Cable insulation improvement

[pmgohpelangi]

With regards to the insulation improvement, Could it be there were moisture present in the air gap of the cable and the moisture was removed during hipot test and that led to an improvement of the insulation level?

 

[7anoter4]

I was present when a low voltage pvc insulated underground cable after installation was tested with 1000 v dc megger and the measured resistance was 0. We isolated the cable receiver end and connected to power source-400 V 50 Hz-for 72 hours. After 72 hours we checked the resistance one more time and this time was almost 1000 Megohms. It seems that the dielectric losses –even very low losses- heated the insulation and evacuated the moisture.