Over-voltage protection relay PCS-921

under-voltageearth-leakageover-current

The PCS-921 numerical relay provides protection for circuit breakers, which includes breaker failure protection, pole discrepancy protection, dead zone protection, phase/ negative sequence overcurrent protection, earth-fault protection, overvoltage protection, undervoltage protection, frequency protection, single and/or three-pole auto-reclosing and synchronism check functions. The PCS-921 relay employs the programmable logic, configurable I/Os and definable 3-color LEDs to provide flexibility for specific applications. Frequency tracking is used to minimize the sampling error caused by system frequency fluctuation. The PCS-921 relay adopts the advanced multi-processor platform, providing the interfaces to station bus and process bus respectively and supporting IEC 61850-8-1 MMS, GOOSE and IEC 61850-9-2 Sampling Value. In addition, the RJ-45 faceplate port serves for testing and setting in effort to make commissioning and maintenance easier. • Breaker failure protection (50BF) • Pole discrepancy protection (62PD) • Dead zone protection (50DZ) • Four stages of phase overcurrent protection (50/51P) • Four stages of neutral overcurrent protection (50/51G) • Four-stage negative sequence overcurrent protection (50/51Q) • Three-stage undervoltage protection and overvoltage protection (27/59) • One-stage negative sequence overvoltage protection (59Q) • Four-stage underfrequency protection and overfrequency protection (81) • Synchronism check (25) • Single and/or three-pole auto-reclosing (79) • Voltage and current drift auto adjustment • Frequency tracking