Functions
Protection and control
l Phase current differential protection (87L)
l Zero sequence current differential protection (87L)
l DPFC ( Deviation of power frequency component) differential protection (87L)
l DPFC distance protection. (21D)
l Phase-to-phase distance protection. (21P)
l Phase-to-ground distance protection. (21G)
l Phase directional overcurrent protection. (67P)
l Phase overcurrent protection. (50/51P)
l Zero sequence directional overcurrent protection. (67G)
l Zero sequence overcurrent protection. (50/51G)
l Under/Over voltage element for blocking (27/59)
l Time overcurrent protection during VT failure. (51P VT)
l Time zero sequence protection during VT failure. (51G VT)
l Switch-onto-fault (SOTF) logic.
l Power swing blocking (68)
l Pole discrepancy detection element.
l Overload alarm function.
l Synchronism check. (25)
l Auto-reclosing (single-pole and three-pole). (79)
l Voltage and current drift auto adjustment.
Monitoring and Metering
l CT failure detection supervision.
l VT failure detection supervision.
l Line voltage failure supervision.
l Operating circuit supervision.
l Self diagnostic test.
l Fault Recorder.
l Fault Locator.
l 64 tripping reports, 64 alarm reports and 64 binary input status change reports.
l High resolution oscillography of last 24 oscillograms. (Compatible with COMTRADE format)
Communications
l High-speed optical fiber channel for protection data exchanging
l 2 optional Ethernet ports with IEC 61850 or IEC 60870-5-103 over TCP/IP
l 2 RS-485 communication rear ports conform to IEC 60870-5-103 protocol
l 1 RS-485 communication rear ports for clock synchronization
l 1 RS-232 communication rear ports or RS-485 for printer
l 1 RS-232 communication faceplate port for testing and setting
Features
l Quickly clearing the internal fault for the whole line, the time is less than 10 ms for faults which is near the busbar, less than 15ms for faults which is in the center of line and less than 25ms for faults which is in the remote end.
l The unique DPFC distance element is integrated in the relay. It can quickly clear the intern fault. The sensitivity of the DPFC distance element is very high and the operation speed is very fast. It is not affected by power swing.
l 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.
l The RCS-931 adopts high restraint factor and self-adaptive floating restraint threshold; it will keep the high reliability and sensitivity even in serious CT saturation case.
l 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 during a power swing and pickup for an internal fault.
l Optical fiber data exchange between terminal equipment at 64 kBit/s or 2048kBit/s.
l The CT ratio of two terminals could be different. Different ratio of various CT on each terminal could be regulated by configurable coefficients in software.
l The teleprotection channel could be monitored automatically. Bit error rate could be displayed online. Differential protection will be blocked during channel failure.
l The relay could receive tripping command from the opposite terminal protection and transmit tripping command to the opposite terminal protection via fiber optical channel.
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 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 The relay provides GPS clock synchronization, such as second pulse, minute pulse, and IRIG-B synchronization.
l The relay is compatible with multiple protocols- IEC61850 and IEC 60870-5-103. The RCS-931 provides networking interface such as RS485, RS232 and Ethernet port.