Protection relay for transformer protection.

  Protective Functions 
„  Line three-stage over-current protection (it is subject to the criterions of direction and 
compound voltage ) 
„  Transformer three-stage over-current protection (it is subject to the criterions of direction 
and compound voltage ) 
„  Instantaneous under-voltage protection 
„  No-voltage protection (it is subject to TV failure blocking ) 
„  Over-voltage protection 
„  Two-stage zero-sequence over-current protection 
„  Zero-sequence over-voltage protection 
„  Auto re-closing (with post-accelerated protection) 
„  Under frequency protection 
„  Charging protection 
„  Breaker failure protection 
„  Overload alarm 
„  Checking synchronization and checking no-voltage 
„  TV and TA failure alarm 
„  Control circuit failure alarm 
„  Four programmable logic control outputs (PLC1,PLC2,PLC3,PLC4) 
(2)  12 digital inputs, 10 AC analog inputs,1 DC analog input,8 digital outputs(relays)  
(3)  Power off alarm for the unit 
(4)  Faults wave recording (the largest recording duration is 20s) 
(5)  Time-adjust: software setting or GPS impulse setting 
(6)  The unit can save the latest 40 alarm records even after an auxiliary power supply fault. 
(7)  The unit has one RS-485 communication interface and one Ethernet communication interface 
that are convenient to accomplish dual-network communication system.