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ANSI06000139 V1 EN-US
Figure 52:
Busbar protection measuring and fault clearing boundaries
where:
1
Busbar Protection measuring boundary determined by feeder CT locations
2
Busbar Protection internal fault clearing boundary determined by feeder CB locations
3
End fault region for feeders as shown in Figure
4
End fault region for feeders as shown in Figure
Figure
shows a single busbar station, where two feeders on the left-hand side having
CTs located on the line side of the breaker, meanwhile two feeders on the right-hand
side of the busbar having CTs located on the busbar side of the breaker. It is assumed
that busbar protection is connected to all four set of CTs in this station.
Due to CT locations in feeder bays, busbar protection will detect all primary faults
located within measuring boundary determined by CT locations, see Figure
However its operation will only completely clear faults within clearing boundary
determined by CB locations as shown in Figure
. Obviously, the primary faults in-
between these two boundaries do pose certain practical problems.
First of all it shall be noted that there is no ideal solution for faults within end zone
region in a feeder bay, when the feeder breaker is closed. Such faults, within end fault
region, will be then cleared with additional time delay either by operation of local
backup protection (that is, feeder circuit breaker failure protection) or by operation of
remote backup protection (that is, remote ends zone 2 distance protection).
However, the overall busbar protection behavior can be improved for primary faults
within end fault regions, when feeder breaker is open. Under such circumstances the
following actions can be taken:
1MRK 505 370-UUS A
Section 6
Differential protection
Busbar protection REB670 2.2 ANSI
129
Application manual
Summary of Contents for RELION REB670
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