

high rated breaking capacity. One great advantage of circuit breakers is their speedy

operation, comparatively speaking, on a small overloads and the considerable control of

operating time under these conditions.

2.3.3 Relay

Relays are used to respond to the various functions of the power system

quantities to protect against system hazards. A protection relay is devices that respond to

fault conditions and give a signal for circuit breaker to operate and isolate the fault.

2.4 RELAYS

A relay is a device that makes a measurement or receives a signal, which causes

it to operate and to effect the operation of other equipment. A protection relay is a device

that responds to abnormal conditions in an electrical power system to operate a circuit

breaker to disconnect the faulty section of the system with the minimum interruption of

supply. Many designs of relay elements have been produced but these are based on a

few basic operating principles. The great majority of electro-mechanical relays are in

one of the following groups:

1. Induction relays

8

2. Attracted-armature relays

3. Moving-coil relays

4. Thermal relays

5. Timing relays

6. Static relays

2.4.1 Induction Relays

The induction relay is based on the domestic kilowatt-hour meter, which

has a metal disc free to rotate between the poles of two electromagnets. Torque is

produced by the interaction of upper electromagnet flux and eddy currents

induced in the disc by the lower electromagnet flux, and vice versa. The torque

produced is proportional to the product of upper and lower electromagnet fluxes

and the sine of the angle between them.

T a b sin A

This means that maximum torque is produced when the angles between

the fluxes are 90 and as are proportional to Ia and Ib T Ia Ib sin A. Torque applied to a disc without control would, of course, continually accelerate

the disc to a speed limited only by friction and windage. Control is provided in

two ways:

1. By a permanent magnet whose field passes through the disc and produces a

braking force proportional to disc speed. This controls the time characteristic

of the relay.

2. By a control spring which produces a torque proportional to disc angular

displacement. This controls disc speed at low values of torque and

determines the relay setting.

9

Disc speed is dependent on torque and as disc travel over a fixed distance is

inversely proportional to time, an inverse time characteristic is produced. Figure

2.1 shows the basic operational of induction relays.

Typical applications:

a) Wattmetric relay

b) KVAr relay

c) Phase-angle-compensated relay

d) Overcurrent relay

e) Over/under voltage relay

Figure 2.1 Induction relays

2.4.2 Attracted-armature relays

The attracted-armature relay comprises an iron-cored electromagnet,

which attracts an armature, which is pivoted, hinged or otherwise supported to

permit motion in the magnetic field. The magnetic circuit can be presented in a

similar manner to an electric circuit, using magneto-motive force (m.m.f) in

ampere-turns applied to the reluctance of the iron and air gap in series-

represented by resistance-which causes a flux to flow in the circuit. The

permeability of the iron is much higher than that of air, which means that most of

10

the mmf will be used to magnetise the air gap. When the relay starts to operate,

the length of the air gap, and therefore the reluctance, decreases which causes the

flux, and the force, to increase. The effect of this in practical terms is that when

the current in the coil reaches a value which produces sufficient force to move

the armature-movement of the armature itself causes the flux and the operating

forces to increase. So that once the armature moves it accelerates with increasing

force until it is fully closed. This is the reason that contactors are very successful

because once the contactor starts to move positive contact making is assured.

In d.c. operated relays residual flux is a problem and may prevent release

of the armature. In order to reduce it to alow value the armature should not bed

entirely on both poles of the electromagnet in the closed position but should

always have a non-magnetic stop, to ensure that there is a small air gap. In

general attracted-armature relays are used:

1. As auxiliary repeat relays and for flag indicators. These are

known as all-or-nothing relays.

2. As measuring relays where a drop-off/pick-up ratio of less than

90% can be tolerated.

Typical applications:

a) All-or-nothing relays

b) Measuring relays

2.4.3 Moving-coil relays

The moving coil relay consists of a light coil which when energized

moves in a strong permanent magnet field. The coil can either be pivoted

between bearings as in the usual moving-coil instrument or suspended in the

magnet field in the manner of the moving-coil. In both cases the movement very

sensitive that is very little energy is required to produce operating force. The

11

forced produced is proportional to the product of the permanent magnet flux and

the coil current. The axial relay is less sensitive but is very robust. It has the

advantage of having no bearings but on the other hand is affected by gravity if

the relay case is not correctly aligned on the panel. In general moving-coil relays

are used:

1. Where a sensitive relay is required

2. To provide a high drop-off/pick up ratio

3. Where the relay can be subjected to a continuous overload of

many times its setting

4. In high-speed protection schemes.

2.4.4 Thermal relays

These are relays in which the operating quantity generates heat in a

resistance winding and so affects some temperature-sensitive component. Most

protective relays of the thermal type are based upon the expansion of metal, a

typical example being the use of bimetal material. Thermal relays are suitable for

use as overload relays where good accuracy and a long time delay are required.

2.4.5 Timing relays

In some circumstances a time delay is required in conjunction with

protection relays. These fall into three distinct groups:

1. Short-time relays

2. Medium-value accurate-time delays

12

3. Long time relays

Design of the protective relays with certain certain principles as:

a) Simplicity

b) High operating force

c) High contact pressure

d) Contact circuit voltage

e) Contact-making action

f) Minimum size of wire

g) Enclosures

2.4.6 Static relays

At the outset, change from electromechanical relays to static relays was

very slow because of the relative costs. Since the cost of electronic relays

became less than the cost of equivalent electromechanical relays the transition

has been rapid and practically all-new installations are being equipped with

electronic types. The electromechanical relay will be with us for many years to

come and so are described not only for this reason but because the operation and

application of the electronic equivalents will be more easily understood.

