Analysis on Distance Relay Setting and Coordination at 150 KV

High Voltage Transmission Line Kentungan Godean Bantul Semanu

Yusnan Badruzzaman and Afrizal Fawaid Fasihfauzi Ahmad

D3 Electrical Engineering Study Program, Electrical Engineering Department, Semarang State Polytechnic,

Jl. Prof. H. Soedarto, SH Tembalang Kota Semarang 50275, Indonesia

Keyword: Distance Relay, Setting, Impedance, Coordination.

Abstract: High voltage power lines of 150 kV are one part of the electric power transmission system that has a fairly

large potential for disturbance. The relevancy of a protection system on the High Voltage Power Lines of

150 kV. Distance relays are commonly used as the main protection of device on high-voltage power lines of

150 kV. Determining the distance relay setting requires calculating the zona impedance value and

coordination, as well as simulating short circuit faults on each line to determine each distance relay

operation. The method used is a comparative method that compares the calculation results with the settings

from PLN and is assisted by the DigSILENT software to make it easier to analyze. The results of

calculations and simulations are compared with setting from PLN. From this comparison, it is obtained the

settings form PLN got zona-3 overlapping at Substation Kentungan in the direction of Godean with zona-3

Substation Godean in the direction of Substation Bantul, the selection of zona impedance values is not

optimal in zona-2 Substation Godean in the direction of Bantul, zona-3 Substation Semanu in the direction

of Bantul and zona -3 Substation Bantul Arah GI Godean, and zona-1 Substation Kentungan in the direction

of Godean does not reach 80% of the main line.

1 INTRODUCTION

An electric power system consists of three main

parts, namely power generation, transmission system

and distribution system. The transmission system is

an important part in the distribution of electrical

energy from power plants to load centers or

consumers. The long distance between the power

plant and the load center makes the transmission

system have the potential for large disturbances.

Disturbances that occur can be caused by system

errors, as well as non-system disturbances such as

natural disturbances such as lightning strikes, fallen

trees, and storms. The fault causes a short circuit of

three phases, three phases to ground, two phases,

two phases to ground and one phase to ground.

The protection system is mandatory in the

electric power system in order to secure equipment

and separate disturbed areas. A very vital component

in the protection system is the relay. The protection

relay is one of the main components in the electric

power system that can have a major impact on the

electric power system. The protection relay will

identify a disturbance in the system by measuring

the electrical quantity that is read by a measuring

instrument which is always read in normal or fault

conditions. The relay will instruct the PMT to trip to

cut off electricity if it detects a fault condition. One

of the protection relays that are often used is the

distance relay which protects the transmission from

short circuit interference.

Distance relays are usually used as the main

safety of overhead lines on transmission networks

both at 150 kV and 500 kV voltages. The way the

distance relay works is to use the current and voltage

measurements obtained from current transformers

and voltage transformers to determine the

impedance value of a transmission line. The distance

relay will work if the impedance value read is less

than the relay setting value. If the read impedance

value exceeds the setting value, the distance relay

will not work.

Setting the distance relay greatly affects the

reliability of the relay itself, with the right setting

value, the distance relay can work optimally and

quickly in separating disturbed parts from other parts

that are still healthy and at the same time securing

healthy parts from damage or greater losses. .

Badruzzaman, Y. and Ahmad, A.

Analysis on Distance Relay Setting and Coordination at 150 KV High Voltage Transmission Line Kentungan Godean Bantul Semanu.

DOI: 10.5220/0011764400003575

In Proceedings of the 5th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2022), pages 307-312

ISBN: 978-989-758-619-4; ISSN: 2975-8246

307

Therefore, the value of the distance relay setting

must be considered properly so that the relay can

work optimally

2 RESEARCH METHODS

2.1 Research Step

Figure 1: Diagram Alir Penelitian.

2.2 Research Data

There are 6 distance relays to protect the studied

channel. The relays include GI Kentungan arag

Godean, GI Godean to Bantul, GI Godean to

Kentungan, GI Bantul to Godean, GI Bantul to

Semanu, and GI Semanu to Bantul. To be able to

calculate the setting, the following data is needed for

the conductor.

Table 1: Conductor Data.

Line Length

(km)

Positive

Sequence

Impedance

(Ω/km)

Zero

Sequence

Impedance

(Ω/km)

Kentungan -

Godean

9,1771 0,137 + j

0,3966

0,287+j

1,19

Godean -

Bantul

13,211 0,137 + j

0,3966

0,287+j

1,19

Bantul -

Semanu

39,043 0,137 + j

0,3966

0,287+j

1,19

To change the value on the primary side of the

conductor into the value of the relay side, the ratio of

the measurement tool is needed as follows.

Table 2: Ratio of Measurement Tools.

