Medium Voltage Cable Acceptance Testing

[Cammando_Cool]

I have been involved in a project that is installing new switchgear and cables and I wanted to know what the best practices were for field acceptance testing of MV cables. The current contractor basically wants to do a DC Hi-pot only, but I'm not sure if there are more tests that should be performed per industry standard. I guess I am not sure when you do a DC Hi-pot or VLF, or Partial Discharge, or Tan Delta. If anyone has any resources or experience about typical tests performed, I would appreciate it.

 

[Hv&Lv]

DC Hi-pot is good, but only if the operator knows and understands what he is doing. It’s easy to stress the cable with too much. Especially XLPE
IEEE 400, 400.1, 400.2, etc. and IEEE 141 would be good reads

 

[Cammando_Cool]

Thanks for the reply! I'll definitely give those a read. So for an acceptance test, the DC Hi-pot by itself is likely sufficient? My guess would be since I am only looking to see if insulation wasn't damaged during installation that doing a voltage withstand test would flush out any issues.

 

[David Castor]

The safest approach is to follow the manufacturer's recommendations. DC hi-pot testing has fallen out of favor, especially for XLPE cables. I believe Okonite is still OK with hi-pot of their EPR cable.

 

[MrJLH]

Check out NETA ATS 7.3.3.

I would perform a VLF/Partial Discharge/Tan Delta so that you have a baseline. This way when you perform future tests on the cable you have a basis for comparison. Additionally consider HFCT's on the drains so that you can perform online partial discharge testing.