Over Current & Earth Fault Protection Relay（OCEF）

Description              

The E0320J OC/EF PROTECTION RELAY is a numerical current protection relay which provides definite time overcurrent protection, inverse time overcurrent protection, thermal overload protection, negative sequence protection(unbalanced load protection), and also up to four-shot auto-reclosure functions, and a breaker failure protection. The device can measure phase current and zero sequence current. It can be used as primary protection for overhead lines, cables, motors and transformers in the high voltage radial distribution system, and also as back-up protection for line, transformer, generator, motor and busbar.

Function overview                                      

Protection functions          

l Time-overcurrent protection for phase and ground, definite-time overcurrent protection (50) / inverse-time overcurrent protection (51, IEC)

l Inrush restraint

l Cold load pick-up (dynamic setting change)

l Negative sequence protection/ unbalanced load protection (46) for recognition of asymmetrical Loadings and phase interruptions. Sensitive back-up protection for line protection

l Thermal overload protection (49) with preload measuring

l Reverse interlocking

l Breaker failure protection

l Auto-reclosure

Control functions            

l Commands for control of a  circuit-breaker

Operational measured values  

l  Currents

l  thermal model (49)

Event logs                   

l 250 event messages with time stamp

Fault logs                  

l 25 power system fault reports with time stamp

Oscillographic fault records   

l 8 oscillographic fault records are saved, even on loss of DC power

Monitoring functions         

l Hardware

l Software

l Trip circuit supervision

Communications            

l Series port (operated with the maintenance software, for connecting a PC)

l System interface (SCADA),RS485

-IEC 60870-5-103

l Time synchronization via PPS,PPM

Hardware                 

l Auxiliary voltages

24~60 V DC

110~220 V DC/AC

l 4 current transformers

l 8 binary inputs

l 6 output relays (five configurable relays and a life relay)

l 9 LEDs(1 RUN, 1 ERROR,1communication indication, 6 configurable dual-color LEDs )