| Project/Area Number |
09450110
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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 | The University of Electro-Communications |
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Principal Investigator |
HAYAKAWA Masashi The Univ.of Electro Communications, Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (80023688)
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| Co-Investigator(Kenkyū-buntansha) |
OHTA Kenji Chubu Univ., Faculty of Engineering, Professor., 工学部, 教授 (10131161)
HOBARA Yasuhide The Univ.of Electro-Communications, Faculty of Electro-Communications, Research, 電気通信学部, 助手 (10303009)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥14,000,000 (Direct Cost: ¥14,000,000)
Fiscal Year 1998: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 1997: ¥9,800,000 (Direct Cost: ¥9,800,000)
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| Keywords | Positive cloud-to-ground discharge / Upper atmosphere discharge / ELF transients / Ionospheric perturbation / Transmission lines / 電離層掻乱 / トリンピ現象 / スプライト / ELF波 / 伝送線路 |
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| Research Abstract |
It is well known that winter lightning in the Japan sea area has a significant characteristic of positive cloud-to-ground discharge (+CG), and that it has an extremely serious influence on the power transmission in the area of Hokuriku. Such +CG is recently found to trigger a strong electric field in the atmosphere, inducing red sprites (or so) and leading to the perturbation in the lower ionosphere. This work will focus on the complete understanding of this upper atmosphere discharges and the associated phenomena, and also on the effect of such discharges on the power transmission.
During the winter of 1997/1998, we tried the first experiment for the Hokuriku winter lightning and the associated phenomena ; (1) optical measurement from Mt. Zao in Tahara town near Toyohashi, (2) observation of ELF transients from the upper atmosphere discharges at Moshiri in Hokkaido, and (3) VLF scattering from the lower ionospheric perturbations (by means of the NWC subionospheric signal propagation).
… More
In the first winter the optical measurement was not so good due to the insufficient preparation, but we can list the important features for other phenomena. When we compare the associated phenomena (ELF sferics and VLF scattering) for +GG and -CG, it is found that +CG could trigger ELF transients and ionospheric perturbation more often (by about twice) than for -CG.However, this difference is not so big when we assume the presence of plasma column below the lower ionosphere, which means that this kind of hypothesis of such a plasma column is questionable.
During the next winter of 1998/1999, we made the successful measurement again, and we are now analyzing the data extensively. We do hope that we could obtain significant results, especially with great emphasis on the optical measurement.
Finally, the coupling of such discharges on the power transmission (or transmission lines) was investigated. Then, we have obtained the voltage and current induced at the end of the transmission line by means of the transmission line model. Less
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