| Project/Area Number |
16360133
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
YASUOKA Koichi Tokyo Institute of Technology, Graduate School of Science and Engineering, Associate professor, 大学院・理工学研究科, 助教授 (00272675)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,300,000 (Direct Cost: ¥15,300,000)
Fiscal Year 2005: ¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥11,900,000 (Direct Cost: ¥11,900,000)
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| Keywords | lightning stroke / windmill blade / space charge / surface charge / insulator / lightning impulse / water film / インパルス電圧発生装置 / 大気圧プラズマ / 波長可変パルスレーザ / 2次元光学観測 |
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| Research Abstract |
With increase in number of wind power generators, the lightning damage on the windmill blade becomes a serious problem. Although many types of lightning protection methods such as a lightning rod and a tower with rod, a grounded metal receptor embedded in a tip of the blade have been installed to reduce the lighting damage but have not sufficient effect. In this study, more active protection method using space charge around the blade or water film covered on the surface has been proposed and examined by applying lightning impulse voltage to the small blade models. The following results are obtained using lightning impulse voltage having 200-300 kV peak values.
The surface of model insulator was charged by the ion wind generated by the wire corona discharge. It was found that the electric discharge channel was formed away from the surface when the polarity of the accumulated charge on the insulator was same as the applied voltage polarity, while the discharge extended around the insulator with opposite polarity. 50% flashover voltage increased when the space charge that voltage polarity was same to the impulse voltage, while decreased when the polarity reversed.
In addition to the surface and space charge effect from the view point of the lightning protection, another method was developed using water films covering the surface of the dielectric materials. The discharge developed on the surface of the water when the conductivity of the water was smaller than one micro S/cm. In this case, the water breakdown was not observed at least over 0.25 mm thickness of water film. But with thinner and higher conductivity water film, the discharge current flowed in the water directly and the surface discharge was not expanded around the breakdown point.
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