13

2.5 REQUIREMENTS

Main characteristics of protective relaying equipment are sensitivity,

selectivity, speed and reliability. Relaying equipment must be sufficiently

sensitive to operate reliably when required under the actual conditions that

produce a slight operating tendency. However, it should not operate in a wrong

manner. The ability of the protective relay system to operate so as to trip only the

minimum number of breakers directly controlling the defective part of the system

is called selectivity of the relaying system. A protective relay must operate at the

required speed and must be reliable. The speed at which relays and circuit

breakers operate has a direct bearing on the quality of service to the consumer,

stability of the system, and the amount of power that could be transmitted

without endangering the life and equipment. The use of protective relays should

be evaluated on the basis of its contribution to the best economy in service to

consumers.

2.6 PROTECTIVE RELAY APPLICATION IN ELECTRICAL NETWORK

1. Phase overcurrent relay

This relay is set to avoid operation on all of those normal conditions to which they may be subjected.

2. Ground overcurrent relays

This relay is advantage of utilizing a current source that supplies little or no normal current to the relays.

3. Directional overcurrent relays.

4. Phase overcurrent relays.

5. Ground overcurrent relays.

14

2.7 PROTECTIVE RELAYING

Protective relaying is the basic form of electrical automatic equipment and is

indispensable for normal and dependable operation of modern power distribution

systems. When a fault occurs, the protection detects and disconnects the faulty section

from the system, acting on the circuit breakers for tripping. When an abnormal

condition, protection detects and depending on the nature of disturbance, performs the

necessary operations to restore the normal conditions or a tripping action to circuit

breaker.

2.7.1 Applications

Types There are two broad categories of protection; primary and backup. The

primary is the first line protection but some form of backup protection must be

provided. There are two such forms; local and remote. Local backup protection is

provided at the same location as the primary protection, whereas remote backup

protection as the name implies, is applied at another switching station. An

example of remote backup protection is the simple time graded relays as shown

in figure 2.2. A fault at F1 would normally be seen first by relay R1 and isolated

by the circuit breaker at R1. In the event of failure of the relay or associated

equipment at R1, the fault would be isolated by the operation of the relay R2.

Similarly, if a fault were at F2, in case the relay or allied equipment fails at R2,

the fault would be cleared by relay R3.

15

Figure 2.2 Circuit of Time Graded Scheme

2.7.2 System

Successful application of protective gear involves thorough knowledge of

the system to be protected and the method of its operation. The maximum and

minimum fault levels for different types of faults occurring at different points of

the system must be calculated. The maximum load current must be known to

determine whether the ratio of the minimum fault current to maximum load

currents is high enough to enable simple overcurrent operated relays to be used

successfully.

R3 R2 R1

F2 F1

16

2.7.3 Scheme

After the system details have been studied, a suitable protective scheme

can be chosen. The choice depends on following factors. The protective scheme

chosen will normally be supplied with samples of the system current and voltage

by means of current and voltage transformers.

The following are the common protection scheme used:

a) Time-graded overcurrent protection

This is based on the time/current principle of protection.

b) Distance protection

It serves the need for faster clearing times as the fault level increases and

also because of the difficulty in grading time/overcurrent relays with the

ever increasing number of switching stations creating more stage of

protection. Normally applied for feeder protection of 66,110 and 132kV

and above lines.

c) Differential protection

It consists of pilot wire protection and is quick acting. Generally applied

for transformers having capacity about 5-10MVA and above.

d) Restricted earth fault protection

Normally used for winding of the transformer connected in star, where

the neutral point is either solidly earthed or earthed through impedance.

The relay used is of high impedance type to make the scheme stable for

external faults.

17

2.8 RELAY COORDINATION CONCEPT

2.8.1 Radial System

The specific protective relay as primary or backup is important in

distribution system. When relay applied to protect its own system element it is

thought of primary relay, when to backup other relays for fault at remote

location, it is serving as backup relay. Providing both functions simultaneously;

serving primary relay for its own zone protection and backup relay for remote

zone of protection. The protective relay must be time-coordinated, so that the

primary relay will always operate faster than the backup relay. So, the setting and

coordination of the relay is the very important part to make sure which relay

stands for primary and the other one for backup.

2.8.2 Ring System

To setting relay, the same method is used for both ring and radial system.

However, the circuit must be opened, start at the source point to form a two

radial circuit before setting the relay. First, followed the clockwise and system

will form the relay as 5-4-3-2-1 by referring figure 2.3. The relay setting start

with R1 and the concept same like radial system. Second, followed the anti-

clockwise and the system will form a radial circuit like e-d-c-b-a as shown

below. The relay setting start with Ra and the coordination concept same like

radial system. For time setting multiplier (TSM) value, set with minimum value

for primary relay and increased for backup relay.

18

Figure 2.3 Relay coordination concepts for ring system

2.9 OVERCURRENT RELAY

2.9.1 Overcurrent Protection

The overcurrent relay is probably the most straightforward type of

protective relay. It monitors the current flowing in the phase conductor and

therefore its operating level must be set above the normal healthy level of current

in the circuit. It is important to realize that overcurrent relays are designed as

fault detecting devices and should not be thought of as overload devices.

19

2.9.2 Overcurrent IDMT Type Relays

The overcurrent relay, which gives inverse definite minimum time

characteristics essentially, consists of an ac metre mechanism modified to give

the required characteristics. The upper electromagnet has two windings. One is

connected to the CT in line for the equipment to be protected and is tapped at

intervals. The tappings are connected to a plug setting bridge by which the

number of turns in use can be adjusted, thus giving the desired current setting.

The second winding is energized by induction from the primary and is connected

to the winding of the lower electromagnet. The disc spindle carries a moving

contact which bridges two fixed contacts when the disc has rotated through an

angle, which can be adjusted to give any desired time setting.

