Moisture EHV Cables

[Lenz81]

Hi every one

A EHV cable was cut and left exposed to High moisture and water( no cap at either end of cut cable ) , i know about effects of moisture on cable specially on insulation deterioration also i know there are methods to dry out MV cable such as using N3 , To make the long story short can i still use this cable ? Is it possible to use these methods on EHV cables?
Considering absorption rate (by time) of different materials is it possible to point out a spot(From exposed ends ) on cable which after that point cable has not been effected by moisture during that X amount of time?


Thanks .
Have a good day .

 

[Jebb]

We had a situation where a 115kV cable was pulled into duct banks but improperly sealed by the manufacturer’s contractor before jointing could take place. The vaults filled with water, which then wicked up the cable. It was only discovered when the manufacturer’s jointers found water in the cable when prepping for the joints. They kept cutting the cable until no water was found hoping there was enough left for making joints. Some sections had to be replaced because of the water damage. The manufacturer did not want to “dry” the cable or inject it with additives because they might run the risk of having a failure during the warranty period. There wasn’t a clear way to determine how far the water migrated. It didn’t seem dependent on how long it was submerged or exposed to damp conditions. I know somebody ate the cable that was removed and it wasn’t us. It was very hard to swallow.

 

[magoo2]

Cable Technology Laboratories did some work on drying out medium voltage cables about 20 years ago. They used N2 and they also used dry air. Carlos Katz was involved with the work.

 

[Lenz81]

oops ! I made a mistake , i had to type N2 not N3 .