Manual MRI3-ITER GB
Woodward
DOK-TD-MRI3 ITERE Rev.A
19
4.5 Earth fault protection
4.5.1 Generator
stator
earth fault protection
With the generator neutral point earthed as shown in Figure 4.4 the MRI3-ITER 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 4.4: Generator stator earth fault protection
4.5.2 System earth fault protection
With the generator neutral point earthed as shown in Figure 4.5, the MRI3-ITER picks up only to
earth faults in the power system connected to the generator. It does not pick up to earth faults on
the generator terminals or in generator stator.
Figure 4.5: System earth fault protection
