vacuum circuit breaker is a device which is used to isolate
the faulty part of the power system from healthy part of the
power system & is used in switchgear.WHEN WE WANT TO SERVICE
OR MAINTEINANCE OF ANY SUBSTATION OR WANT TO CLEAR THE FAULT
DURING THAT CONDITION WE CAN ISOLATE THAT PART OF POWER
SYSTEM SO THAT WE CAN WORK IN THAT CONDITION ISOLATOR IS
OPEN AND SUPPLY CAN BE INTERRUPTED.
Vaccum circuit breaker,as the name indicates is used to
break the circuit in faulty conditions and Arc quenching
medium is Vaccum. Isolator, as the name indicates isolates
the part of the system on occurence of fault without
actually being quenching/interrupting the arc....
The vaccum c.b are used to dissconnect the ckt when fault
accurse in the ckt,aswell as the vcb is used to break the
ckt in abnormall condition,in tn the name indicates the
isolators are used to isolates the ckt and the supply can
be intterupted by the mains.
the purpose of the vacuum circuit breaker is to isolate the fault system after the occurance of the fault. So that circuit breaker contacts open, in case of isolator it isolate the power for maintenance of the sub station as u like depends on us and it should not require any relay for finding the type of fault and interrupt the supply. In case of circuit breaker relay is required for finding the type of fault and it interrupt the circuit breaker.
last week we did the REF relay test by closing single pole
(R phase) of CB and apply 380V at the primary of delta
transformer. we get 33A at the primary of the R phase star
end. but we get 380A at both R an B in delta side. how and why?