Paralleling of Metering circuits
Paralleling of Metering circuits
(OP)
In a double switched Bay at a substation we have 2 circuit breakers, each with CT's on each phase. (Bus 1 CB and Bus 2 CB) A line is terminated between the circuit breakers, hence the need to measure this line current through the breakers.
The metering cores of the CB1 and CB2 CT's are wired to various instruments on their respective secondary circuit.
Naturally, I want to 'cut' into each metering circuit and energise a new device's CT inputs for another application.
This should be acceptable, but, not using summation CT's, I want to wire them to common inputs so that they are in parallel.
This creates the question. When one of the CB's is open, will secondary current flowing in the other metering circuit now flow in the secondary circuit of the open CB, and thus indicate that current is flowing in that primary circuit. It may help to draw this.
Thanks,
Ez
The metering cores of the CB1 and CB2 CT's are wired to various instruments on their respective secondary circuit.
Naturally, I want to 'cut' into each metering circuit and energise a new device's CT inputs for another application.
This should be acceptable, but, not using summation CT's, I want to wire them to common inputs so that they are in parallel.
This creates the question. When one of the CB's is open, will secondary current flowing in the other metering circuit now flow in the secondary circuit of the open CB, and thus indicate that current is flowing in that primary circuit. It may help to draw this.
Thanks,
Ez






RE: Paralleling of Metering circuits
RE: Paralleling of Metering circuits
RE: Paralleling of Metering circuits
Could you please attach scheme of your CT connections, it will be more easy for us.
Best Regards.
Slava
RE: Paralleling of Metering circuits