2.10 OVERCURRENT SCHEMES

2.10.1 Shortcomings

The inherent shortcomings of overcurrent schemes are:

a. Inability to distinguish between operating conditions at maximum

generation and fault conditions at minimum generation.

b. Comparatively large fault clearing time involved in clearing the

faults.

c. Increased settings at the generating ends in order to provide

suitable discrimination times between sections.

20

2.10.2 Overcurrent Relay in a Distribution System

The application of overcurrent relays in a system is not simple and

requires a thorough checking of the other components for coordination within the

system for reliable protection. To ensuring proper protection in distribution

system, the following steps are involved. A single line diagram of the system is

drawn with various elements, such as bus bars, transformers, CTs ratio marked

so that a clear picture is obtained of the system. Information of the relays used

and all the settings must collect and recorded. Current settings are tentatively

decided next to allow maximum full load currents continuously.

2.11 TIME GRADED OVERCURRENT PROTECTION

The principle electromechanical relay used for this application is the

inverse-time relay that is an induction relay in which torque is proportional to I2.

This relay has a range of current settings, usually 50% to 200% of nominal

current in 25% steps. The setting is generally selected by the position of a plug in

a plug bridge, which determines the number of active turns on the operating coil

and therefore the current setting. The relay operating time can also be varied. At

the maximum time setting the disc has to travel through 180 before contact is made. By moving the disc reset position closer to the contact-making position the

operating time can be reduced. There is an adjuster, known as the multiplier,

with a calibrated scale of 0.1 to 1.0, which is used to set, the disc reset position.

The standard relay has a characteristic:

T = 3(logM)-1 or 3/ log M

21

Where, M is the multiple of setting. This type of relay is known as the Inverse

Definite-Minimum Time (IDMT) relay.

2.11.1 Settings

When determining a setting for an IDMT relay a number of allowances

made by BS142 must be taken into account. BS142 states that the relay must

definitely operate at 130% setting. Modern electromechanical relays have a reset

figure of 90% and a operate figure of 110%. These affect the choice of plug

setting in two ways:

1. Under normal full-load conditions, the relay occupies the fully reset position

2. Plug setting should be chosen so that the overload current does not exceed

1.1 times the setting.

The current setting can be adjusted in 5% steps which allow a much closer

setting than that which is possible with the 25% steps associated with

electromechanical relays. If the relay which should operate first was given a

current setting higher than the following relay, at lower values of current

discrimination may result. Therefore the general rule is that the current setting of

a relay nearer the source must always be the same or higher than the setting of

the preceding relay.

2.11.2 Time-multiplier setting

There are four factors which affect the discrimination period between relays.

1. A variation from the ideal characteristic curve for which an error in time of

0.1s is used for calculation purposes.

22

2. Overshoot, disc movement after the removal of current.

3. Circuit breaker operating time, 0.15s is allowed.

4. Contact gap. To ensure that a relay still has a short distance to travel when

the fault is cleared by the relay with which it is discriminating.

The minimum discrimination period of 0.4s is the time interval between relay

operations at the maximum fault level. Figure 2.4 shows the standard IDMT

current-time characteristic of different value Time Setting Multiplier. The

vertical axis of current-time graph is Time Setting multiplier and horizontal axis

is Plug Setting Multiplier.

Figure 2.4 Standard IDMT current-time characteristic

CHAPTER 3

SOFTWARE

3.1 INTRODUCTION

This project used SKM Power Tools for Windows for simulation part. Two

functions, Distribution Analysis for Power Planning Evaluation and Reporting

(DAPPER) and Computer Aided Plotting for Time Overcurrent Reporting (CAPTOR)

are used to setting and coordination of overcurrent relay. The simulation used real data

such as bus voltage, load demand, and nominal transformer rating, which are taken from

Universiti Teknologi Malaysia Distribution.

Figure 3.4 shows the single line diagram of UTM Distribution used in this

project. For simulation using SKM Power Tools, the whole system was dividing into 2

zones. This will make the coordination work easier and systematic.

24

3.2 SKM Power Tools for Windows

SKM Power Tools for Windows is used to model and analyze power system and

coordinate protective relays. SKM Power Tools is electrical engineering analysis

software developed by SKM Systems Analysis. SKM also provides several analysis and

simulation with the functions of report and graph generating automatically. The several

purposes are:

1. Power Systems designing/modeling

2. Short circuit test and fault analysis

3. Load flow and demand load current analysis

4. Time current coordination for protection system

5. Harmonic analysis

6. Motor starting analysis

7. Transient stability simulation

Two main functions from SKM Power Tools will be used in the simulation, namely

Distribution Analysis for Power Planning Evaluation and Reporting (DAPPER) and

Computer Aided Plotting for Time Overcurrent Reporting (CAPTOR).

3.2.1 DAPPER (Distribution Analysis for Power Planning Evaluation and

Reporting)

This function is used to analyze and modeling power system with balance system

studies including load flow, demand load and power system fault. Start with modeling

the single line diagram and enter all the required data for the component that been used

in the system. After modeling, run the balance system and all the result will be listed

down in report function. Results will be used for other studies such as relay setting and

coordination.

25

Component editor

Component Editor is a dialog box that lets you easily add, edit, copy, and delete

system components in a convenient list format. Automatically generate one-line

diagrams from system data entered through the Component Editor. Equipment list

expands to show connections between system components allowing easy navigation.

Sort devices by type, or run queries to list equipment according to your own criteria such

as component type, voltage drop limits, voltage range, group association, etc. Figure 3.1

shows the component editor function used in SKM to modeling the single line power

system.

