| Project/Area Number |
60460112
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電力工学
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| Research Institution | University of Tokyo |
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Principal Investigator |
KAWAMURA Tatsuo (1986) Institute of Industrial Science, University of Tokyo, Professor, 生産技術研究所, 教授 (20013097)
河村 達雄 東京大学, 生産技術研究所, 教授
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Takaie Faculty of Engineering, Shizuoka University, Associate Professor, 工学部, 助教授 (40157368)
HOJO Jun'ichi Institute of Industrial Science, Univ. of Tokyo, Research Assistant, 生産技術研究所, 助手 (70013175)
ISHII Masaru Institute of Industrial Science, Univ. of Tokyo, Associate Professor, 生産技術研究所, 助教授 (40107397)
HARASHIMA Fumio Institute of Industrial Science, Univ. of Tokyo, Professor, 生産技術研究所, 教授 (60013116)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1986: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1985: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Electric Power System / Insulation Design / Impulse Voltage / 放電機構 |
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| Research Abstract |
For the purpose of investigating the current waveform of natural lightning as one of the sources to induce surge voltages in the electric power system, measurements of electric and magnetic fields have been carried out. Comparing these waveforms with lightning waveforms already published, the rising part of the lightning current waveform has tuned out to be convex instead of concave, which has been known as the standard lightning impulse voltage waveform.
Based on these results, an impulse generator with charging voltage of 200kV capable of generating a non-standard impulse voltage similar to a lightning current waveform has been constructed. This device can generate a waveform with a convex rising wave front by using a non-linear circuit element.
Non-standard lightning impulse voltages were applied to a 10cm rod-plane airgap. Luminous phenomena were observed by an image converter camera. Together with this observation, 50% flashover voltages were determined and were compared with the da
… More
ta for a standard lightning impulse voltage. The results showed that the waveform of the rising front did not much affect the flashover voltage which was confirmed from the standpoint of the physical mechanism of the electrical discharge.
Concerning the switching surge generated in the electric power system, statistics of switching surge waveforms has been studied. The temporal distribution of space charge in the pre-discharge process of breakdown of a long airgap, related to the discharge mechanism under phase-to-phase switching surges, was determined by measurement of electric fields by using Pockels' cells suspended in the gap.
Based on the flashover characteristics of airgaps for waveforms of non-standard switching impulse voltages, a method of accurately determining flashover probability of a transmission line has been proposed. Moreover, the insight to realize the ultimate design in the insulation of electric power systems has been obtained by combining the results together with the experimental data for the non-standard lightning impulse voltages. Less
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