Substation Protection

Direction

Ratio

Measurement Transformer

Kentungan Godean CT 800/1 A

CVT 150.000/100V

Godean Kentungan CT 600/1 A

CVT 150.000/100V

Bantul CT 600/1 A

CVT 150.000/100V

Bantul Godean CT 1000/1 A

CVT 150.000/100V

Semanu CT 500/1 A

CVT 150.000/100V

Semanu Bantul CT 500/1 A

CVT 150.000/100V

In setting the distance relay also consider the

impedance of the power transformer in the front

substation. The following is the power transformer

impedance data at each substation:

Table 3: Power Transformer Impedance Data.

Substation Power

Transformer

Impedance (pu)

Kentungan Trafo 2 11,93 %

Trafo 3 12,06 %

Trafo 4 12,13 %

Godean Trafo 1 12,25 %

Trafo 2 12,11 %

Bantul Trafo 1 11,92 %

Trafo 2 11,51 %

Trafo 3 11,86 %

Semanu Trafo 1 12,18 %

Trafo 2 11,31 %

The distance relay works based on the read

impedance. If the read impedance is less than the

setting impedance, the relay will work, but if the

read impedance is more than the setting impedance,

the relay will not work. To be able to determine the

setting on the distance relay, the following equation

is used.

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1. Total Impedance of Conductor

In determining the setting required the total line

impedance obtained from the equation:

ZL = Z × L (1)

Where:

ZL = Total Conductor Impedance (Ω)

Z = Impedance of conductor (Ω/km)

L = conductor length (km)

1. Power Transformer Impedance

Setting the distance relay must pay attention to

the impedance of the power transformer at the

front substation. The data taken from PLN is still

in the form of pu, so it must be converted into

ohms with the equation:

Xt =

% ×





(2)

Where:

Xt = Transformer impedance (Ω)

Zt = transformer impedance (pu)

V = nominal voltage (kV)

S = Transformer capacity (MVA)

1. Ratio of CT and CVT

To change the impedance that is read on the

primary side, it is necessary to transform the

impedance to the relay side using the existing CT

and CVT ratios with the equation:

n =

 

 

(3)

Where:

n = Ratio of measuring tool

kCT = CT ratio

kCVT = CVT ratio

1. Setting Zone-1

To determine the impedance setting zone-1 can

use the following equation:

Zone-1 = n × 0.8 × ZL1 (4)

Where:

n = Ratio of measuring tool

ZL1 = Total impedance of main conductor

Zone-1 working time also needs to be set with a

working time of 0 seconds (instant)

2. Setting Zone-2

To determine the impedance setting for zone-2,

you can use the following equation:

Zona-2

min

= n × 1,2 × ZL1 (5)

Zona-2

mak1

= n × 0,8 (ZL1+0,8.ZL2) (6)

Zona-2

mak2

= n × (ZL1+0,5Xt) (7)

Where:

n = Ratio of measuring tool

ZL1 = Total impedance of main conductor

ZL2 = Total impedance of front GI shortest

conductor

Xt = Power transformer impedance

From equations (5) and (6) the largest value is

chosen but it should not exceed the impedance

value (7). Zone-2 working time also needs to be

set with a working time of 0.3-0.8 seconds.

1. Setting Zone-3

To determine the impedance setting for zone-3,

you can use the following equation:

Zona-3

min

= n × 1,2 (ZL1+ZL3) (8)

Zona-3

mak

= n × 0,8 (ZL1+0,5.Xt) (9)

Where:

n = Ratio of measuring tool

ZL1 = Total impedance of main conductor

ZL3 = Total impedance of front GI longest

conductor

Xt = Power transformer impedance

From equations (5) and (6) the largest value is

chosen. Zone-3 working time also needs to be set

with a working time of 0.8-1.6 seconds.

3 RESULTS AND DISCUSSION

3.1 Distance Relay Setting

From the results of calculations with the equations in

chapter 2, the results of the settings are as follows:

Table 4: Calculation Results of Distance Relay Settings.

Substation Protection

Direction

Zone Impedance

(Ω)

Working

Time

Kentungan Godean Zona-1 1,643 0 s

Zona-2 3,535 0,4 s

Zona-3 11,256 1,6 s

Godean Kentungan Zona-1 1,232 0 s

Zona-2 2,753 0,4 s

Bantul Zona-1 1,774 0 s

Zona-2 3,405 0,4 s

Zona-3 10,524 1,2 s

Analysis on Distance Relay Setting and Coordination at 150 KV High Voltage Transmission Line Kentungan Godean Bantul Semanu

309

Table 4: Calculation Results of Distance Relay Settings

(cont.).

Substation Protection

Direction

Zone Impedance

(Ω)

Working

Time

Bantul Godean Zona-1 2,956 0 s

Zona-2 4,599 0,4 s

Zona-3 14,939 1,2 s

Semanu Zona-1 4,369 0 s

Zona-2 6,553 0,4 s

Semanu Bantul Zona-1 4,369 0 s

Zona-2 6,553 0,4 s

Zona-3 9.987 1,6 s

From the table, the impedance setting and working

time of zone-1, zone-2, and zone-3 are obtained for

each relay for each substation.

