Transformer Fault Current and C57.12
Transformer Fault Current and C57.12
(OP)
Good afternoon folks,
I have some questions regarding fault currents and calculating these fault currents for oil-filled transformers:
I have some questions regarding fault currents and calculating these fault currents for oil-filled transformers:
- When calculating the fault current [full load current / impedance of transformer], do we use full load current at base rating or the full rating with cooling fans running?
- Are limitations of fault current that a transformer can withstand according to C57.12.00 (Section 7) based on external faults only?
i.e. full load current / impedance = fault current transformer can withstand for external faults only?
i.e. if a transformer winding failed, its probably going to generate fault currents higher than this FLA/impedance value depending on utility contribution and where the fault is in the windings?






RE: Transformer Fault Current and C57.12