What is stator ground fault?
During a ground fault on the stator winding, the ground fault current flowing through the NGT causes a voltage to be impressed across the grounding resistor. The function of the overvoltage relay is to measure the fundamental voltage magnitude and thereby detect a ground fault in the stator winding.
How do you protect generator against stator faults?
So to protect the stator against over heating, embed resistance temperature detector or thermocouples are used in the slots below the stator coils. These detectors are located on the different places in the windings so that to detect the temperature throughout the stator.
What is 59N protection?
The 59N relay will detect and protect the generator for earth faults over about 95% of the generator winding. The chosen 59N relay needs to be chosen so as to not react to third harmonic voltage generated during normal service.
How does a restricted earth fault relay work?
Restricted earth fault is to detect earth faults in the zone from secondary winding to Secondary CTs. The working principle is “Merz-Prize Circulating Current Principle”. … The CT arrangement will generate equal and opposite currents which cancel out each other at the relay.
Which protection is used for stator fault of synchronous generator?
The main protection provided in the stator winding against phase to phase or phase to earth fault, is longitudinal differential protection of generator. Second most important protection scheme for stator winding is inter turn fault protection.