ABB Relion 670 Series Applications Manual page 126

Section 6
Differential protection
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252
352
ANSI11000240 V1 EN-US
Figure 60:
All breakers are normally closed. The requirement for the 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, all circuit breakers associated with the faulty busbar have to be tripped, but the supply to
any load will not be interrupted. The breaker failure protection tripping logic also needs careful design.
This type of busbar arrangement can be very easily protected. The most common setups for this type of
station are described in the following table.
Table 19:
Version of REB670 IED
3PH; 2-zones, 4-bays BBP (A20)
3PH; 2-zones, 8-bays BBP (A31)
1Ph; 2-zones, 12-bays BBP (B20)
1Ph; 2-zones, 12-bays BBP (B21)
1Ph; 2-zones, 24-bays BBP (B31)
Please note that Table
inputs.
A principle overall drawing of how to use REB670 for breaker-and-a-half station including internal CBF
protection for middle breaker is given in Figure 61.
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352
Example of breaker-and-a-half station
Typical solutions for breaker-and-a-half stations when CBF for middle breaker is not required
19 is given for the preconfigured versions of REB670 which do not contain any VT
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152
152
252 252
352 352
Number of diameters
in the station
2/4
4/8
6/12
6/12
12/24
1MRK 505 370-UUS Rev. K
ZA
152
252
352
ZB
ANSI11000240-1-en.vsd
Number of REB670 IEDs required for the
scheme
1/2
1/2
3/6
3/6
3/6
Busbar protection REB670
Application manual