3.2 R-X Plot Diagram

The setting results that have been obtained are

entered in the DigSILENT software simulation

program and an R-X Plot Diagram is obtained as

shown in the following figure:

Figure 2: R-X Plot Diagram of GI Distance Relay

Kentungan direction Godean.

Figure 3: R-X Plot Diagram of GI Godean Distance Relay

in Kentungan direction.

Figure 4: R-X Plot Diagram of the Godean GI Distance

Relay in the direction of Bantul.

Figure 5: R-X Plot Diagram of the Distance Relay of GI

Bantul in Godean direction.

Figure 6: R-X Plot Diagram of the Distance Relay of GI

Bantul in Semanu direction.

Figure 7: R-X Plot Diagram of the Semanu GI Distance

Relay in Bantul.

From Figure 3 to Figure 8, the protection area of

each zone is shown in a circle.

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3.3 Time Distance Diagram

The following is the Time-Distance diagram of the

simulation results using the DigSILENT software.

Figure 8: Time-Distance Diagram Setting Calculation

Results.

From Figure 8, it can be seen that the distance relay

coordination between substations is correct.

3.4 Comparison with PLN's Existing

Settings

Setting the calculation results in theory compared to

the existing PLN settings can be seen in the

following table:

Table 5: Comparison of Calculation Settings with PLN.

Substations

Direction

Protection

Zone

Calculation

Setting (Ω)

PLN

Setting

(

Ω

)

Kentungan Godean Zona-1 1,643 1,55

Zona-2 3,535 3,34

Zona-3 11,256 11,23

Godean Kentungan Zona-1 1,232 1,232

Zona-2 2,753 14,151

Bantul Zona-1 1,774 1,774

Zona-2 3,405 4,169

Zona-3 10,524 10,637

Bantul Godean Zona-1 2,956 3,138

Zona-2 4,599 4,841

Zona-3 14,939 7,7

Semanu Zona-1 4,369 4,567

Zona-2 6,553 8,194

Semanu Bantul Zona-1 4,369 4,369

Zona-2 6,553 6,553

Zona-3 9.987 14,082

From the comparison above, it can be seen that there

are existing PLN settings that are less than optimal

and there is still overlapping in the distance relay of

the Kentungan GI in the Godean direction, the

Godean GI in the Bantul direction, the Bantul GI in

the Godean direction, and the Semanu GI in the

Bantul direction.

4 CONCLUSION

1. a. Zone-1 range of distance relay protection is

80% of the main line length with formula 0.8

× ZL1.

b. The protection area from zone-2 must reach

the substation in front of it and take into

account the transformer impedance, which is

50% of the transformer impedance of the

substation in front of it with the formula ZL1

+ 0.5 Xt, and in determining the impedance

value choose the largest value between zone-

2 at least 120 % main line (1.2 × ZL1) with

zone-2 maximum (0.8 (ZL1 + 0.8 ZL2)

which pays attention to the shortest line

connected to the substation in front of it.

c. The protection area from zone-3 must cover 2

(two) substations in front of it, and in

determining the impedance value choose the

largest value between zone-3 at least (1,2

(ZL1 + ZL3) which considers the longest line

connected to the substation in front of it, with

a maximum-3 zone (0.8 (ZL1 + 0.5 Xt) with

and considering the transformer impedance at

the front substation.

d. The choice of working time for each zone

must be considered to obtain good

coordination to avoid overlapping and

optimize the performance of the protection

zone on each secured channel, namely in

zone-1 working 0 seconds (instant), in zone-2

working 0.3 - 0.8 seconds (as needed) and in

zone-3 it works 0.8 – 1.6 seconds (as

needed).

2. In the PLN settings, it is found that the protection

zone is less than optimal and overlapping,

namely at

a. zone-3 GI Kentungan is directed to GI Godean

with zone-3 GI Godean to GI Bantul with a

working time of 1.6 seconds, so it needs to be

reset.

b. In the PLN setting, it was found that zone-1

did not reach 80% of the main line, namely

the distance relay from GI Kentungan to GI

Godean with a range of 75%, so resetting was

necessary.

c. The value of the PLN zone-3 setting on the

distance relay of the Semanu GI to the Bantul

GI is 4.095 less than the calculation results,

because in determining the longest line (L3)

connected to the substation in front of it, data

is not in accordance with current conditions,

so the performance of the protection zone is

not optimal.

Analysis on Distance Relay Setting and Coordination at 150 KV High Voltage Transmission Line Kentungan Godean Bantul Semanu

311

d. The PLN setting for zone-2 relay distance

from the Godean GI to the Bantul GI

direction is greater than 0.764 because it does

not consider the High Voltage Cable Channel

(SKTT) as the shortest line, thus allowing

overlapping with the Bantul GI zone-2 in the

Wirobrajan GIS direction using SKTT.

e. The PLN setting value for zone-3 relay

distance from the Bantul GI to the Godean GI

is 7.293 less than the calculation results,

because in determining the impedance value

for zone-3, the zone-3mak does not take into

account the transformer impedance.

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