著者

高岡 将臣 木内 徹 佐藤 正弘

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.125, no.6, pp.585-594, 2005 (Released:2005-09-01)

参考文献数

13

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A severe fault may cause loss of synchronism of a small number of generators. And it may make many generators out of service resulting in wide area blackout. When two groups of generators lose synchronism, the magnitudes of voltage on some lines becomes zero. Therefore an approach that lines with zero voltage are opened has been employed actually in order to prevent loss of synchronism from extension. This paper presents a new method using voltage and current measured on a line during disturbance to detect the line with zero voltage at the instant when loss of synchronism takes place. A method to detect loss of synchronism using voltage and current measured on a line was already proposed. This paper presents results of the tests performed by using power system simulator which is composed of a DC-motor, a synchronous generator, artificial transmission line, circuit breaker equipments and so on. The validity of proposed methods was verified by finding loss of synchronism correctly.

著者

本郷 保二 道下 幸志

出版者

The Institute of Electrical Engineers of Japan

雑誌

電気学会論文誌. B, 電力・エネルギー部門誌 = The transactions of the Institute of Electrical Engineers of Japan. B, A publication of Power and Energy Society (ISSN:03854213)

巻号頁・発行日

vol.128, no.12, pp.1535-1542, 2008-12-01

被引用文献数

6 1

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The overvoltage associated with direct lightning hits has been the important factor for the insulation design of a distribution line. In this paper, the sparkover rate of a medium-voltage line associated with direct lightning hits is investigated based on numerical calculations obtained by using EMTP and statistical analysis by taking account of the correlation between the peak value and the front duration of return-stroke current waveform. When the line is equipped with surge arresters at the interval of 100m in addition to the overhead ground wire, the sparkover rate associated with subsequent strokes is higher than that associated with first strokes. This demonstrates the importance of the study of current parameters for subsequent strokes.

著者

山崎 克巳 石上 洋希

出版者

一般社団法人 電気学会

雑誌

電気学会論文誌B(電力・エネルギー部門誌) (ISSN:03854213)

巻号頁・発行日

vol.127, no.8, pp.882-888, 2007-08-01 (Released:2007-09-01)

参考文献数

10

被引用文献数

1 1

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A modification method of finite element meshes based on the adaptive meshing for optimization of electric machines is proposed. In the optimization process of the machine, the proposed method generates the mesh for the new shape from the previous mesh with minor modification. The locations of the nodes for the new shape are decided by solving the Laplace's equation, whose unknowns are displacements of the nodes. The advantages are clarified by the application to the shape optimization of an IPM motor.