Transformers require sensitive protection against internal short circuits, winding faults, overheating, and external overloads. Medium voltage units benefit from a mix of differential, overcurrent and thermal protection to ensure high reliability and a long service life. Fast fault detection minimizes mechanical and thermal stress for the equipment, while avoiding false trips (such as inrush current during energization).
Common transformer protection functions include:
- ANSI 50/51 overcurrent
- ANSI 50/51G/N ground fault protection
- ANSI 64REF restricted earth fault
- ANSI 87 transformer differential (2- and 3-winding)
- ANSI 49 thermal overload
- ANSI ANSI95i harmonic stabilizer
For transformer protection, following product options are suitable:
- SYMAP®Compact(+) product line
- SYMAP®T
- SYMAP®BC – for 3-winding differential protection