Figure 3.1 Component editor function

Libraries Save Time, Automate Data Entry, and Standardize Designs

User-definable libraries for cables, transformers, loads, motors and protective

devices ensure consistency and minimize data entry. Customize libraries to precisely

model equipment from the manufacturers published data. Switch libraries within a

single project to rapidly evaluate what if scenarios. Extensive default libraries can be

applied directly to any project. Advanced libraries for sub-transient level generator and

26

motor models, user-definable governors, exciters, power system stabilizers, frequency-

sensitive loads, protective devices, harmonic sources, reliability failure rates, DC

components, and transmission line configurations.

3.2.2 CAPTOR (Computer Aided Plotting for Time Overcurrent Reporting)

This function is used for coordination the protective devices. CAPTOR allows us

to change the setting for protective devices and plot the current-time graph

automatically. The current-time coordination report shows the information of device

setting, operating time and fault duty of the relay. Appendix A shows the example of

CAPTOR Report.

3.3 SKM in Relay Coordination

There are four major steps for setting and coordination of overcurrent relay in

distribution system in order to design good protection system.

1. Modeling

2. Simulation and analysis

3. Coordination

4. Evaluation

27

3.3.1 Modeling

Start with modeling the single line diagram based on real diagram. Select the

components in software library that categorized by function and specification. Based on

the real data of the component, components rating will be set in Component Editor.

3.3.2 Simulation and analysis

After modeling the system, run the model to get basic data such as fault current

and load flow. To run the system, select the balanced system studies function. The

output report will generate automatically for each studies for review. The examples of

balanced system study setup are demand load (dl.rpt), load flow (lf.rpt) and short circuit

(sc.rpt) shown in Appendix E and Appendix F.

3.3.3 Coordination

After running the balanced system studies, the simulations continue with

coordination part. In order to do that, data like fault current and demand load must be

obtained in advanced. To start the coordination, select the specific component in single

line diagram, and then press the right click mouse. Select the TCC drawing and as a

result, the current-time graph will be plotted together with component curve. The

voltage and fault current that applied to component are shown in component setting.

From the voltage and fault current data, the setting and coordination for overcurrent

relay can be done. The series rating must be filled with a value that larger than fault

current. Series rating is the value of current rating multiple with instantaneous value. So

that, the specified device can operates within the current range. The current transformer

28

ratio and relay setting can be found in setting section. The value of current transformer

ratio should be referring to demand load of that components, normally set higher than

demand current. Relay setting- (Tap, Standard Inverse, and Instantaneous) will make the

curve and operating time of relay change depend on that value. Adder/Shifter has to be

set to find out the operating time of protection devices. Figure 3.4 shows the relay adder,

shifter, and calibration points function. The value of adder/shifter should refer to

Instantaneous.

Figure 3.2 Relay adder, shifter, and calibration points function.

3.3.4 Evaluation

The TCC report includes the device setting, fault duty, voltage and operating

time. The report is generating automatically, choose the report function to see all the

report data. Coordination of protection devices can be evaluated by referring to TCC

report and checking the relay operating time. TCC also give the information about

functionality of protection system. There are four setting used in this report:

1. Time Setting Multiplier (TSM) is the Standard Inverse

29

2. Plug Setting Multiplier (PSM) is the Instantaneous

3. Relay Operating Time (ROT) is the Test Point in TCC report

4. RCOT is ROT/TSM

Figure 3.5 shows the example settings of IDMT overcurrent relay.

Figure 3.3 Setting of IDMT overcurrent relay

30

Figure 3.4 Single Line Diagram of UTM Power Distribution [7]

CHAPTER 4

RESULT AND DISCUSSION

4.1 Introduction

This chapter presents the simulation results of setting and coordination of

overcurrent relay in UTM distribution system. Start with modeling the single line using

DAPPER in SKM Power Tools and enter the real components rating. Then, run the

balanced system studies to get the data like load flow, short circuit current and demand

load. To setting and coordinate the overcurrent relays, used the CAPTOR TCC function

for each relay and the current-time graph will be plotted automatically. Finally, go to the

TCC report function to generate the CAPTOR TCC report that shown in Appendix A.

Figure 4.1 shows the single line diagram for Zon 1 that used in simulation part. For

simulation using SKM Power Tools, the whole system was dividing into 2 zones, Zon 1

and Zon 2. This will make the coordination work easier and systematic.

32

4.2 RESULT OF SIMULATION FOR ZON 1

Figure 4.1 Single line diagram of UTMs distribution for ZON 1 [7]

22kV

R7

R13

R1

R12

R2

R11

R15

R16

R14

R6

R8

R5

R27

R26

R9

R4

R3

R10 R22

R25 R23

R21

R20 R19

R18 R17

R24

PMU

33

Figure 4.2 shows the single line for Zon 1, UTM that modeling in DAPPER

functions. All the components rating must be correct to make sure the system working

properly.

Figure 4.3 shows the current-time graph for Zon1, UTM. From the graph, the

coordination of the relay will be obtained. For example, R21, R22 and R27 will be work

as primary relay because the curve was plotted at minimum operating time. But, R13

and R14 will be work as back-up relay because the curve was plotted at maximum

operating time.

Figure 4.4 shows the current-time graphs for different setting of TSM in Zon 1,

UTM. Compare the graph from figure 4.3; the curve of selected relay was plotted at

different operating time because the different setting of Time Setting Multiplier. Figure

4.4 shows when the TSM increased, the operating time of relay also increased.

