Grounding Multi-Ratio CTs

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mivey said:
You don't ground polarity. Polarity is the smaller number and goes to the instrument (X1 for your example). The higher of the used numbers gets grounded (X2 for your example).
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Whether you ground the polarity side or the non-polarity side is a matter of application. Some devices use the non-polarity instead.....metering comes to mind since many times it uses the opposite side that of the relaying. There is also the off-chance that the CT was incorrectly installed in reverse.
 
Bugman1400 said:
Whether you ground the polarity side or the non-polarity side is a matter of application. Some devices use the non-polarity instead.....metering comes to mind since many times it uses the opposite side that of the relaying. There is also the off-chance that the CT was incorrectly installed in reverse.
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True enough.:thumbsup: I was in substation mode.
 
Phil Corso said:
Sunny,

X1-X2 has, say=40 turns; X2-X3=30; X3-X4=20; X4-X5=10! Always maintain the ground-connection at X5! Then, connect burden-devices between X1, and X5!

Thus, Max turns-ratio, available, between X1-X5 is 100:1!

Example 2: you want 50:1 ratio, simply short terminals X2-X3-X4!

Example 3: you want 10:1 ratio, simply short terminals X1-X2-X3-X4!

And, you must never leave turns open-circuited!

Regards, Phil Corso
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Phil
Looks like you are thinking of a different device;

http://www.schneider-electric.us/en/faqs/FA111406/
 
mivey said:
You don't ground polarity. Polarity is the smaller number and goes to the instrument (X1 for your example). The higher of the used numbers gets grounded (X2 for your example).
Click to expand...

i disagree this depends on your application.. you can ground either X1/X2, in my example, if the use of such CT demands it and as long as you only ground one point..


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Bugman1400 said:
Whether you ground the polarity side or the non-polarity side is a matter of application. Some devices use the non-polarity instead.....metering comes to mind since many times it uses the opposite side that of the relaying. There is also the off-chance that the CT was incorrectly installed in reverse.
Click to expand...

i agree with this


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