We have 11kV/415 V delta-star, 2500 kVA distribution transformer with over current and earth fault protection on Primary (11 kV) and secondary (415V) sides.

I would like to know is it necessary to provide an Restricted earth Fault (REF) protection, connecting the Neutral CT of the transformer and the LT side 3-Phase CT's (In power control centre). This scheme is proposed to protect the 4000 A LT Busduct. Please note, becasue the rating is only 2500 kVA, differentil protection is not considered.

Prasanna

 

Prasanna....

See Thread # 1026243454 "Knee Point of REF CTs!"

Regards, Phil Corso ([email protected])