34

Figure 4.2 Single line diagrams for Zon 1, UTM using SKM Power Tools [7]

35

Figure 4.3 Current-time graphs for Zon 1, UTM

36

Figure 4.4 Current-time graphs for different setting of TSM in Zon 1, UTM

37

4.2.1 Result for overcurrent relay setting in Zon 1, UTM

Table 4.1 shows the setting of overcurrent relay in Zon 1, UTM. A relay setting

like PSM, TSM, ROT and RCOT was shown in this table. The different value of Relay

Operating Time (ROT) depends on the setting of Plug Setting Multiplier (PSM) and

Time Setting Multiplier (TSM). For example, the setting of PSM for relay R1 is 18 and

setting of TSM is 0.1. Then, the relay will take 0.235s to send the signal to circuit

breaker to operate. This time is called as Relay Operating Time (ROT).

Table 4.1 Setting of overcurrent relay in Zon 1, UTM

Relay Setting Result

R1 PSM

RCOT

TSM

ROT

18

2.35

0.1

0.235s

R2 PSM

RCOT

TSM

ROT

18

2.355

0.2

0.471s

R3 PSM

RCOT

TSM

ROT

18

2.353

0.3

0.706s

R4 PSM

RCOT

TSM

ROT

18

2.353

0.4

0.941s

38

R5 PSM

RCOT

TSM

ROT

18

2.353

0.45

1.059s

R6 PSM

RCOT

TSM

ROT

11

2.85

0.5

1.425s

R7 PSM

RCOT

TSM

ROT

11

2.85

0.6

1.710s

R8 PSM

RCOT

TSM

ROT

18

2.35

0.1

0.235s

R9 PSM

RCOT

TSM

ROT

18

2.355

0.2

0.471s

R10 PSM

RCOT

TSM

ROT

18

2.353

0.3

0.706s

R11 PSM

RCOT

TSM

ROT

18

2.353

0.4

0.941s

R12 PSM

RCOT

TSM

18

2.353

0.45

39

ROT 1.059s

R13 PSM

RCOT

TSM

ROT

11

2.85

0.5

1.425s

R14 PSM

RCOT

TSM

ROT

11

2.85

0.6

1.710s

R15 PSM

RCOT

TSM

ROT

18

2.352

0.25

0.588s

R16 PSM

RCOT

TSM

ROT

18

2.353

0.3

0.706s

40

4.2.2 Different setting of Time Setting Multiplier (TSM) in Zon 1, UTM

Meanwhile, results for different setting of overcurrent relay in Zon 1 are shown

in Table 4.2. A relay setting like PSM, TSM, ROT and RCOT was shown in this table.

The different value of Relay Operating Time (ROT) depends on the setting of Plug

Setting Multiplier (PSM) and Time Setting Multiplier (TSM). Different setting of Time

Setting Multiplier was conduct to see the relation between Time Setting Multiplier and

Relay Operating Time. From the result, when the TSM value is minimum (0.1), the

operating time of relay will be the minimum value. That means, the operating time of

relay depends on the setting of TSM value. For example, the setting of PSM for relay

R27 is 27 and setting of TSM is 0.1. Then, the relay will take 0.205s to send the signal to

circuit breaker to operate. This time is called as Relay Operating Time (ROT). But,

when the TSM is 0.5 the relay will take 1.027s to send the signal to circuit breaker.

Table 4.2 Setting of overcurrent relay in Zon 1, UTM (different setting of TSM)

Relay Setting Result 1 Result 2

R17 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R18 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R19 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R20 PSM 30 30

41

RCOT

TSM

ROT

1.99

0.1

0.199s

1.988

0.5

0.994s

R21 PSM

RCOT

TSM

ROT

27

2.05

0.2

0.205s

27

2.054

0.5

1.027s

R22 PSM

RCOT

TSM

ROT

27

2.05

0.1

0.205s

27

2.054

0.5

1.027s

R23 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R24 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R25 PSM

RCOT

TSM

ROT

30

1.99

0.1

0.199s

30

1.988

0.5

0.994s

R26 PSM

RCOT

TSM

ROT

27

2.05

0.1

0.205s

27

2.054

0.5

1.027s

R27 PSM

RCOT

TSM

ROT

27

2.05

0.1

0.205s

27

2.054

0.5

1.027s

42

4.3 RESULT OF SIMULATION FOR ZON 2

Figure 4.5 Single line diagram of UTMs distribution for ZON 2 [7]

22kV

R1

R2

R10

R9

R8

R7

R6

R5

R11

R4

R3

R24 R23

R22

R21

R20

R19

R18

R17

R16

R15

R14

R13

R12

R35

R33 R32

R31

R29

R28

R27

R26 R25

R34

PMU

R30

43

Figure 4.6 shows the single line for Zon 2, UTM that modeling in DAPPER

functions. All the components rating must be correct to make sure the system working

properly.

Figure 4.7 shows the current-time graph for Zon 2, UTM. From the graph, the

coordination of the relay will be obtained. For example, R27, R28 and R29 will be work

as primary relay because the curve was plotted at minimum operating time. But, R10

and R11 will be work as back-up relay because the curve was plotted at maximum

operating time.

Figure 4.8 shows the current-time graphs for different setting of TSM in Zon 2,

UTM. Compare the graph from figure 4.7; the curve of selected relay was plotted at

different operating time because the different setting of Time Setting Multiplier. Figure

4.8 shows when the TSM increased, the operating time of relay also increased.

44

Figure 4.6 Single line diagrams for Zon 2, UTM using SKM Power Tools [7]

45

Figure 4.7 Current-time graphs for Zon 2, UTM

46

Figure 4.8 Current-time graphs for different setting of TSM in Zon 2, UTM

47

4.3.1 Result for overcurrent relay setting in Zon 2, UTM

Table 4.3 shows the setting of overcurrent relay in Zon 2, UTM. A relay setting

like PSM, TSM, ROT and RCOT was shown in this table. The different value of Relay

Operating Time (ROT) depends on the setting of Plug Setting Multiplier (PSM) and

Time Setting Multiplier (TSM). For example, the setting of PSM for relay R22 is 11 and

setting of TSM is 0.9. Then, the relay will take 2.565s to send the signal to circuit

breaker to operate. This time is called as Relay Operating Time (ROT).

