Experimental study on the causes of electrical breakdown of EHV XLPE insulation using 'prebreakdown partial discharge detection method'

摘要

The causes of electrical breakdown in EHV XLPE (cross-linked polyethylene) cables were clarified by carrying out the prebreakdown partial discharge (PBPD) detection test under electric stresses from 40 to 70 kV/mm. Ten causes of electrical breakdown were observed in the PBPD test. As expected, it was found that they were associated with very small contaminants and protrusions. The electrical tree inception stress was estimated to be 270 kV/mm on the average. The prebreakdown time was estimated to be on the order of 1 hour under an applied electric field of 5 kV/mm.