Unbalance Current Detection

[Humble2000]

I am looking for a meter to detect unbalanced current. This means if one phase current is more than 10% in difference with other two ,the unit initiates a trip.
I also have one set of CT’s which are source for Crompton Ammeters. There is diagram for connecting two meters in series, is this going to be accepotabel and provide enough current for proposed meters. I apprecite any feedback on this.

 

[waross]

Here is one sample.

http://www.ssac.com/standard/ff-mp2.htm

I am used to nits similar to the WVM series.

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

 

[slavag]

Hi Bill.
I know .
For this issue, I hope enough attached

http://www.abb.com/product/us/9AAC132574.aspx?country=US

Regards.
Slava

 

[slavag]

Bill. Good co-operation!!!!!
Regards.
Slava

 

[Humble2000]

Guys..
These are all based on voltage sensing concept.
slavag : That company doesnt have any sensor.
I sourced out BE1-700C it has 46 element.I wish I could find a single element relay out there that does my requirment.

 

[waross]

Add resistors across the CTs to develop a voltage proportional to the current. Then use voltage monitors.

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

 

[davidbeach]

Bill, I had thought of that, and if it works - great, but most voltage monitors will tend to want some nominal voltage for normal operation or to reset from a trip condition. To work here any voltage monitor to be considered would have to accept what ever voltage the shunt produced, and not be damaged by the voltages associated with faults and locked rotor.

 

[Humble2000]

Bill,
Question is that how heat could affect the resistor performance and overall accuracy of the setup?

 

[waross]

I defer to David Beach.

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