Current Transformer on a TECK cable

[kikirapid]

If I install a CT over a TECK cable, will there be any problem getting a correct measurement due to the armor on the cable?

 

[rcw retired EE]

Single core or multi-core cable? If it is single core, is the metal jacket connected to ground at both ends? If the metal jacket is connected to ground at both ends, the CT will read the vector sum of the current in the conductor and the induced currents in the jacket. If the metal jacket is only connected to ground at one end, the CT will work for load currents but may not read correctly for a phase to ground fault on that phase

If the CT is to measure zero sequence (ground fault) currents on a multi-core cable, it will only work if the jacket ground connection is brought back through the CT also. Otherwise fault current flowing in the jacket will cancel the zero sequence current and the CT will not measure the correct fault current.

 

[kikirapid]

Thanks for your reply. It is single conductor cable and the CT is used only for station metering, not protection. So induced currents should not be an issue.

 

[ccamts]

Hi RCWilson,
A good observation for use of CT's through cables, could you advice where can I read about it conceptually. I would appreciat it, I got it what u said but not conceptually. This is not my question but interfering as I found it interesting.
Thanks