Cable test

[triniboy]

Can anyone give me some instructions on how to perfom Zero Sequance Impedance Test on an HV cable and what test equipment I would have to use, any help appreciated.

 

[zog]

Can anyone give me some instructions on how to perfom Zero Sequance Impedance Test on an HV cable and what test equipment I would have to use, any help appreciated.

Never heard of it. Where are you getting that from? MV/HV cables should be tested by one of 3 methods.
1. Tan Delta
2. Partial Discharge
3. VLF

All 3 of these require special test equipment that cost in the 5 figure range.

Zero sequence is a term used in protection schemes.

 

[jcrispy3]

Zero Sequence Impedance is the impedance to ground so if you want to measure the impedance to ground you want to megger the cable or perform a power factor test.

 

[zog]

Zero Sequence Impedance is the impedance to ground so if you want to measure the impedance to ground you want to megger the cable or perform a power factor test.

I think it is the Z of the conductor, not the insulation he is refering to. Megger is a DC test and would not test Z anyways. Not sure this is what he is looking for.

 

[zog]

Can anyone give me some instructions on how to perfom Zero Sequance Impedance Test on an HV cable and what test equipment I would have to use, any help appreciated.

Cable impedence testing is for measuring the cable impenence, as it is effected installed in the system by outide influnences. These values effect the proper setting of distance relays in transmission systems. I have seen this test done on transmission lines but not cables, but I suppose there could be an application there for long runs. I dont do much transmission testing so thats why I didnt remmember it before.

I saw a impedence test set for line/cable testing at a conference (Finepoint) last week, it was made by Omicron. I would guess it is a $50k or so test set, I have a contact there, PM me if you want his info.

 

[elec_eng]

Never heard of it. Where are you getting that from? MV/HV cables should be tested by one of 3 methods.
1. Tan Delta
2. Partial Discharge
3. VLF

Zog,

How about DC Hi-Pot test?

 

[zog]

Zog,

How about DC Hi-Pot test?

We have done the DC hipot test arguement here several times. But in case you missed it, MV/HV serviced aged (5 years) cables should not be DC hipot tested per IEEE, ANSI, NETA, and ICEA cable testing standards. It is considered a destructive test and has proven to shorten the life expectantcy of the cable.

 

[elec_eng]

We have done the DC hipot test arguement here several times. But in case you missed it, MV/HV serviced aged (5 years) cables should not be DC hipot tested per IEEE, ANSI, NETA, and ICEA cable testing standards. It is considered a destructive test and has proven to shorten the life expectantcy of the cable.

Zog,

I must have missed it..Can you provide me the link to that discussion?

 

[zog]

Zog,

I must have missed it..Can you provide me the link to that discussion?

There have been a ton, just search threads for "hipot cable"