RCS-9679 Transformer Protection

The RCS-9679 relay is a microprocessor-based relay designed for the protection of two-winding power transformers with various kinds of connect groups. Up to three CT inputs can be provided.

  • Overview
  • Functions
  • Features

The RCS-9679 relay is a microprocessor-based relay designed for the protection of two-winding power transformers with various kinds of connect groups. Up to three CT inputs can be provided.

  • Unrestraint current differential protection. (87UT)
  • Percentage restraint current differential protection. (87PT)
  • Second harmonic blocking for differential protection.
  • Three-stage voltage controlled overcurrent protection for HV side. (50P/51P)
  • Three-stage voltage controlled overcurrent protection for LV side. (50P/51P)
  • Zero sequence overvoltage protection. (50N/51N)
  • Thermal overload protection. (49)
  • Overload initiating cooling function. (49)
  • Blocking OLTC (on-load tap change) function during overload. (49)
  • Restricted earth fault protection. (REF)
  • Zero sequence overvoltage alarm function. (59N)
  • (up to 10) channels of mechanical protection. (MR)
  • Remote control and measurements.
  • VT circuit failure supervision.(VTS)
  • CT circuit failure supervision.(CTS)
  • Tripping circuit supervision.
  • Self diagnostic.
  • Fault and disturbance recorder.
  • Rear communication ports: Ethernet with IEC 61850, 2 RS-485 with IEC 60870-5-103, 1 RS-485 for clock synchronization, 1 RS-232 for communication to printer.

  • The typical operating time of unrestraint current differential protection is 35ms.
  • Current differential protection could be supervised by second harmonics to distinguish inrush current.
  • The ratio of CT on each side could be different. Different ratio of various CT on each side could be regulated by configurable parameters in software.
  • Various transformer and CT connection types at each side could be compensated by configuring logic setting in the relay.
  • On the premise of 24 samples per cycle, all data measurement, calculation and logic discrimination can be finished within one sampling period. The event recording and protection logic calculation are completed simultaneously.
  • The relay provides GPS clock synchronization, including message, second pulse and IRIG-B synchronization.
  • The relay can communication with SAS or RTU based on IEC 61850 and IEC60870-5-103.
  • Fault and disturbance recording function: 64 latest tripping records, 8 latest fault wave (up to 15s), 64 latest equipment self-check alarm records, 64 latest alarm records of equipment operating abnormality, 64 user operating records and 256 records of time-tagged sequence of event can be recorded.