Line differential protection swiftly detects and isolates faults by comparing currents at each end of the protected line, ensuring system reliability and minimizing disruptions.
Function overview
Protection functions
Differential protection for universal use with power lines and cables on all voltage levels with phase-segregated measurement (87L)
Two line ends capability
Suitable for transformers in protected zones (87T)
Restricted ground-fault protection (87N) if a transformer is within the protection zone
Well-suited for serial compensated lines
Well-suited for serial compensated lines
Two independent differential stages: one stage for sensitive measuring for high-resistance faults and one stage for high- current faults and fast fault clearance
Breaker-failure protection (50BF)
Phase and ground over current protection with directional element (50, 50N, 51, 51N, 67, 67N)
Phase-selective intertripping (85)
Overload protection (49)
Over/under voltage protection (59/27)
Over/under frequency protection (81O/U)
Auto-reclosure single/three-pole (79)
Control function
Command and inputs for control of CB and disconnectors (isolators)
Monitoring functions
Self-supervision of the relay
Trip circuit supervision (74TC)
8 oscillographic fault records
CT-secondary current supervision
Event logging / fault logging
Switching statistics
Front design
User-friendly local operation
PC front port for convenient relay setting
Function keys and 8 LEDs for local alarm
Communication interfaces
1 serial protection data (R2R) interface
Front interface for PC connection
System interface
IEC 61850 Ethernet
IEC 60870-5-103 protocol
PROFIBUS DP, DNP 3 and MODBUS
Service / modem interface (rear)
Time synchronization via IRIG-B, DCF77 or system interface
Features
Browser-based commissioning tool
Direct connection to digital communication networks