Switching between Synchronism voltage and 3V0 (polarization voltage)

[jhonsom]

We have only one extra voltage input in the Relay other than the 3ph voltage input . Has anybody heard of any application where you can switch between two PT inputs ? one from VS PT( synchronism voltage) for doing 25 function and other from 3V0 PT (broken delta) for directional protection.

We need both 25 and 3V0 to work and not simultaneously, this is for a open deta connected PT input, where 3V0 is not internally calcuated.

Thanks

 

[rbulsara]

See thread238-276354, may be it is relevant to you.

Rafiq Bulsara

http://www.srengineersct.com

 

[cranky108]

Can't the relay derive 3V0 from the three phase voltages?

Or just purchase another relay to do the 25 function. Can't be more that a couple thousand dollars.

 

[davidbeach]

Nothing can be derived from open delta VTs, shouldn't be used for important stuff.