ON SITE TESTING OF AUTO RECLOSER RELAYS

B.VENU (09C31A0206)

Numerical Current Relay & Auto Recloser (JNC268)

Introduction

• Autorecloser relays are widely implemented in the electric utilities Over Head Lines networks to improve power availability and to maintain system stability.

• Site testing need to be performed before operation to ensure proper function of Autoreclosers.

• There is not much manufacturer guidance in functional site testing of Autoreclosers. Therefore, testing engineers have to carry out the functional site tests according to specific requirements of the installations.

• Application of multifunction and numerical relays has reduced the number of elements and wirings to be tested on site, but it would not eliminate the requirement to perform site testing.

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Numerical Current Relay & Auto Recloser

We are engaged in offering Numerical Current Relay & Auto Recloser.

FEATURES

• Suitable for 1A / 5 A relay rating

• Choice of 5 IDMT curve and definite time

• Programmable Over current relay or Over current relay with multi shot auto re-close

• Trip test facility

• History of 6 latest faults

• Self supervision facility

• Independent trip sequence setting (IDMT / Def. time)

• Breaker status monitoring

• Disturbance records (DR) in IEEE COMTRADE format

• Event Records ( ER)

• MODBUS open protocol over RS - 485 port

• MODBUS protocol over RS - 232 port

• Draw out facility with inbuilt CT shorting

• Standard dimension - 144mm x 144mm

PRINCIPLE OF OPERATION

The relay measures the line current from each of the phases and if it exceeds the set threshold, then relay extends a trip signal after an operating time. The relay's operating time is determined by selecting definite time OR one of the five inverse time characteristics.

Multi shot auto-re-closer facilitates automation related to closing of a breaker. Auto re-closer functionality can be programmed to provide a maximum of five shots. Dead time starts only when phase or earth fault trip occurs. After an elapse of a time interval equal to dead time, closing command will be extended. The reclaim time timer starts at the instant the dead time timer expires. If, after extending the "breaker close" signal an over current fault was detected before the reclaim time timer reached its terminal count, then the relay understands that the fault in the system is still persisting and the over current relay will issue a trip signal. The relay tries to close the breaker for a maximum of the programmed number of shots before it choses to lockout.

TECHNICAL DATA

RATINGS  

Current rating ( In ) 1A/5A( Site selectable)

Aux. Supply 20 to 60V DC

  80 to 260V AC / DC

 

An Over head line with Auto recloser relays

1. A temporary fault occur

2. Protective relays operate

– breaker tripped

CustomersUtility Substation – Power off

1. Fault extinguished

2. Autorecloser relays order the breaker to reclose

– Breaker reclose

– Power is restored automatically

An Over head line without Auto recloser relays

1. A temporary fault occur

2. Protective relays operate

Utility Substation–

breaker trippedCustomers

– Power off

1. Fault extinguished

2. Breaker need to be closed manually to restore power

TYPICAL CONFIGURATION & SETTINGof AUTORECLOSER RELAY in INDONESIA

Basic Requirement of Autorecloser Relay Performance

The Autorecloser Relay should reclose the Breaker(s) whenever it is initiated by Protective Relay

The Autorecloser Relay should not reclose the Breaker(s) if the initiation occurs during the Reclaim Time

For single pole mode, the Autorecloser Relay should only reclose the Breaker(s) for single phase to earth fault.

The Autorecloser Relay should never reclose the Breaker(s) if :

no initiation from Protective Relay (e.g. when the Breaker(s) are intentionally opened by people)

Any of the Breaker(s) is not ready

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For single and three poles mode :

The Autorecloser Relay should reclose the Breaker(s) for line-line fault under control of synchrocheck relay

The Autorecloser Relay should reclose the Breaker(s) for single phase to earth fault

Three poles reclosing should be under Synchro Check control (except for 20kV radial networks)

Failure of reclosing after single pole tripping should be followed by tripping of all poles

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Basic Requirement of Autorecloser Relay Performance (2)

Specific requirement for 500 kV Autorecloser Relay

The Autorecloser Relay should reclose the

Breaker(s) when initiated by any Distance Relay (due to duplex configuration of 500 kV protectionscheme)

Since 500kV Substations are one & half breaker type, the Autorecloser Relay should be able to recognize and control

each of the Breaker as “leader Breaker ” and “follower Breaker”

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TYPICAL SITE TESTS ITEMS OFAUTORECLOSER RELAY

Visual Check

INSTALLATIONCheck of the

Power Supply

Test of theAutorecloser settings

Functional TestingOPERATION

(involving operation of

Protective Relays

& Circuit Breaker(s)

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Protective Relay technology development

Electro mechanical Electronic Digital/numerical

Multi elements Single Module Multifunction

RelaysRelays

Relays

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Effect of relay technology development to Autorecloser site testing:

Type of Advantage Disadvantage

Autorecloser

• Only few problems can be

• Elements to be testeddetected early by visual

inspection

Single moduloon site are less than

• • Defective Autorecloserthe multi elements

(Single elements might effecting

type of Autorecloserelectronic the whole functions

of

• Site wiring to be testedmodule perform Autorecloser. and usually

Autorecloserare less than the multi

can not be repaired on siteelements type offunction) • The site test is depend onAutorecloser

the manufacturer. The test• Often, relay power

engineers need to studyconsumption is lower,

Manufacturer Manuals to

perform the site test

Effect of relay technology development toAutorecloser site testing

Type ofAdvantage Disadvantage

Autorecloser

• Elements to be• It is difficult to detect problems by

tested on site arevisual inspection

less then the• The site test is highly depend on the

multifunctionsingle modulo

• manufacturer. Even an experiencedtype of

relay test engineers need to carefully studyAutorecloser

(Autorecloser Manufacturer Manuals. Moreover a• Only few site

function special software and hardware iswiring need to be

integrated in a needed to perform the site test.tested

multifunction • Defective in Autorecloser element can

relay)• Often, relay

not be repaired on site. In some

cases, the whole relay need to bepower

replacedconsumption is

• Modern and computerized relay testlower, set is needed to perform the site test