SEG Electronics GmbH
Manual MRG3
30
DOK-TD-MRG3, Rev. D
4.7 Earth fault protection
4.7.1 Generator stator earth fault protection
With the generator neutral point earthed as shown in Figure 4.9, the MRG3 picks up only to phase
earth faults between the generator and the location of the current transformers supplying the relay.
Earth faults beyond the current transformers, i.e. on the consumer or line side, will not be detected.
Figure 4.9: Generator stator earth fault protection
4.7.2 System earth fault protection
With the generator neutral point earthed as shown in Figure 4.10 , the MRG3 picks up only to earth
faults at consumer or line side. It does not pick up to earth faults on the generator terminals or in
generator stator.
Figure 4.10: System earth fault protection
