ABB RELION 670 Series Applications Manual page 36

Section 2
Application
limited to a certain level, typically between 300A and 2000A primary by a neutral point reactor or
resistor). Alternatively this sensitive pickup can be used when high sensitivity is required from
busbar differential protection (that is, energizing of the bus via long line).
Overall operating characteristic of the differential function in the IED is shown in figure 2.
Diff Oper Level
Sensitive Oper Level
IEC06000142 V1 EN-US
Figure 2:
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.
30
s=0.53
IED operating characteristic
Sensitive
differential
protection
Operate
region
Differential protection
operation characteristic
Sens Iin Block
I [Primary Amps]
in
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1MRK 505 337-UUS A
Application manual