S150-34-1
5
GENERAL CHARACTERISTICS AND OPERATION
1.12 Modular Low Impedance Bus Bar Protection M-LIB3
The M-LIB system is constituted of a number of modular units, which can be combined to suit to any
busbar configuration and allow for easy extension.
1.13 Main features
q Low impedance and low burden on main CTS.
q High stability with zone biased differential elements and CT saturation detectors.
q High speed of operation.
q High reliability: duplicated measuring circuits, CTs’ secondary circuits supervision, wide and
consistent setting ranges
q Self-contained input CTs for main zone and for check zone feature without duplication of main CTs.
q Self-contained isolator repeat relays switching at secondary of the zone input CTs.
q Self-contained discrepancy alarm relays
q Multivoltage power supply.
q Comprehensive self-diagnostic.
q User friendly MMI.
q Real time and recorded measurements.
q Event records and oscillography
q RS 485 serial port with ModBus protocol.
1.14 Component Modules
The system includes three basic modules:
1.14.1 M-BF3 = Income/Feeder Breaker input module (SCE1577)
Including :
q sets of three CTs. 1 set for the Main Zone and 1 for the Check Zone.
q CT saturation detectors.
q bistable isolator repeat relays for switching the secondary circuits of the input CTs and the zone
trip input signal.
q Time delayed isolator discrepancy alarm feature
q Power supply unit