Creeping discharges in transformer oil under lightning impulse voltages over 100 kV peak value

Abstract

This paper describes the experimental results on the creeping streamer progressing the surface of a bakelite board immersed in transformer oil under the application of a standard lightning impulse voltage with peak values of ±100～350 kV. The growth of streamers is significantly affected by the thickness of bakelite board and the streamers are extended longer exponentially for the applied voltage more than ~±200 kV. These streamers leave the remarkable discharge scars on the bakelite surface. The discharge scars are different by the voltage polarity which influences strongly to the streamer growth. The mean streamer velocities in both polarities have also been examined.

First mode negative streamers along mineral oil-solid interfaces

“…Extensive research has been performed on streamers in liquids during the last decades [1], with some studies dedicated to their propagation along liquid-solid dielectric interfaces [2][3][4][5][6][7][8][9][10][11][12][13][14]. Particularly, technological advances in the performance of high speed cameras and optical techniques have been groundbreaking when it comes to the observations of streamers in liquids and along liquids-solid interfaces [1,[15][16][17].…”

“…The length, velocity, charge, current, light emitted and voltage gradient of streamers are some of the parameters affected by the presence of dielectric solid barriers [2][3][4][5][6][7][8][9][10][11][12][13][14][21][22][23][24][25][26][27][28]. Strong indications of the influence of the permittivity and thickness of the solid on the mechanism of streamer propagation has been reported [1,5].…”