Answer / gajanan koshatwar

generator earth fault relay basically monitors the
insulation level of roror winding and shaft ground. The
rotor earth fault relay injects the low frequency pulse in
one field winding terminal wrt ground and in turn it
measures the value of refelcted pulse and claculates the
insulation value.

For testing generator earth fault relay put specific values
of precision resistors across terminals and observe the
values in relay if display is provided, or set the trip
value less than the resistace put for testing , then relay
will issue trip command and this proves relay is heathy.

Gajanan koshatwar manager Power plant

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