Table 4.3 Setting of overcurrent relay in Zon 2, UTM

Relay Setting Result

R1 PSM

RCOT

TSM

ROT

11

2.85

0.1

0.285s

R2 PSM

RCOT

TSM

ROT

11

2.85

0.2

0.570s

R3 PSM

RCOT

TSM

ROT

11

2.85

0.3

0.855s

R4 PSM

RCOT

TSM

ROT

11

2.849

0.35

0.997s

R5 PSM

RCOT

11

2.85

48

TSM

ROT

0.4

1.140s

R6 PSM

RCOT

TSM

ROT

11

2.849

0.45

1.282s

R7 PSM

RCOT

TSM

ROT

11

2.85

0.5

1.425s

R8 PSM

RCOT

TSM

ROT

11

2.85

0.6

1.710s

R9 PSM

RCOT

TSM

ROT

11

2.85

0.7

1.995s

R10 PSM

RCOT

TSM

ROT

11

2.85

0.8

2.820s

R11 PSM

RCOT

TSM

ROT

11

2.85

0.9

2.565s

R12 PSM

RCOT

TSM

ROT

11

2.85

0.1

0.285s

R13 PSM 11

49

RCOT

TSM

ROT

2.85

0.2

0.570s

R14 PSM

RCOT

TSM

ROT

11

2.85

0.3

0.855s

R15 PSM

RCOT

TSM

ROT

11

2.849

0.35

0.997s

R16 PSM

RCOT

TSM

ROT

11

2.85

0.4

1.140s

R17 PSM

RCOT

TSM

ROT

11

2.849

0.45

1.282s

R18 PSM

RCOT

TSM

ROT

11

2.85

0.5

1.425s

R19 PSM

RCOT

TSM

ROT

11

2.85

0.6

1.710s

R20 PSM

RCOT

TSM

ROT

11

2.85

0.7

1.995s

50

R21 PSM

RCOT

TSM

ROT

11

2.85

0.8

2.280s

R22 PSM

RCOT

TSM

ROT

11

2.85

0.9

2.565s

4.3.2 Different setting of Time Setting Multiplier (TSM) in Zon 2, UTM

Table 4.4 shows the different setting of overcurrent relay in Zon 2, UTM. A relay

setting like PSM, TSM, ROT and RCOT are shown in this table. The different value of

Relay Operating Time (ROT) depends on the setting of Plug Setting Multiplier (PSM)

and Time Setting Multiplier (TSM). Different setting of Time Setting Multiplier was

conduct to see the relation between Time Setting Multiplier and Relay Operating Time.

From the result, when the TSM value is minimum (0.1), the operating time of relay will

be the minimum value. That means, the operating time of relay depends on the setting of

TSM value. For example, the setting of PSM for relay R35 is 25 and setting of TSM is

0.1. Then, the relay will take 0.211s to send the signal to circuit breaker to operate. This

time is called as Relay Operating Time (ROT). But, when the TSM is 0.5 the relay will

take 1.053s to send the signal to circuit breaker.

51

Table 4.4 Setting of overcurrent relay in Zon 2, UTM (different setting of TSM)

Relay Setting Result 1 Result 2

R23 PSM

RCOT

TSM

ROT

15

2.52

0.1

0.252s

15

2.515

0.4

1.006s

R24 PSM

RCOT

TSM

ROT

15

2.52

0.1

0.252s

15

2.515

0.4

1.006s

R25 PSM

RCOT

TSM

ROT

18

2.35

0.1

0.235s

18

2.353

0.3

0.706s

R26 PSM

RCOT

TSM

ROT

18

2.35

0.1

0.235s

18

2.353

0.3

0.706s

R27 PSM

RCOT

TSM

ROT

25

2.11

0.1

0.211s

25

2.106

0.5

1.053s

R28 PSM

RCOT

TSM

ROT

16

2.46

0.1

0.246s

16

2.456

0.5

1.228s

R29 PSM

RCOT

TSM

25

2.11

0.1

25

2.104

0.25

52

ROT 0.211s 0.526s

R30 PSM

RCOT

TSM

ROT

16

2.46

0.1

0.246s

16

2.456

0.25

0.614s

R31 PSM

RCOT

TSM

ROT

25

2.11

0.1

0.211s

25

2.105

0.4

0.842s

R32 PSM

RCOT

TSM

ROT

19

2.31

0.1

0.231s

19

2.307

0.3

0.692s

R33 PSM

RCOT

TSM

ROT

19

2.31

0.1

0.231s

19

2.308

0.5

1.154s

R34 PSM

RCOT

TSM

ROT

25

2.11

0.1

0.211s

25

2.104

0.45

0.947s

R35 PSM

RCOT

TSM

ROT

25

2.11

0.1

0.211s

25

2.106

0.5

1.053s

53

4.3 DISCUSSION

Based on the result, it is observed that the Time Setting Multiplier (TSM) was set

to 0.1 for primary relay and the delay time for backup relay is 0.5s. The setting of relay

can be adjusted from the TCC graph in order to determine the right setting and

coordination. For relay setting, Tap will set the starting operate time for relay and it will

move the curve vertically. Standard inverse will influence the real operating time (ROT)

as it is the time setting multiplier. The standard inverse also will move the curve

vertically in the current-time graph. Instantaneous is plug setting multiplier (PSM) it will

control the operating range of relay and can extend the curve in TCC graph. For the different setting of TSM, the lower value of TSM will make the relay work as primary

relay. Appendix A, Appendix B, Appendix C, and Appendix D shows CAPTOR TCC

report for single line diagram in UTMs distribution. The setting value of overcurrent

relay such as Plug Setting Multiplier, Time Setting Multiplier, Tap, and Current Rating

will be checked by referring this CAPTOR Report.

