ABB Relion 670 Series Applications Manual page 120

Section 6
Differential protection
6.1.4.2 Single busbar arrangements
The simplest form of busbar protection is a one-zone protection for single busbar configuration, as shown
in Figure 54. When different CT ratios exist in the bays compensation is done by setting the CT ratio
individually for each bay.
The only requirement for busbar protection is that the protection scheme must have one differential zone.
For any internal fault all circuit breakers must be tripped, which will cause loss of supply to all loads
connected to the station.
ZA
152
ANSI06000087 V1 EN-US
Figure 54:
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 14:
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 the above Table
contain any VT inputs.
6.1.4.3 Single busbar arrangements with sectionalizer
This arrangement is very similar to the single busbar arrangement. The sectionalizer allows the operator
to split the station into two separate buses. However, switching of the sectionalizing disconnector has to
be done without any load. This means that one of the two busbars has to be de-energized before any
opening or closing of the sectionalizer.
For this case the protection scheme must have two differential zones, which can be either split to work
independently from each other or switched to one overall differential zone when sectionalizing
disconnector is closed. Nevertheless, when sectionalizer is closed, for internal fault on any of the two
buses all feeder circuit breakers have to be tripped, which causes loss of supply to all loads connected to
this station.
114
152
152 152
Example of single busbar section with six feeder bays
Typical solutions for single busbar arrangement
14
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xx06000087_ansi.vsd
Numbers of feeders
per busbar
4
8
12
12
24
is given for the preconfigured versions of REB670 which do not
1MRK 505 370-UUS Rev. K
Number of REB670 IEDs required for the
scheme
1
1
3
3
3
Busbar protection REB670
Application manual
M6641-3 v5
M6642-3 v5