common CT

[teke]

Can anybody tell me where can I get a typical diagram for connection of one power meter and one protection relay on one common CT set(Three phase).
The case here is originally built with one relay, now want to add a meter on the same CT set and PT set.

 

[waross]

When more than one device is connected to a CT they are connected in series. You may not get revenue quality accuracy from a protection class CT.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[safy2004]

Its easy you can connect the new power meter to the existing CT and PT, but you should be careful because CT connection should be in series and if there is any cut you may face troubles with the old metering or protection system as well as the dangerous of the high voltage may occur on the secondary side of the CT.
At the same time if you have any short circuit on the PT, you will face troubles with the existing metering and protection system and the PT may be exploded!
These are just precautions! you can do it
See attached file in the link
Regards,
Safy

 

[slavag]

Hi
teke
You must check thermal stnaded of PM current input
Meas core usually sturated ..about 2In and this saturation is protected CT input of PM.