Two Main Switchgear

The answer to the question may be determined by stating whether the machines may run concurrently or whether they must not. Once this has been decided, the rest is detailed design.

Do you mean providing mechanical and electrical interlock facitlity for the two incoming swithgears? If you want to have an alternate power source in case one of the transformers is down and there is essential or critical loads require power supply. Just provide a coupler VCB between the two incoming switchgears. You may need to do load sharing as one transformer may not be able to take care all the electrical loads.

Hello folks,

No devices are useful. Your LV swgr has to make the protection and the discrimination between your two engines. If you don't have any MCR, put an electrical contact (in X) in each trip coil of your outgoings, in order to cut both outgoing in case of a transformer fault. One motor can run with the other tripped. The transformer protection will not see any trouble. It is a standard case of running. After that, all depends of your case of motor runnings. But this is the minimum you have to do. If you have no MCR, it is more complicate. It is a litanie of tripping contacts, that i can not describe here. Be careful to start each engine with a slight delay between them. If not the starting voltage could be seen as a fault by the transformer protection.

Good year and good luck

BRZK

Very good answer sir; we did same at a Coca Cola facility, to solve a problem. Delay was not long enough and we had to calibrate for that.