Functions
= Over frequency protection. (81)
= Under frequency protection. (81)
= Over voltage protection. (59)
= Under voltage protection. (27)
= Frequency changing rate df/dt element. (7F)
= AC voltage changing rate dU/dt element. (7V)
= CT failure detection logic.
= VT failure detection logic.
= Voltage drift auto adjustment.
= Self diagnostic test.
= GPS clock synchronization.
= Fault Recorder.
= 128 Event reports.
= High resolution oscillography of last 24 oscillograms (compatible with international COMTRADE format)
= Rear communication ports: Ethernet (Optional) or 2 RS-485 with IEC 60870-5-103 protocol, 1 RS-485 with clock synchronization, 1 RS-232 or RS-485 with printer.
= Front communication port: 1 RS-232 for testing and setting.
Features
= The RCS-994 relay provides wiring connectors from the relay rear panel to the terminal blocks on the rack or cabinet. This kind of connectorized wiring makes the on-site commissioning and replacement much easier than what you do the commissioning using the traditional screw terminals on the rear panel. NR provides the special and dedicated test set, HELP-90, for a low-level voltage injection test.
= The RCS-994 relay provides some special measurement to prevent any undesired trip. The relay has two independent data acquisition paths, one for a fault detector and one for protection and its logic. Tripping outputs are supervised by the fault detector to prevent a mis-operation caused by any component failure in the relay.
= 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.
= Four basic stages and two special stages are provided respectively for the underfrequency and undervoltage load shedding. 14 sets of trip outputs can be flexibly configured to the corresponding steps.
= The relay provides GPS clock synchronization, including second pulse, minute pulse and IRIG-B synchronization.
= The HMI interface with a LCD and a 9-button keypad on the front panel is friendly to users.
= The format of event report is compatible with international COMTRADE file.
= The relay is equipped with Ethernet port and RS-485/232 ports with the IEC 60870-5-103 protocol.