Overcurrent relays are added to protect the system and relay coordination can be

done. For a huge system, separate the whole system to several zones according to bus

voltage. This will make the setting and coordination work much easier and systematic.

CHAPTER 5

CONCLUSION AND RECOMMENDATION

5.1 CONCLUSION

For the conclusion, the main objective to setting and coordinate the overcurrent

relay types IDMT for power distribution system are obtained. The setting and

coordination of relay has been done for radial and ring system. The current-time graph

for each relays that used in distribution system was automatically plotted by CAPTOR

TCC function. The Relay Operating Time depends on the setting of PSM and TSM

value. The effect of increasing Time Setting Multiplier is to increase the Relay

Operating Time.

55

5.2 RECOMMENDATIONS

There are some recommendations for further study in this topic:

1. Used different types of relays such as directional overcurrent relay, earth

fault protection and others. Some distribution system used different types of

relay like earth fault relay and directional overcurrent relay. The different

types of relay can be used to compare the operating time at different setting

of relays.

2. Combined all the protection system for distribution system and transmission

system. For transmission system, the protection that applied was different

with distribution system. So, if distribution and transmission system was

combined, we should get the different setting and coordination according to

the system.

56

REFERENCES

[1] Mohd Zin, A.A., Kejuruteraan Sistem Kuasa, Edisi Kedua, UTM, 2007

[2] Davies, T., Protection of Industrial Power Systems, Second Edition, Newnes,

1996

[3] Alberto J.Urdaneta, Luis G. Perez (1999), Optimal Coordination of Directional

Overcurrent Relay considering Definite Time Backup Relaying, Venezuela:

Universidad Simon Bolivar.

[4] Pabla, A. S., Electic Power Distribution, McGraw-Hill, 2005

[5] A.R. Van C. Warrington, Protective Relays: Theory and Practice, Chapman and

Hall Ltd., 1968.

[6] SKM Power Tools for Windows Manual & www.skm.com

[7] Single Line Diagram of 22kV Distribution Substation UTM, Pejabat Harta Bina

UTM Skudai, 2007.

[8] Ravindranath, B. and Chander, M., Power System Protection and Switchgear,

John Wiley & Sons, 1987

57

APPENDIX A

CAPTOR TCC Report for Single Line Zon 1, UTM

----------------------------------------------------------------------------------------- Apr 15, 2008 15:11:08 Page 1 Project Name: zon1 TCC Name: latest.tcc Reference Voltage: 22000 V Current Scale: X 10^0 TCC Notes: TCC Comment: Fault Duty Option: Study Result - Bus Fault Current ----------------------------------------------------------------------------------------- ALL INFORMATION PRESENTED IS FOR REVIEW, APPROVAL, INTERPRETATION, AND APPLICATION BY A REGISTERED ENGINEER ONLY. SKM DISCLAIMS ANY RESPONSIBILITY AND LIABILITY RESULTING FROM THE USE AND INTERPRETATION OF THIS SOFTWARE. ----------------------------------------------------------------------------------------- CAPTOR (Computer Aided Plotting for Time Overcurrent Reporting) COPYRIGHT SKM SYSTEMS ANALYSIS, INC. 1983-2006 ----------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------- Device Name: R-7 TCC Name: latest.tcc Bus Name: BUS-1 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5248.6A Current Rating: 500A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (500A) Test Points: @11.0X, 1.710s 2) [S] Standard Inverse 0.6 @8.0X, 1.978s 3) INST 11 (5500A) @5.0X, 2.568s ----------------------------------------------------------------------------------------- Device Name: R-13 TCC Name: latest.tcc Bus Name: PE02 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5239.1A Current Rating: 500A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (500A) Test Points: @11.0X, 1.425s 2) [S] Standard Inverse 0.5 @5.0X, 2.140s 3) INST 11 (5500A) @2.0X, 5.015s

58

----------------------------------------------------------------------------------------- Device Name: R-17 TCC Name: latest.tcc Bus Name: BUS-3 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29658.6A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-18 TCC Name: latest.tcc Bus Name: BUS-3 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29658.6A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-1 TCC Name: latest.tcc Bus Name: PE02 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5239.1A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.235s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 18 (5400A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-12 TCC Name: latest.tcc Bus Name: PE03 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5228.9A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 1.059s 2) [S] Standard Inverse 0.45 @15.0X, 1.132s 3) INST 18 (5400A) @10.0X, 1.337s

59

----------------------------------------------------------------------------------------- Device Name: R-15 TCC Name: latest.tcc Bus Name: PE03 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5228.9A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.588s 2) [S] Standard Inverse 0.25 @5.0X, 1.070s 3) INST 18 (5400A) @2.0X, 2.507s ----------------------------------------------------------------------------------------- Device Name: R-16 TCC Name: latest.tcc Bus Name: PE17 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5217.8A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.706s 2) [S] Standard Inverse 0.3 @15.0X, 0.755s 3) INST 18 (5400A) @10.0X, 0.891s ----------------------------------------------------------------------------------------- Device Name: R-19 TCC Name: latest.tcc Bus Name: BUS-15 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29643.9A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-20 TCC Name: latest.tcc Bus Name: BUS-15 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29643.9A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s

