ABB RELION 670 Series Applications Manual page 122

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 53. 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 53: Example of single busbar section with six feeder bays
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 13:
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.
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152
152 152
Typical solutions for single busbar arrangement
13
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 505 337-UUS A
Number of REB670 IEDs required for the
scheme
1
1
3
3
3
Application manual
M6641-3 v4
M6642-3 v4