Protection Engineering Basics and Schemes Protection Engineering | Page 224

Testing: Circuit Diagram: Method:

� 1 st isolate Differential relay from system, in case of differential relay we need to dead transformer / bus bar / cable from all possible power supply side, and check it accordingly, only 0volt condition from all power source is acceptable then we need to remove the test block cover.

� We need injection kit with 6 current source and two return paths, each source able to supply up to 20A minimum � We must have circuit diagram for relay also � We have below settings( Case 1) for this test

I diff > 0.2A I diff ≫ 11A

� We will use CMC 356

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