Grant-in-Aid for Scientific Research (C).
Electronic materials/Electric materials
|Research Institution||Nagoya Institute of Technology|
MIZUNO Yukio Nagoya Institute of Technology, Department of Electrical & Computer Engineering Associate professor, 工学部, 助教授 (50190658)
|Project Fiscal Year
1998 – 1999
Completed(Fiscal Year 1999)
|Budget Amount *help
¥3,500,000 (Direct Cost : ¥3,500,000)
Fiscal Year 1999 : ¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1998 : ¥2,500,000 (Direct Cost : ¥2,500,000)
|Keywords||Silocone rubber / Water droplet / Vibration / Flashover / Resonance / Wetting and contamination / Partial discharge / Degradation / シリコーンゴム / 水滴 / 振動 / 共振 / フラッシュオーバ / 汚損湿潤 / 部分放電 / 劣化 / フラッシオーバ / 加速試験 / フラッシオーバ電圧|
Flashover phenomenon of polymer insulator was investigated by carrying out the following three experiments : (1) behavior of water droplet(s) on silicone rubber under ac voltage application, (2) effect of surface condition on partial discharge characteristics of silicon rubber sheet and (3) acceleration test of silicone rubber by the salt fog method.
The main results obtained are as follows :
1. Water droplets on silicone rubber began to vibrate when the applied voltage was higher than a threshold value. With further increase in applied voltage, droplets were extended in the direction of electric field and finally flashover occurred by bridging droplets.
2. Flashover voltage decreased when he volume/number of water droplet became larger. It seemed that a droplet near the high voltage electrode seemed to affect flashover voltage.
3. Resonance phenomenon was observed for 18 micro-liter droplet under 60Hz voltage application. Electrical insulating capability may be affected by the resonance.
4. Active partial discharges were observed on silicone rubber, where hydrophobisity of its surface was artificially reduced.
5. Salt fog resulted in less active partial discharge compared with clean fog. This may be attributed to the fact that local electric field around water droplets on the silicone rubber is moderated due to higher conductivity of salt fag.
6. Little degradation of silicon rubber was observed by chemical analysis of samples after the acceleration test.
7. For acceleration test of silicone rubber rod by the salt fog method, electric stress of 60V/mm, conductivity of salt water of 800μs/cm and fog flow rate of 0.6 liter/h were seemed preferable.