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  • PCS-985BT/TW/TS/T Transformer Relay

  • PCS-985 transformer relay can be applied for transformer with various voltage levels and wiring modes, and provides interfaces for power plant automation. The full-integrated transformer protection integrates protection, control and monitoring functions to provide users with a comprehensive, reliable and cost-effective solution. It supports conventional CT/VT and ECT/EVT, and fully compatible with IEC-61850 communication.

    For a large-scale transformer, two sets of PCS-985 protection can be used to achieve duplicated protection configuration. Two PCS-985 protections use different CT groups, and main and backup protection in one PCS-985 share one group of CTs.

    • PCS-985TW is adaptive from medium to large main transformer in hydro power plant.
    • PCS-985TS is adaptive to small main transformers, auxiliary transformers and startup/standby transformers in power plants. It can be used for the transformer with up to 4 branches at LV side.
    • PCS-985T is adaptive from medium to large startup/standby transformers and auxiliary transformers in power plants. It can be used for the transformer with up to 8 branches at LV side.
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Protection and Control
  • Current differential protection of generator-transformer unit (87GTU)
  • Current differential protection of main transformer (87T)
  • Current differential protection of step-down transformer (87T)
  • Transformer restricted earth fault protection (64REF)
  • High-voltage cable differential current protection. (87L)
  • High-voltage stub cable differential current protection (87S)
  • High-voltage stub cable overcurrent protection (50/51P)
  • Voltage controlled overcurrent protection (50/51P)
  • Reverse current protection (50/51R)
  • Phase-to-phase impedance protection (21)
  • Ground overcurrent protection (50/51G)
  • Gap zero-sequence overvoltage/overcurrent protection.
  • Overexcitation protection (24)
  • Pole disagreement protection (62PD)
  • Breaker flashover protection (50F)
  • Breaker failure initiation (50BF)
  • Residual voltage alarm at LV side (59GAlm)
  • Overload protection. (49)
  • Cooling initiation function. (49)

  • Mechanical protection. (MR)
  • Fault detector. (FR)
  • VT circuit failure supervision. (VTS)
  • CT circuit failure supervision. (CTS)
  • CT saturation detection.
  • Inrush current detection.
  • Voltage and current drift auto adjustment.
  • Self diagnostic.
  • GPS clock synchronization.
  • Fault Recorder.
  • IEC61850 MMS & GOOSE for station bus.
  • IEC60870-5-103 protocol.
  • MODBUS protocol.

  • Parallel calculation of double DSP system
    The hardware of the device comprises a 32-bit microprocessor and two 32-bit digital signal processors (DSP). Those processors can operate in parallel companied by fast A/D converter. The 32-bit microprocessor performs logic calculation and the DSP performs the protection calculation. High performance hardware ensures real time calculation of all protection relays within a sampling interval. On the premise of 24 samples per cycle, all data measurement, calculation and logic discrimination could be done within one sampling period. The event recording and protection logic calculation are completed simultaneously.
  • Independent fault detector
    Independent fault detectors in fault detector DSP module for connecting power supply of output relays. The relay can drive a tripping output only when protection element on protection DSP module operates with the fault detector in the fault detector DSP module operating simultaneously. This kind of independent supervision of tripping outputs using fault detectors can avoid any mal-operation possibly caused by any hardware component failure. This highly increases the security.
  • Configurable tripping output
    The tripping output contacts can be configured by tripping matrix and suitable to any mode of tripping.
  • Fault recording function
    Event records include 1024 binary input events and 1024 alarm events. Disturbance records including 64 fault reports, and 64 disturbance waveforms, and file format of waveform is compatible with international COMTRADE91 and COMTRADE99 file. Analog inputs and binary inputs can be recorded, and three oscillography triggering mode are supported, which are protection pickup triggering, manual triggering on keypad of device, and remote triggering through PCS-Explorer software.
  • Integration of main and backup protection
    Main and backup protection are integrated in one set of protection device. Protection information is shared by all parts. The device can record all relevant waveforms of any fault.
  • Reliable CT saturation detection
    Based on the operation sequence of DPFC restraint current element and DPFC differential current element of differential protection, external fault with CT saturation or internal fault can be distinguished correctly.