60

----------------------------------------------------------------------------------------- Device Name: R-21 TCC Name: latest.tcc Bus Name: BUS-5 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 8085.0A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @27.0X, 0.205s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 27 (8100A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-2 TCC Name: latest.tcc Bus Name: PE03 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5228.9A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.471s 2) [S] Standard Inverse 0.2 @15.0X, 0.503s 3) INST 18 (5400A) @10.0X, 0.594s ----------------------------------------------------------------------------------------- Device Name: R-11 TCC Name: latest.tcc Bus Name: PE04 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5223.6A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.941s 2) [S] Standard Inverse 0.4 @10.0X, 1.188s 3) INST 18 (5400A) @2.0X, 4.012s ----------------------------------------------------------------------------------------- Device Name: R-22 TCC Name: latest.tcc Bus Name: BUS-7 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 8084.7A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @25.0X, 0.211s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 27 (8100A) @10.0X, 0.297s

61

----------------------------------------------------------------------------------------- Device Name: R-3 TCC Name: latest.tcc Bus Name: PE04 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5223.6A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.706s 2) [S] Standard Inverse 0.3 @10.0X, 0.891s 3) INST 18 (5400A) @5.0X, 1.284s ----------------------------------------------------------------------------------------- Device Name: R-10 TCC Name: latest.tcc Bus Name: PE05 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5223.6A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.706s 2) [S] Standard Inverse 0.3 @15.0X, 0.755s 3) INST 18 (5400A) @10.0X, 0.891s ----------------------------------------------------------------------------------------- Device Name: R-23 TCC Name: latest.tcc Bus Name: BUS-9 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29648.1A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-24 TCC Name: latest.tcc Bus Name: BUS-9 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29648.1A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s

62

----------------------------------------------------------------------------------------- Device Name: R-25 TCC Name: latest.tcc Bus Name: BUS-9 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29648.1A Current Rating: 1000A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (1000A) Test Points: @30.0X, 0.199s 2) [S] Standard Inverse 0.1 @20.0X, 0.227s 3) INST 30 (30000A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-4 TCC Name: latest.tcc Bus Name: PE05 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5223.6A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.941s 2) [S] Standard Inverse 0.4 @15.0X, 1.006s 3) INST 18 (5400A) @10.0X, 1.188s ----------------------------------------------------------------------------------------- Device Name: R-9 TCC Name: latest.tcc Bus Name: PE06 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5228.9A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.471s 2) [S] Standard Inverse 0.2 @15.0X, 0.503s 3) INST 18 (5400A) @10.0X, 0.594s ----------------------------------------------------------------------------------------- Device Name: R-26 TCC Name: latest.tcc Bus Name: BUS-11 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 15693.2A Current Rating: 600A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (600A) Test Points: @27.0X, 0.205s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 27 (16200A) @10.0X, 0.297s

63

----------------------------------------------------------------------------------------- Device Name: R-5 TCC Name: latest.tcc Bus Name: PE06 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5228.9A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 1.059s 2) [S] Standard Inverse 0.45 @15.0X, 1.132s 3) INST 18 (5400A) @10.0X, 1.337s ----------------------------------------------------------------------------------------- Device Name: R-8 TCC Name: latest.tcc Bus Name: PE07 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5235.1A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @18.0X, 0.235s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 18 (5400A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-27 TCC Name: latest.tcc Bus Name: BUS-13 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 8085.3A Current Rating: 300A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (300A) Test Points: @27.0X, 0.205s 2) [S] Standard Inverse 0.1 @15.0X, 0.252s 3) INST 27 (8100A) @10.0X, 0.297s ----------------------------------------------------------------------------------------- Device Name: R-6 TCC Name: latest.tcc Bus Name: PE07 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5235.1A Current Rating: 500A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (500A) Test Points: @11.0X, 1.425s 2) [S] Standard Inverse 0.5 @5.0X, 2.140s 3) INST 11 (5500A) @2.0X, 5.015s

64

----------------------------------------------------------------------------------------- Device Name: R-14 TCC Name: latest.tcc Bus Name: BUS-1 Bus Voltage: 22000.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 5248.6A Current Rating: 500A / 5A Curve Multiplier: 1 Setting: 1) Tap, Is 1 (500A) Test Points: @11.0X, 1.710s 2) [S] Standard Inverse 0.6 @5.0X, 2.568s 3) INST 11 (5500A) @2.0X, 6.017s

65

APPENDIX B

CAPTOR TCC Report for Single Line Zon 1, UTM (Different setting of TSM)

---------------------------------------------------------------------------------------- Apr 15, 2008 15:36:19 Page 1 Project Name: zon1 TCC Name: diffsetting.tcc Reference Voltage: 433 V Current Scale: X 10^0 TCC Notes: TCC Comment: Fault Duty Option: Study Result - Bus Fault Current ----------------------------------------------------------------------------------------- ALL INFORMATION PRESENTED IS FOR REVIEW, APPROVAL, INTERPRETATION, AND APPLICATION BY A REGISTERED ENGINEER ONLY. SKM DISCLAIMS ANY RESPONSIBILITY AND LIABILITY RESULTING FROM THE USE AND INTERPRETATION OF THIS SOFTWARE. ----------------------------------------------------------------------------------------- CAPTOR (Computer Aided Plotting for Time Overcurrent Reporting) COPYRIGHT SKM SYSTEMS ANALYSIS, INC. 1983-2006 ----------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------- Device Name: R-17 TCC Name: diffsetting.tcc Bus Name: BUS-3 Bus Voltage: 433.0V Function Name: Phase Manufacturer: GEC Description: In=5A Sub Type: MCGG 22, 42, 52, 53, 62, 63, 82 Class Description:MCGG AIC Rating: N/A Fault Duty: 29658.6A Current Rating: 1000A / 5A