PT Ratio Meaning
PT Ratio Meaning
(OP)
Kind sirs,
Please englighten me with this issue.
We are using PT with Ratio: 13.8 kV/3R/110V/3R/110V/3V
What does this mean?
Thank you in advance and sorry for the ignorance.
Please englighten me with this issue.
We are using PT with Ratio: 13.8 kV/3R/110V/3R/110V/3V
What does this mean?
Thank you in advance and sorry for the ignorance.






RE: PT Ratio Meaning
see http://eng-tips.com/viewthread.cfm?qid=321282 for more on PTs with similar markings.
RE: PT Ratio Meaning
RE: PT Ratio Meaning
I believe the consensus was that the divide by 3 winding was to be feeding a 59N relay, used as a ground (earth) over voltage relay.
Do you have schematics to confirm that this is what is connected to the PT?
RE: PT Ratio Meaning
Correct...110/3V winding would be connected in a broken delta configuration and used for zero-sequence voltage detection.
RE: PT Ratio Meaning
thank you for the insight sir. i will try to upload the diagram for the connections.
scottf,
sir i believe both you and smallgreek are correct on this. thank you for your time.
RE: PT Ratio Meaning
As far as nameplate data requirements are concerned, is there something new in relevant standards that calls for this? I don't recall seeing that in North American standards.
@NorEE-
You are welcome! Please post a picture of nameplate, if you can.
RE: PT Ratio Meaning
No, this is normally seen in IEC applications.
IEEE VTs would normally use a 120V rated secondary or 69/67V rated secondary.
RE: PT Ratio Meaning
sir sorry for the late reply.
For now i can only provide a connection diagram as the plant is currently running and their are no provisions to take pictures of VT nameplates. ^^