Prebreakdown and breakdown phenomena in large oil gaps under AC
- CNRS, Grenoble (France). Lab. d`Electrostatique et de Materiaux Dielectriques
- Inst. de Recherche d`Hydro-Quebec, Varennes, Quebec (Canada)
- Jeumont-Schneider Transformateurs, Lyon (France)
This paper presents a study of prebreakdown and breakdown phenomena under AC voltage in mineral oil in large gaps to 60 cm. The investigations presented concern the study of streamers and the measurement of breakdown voltages in rod-plane and sphere-plane gaps. Also, the influence of a contamination by solid particles in the oil has been considered. A specific breakdown mode under AC voltage is evidenced, where bursts of streamers lead to the lowest breakdown fields recorded. Numerical values of the mean field in oil required for direct or burst breakdown modes are derived from the experiments. As a consequence, the great sensitivity to the presence of particles on EHV transformers insulation with large oil gaps is pointed out.
- OSTI ID:
- 529623
- Report Number(s):
- CONF-960614--; ISBN 0-7803-3531-7
- Country of Publication:
- United States
- Language:
- English
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