RCS-941 Line Distance Relay

The RCS-941 relay is a digital distance protection used as the main and back-up protection for overhead transmission lines and ungrounded cables, including phase-phase and phase-ground distance element, overcurrent element with three-pole tripping and au

  • Overview
  • Functions
  • Features

The RCS-941 relay is a digital distance protection used as the main and back-up protection for overhead transmission lines and ungrounded cables, including phase-phase and phase-ground distance element, overcurrent element with three-pole tripping and auto-reclosing. Pilot scheme can be comprised in the relay. It is fully compatible with IEC 61850 communication.


Protection and Control
  • Optional Pilot distance protection(PUTT, POTT, blocking and DTT). (85)
  • Optional Pilot zero sequence directional comparison protection. (DEF)
  • Phase-to-phase distance protection. (21P)
  • Phase-to-ground distance protection. (21G)
  • Directional phase overcurrent protection. (67P)
  • Phase overcurrent protection. (50P, 51P)
  • Directional zero sequence overcurrent protection. (67N)
  • Zero sequence overcurrent protection. (50N, 51N)
  • Switch-onto-fault (SOTF) logic.
  • Under frequency protection. (81)
  • Under/over voltage protection. (27/59)
  • Frequency rate-of-change element. (7F)
  • Voltage rate-of-change element. (7V)
  • Power swing blocking. (68)
  • Accelerated tripping for asymmetric faults.
  • Accelerated tripping for double circuit faults.
  • Overload alarm function.
  • Synchronism check. (25)
  • Auto-reclosing (three-pole). (79)

  • Monitoring and Metering
  • Voltage auto-switching for double busbar application
  • Circuit breaker monitoring.

  • CT failure detection logic.
  • VT failure detection logic.
  • Tripping circuit supervision.
  • Voltage and current drift auto adjustment.
  • Self diagnostic.
  • Fault Recorder.
  • Fault Locator.
  • GPS clock synchronization.
  • 64 tripping reports, 64 alarm reports and 64 binary input status change reports.
  • High resolution oscillography of last 24 oscillograms (Compatible with international COMTRADE format).

Communications
  • Pilot communication schemes with fiber, carrier or other channels.
  • 2 optional Ethernet ports with IEC 61850 protocol.
  • 2 RS-485 communication rear ports with IEC 60870-5-103 protocol.
  • 1 RS-485 communication rear ports for clock synchronization.
  • 1 RS-232 communication rear ports or RS-485 for printer.
  • 1 RS-232 communication faceplate port for testing and setting.
  • The relay integrates AC voltage auto-switching module. In the double-busbar scheme, when the transmission line is switched between the two busbars, the AC voltage inputs of the relay will be auto-switched according to the actual busbar VT based on the states of isolators.
  • Unique accelerated trip for double-circuit line and accelerated trip for asymmetric fault can reduce the tripping time during double-circuit line fault and asymmetric fault. The two schemes guarantee a fast clearance time even without pilot protection.
  • The built-in reliable power swing blocking logic can properly supervise the distance elements during a power swing. The power swing blocking logic can make the relay untrip for an external fault and pickup for an internal fault during a power swing.
  • The patented adaptive floating threshold method is adopted, which is insensitive to system unbalance and disturbance. The measuring element can get both high security and high speed simultaneously.
  • Innovative technology to prevent any undesired trip caused by any component failure is adopted. The relay has two independent data acquisition paths, one for a fault detector and the other for protection and its logic. Tripping outputs are supervised by the fault detector to prevent a mal-operation.
  • The connector type can be selected as plug in/out terminal connector or crimp terminal connector. The unique plug in/ out terminal connectors from the relay rear panel to the terminal blocks on the rack or cabinet makes the on-site commissioning and replacement much easier than the traditional screw terminals when you do the commissioning.
  • The relay provides GPS clock synchronization, including message, second pulse, minute pulse and software IRIG-B synchronization.
  • The format of event report is compatible with international COMTRADE file.
  • The relay is compatible with multiple protocols- IEC61850 and IEC 60870-5-103. It provides networking interface such as RS485, RS232 and Ethernet port.