PCS-915ID Distributed Busbar Protection

The PCS-915ID distributed busbar protection is used for protecting and monitoring various busbar arrangement with all voltage levels, including single busbar with/without section, double busbar with/without sections, double busbar with transfer bus......

  • Overview
  • Functions
  • Features

The PCS-915ID distributed busbar protection is used for protecting and monitoring various busbar arrangement with all voltage levels, including single busbar with/without section, double busbar with/without sections, double busbar with transfer bus, breaker-and-a-half arrangement and ring-breaker arrangement. It adopts distributed structure, consisting of one Central Unit (CU) and a number of Bay Units (BU). The central unit is linked to bay units via optical fibers in point-to-point communication mode. The central unit is responsible for the protection calculation and relay management, the bay unit acquires and transmits the analog and binary data and executes the trip/close command issued from Central Unit.

The device provides fast and secure low impedance busbar protection with sub-cycle tripping time. It integrates advanced and patented features to improve its sensitivity and security, such as innovative DPFC current differential protection and unique weighted CT saturation detection method. It also provides breaker failure protection for all bays. The integrated frequency-tracking algorithm is used to acquire accurate current/voltage value. It provides the interfaces for station bus and process bus respectively and supports IEC 61850-8-1 MMS, GOOSE, IEC 61850-9-2 Sampling Value.

Protection and Control
  • Busbar current differential protection (87B)
    It composites phase current differential protection and DPFC differential protection. Voltage control element and CT saturation blocking element are available to supervise this current differential protection.
    • Percentage restraint phase current differential protection Dual restraint coefficients are provided to enhance the sensitivity of weak-sourced bus with opened bus coupler/section.
    • Percentage restraint DPFC differential protection
      DPFC differential protection is sensitive to high resistance fault and is immune to load current variation.
    • Voltage control element
      The voltage could be selected to use phase voltage, residualvoltage and/or negative sequence voltage.
    • CT saturation inhibit
      Two principles for CT saturation detection are provided: patented adaptive weighted anti-saturation algorithm and harmonics. It keeps the current differential protection stable to external fault and quickly clears internal fault and external-to-internal evolving fault during CT saturation.
    • Check zone and discrimination zone
      Check zone differential element and discrimination zone differential element are both provided to enhance the reliability.
  • Bus coupler/section protection
    • Breaker failure protection (50BF)
      It can be supervised by voltage control element. Re-tripping, bus coupler/bus section tripping and bay breaker tripping are issued sequentially.
    • Dead zone protection (50DZ)
      It is provided to clear the dead zone fault between CT and breaker for bus coupler/section bays.
    • Pole disagreement protection (62PD)
      Pole discrepancy detection element is used to protect pole position disagreement.
    • Switch-onto-fault protection (50SOTF)
      Switch-onto-fault logic of bus coupler/section is used for bus energizing.
    • Overcurrent protection (50/51)
      Phase and neutral overcurrent protection with time delay are both provided.
  • Feeder protection
    • Breaker failure protection (50BF)
      It can be supervised by voltage control element. Re-tripping, bus coupler/bus section tripping and bay breaker tripping are executed sequentially.
    • Dead zone protection (50DZ)
      It is provided to clear the dead zone fault between CT and breaker for all feeder bays.
    • Pole disagreement protection (62PD)
      Pole discrepancy detection element is used to protect pole position disagreement.
    • Overcurrent protection (50/51)
      Overcurrent protection consists of phase overcurrent element and neutral overcurrent element, each can be set as inversetime or definite-time.
  • Voltage and current drift auto adjustment.
    The relay automatically traces the drift and adjusts zero point to normal value for voltage and current.
  • Frequency tracking.
    Frequency tracking is provided to accommodate the frequency shift in power system.

  • Monitoring and Metering
    • CT failure supervision
    • VT failure supervision
    • Dynamic busbar replica
    • Isolator contact discrepancy alarm
    • Self diagnostic
    • Event recorder including 1024 disturbance records, 1024 binary events, 1024 supervision events and 1024 operating logs
    • Disturbance recorder including 64 disturbance records with waveforms (The file format of disturbance recorder is compatible with international COMTRADE file.)
    • Fault Recorder

    Communications
    • Point-to-point optical fiber communication between Central Unit and Bay Unit
    • Two 10Base-T/100Base-TX (RJ45) ports and two optional 100Base-FX ports with IEC 61850-8-1 MMS and GOOSE for non-time-critical message, IEC 60870-5-103 over TCP/IP or DNP 3.0
    • Two RS-485 rear ports with IEC 60870-5-103
    • Six or Eight 100Base-FX ports with IEC 61850-9-2 Sampling Value and GOOSE for time-critical message
    • One RS-485 rear port for clock synchronization
    • One RS-232 rear port for printer
    • One faceplate RJ45 port for testing and setting
    • Clock synchronization via Pulse-Per-Second, IRIG-B and SNTP
  • The typical pickup time of current differential protection is less than 15 ms.
  • The relay adopts the distributed structure based on multiprocessor platform. The optical fiber communication between Central Unit and Bay Units are continuously monitored. If a failure occurred in the communication of Central Unit to any Bay Unit, the current differential protection will be blocked to prevent mal-operation.
  • The relay can select the faulty bus and make a selective trip correctly via check zone and discrimination zone of differential protection.
  • The ratio of CT on each bay could be differential and could be regulated by configurable coefficients in software.
  • The relay detects dynamic connection status of each bay in order to dynamically introduce the current input into the differential calculations or not.
  • The relay provides isolator monitoring function responding to both normally open and normally closed auxiliary contacts.
  • Traditional harmonics and patented adaptive weighted antisaturation algorithm are provided for CT saturation detection.
  • DPFC differential protection is integrated to coordinate with percentage restraint phase current differential protection and improve the sensitivity and tripping speed.
  • Innovative technology to prevent any undesired trip caused by any component failure is adopted. The relay has two independent data acquisition paths, one for fault detector and the other for protection and its logic. Tripping outputs are supervised by the fault detector to prevent any maloperation.
  • The connector type can be selected as plug in/out terminal connector or screw terminal connector. The unique plug in/out terminal makes the on-site commissioning and replacement much easier than the traditional screw terminals when you do the commissioning.
  • The relay is compatible with IEC 61850-8-1 MMS, GOOSE and IEC 61850-9-2 Sampling Value and provides the independent interfaces for station bus and process bus respectively.