電気学会論文誌B(電力・エネルギー部門誌)
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
131 巻, 6 号
選択された号の論文の16件中1~16を表示しています
解説
  • 道下 幸志
    2011 年 131 巻 6 号 p. 481-484
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    The portion of the faults of a medium-voltage line, cause by lightning, tends to increase with often reaching beyond 30%. However, due to the recent progress of the lightning protection design, the number of faults has decreased to 1/3 of that at 30 years ago. As for the low-voltage distribution line, the fault rate has been estimated primarily, although the details of the overvoltages have not been studied yet. For the further development of highly information-oriented society, improvement of reliability of electric power supply to the appliance in a low-voltage customer will be socially expected. Therefore, it is important to establish effective lightning protection design of the low-voltage distribution system, defined to be composed of lines having mutual interaction on the customers' electric circuits, such as a low-voltage distribution line, an antenna line and a telecommunication line. In this report, the author interprets the recent research on the lightning overvoltage on a low-voltage distribution system.
論文
  • 椎野 輝晋, 青木 秀憲
    2011 年 131 巻 6 号 p. 485-492
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    This paper presents a new approach to the optimal placement of a step voltage regulator (SVR) taking into consideration the installation of distributed generators (DG) based on a genetic algorithm (GA). In this case, it is necessary to solve problems such as the upper and lower limits of voltage at each node and line capacity. In addition, considering that the load and output of DG changes, it is important to solve more than one of these problems. In order to solve these problems, the conventional GA was improved and the proposed method was applied to the complex operative conditions of a distribution power system.
  • 小西 武史, 中村 武恒, 西村 敏治, 雨宮 尚之
    2011 年 131 巻 6 号 p. 493-501
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    Induction motor instead of dc one has been applied widely for dc electric rolling stock because of the advantage of its utility and efficiency. However, further improvement of motor characteristics will be required to realize environment-friendly dc railway system in the future. Therefore, it is important to study more efficient machine applying dc electric rolling stock for next generation high performance system. For the first step, we reproduced torque characteristics of a dc motor that is utilized in an electric rolling stock, by analyzing specific current waveforms of dc substations. And then, we tried to reflect such torque characteristic to the conventional squirrel-cage induction motor based on the equivalent circuit. Furthermore, we tried to obtain the specification of high temperature superconductor induction/synchronous motor (HTS-ISM), which performance is similar with that of the above-mentioned conventional motors. We succeeded in showing the effectiveness of the introduction of HTS-ISM in DC electrified railway system.
  • Toshiharu Tada
    2011 年 131 巻 6 号 p. 502-515
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    This paper discusses temperature distribution based on fundamental formulas, and each thermal resistance calculated by temperature data measured during operational examinations on a NaS battery in 1997. Profiles of temperature distribution at divergence and convergence depend on profiles of thermal current. Thermal current and thermal resistance are changed by temperature distribution profiles, and are calculated by applying a new style formula of thermal resistance which is proportional to volume. A new theory of temperature distribution is discussed by applying this new formula and differential equations.
  • 石井 綱吉, 小口 修一, 坂本 芳樹, 岡部 成光
    2011 年 131 巻 6 号 p. 516-523
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    Recently, the number of home electric appliances, such as personal computers and telephones, is rapidly increased. Lightning damage to these home electric appliances has a great impact on highly sophisticated information society. There are some cases that lightning overvoltages on low-voltage distribution lines cause malfunction of them, though they equipped surge protective devices to protect against lightning overvoltages. Therefore, for lightning protection of low-voltage equipments including home electric appliances, it's important to understand the phenomenon of lightning overvoltages on low-voltage distribution lines. However, it's not so clear including the generation of them.
    The Tokyo Electric Power Company carries out the lightning observation on low-voltage distribution lines. The observation results provide the statistical distribution of lightning overvoltages on low-voltage distribution lines. The generation mechanism of lightning overvoltages on low-voltage distribution lines is assumed based on observed waveforms and facilities data.
  • 山城 迪, 仲村 宏一
    2011 年 131 巻 6 号 p. 524-529
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    For a better understanding and detailed analysis of electric behavior of EDLC, we present one dynamic and two static equivalent circuit models each of which consists of a resistance and a capacitance varying with voltage. The differential capacity based dynamic model is used to simulate the discharge curve. Also the integral and effective capacity based static models are applied to estimate the energy efficiency and the constant current charge-discharge time. Owing to the energy oriented approach, the effective capacity based model shows its excellence in estimating efficiency and capacitance over the integral capacity based model.
研究開発レター
  • