Protection Engineering Basics and Schemes Protection Engineering | Page 26

1.1.8.2 Primary injection Method:
This method usually employees on switchgear bar CTs and
outdoor CTs
Circuit diagram
1.1.7.2.1 Method:
 1 st of all off the breaker
 Check the zero voltage state by high voltage tester ,
also earthed the dead circuit
 Now short your incoming side red, yellow and blue
phase primary conductor
 Place one ammeter (digital will be good) in neutral or
star point of CTs secondary. Make sure test block
cover must be removed, so you can ensure the circuit
completed within CT loop, no need to involve Relay in
circuit.
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