Neutral Quality of MV Cable

[VLFit]

I have rarely seen or even heard of utilities and others testing the neutral quality of a cable. Of course it's needed to carry fault currents if needed but why else test it? Don't people testing cables for partial discharge or Power Factor/Tan Delta have to first verify the neutral is good to make the test results worthwhile. Any words of wisdom out there on the subject would be appreciated. I don't think there is an IEEE standard for it. ???

Thanks

 

[magoo2]

The integrity of the neutral was an issue when the industry was using unjacketed direct buried cable. Neutral corrosion does occur and this leads to high voltages on the neutral which in turn connects to the neutal of the transformers and the customer neutrals. Can be a shocking experience.

With the use of jacketed cable, the neutral corrosion is not really an issue anymore.

 

[VLFit]

Thanks for the answer. What about prior to cable injection. A tdr doesn't work that great, that I have seen anyway. Many utilities inject their cable if the cable is jacketed, do they skip this step and assume the neutral is good enough to warrant injection?

 

[dpc]

The cable injection companies that I am aware of will test the integrity of the neutral prior to doing injection. If the neutral has corroded, they will not fill that cable because they do not want to warrant it against failure.