Medium Voltage Cable Testing

[jerebear]

I have heard differing opinions on whether or not to Hi-Pot test service aged medium voltage cable. What are the NETA standards in regard to this. These cables are approximately 3 years old at 13.2 kV.

 

[slavag]

Hi Jerebear.
Please see attached link:
thread238-177464
In this link you have links to others Threads.
Many, many useful information.
Good Luck.
Slava

 

[dpc]

There has been a lot of discussion in previous threads on this topic. I'd just emphasize that I would not do anything that was not recommended by the cable manufacturer for field testing of installed cable.

 

[whycliffrussell]

Three year old cable is 'practially' brand new.

 

[davidbeach]

whycliffrussel, three year old cable may have most of its expected life left, but for testing purposes it is used. The differential between new and used is that it has been placed in service carrying AC load current.

 

[dpc]

Once it's "pulled" in, it is definitely not new anymore.

 

[Zogzog]

NETA says to not DC hipot service aged cables >5 years old. A VLF ,Tan Delta, or PD test is recommended

 

[jerebear]

whycliffrussel - While the cable is only three years old, the issue at hand is as follows: I will try to keep this as short as possible.
A customer of ours has 10 - 2 mW generators at 13.2 kV, one of these generators had a fault in the 15 kV cables leading to the PTs. These 3 - #14 15 kV cables were routed through the generator termination housing to the PTs through a 1/2" non metallic sealtite conduit. The fault occured in the middle of the sealtite which would lead one to believe there was some leakage that occurred. While this cable was non-shielded cable it is being replaced with shielded cable which is not being installed in conduit. It is however being routed away from other conductors in the enclosure. This faulting of the cables has prompted our customer to ask for testing of all of the existing cables on all of the generators.