GE P742

A
pplication Notes P74x/EN AP/N
a7
MiCOM P74
1, P742, P743 (AP) 6-
53
AP
Solution Solution A
1 CT on BC
& 1 CT on BS
Solution B
2 CT on BC
& 2 CT on BS
Solution C
1 CT on BC
& 2 CT on BS
Solution D
2 CT on BC
& 1 CT on BS
Using solution 1
for the 2
nd
coupler
   
Using solution 1a
for the 2
nd
coupler
   
Number of
peripheral units
required
n + 3 n + 6 n + 4 n + 5
TABLE 4: NUMBER OF REQUIRED PU’S FOR FIGURE 34
The additional peripheral unit being for the bus section isolators is optional.
The number of additional peripheral units being dependant on the number of bus section/bus
coupler CTs. The type of peripheral unit used for each bay will depend on the i/o
requirements of the bay in question.
P3788ENa
FIGURE 35: DOUBLE BUSBAR APPLICATION WITH BUS COUPLER
AND DOUBLE BUS SECTION CIRCUIT BREAKER ARRANGEMENT
The above example shows a double busbar with both a bus section and a bus coupler.
There are circuit breakers on both the upper and lower bars. The scheme is split into four
zones. There are n feeders connected to the busbar. The bus coupler and bus section
circuit breakers can have either a single CT (solution 1 and 2) on one side or CTs on both
sides (solution 1a or 2a). This configuration requires 1 central unit and n plus the following
number of peripheral units. The total number of peripheral units required allows for a
peripheral unit for the bus section isolator on the upper bar.
Solution Solution A
1 CT on BC
& 1 CT on
each BS
Solution B
2 CT on BC
& 2 CT on
each BS
Solution C
1 CT on BC
& 2 CT on
each BS
Solution D
2 CT on BC
& 1 CT on
each BS
Solution 1
   