High Voltage testing

[dsjr114]

We megged some high voltage termination today.The first cable tested at 800 megs the next 2 megged at 50 gigs .What could have cause this big of a different between the first cable and the other 2.

 

[dsjr114]

these cable were megged at 5000V

 

[LEO2854]

these cable were megged at 5000V

Loose connection maybe?

 

[dsjr114]

Loose connection maybe?

like a bad crimp?

 

[don_resqcapt19]

Failure to completely remove the semi-conductor at the termination.

 

[masterinbama]

I have had tests fail because of enough bleed through the lightning arrestors. Did you disconnect those?

 

[junkhound]

moisture or simply high humidity

example - put a nylon spoon fresh from being washed and dried into your microwave - you will melt the nylon spoon....

new spoon,
leave the nylon spoon in a low humidity area (<10%rh) for a day and then put it in the microwave and it barely gets warm

 

[dsjr114]

moisture or simply high humidity

example - put a nylon spoon fresh from being washed and dried into your microwave - you will melt the nylon spoon....

new spoon,
leave the nylon spoon in a low humidity area (<10%rh) for a day and then put it in the microwave and it barely gets warm

Moisture? all three legs were cut and termed on one end and rolled up on a reel. If it was moisture would it just affect one or all of the legs.And one other question we wrapped plastic on the aerial end because it was going to rain and they weren't getting tied in yet .The transformer end we termed and land the legs and shut the transformer,will the moisture in the air affect these cable at the transformer they?

 

[GoldDigger]

The Megger measures resistance between the two connection points. That resistance can be anywhere along the cable, including at the aerial end if it is badly terminated, dirty or wet.

Sent from my XT1080 using Tapatalk

 

[zog]

We megged some high voltage termination today.The first cable tested at 800 megs the next 2 megged at 50 gigs .What could have cause this big of a different between the first cable and the other 2.

What type of cable? What voltage rating? (HV is >69kV so you need to clarify)

A Megger test on MV cable wont tell you much at all, you need to do a VLF, TD, or PD test per industry standards.