RCS-915 Centralized Busbar Protection

The RCS-915 series busbar protection devices provide main and back-up protection of busbars for all kinds of busbar wiring configurations, such as single busbar, double busbar,double busbar with transfer bus, double busbar with section,one-and-a-half.....

  • Overview
  • Functions
  • Features

The RCS-915 series busbar protection devices provide main and back-up protection of busbars for all kinds of busbar wiring configurations, such as single busbar, double busbar, double busbar with transfer bus, double busbar with section, one-and-a-half breaker, etc. It is fully compatible with IEC 61850 communication with an additional communication unit.

  • Busbar differential protection. (87B) - Steady-state percentage differential protection - DPFC percentage differential protection
  • Bus coupler/section protection. - SOTF protection (50) - Dead zone protection (51/62EF) - Breaker failure protection (50BF) - Overcurrent protection (51P/51N) - Pole discrepancy protection (51/62PD)
  • Feeder protection. - Breaker failure protection (50BF) - End fault protection (51/62EF) - Pole discrepancy protection (51/62PD) - Transfer trip (TT)
  • CT circuit failure supervision.
  • VT circuit failure supervisionCT failure detection logic.
  • Disconnected position alarm.
  • Busbar voltage switching.
  • Receiving PPS (pulse per second) and PPM (pulse per minute) via external contact
  • Receiving PPS, PPM and IRIG-B signal via RS-485
  • Receiving time synchronization message from substation automation system
  • 32 latest fault reports, 32 latest self-supervision reports and 32 latest status change of binary input reports
  • 8 latest fault waveforms (The file format of disturbance recorder is compatible with international COMTRADE file)
  • 2 RS-485 communication rear ports (option optical fibre interface)
  • 1 RS-485 communication rear ports for time synchronization
  • 1 RS-232 communication rear ports for printer
  • 1 RS-232 communication front port for debugging
  • Support IEC60870-5-103 protocol
  • Support ModBus protocol
  • Support IEC61850 protocol (through external auxiliary device) and IEC 60870-5-103 communication protocol


  • The RCS-915 provides less than 20ms typical trip time for busbar differential protection.
  • The CPU system adopts parallel calculation.
  • Independent fault detector element is equipped.
  • The device integrates high sensitive percentage differential protection.
  • It is matching to different CT ratios and settable CT adjustment coefficient.
  • Busbar differential element can be supervised by voltage elements.
  • The sensitive and high-speed DFPC current differential element is integrated in the relay.
  • A fully-fledged adaptive weighted anti-saturation algorithm.
  • The breaker failure protection of all feeders, bus coupler and bus section is integrated in the RCS-915 relay.
  • Various GPS clock synchronizations are provided: second/ minute pulse via binary input or RS-485, message via communication ports and IRIG-B synchronization.