ABB REB670 Applications Manual page 39

1MRK 505 337-UUS -
Application manual
Integrated overall check zone feature, independent from any disconnector position, is
available. It can be used in double busbar stations to secure stability of the busbar
differential protection in case of entirely wrong status indication of busbar disconnector
in any of the feeder bays.
Flexible, software based dynamic Zone Selection enables easy and fast adaptation to the
most common substation arrangements such as single busbar with or without transfer bus,
double busbar with or without transfer bus, breaker-and-a-half stations, double busbar-
double breaker stations, ring busbars, and so on. The software based dynamic Zone
Selections ensures:
• Dynamic linking of measured CT currents to the appropriate differential protection
zone as required by substation topology
• Efficient merging of the two differential zones when required by substation topology
(that is load-transfer)
• Selective operation of busbar differential protection ensures tripping only of circuit
breakers connected to the faulty zone
• Correct marshaling of backup-trip commands from internally integrated or external
circuit breaker failure protections to all surrounding circuit breakers
• Easy incorporation of bus-section and/or bus-coupler bays (that is, tie-breakers) with
one or two sets of CTs into the protection scheme
• Disconnector and/or circuit breaker status supervision
Advanced Zone Selection logic accompanied by optionally available end-fault and/or
circuit breaker failure protections ensure minimum possible tripping time and selectivity
for faults within the blind spot or the end zone between bay CT and bay circuit breaker.
Therefore the IED offers best possible coverage for such faults in feeder and bus-section/
bus-coupler bays.
Optionally available circuit breaker failure protection, one for every CT input into the
IED, offers secure local back-up protection for the circuit breakers in the station.
Optionally available four-stage, non-directional overcurrent protections, one for every
CT input into the IED, provide remote backup functionality for connected feeders and
remote-end stations.
Optionally available voltage and frequency protection functions enable to include voltage
release criterion for busbar protection or to integrate independent over-, under-voltage
protection for the bus in the busbar protection IED.
Optionally available over-current, thermal overload and capacitor bank protection
functions open possibilities to integrate protection of shunt reactors and shunt capacitor
banks into the busbar protection IED.
Section 2
Application
33