Space charge characteristics of multi-layer oil-paper insulation under different DC voltages

Abstract

Abstract:In this paper, space charge in oil-paper insulation system has been investigated using the pulsed electroacoustic (PEA) technique. A series of measurements were carried out when the insulation system was subjected to different applied voltages. Charge dynamics in the insulation system during the volts-on, volts-off and decay have been analyzed. It has been found that homocharge injection occurred both at the anode and the cathode. Positive charges are observed to accumulate in the layers, which indicate that the oil-paper layer interfaces act as a barrier for positive charges. The decay tests showed that after 30min, about a quarter of space charges remained in the sample, about 90% charges disappeared after 2 hours. Finally, total charge variation in these tests were analyzed.

Investigation on space charge properties of Nomex insulation paper in the mining dry type transformer during hygrothermal ageing

“…Considerable research works [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have been done on the mechanism of dielectric degradation and space charge characteristics of transformer insulation paper especially in cellulose paper and oil-immersed Nomex insulation paper. Liuet al [18] measured the space charge distribution of oil-impregnated synthetic fibreboard with different moisture contents at room temperature and indicated that the space charge characteristics of insulation paper would change within the difference of moisture contents.…”