研究者詳細 - 小島　寛樹

By using Kerr electro-optic technique, electric field in oil / pressboard (PB) composite insulation system, which is the typical insulation system of a transformer, was investigated at polarity reversal of HVDC voltage. When the applied voltage polarity was sharply reversed, the applied electric field was superimposed by the electric field of accumulated charges on PB, and very strong field appeared right after the polarity reversal. This could cause the discharge in the oil gap and on the PB surface. The critical value of the discharge initiation at the polarity reversal was verified to be determined by the sum of the applied electric field and the electric field of accumulated charges on PB. The discharge was observed by a high-speed video camera. It was clarified that the surface discharge on PB did not overlap with each other, which was explained by that the surface discharge could neutralize the charges on PB. ©2010 IEEE.

DOI： 10.1109/CEIDP.2010.5724003

Scopus

その他リンク： https://www.webofscience.com/wos/woscc/full-record/WOS:000398821400069

Improvement of Cu-Cr Electrode Surface under Impulse Voltage Conditioning in Vacuum 国際会議

H. Kojima, H. Yasukawa, R. Nishimura, H. Okubo, H. Sato, H. Saito, Y. Noda

2010 International Conference on High Voltage Engineering and Application 2010年10月11日 Mississippi State University and Chongqing University

開催年月日： 2010年10月

記述言語：英語会議種別：口頭発表（一般）

開催地：New Orleans 国名：アメリカ合衆国

As vacuum attracts attention from a viewpoint of high insulation performance and environmental-friendliness, vacuum circuit breakers (VCBs) are expected to develop into higher voltage level. In this paper, we discuss the relations between the surface state and the conditioning mechanism of Cu-Cr electrode during impulse voltage application process in vacuum. The experimental results showed that the deposited layer at the cathode surface was formed by the anode material due to the impulse voltage application process. We finally clarified and concluded that under impulse voltage application process, characteristics of the cathode surface are changing to those of the anode material, and anode material could determine the final states of conditioning process. ©2010 IEEE.

DOI： 10.1109/ICHVE.2010.5640856

Scopus

CiNii Research

Electric Field Optimization of Floating Electrode Configuration in Vacuum Interrupter 国際会議

H. Kojima, K. Suzuki, K. Kato, H. Okubo

2010 International Conference on High Voltage Engineering and Application 2010年10月11日 Mississippi State University and Chongqing University

開催年月日： 2010年10月

記述言語：英語会議種別：口頭発表（一般）

開催地：New Orleans 国名：アメリカ合衆国

For environment-friendly vacuum interrupter (VI), higher voltage operation and more compactness are required. From this point of view, and to enhance the electrical insulation performance of VI, it is needed to introduce the field optimization techniques. In this paper, we propose a new optimization technique for electrode configuration with floating potential in VI. We applied this optimization technique to the edge configuration of center shield in VI with considering the arrangement of grounded tank. Consequently, the maximum electric field strength decreased to 70% of non-optimized shape. From the results, we verified the effectiveness of the proposed automatic numerical optimization technique for the improvement of the insulation performance in high voltage vacuum insulated equipment. ©2010 IEEE.

DOI： 10.1109/ICHVE.2010.5640872

Scopus

その他リンク： http://hdl.handle.net/2237/14457

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講演・口頭発表等 - 小島　寛樹