Double Bus With Two Ct Bus Coupler - GE P741 Technical Manual

Application Notes
MiCOM P741, P742, P743
There is one zone for BB1 to CT3 and one zone for BB2 to CT3.
Zone 1 = CT1
Zone 2 = CT2
Zone 1 = BB1
Zone 2 = BB2
A zone is defined from a CT to an other CT or an open electrical element (coupler CB or
isolator).
When one CT is used in the coupling and the coupler CB is open, the coupler CT
measurement is not taken into account and a zone is created from each bar feeder CT to
that open coupler CB.
There is one zone for BB1 and one zone for BB2.
6.5.3

Double bus with two CT bus coupler

Zone 1 Zone 1
BB1 BB1
CT 3 is not taken into account
Coupling Open
Isolator Closed
CB Closed
Check Zone = CT1 + CT2
FIGURE 17: BUS COUPLER OPEN
Virtual Zone Virtual Zone
P742/3
P742/3
1 1
3 3 4 4
P742/3 P742/3
P742/3 P742/3
FIGURE 18: BUS COUPLER CLOSED
(3 (fixed)) (3 (fixed))
P742/3 P742/3 P742/3
P742/3
n+2 n+2
n+1 n+1
5 5
P742/3
P742/3
P74x/EN AP/Na7
(AP) 6-35
Isolator Closed
CB Closed
P0877ENa
P742/3
P742/3
2 2
Zone 2 Zone 2
BB2 BB2
n n
P742/3
P742/3
P0882ENa
AP