Properties of Creeping Discharge in Narrow Gap between Dielectric Plates in PFAE Oil
Abstract
Using the lightning impulse voltages of ±1.2/50 μs and ±1.2/1000 μs with ±140 kVpeak in maximum, the behaviors of creeping streamers progressed in a narrow gap between two solid dielectric plates immersed in palm fatty acid ester (PFAE) oil were investigated. The discharge shapes and the streamer lengths were observed using a still camera equipped with a night viewer and the progression steps of the streamer were observed using a high-speed image converter camera. The effects of two interfaces between solid dielectrics, the back side electrode (BSE) and the wave tail of impulse voltages were examined on the growth of positive and negative streamers, the flashover voltage and the streamer velocity. The streamer length is extended by the presence of the BSE and a long wave tail of impulse voltage. This results in the reduction of the flashover voltage. It is worthy of notice that the negative streamer progressed in a narrow gap grows longer than the positive streamer under identical applied voltage. This polarity effect on the streamer length is the inverse from that in an oil/pressboard interface without a narrow gap. The streamers in both polarities also slow down its velocity because of a narrow gap with two solid interfaces. These results on the creeping discharge have been compared with those in commercial mineral oil.
- Publication:
-
IEEJ Transactions on Fundamentals and Materials
- Pub Date:
- 2011
- DOI:
- 10.1541/ieejfms.131.817
- Bibcode:
- 2011IJTFM.131..817U
- Keywords:
-
- PFAE oil;
- mineral oil;
- narrow gap between dielectric plates;
- creeping discharge;
- lightning impulse voltage;
- flashover