Frequency protection relay PCS-978

under-frequencyover-frequencythermal

Product Overview
PCS-978 delivers a full-scheme protection and control solution for power transformers including multi‑winding transformers, auto‑transformers and shunt reactors. The device integrates up to 36 current/voltage inputs and up to 6 group CT inputs, making it suitable for one‑and‑a‑half breaker, ring‑breaker and other substation arrangements. It supports 288 vector groups for three‑winding transformers and 24 vector groups for two‑winding transformers. Differential protection combines conventional phase current differential elements and DPFC differential elements. Dedicated high‑threshold binary inputs cover mechanical protection. Automatic CT ratio compensation and vector group compensation remove the need for external interposing CTs. PCS-978 is compatible with IEC 61850 station and process bus applications and supports IEC 61850‑8‑1 MMS, GOOSE and IEC 61850‑9‑2 Sampled Value. A front RJ‑45 port eases testing and commissioning.

Protection and Control

• Transformer biased current differential protection (87T)
• Transformer unrestrained instantaneous current differential protection (87T)
• Transformer biased DPFC current differential protection (87T)
• Reactor biased current differential protection (87R)
• Reactor unrestrained instantaneous current differential protection (87R)
• Reactor biased DPFC current differential protection (87R)
• Inrush blocking
• CT saturation blocking
• Overexcitation blocking
• CT circuit failure blocking
• Amplitude compensation
• Phase angle compensation
• Restricted Earth Fault Protection (64REF)
• Winding differential protection (87W)
• Inter-turn fault protection for reactor (21IT)
• Overexcitation protection (24)
• Underfrequency and overfrequency protection (81U/81O)
• Mechanical protection (MR)
• Temperature protection (26)
• Two-stage phase-to-phase impedance protection (21P)
• Two-stage phase-to-ground impedance protection (21G)
• Power swing blocking releasing (PSBR)
• Four-stage phase overcurrent protection (50/51P)
• Four-stage neutral overcurrent protection for each side (50/51G)
• Two-stage negative-sequence overcurrent protection (50/51Q)
• Two-stage phase overvoltage protection (59P)
• Two-stage residual overvoltage protection (59G)
• Four-stage undervoltage protection (27P)
• Thermal protection (49)
• Breaker failure protection (50BF)
• Pole disagreement protection (62PD)
• Phase overcurrent alarm (51PAlm)
• Residual overvoltage alarm (59GAlm)
• Voltage and current drift auto adjustment
• Frequency tracking

Monitoring and Metering

• CT failure supervision
• VT failure supervision
• Self diagnostic
• Event recorder: 1024 change‑of‑binary‑input events, 1024 supervision events and 1024 device logs
• Disturbance recorder: 32 disturbance records with waveforms (COMTRADE compatible)
• Clock synchronization: IRIG‑B, SNTP, PPS, PPM and IEEE 1588

Communication

• Optional two or four 10Base‑T/100Base‑TX copper Ethernet ports supporting IEC 61850, DNP3.0 or IEC 60870‑5‑103 over TCP/IP
• Optional two 100Base‑FX optical Ethernet ports (shares two copper ports) supporting IEC 61850, DNP3.0 or IEC 60870‑5‑103 over TCP/IP
• Optional two RS‑485 serial ports using IEC 60870‑5‑103
• One RS‑485 serial port for clock synchronization
• One RS‑232 rear port for printer
• One front RJ‑45 port for testing and setting
• Optional sampled value and GOOSE communication module with six optical Ethernet ports (IEC 61850‑9‑2 and IEC 61850‑8‑1 GOOSE)

Compatibility and Additional Features
Compatible with IEC 61850 station and process bus; supports IEC 61850‑8‑1 MMS, GOOSE and IEC 61850‑9‑2 Sampled Value. Front RJ‑45 port for testing/setting. Integrates up to 36 current/voltage inputs and up to 6 group CT inputs for differential protection. Automatic CT ratio compensation and vector group compensation included. Dedicated high‑threshold binary inputs for mechanical protection.

Technical specifications

• Model: PCS-978
• Application: Protection and control for power transformers (multi‑winding, auto‑transformers) and shunt reactors
• Current/Voltage inputs: up to 36
• Group CT inputs: up to 6 for differential protection
• Vector groups: 288 for 3‑winding transformers; 24 for 2‑winding transformers
• Event recorder: 1024 change‑of‑binary‑input events, 1024 supervision events, 1024 device logs
• Disturbance recorder: 32 records with waveform, COMTRADE compatible
• Clock sync: IRIG‑B, SNTP, PPS, PPM, IEEE 1588
• Communication protocols: IEC 61850 (including IEC 61850‑9‑2 sampled value and GOOSE), DNP3.0, IEC 60870‑5‑103
• Communication ports: optional copper Ethernet (2 or 4 × 10/100Base‑TX), optional optical Ethernet (2 × 100Base‑FX), optional RS‑485 ports, RS‑232 rear port, front RJ‑45
• Optional sampled value and GOOSE module: six optical Ethernet ports
• Protection functions: comprehensive list including 87T/87R/87W, 64REF, 21IT, 24, 81U/81O, MR, 26, 21P, 21G, PSBR, 50/51P, 50/51G, 50/51Q, 59P, 59G, 27P, 49, 50BF, 62PD
• Reliability features: high‑threshold binary inputs for mechanical protection; CT saturation/inrush/CT circuit‑failure blocking; automatic CT ratio and vector group compensation