7SR220 Overcurrent Relay

7sr220 series relays include for directional control of the overcurrent and earth fault functionality and are typically installed where fault current can flow in either direction i.e. On interconnected systems. Relays have five current and four voltage inputs they are housed in e6 or e8 cases.integrated logic is provided to allow the optimal configuration of relay functionality with the relays analog inputs and binary input/output circuits. The optional auto-reclose feature offers an integrated solution for use on ohl feeders. ?the relay functionality allows highly flexible settings for current and time grading making it compatible with all types of overcurrent protections. ?protection, instrumentation and metering functionality is accessible via data comms channel(s). A front usb port for local pc connection and rear electrical rs485 port for remote connection are provided as standard, additional ports are available as options.

protection functions

• undercurrent (37)
• broken conductor (46bc)
• negative phase sequence overcurrent (46nps)
• thermal overload (49)
• overcurrent (50, 51)
• earth fault (50g, 50n, 50sef, 51g, 51n, 51sef)
• directional control of overcurrent & earth fault (67)
• high impedance ref (64h)
• under/over voltage (27/59)
• negative phase sequence voltage (47)
• voltage controlled overcurrent (51v)
• neutral voltage displacement (59n)
• under/over frequency (81)

supervision functions

• ct supervision (60cts)
• trip & close circuit supervision (74t/ccs)
• vt supervision (60vts)
• inrush detector (81hbl2)
• circuit breaker fail (50bf)

control functions

• auto reclose (79)

monitoring functions

• primary/secondary current phases and earth direction
• primary/secondary line and phase voltages
• apparent power and power factor
• real and reactive power
• w hr & var hr forward and reverse
• historical demand record
• positive phase sequence (pps) voltage & current
• negative phase sequence (nps) voltage & current
• zero phase sequence (zps) voltage