ANALISIS SETTING PENGAMAN TRANSFORMATOR DAYA DI GARDU INDUK NUSA DUA JIKA TERJADI GANGGUAN HUBUNG SINGKAT SATU PHASA TANAH

Abstrak

REF (Restricted Earth Fault) Relay is used as protective equipment against single phase
short circuit to the ground. It prevents the interference current from flowing into the transformer
neutral point when the Neutral Ground Resistor (NGR) wire terminates. The single phase shortcircuit
current to the ground before the wiring termination was 288.67 NGR Ampere, whereas
the short circuit current after the termination was 884.15 Ampere NGR. An analysis of the REF
relay’s installation on transformer at 60 MVA against short circuit current single phase to ground
during the termination of NGR wiring was conducted. The results showed a reasonably good
protection capability based on the calculation of the current interruption simulation during the
NGR ground wiring termination with the short circuit current of 884.15 Ampere. This finding
means that the flow of the current on REF relay was at 0.263 Ampere, while the REF relay was
set at 0.233 Ampere. Thus, it can be assured that the REF relay works properly, because the
REF relay’s working time is 0 second or without time delay.