l Unrestraint current differential protection. (87UT)
l Percentage restraint current differential protection. (87PT)
l Three-level overcurrent protection for HV side and LV side. (50P or 51P)
l Thermal overload protection. (49)
l Ten (10) channels of non-electrical quantity protection. (NE)
l Second harmonic blocking function.
l Activating cooling equipment function.
l On-load tap changer (OLTC) blocking function during overload.
l Zero sequence overvoltage alarm function.
l Circuit breaker monitoring.
l VT failure detection logic.
l CT failure detection logic.
l Operating circuit supervision.
l Current drift auto adjustment.
l Self diagnostic test.
l GPS clock synchronization.
l Fault Recorder.
l 64 tripping reports and 256 SOE (Sequence of Events) records.
l High resolution oscillography of last 8 oscillograms
(Compatible with international COMTRADE format)
l Rear communication ports: Ethernet with IEC 61850, 2 RS-485 with IEC 60870-5-103, 1 RS-485 for clock synchronization, 1 RS-485/232 for communication to printer.
l The typical operating time of Unrestraint current differential protection is 15ms.
l Current differential protection could be supervised by second harmonics to avoid CT saturation.
l The ratio of CT on each side could be different. Different ratio of various CT on each side could be regulated by configurable coefficients in software.
l 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.
l The relay provides GPS clock synchronization, including second pulse and IRIG-B synchronization.
l The HMI interface with a LCD and a 9-button keypad on the front panel is friendly to users.
l The format of event report is compatible with international COMTRADE file.
l The relay is equipped with Ethernet ports with the IEC 61850 protocol and RS-485 ports and IEC 60870-5-103 protocol.