MBCH12 Relay
MBCH12 Relay
(OP)
Please, I want to wire an MBCH12 (ALSTOM) differential relay to protect a 132/11KV, 15MVA, Yy0 transformer. It is to replace an old relay.
In the present scheme the primary and secondary CTs are wired in star while interposing CTs on both primary and secondary are wired in star/delta.
The literature show terminal 27 of the relay connected to neutral. In the present scheme, no neutral goes to the relay. What do I connect to the terminal? Can I leave the terminal unconnected?
In the present scheme the primary and secondary CTs are wired in star while interposing CTs on both primary and secondary are wired in star/delta.
The literature show terminal 27 of the relay connected to neutral. In the present scheme, no neutral goes to the relay. What do I connect to the terminal? Can I leave the terminal unconnected?






RE: MBCH12 Relay
RE: MBCH12 Relay
RE: MBCH12 Relay
What i understand is that there is a terminal to be connected to a star point, that is terminal 27, and even if he eliminated the interpossing CTS that terminal will be left unconnected since inputs to the relay will both be in delta.
RE: MBCH12 Relay
The main CTs on primary and secondary are wired in star. So without the ICTs I have something to connect to terminal 27.
RE: MBCH12 Relay
Primary and secondary CT's are wired in Y.
I guess you can rewire all your CT's in Y to gain neutral wires for terminal 27. No ICT used. I would try that to see
if it works for a xfo.
RE: MBCH12 Relay
If i understand what you are trying to say, your transformer is star/star and therefore your CTs should be in delta both sides.
RE: MBCH12 Relay
Since you have no 30 degree shift to account for, the CT's can be both Y-Y or D-D. Use of Y-Y gives neutral wires for terminal 27.
RE: MBCH12 Relay
RE: MBCH12 Relay
RE: MBCH12 Relay
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RE: MBCH12 Relay
The MBCH12 relay come in single phase units. So, the terminals 27 of the three relays are linked and nothing is connected to them.
RE: MBCH12 Relay
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I don't suffer from insanity. I enjoy it...