ABB RELION REB670, Applications Manual

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ANSI11000239 V1 EN-US
Figure 62: Example of double busbar station
This type of busbar arrangement is very common. It is often preferred for larger
installations. It provides good balance between maintenance work requirements and
security of supply. If needed, two busbars can be split during normal service. The
requirement for busbar protection scheme is that the scheme must have two
independent differential zones, one for each busbar. In case of an internal fault on one
of the two buses, bus-coupler circuit breaker and all feeder circuit breakers associated
with the faulty bus have to be tripped, leaving other busbar still in normal operation.
Provision for zone selection, disconnector replica and zone interconnection have to be
included into the scheme design.
This type of busbar arrangement can be protected as described in the following table:
Table 20: Typical solutions for double busbar stations
Version of REB670 IED Number of feeders in the
station (excluding bus-
coupler bay)
Number of REB670 IED
required for the scheme
3PH; 2-zones, 4-bays BBP (A20)
3*
)
1
3PH; 2-zones, 8-bays BBP (A31)
7*
)
1
1Ph; 2-zones, 12-bays BBP (B20) NA NA
1Ph; 2-zones, 12-bays BBP (B21)
11*
)
3
1Ph; 2-zones, 24-bays BBP (B31)
23*
)
3
*) with just one CT input from bus-coupler bay
Please note that Table 20 is given for the preconfigured versions of REB670 which do
not contain any VT inputs.
Section 6
1MRK 505 370-UUS A
Differential protection
146 Busbar protection REB670 2.2 ANSI
Application manual