Transformer differential protection
RADSB is a protective relay intended for all types of three-phase power transformers. By including additional input restraint modules, up to 6 transformer windings or restraining inputs can be connected. The relay is well suited for generator and step-up transformer overall protection, often including the auxiliary transformer in the protected zone.
The non-linear percentage restraint characteristic provides the required restraint for external faults, making it suitable for use with multi-winding transformers, autotransformers or in a system where one transformer winding is directly connected to two or more breakers. The characteristics are designed to provide excellent internal fault sensitivity.
Main Features:
- Complete phase and earth-fault protection
- Built-in trip relay, indicator and test switch
- Variable percentage restraint for external fault security
- Stable against CT saturation effects
- Redundant instantaneous operating element for severe internal faults
- Inrush security by 2nd harmonic restraint
- Overexcitation security by 5th harmonic restraint
- High-speed operation