ERL MIT161 - System Earth Fault Protection

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FAULT

CURRENT

ELECTROMECHANICAL

SLOW RESET

STATIC

INSTANTANEOUS RESET

NUMERICAL (MIT)

DELAYED RESET

TRIP

Fault becomes

permanent

Flashing Faults

Figure 1 Flashing Fault Protection

4. SYSTEM EARTH FAULT

Distribution Feeder Fault Current magnitude depends upon the amount of fault resistance

and it can vary from reasonable value to a very low value.

MIT161 has two elements, which can be set for IDMTL and SEF protection to get

complete protection for line ground fault.

Fig. 2. CT Residual Connection.

Fig.2 shows the CT residual connection for detecting earth faults.

YRB

MIT

161