l Phase current differential protection. (87PB)
l DPFC current differential protection. (87DB)
l Check-zone and discrimination-zone for the selection of a faulty bus
l Breaker failure protection for each line or transformer connected to the bus. (50BF)
l Breaker failure protection for bus coupler and bus section. (50BF BS, 50BF BC)
l Overcurrent protection for energizing a bus. (50E)
l Overcurrent protection for detecting a dead zone fault of bus coupler. (50D)
l Time overcurrent protection for bus coupler. (51P, 51G)
l CT saturation detection logic.
l Voltage supervision element.
l Pole discrepancy function.
l Circuit breaker monitoring.
l CT failure detection logic.
l VT failure detection logic.
l Operating circuit supervision.
l Voltage and current drift auto adjustment.
l High resolution oscillography of last 8 oscillograms
(compatible with international COMTRADE format)
l GPS clock synchronization.
l Communication ports: Ethernet with IEC 61850 or 2*RS-485 with IEC 60870-5-103, 1 RS-485
for clock synchronization, 1 RS-232 or RS-485 for communication to printer, 1 RS-232 for testing
and setting at the front.
Features
l The typical operating time of bus differential protection is less than 15 ms.
l The relay can select the faulty bus and make a selective trip correctly by check zone and discrimination zone.
l The ratio of CT on each terminal could be different. Different ratios of various CT could be regulated by configurable coefficients in software.
l There are two different algorithms for CT saturation detection to prevent any incorrect operations caused by CT saturation.
l Busbar differential element could be supervised by the voltage elements.
l The sensitive and high-speed DFPC current differential element is integrated in the relay.
l One overcurrent element is used as dead zone protection to clear the fault between breaker and CT.
l The breaker failure protection of all feeders, bus coupler and bus section is integrated in the RCS-915 relay.
l The RCS-915 relay is based on NR’s well established and proven hardware platform of multi-processor. Two CPU modules are adopted in the relay. Each CPU module has one microprocessor and two digital signal processors (DSP). All CPUs can operate in parallel.
l The connector type can be selected as connectorized wiring connector and crimp terminal connector. The unique connectorized wiring 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 when you do the commissioning using the traditional screw terminals on the rear panel.
l 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.
l Various GPS clock synchronizations are provided: second/minute pulse via binary input or RS-485, message via communication ports and IRIG-B synchronization.
l The format of event report is compatible with international COMTRADE file.
l The relay is equipped with Ethernet with IEC 61850 (one additional communication unit is required) and RS-485 port with IEC 60870-5-103.