Particle-initiated breakdown in a quasi-uniform field in transformer oil

Author

Rain, P. ; Tobazeon, R.

Volume

2

Issue

6

fYear

1995

fDate

12/1/1995 12:00:00 AM

Firstpage

1052

Lastpage

1063

Abstract

The breakdown voltage induced by single metallic cylinders of millimeter lengths in a quasi-uniform AC field are reported. A particular electrode arrangement, including forced oil circulation, has been designed in order to avoid particle ejection out of the gap. Breakdown occurred in the range 25 to 80 kV/cm depending on the particle dimensions, and always when the particle was in contact with the positive electrode. These breakdown levels are clearly lower than those measured with a fixed particle subjected to a positive step voltage. All these measurements were sensitive to the influence of carbon contaminants, especially under step impulse voltage. As concerns free particles, the breakdown is thought to be controlled in our experimental conditions by the initiation of positive streamers. Calculations showed that the initiation field at the particle tip is not constant but mainly depends on the particle diameter

Keywords

carbon; discharges (electric); electric breakdown; electric fields; electrodes; impurities; insulation testing; particle size; power transformer insulation; power transformer testing; transformer oil; voltage measurement; AC field; C; breakdown voltage; carbon contaminants; electrode arrangement; forced oil circulation; free particles; particle diameter; particle-initiated breakdown; positive electrode; positive streamers initiation; quasi-uniform field; single metallic cylinders; step impulse voltage; transformer oil; Breakdown voltage; Dielectric breakdown; Dielectric liquids; Electric breakdown; Electrodes; Oil insulation; Particle measurements; Petroleum; Rain; Voltage measurement;

fLanguage

English

Journal_Title

Dielectrics and Electrical Insulation, IEEE Transactions on

Publisher

ieee

ISSN

1070-9878

Type

jour

DOI

10.1109/94.484307

Filename

484307