How to coordinate Bus couplers
How to coordinate Bus couplers
(OP)
I want help from you people to understand the philosophy adopted to coordinate relay settings of Bus couplers.
I am talking about a bus, which has 3 incomers, and each incomer is separeted by a Bus coupler. So there are 2 bus couplers and 3 incomers in a bus and normally bus couplers are closed making all the incomers parallel.
I am talking about a bus, which has 3 incomers, and each incomer is separeted by a Bus coupler. So there are 2 bus couplers and 3 incomers in a bus and normally bus couplers are closed making all the incomers parallel.






RE: How to coordinate Bus couplers
What kind of bus-zone protection do you have at the Bus couplers? It would be a type of differential protection, most probably a high-impedance sceme for older installations, and a high- or low-impedance sceme for new installations. Thus if all the incomming currents equal the outgoing currents in a certain zone, there would be no relay-operation.
Normally you would use a kind of zone-protection on each busbar, in your case there would be three different zones. Thus for a fault on one zone you would open all the incoming and outgoing feeders on that zone to isolate the fault. Take for instance a fault on the middle-busbar. If the bus-protection sense a fault, both bus couplers, the middle incomer and the middle-feeder have to open to isolate the fault. Zone protection covers just a certain zone, and need not to coordinate with downstream devices, thus it can be as fast as possible to minimize damage.
You can also view:
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(copy and paste whole address)
Download chapter 15 (Busbar protection)
Regards