Atsushi Toya

Development of a method of partial discharge detection in extra-high voltage cross-linked polyethylene insulated cable lines

Deterioration in the insulation performance of extra-high voltage XLPE (cross-linked polyethylene) cables is believed to be attributable to the deterioration caused by partial discharges. After using an XLPE cable to investigate the behavior of partial discharges under various adverse conditions, the authors succeeded in developing a highly sensitive novel method of measuring partial discharge in XLPE cable lines. Partial discharges in a 275 kV XLPE cable live line have been measured using this method. As a result, a detection sensitivity of 1 pC has been achieved. >

Influence of defects on insulating properties of XLPE cable

The influence of defects on the insulating properties of XLPE (cross-linked polyethylene) cables was studied using XLPE cables containing artificial defects. It was confirmed that the AC breakdown strength of the cables decreases with the increase of void size, while the existence of voids does not have any effect on impulse breakdown strength. The contaminants and the protrusions decrease both AC and impulse breakdown strengths. The value of the life exponent, n, of the V-t characteristics of the XLPE cable containing voids was estimated to be smaller than that of the cables containing contaminants or protrusions. In addition to to the influence of those defects on initial and long-term performance of the cables, the influence of impulse voltage on the long-term performance of the cable, together with the behavior of the space charge accumulated around the defects, was investigated. It was found that impulse voltage greatly affects the long-term performance of cables containing voids.<<ETX>>