Protect your power transformer or your generator-transformer units with the stabilized differential relay SPAD
The stabilized differential relay SPAD 346 C is designed for protecting two-winding power transformers and generator-transformer. The main features include protection for winding short-circuits, interturn faults, earth faults and short circuits, as well as interwinding short-circuits and pole short circuits. In addition, the relay can be used for protection of three-winding power transformers, provided that 75% of the short circuit power to the power transformer is supplied from the same direction.
Features
- Integrated three-phase differential relay, three-phase overcurrent relay and multi-configurable earth-fault relay
- Three-stage overcurrent module providing protection for power transformers and generators and two-stage backup earth-fault protection
- Stabilized against unwanted operations at faults occurring outside the protected area and at transformer inrush
- Second harmonic restraint for prevention of unwanted relay operations at transformer inrush
- Fifth harmonic restraint for prevention of unwanted relay operations at transformer overexcitation
- Wide CT ratio correction range - accurate correction through digital setting
- Four heavy-duty output relays for circuit breaker tripping and five output relays for signalling
- Five programmable external control inputs
- Integrated circuit breaker failure protection with adjustable operate time
- Differential relay and earth-fault relay modules with integrated disturbance recorder functions for analog and digital signals
- Sensitive phase current and phase angle displays facilitate checking of energizing circuit connections and vector group matchings
- High immunity to electrical and electromagnetic interference allows the relay to be used in severe environments
- High availability and system reliability due to continuous supervision of hardware and software