MV switfchgear coupler
MV switfchgear coupler
(OP)
I have noticed in 11 kV switchgear with sectionalized bus that a load break switch is added in series with the bus coupler circuit breaker (in the bus riser cubicle). I don't know a specific purpose of it as I have seen other designs without a load break switch.
Do you guys know the purpose of having it?
Do you guys know the purpose of having it?






RE: MV switfchgear coupler
RE: MV switfchgear coupler
Hard to say for sure without the single line diagram.
RE: MV switfchgear coupler
here is a generic SLD, seems that it shows two CBs but practically it is usually one CB coupler and the other is a load break switch.
RE: MV switfchgear coupler
RE: MV switfchgear coupler
I wonder if it is two lineups with cables interconnecting the bus that two breakers are needed to isolate faults in the interconnecting cables, is that mandatory? what if a non-segregated busduct is used instead of cables? I think it is much more to do with the switchgear manufactures that can't connect a cable to the bus without a breaker or a switch?
RE: MV switfchgear coupler
RE: MV switfchgear coupler
RE: MV switfchgear coupler
RE: MV switfchgear coupler
RE: MV switfchgear coupler
Then the switch is just for maintenance, nothing to do with protection.
davidbeach hinted that a cable must come with an isolation.
If the switchgear is two lineups, a cable will act as part/continuation of the bus, will it need a CB in both sides? or just one CB and a switch on the other side for isolation? in case of a fault in that cable, the upstream breaker will trip to clear the switch bus side, as the coupler breaker breaks the other...but the power supply for the switch side bus is lost!...this is not the case for two breakers.
Reliability comes for a cost.
The case of interconnecting cable may be argued that a cable is always prone to a fault, not like that with a non segregated busduct (but a fault can still happen, rarely, very...), this very rare probability justifies the cost for two breakers?I doubt!