CT Connection 1

[isquaredr]

Hi
I have encountered a curious CT connection and need some assistance.
(1)2 CT's one in "a" phase the other in "b" phase.
(2)s1 of the "a" phase CT is connected to s2 of the "b" phase CT.
(3) s2 of the "a" phase CT is connected to s1 of the "b" phase CT

The combined output is used in a OLTC control scheme, load is balanced.

My question is what does this CT connection achieve given that "a" phase is zero degrees and "b" phase is -120 degrees.

 

[davidbeach]

So, if s1 is the polarity (and assuming that both primary windings point the same direction), you have "a"-"b", aka Iab.

 

[isquaredr]

Thanks David for your speedy reply.
Indeed P1 & P2 in both CT's are of the same polarity, CT ratios are the same.
I will give your comments some thought in terms of phase angle relative to "a" phase.

 

[Bramb]

Hi isquredr,
it is a typical connection for OLTC controller.

More explanations can be found for example at

http://www.reinhausen.com/en/XparoDownload.ashx?raid=16747

(Maschinenfabrik Reinhausen Tapcon 240 Manual page 144).

Ciao
Erminio

The difference between overload and short circuit lies in the nature of the fault, not in the value of the current.

 

[isquaredr]

Thanks ErmBra
Page 144 in this rather large manual was just what I needed.

Thanks again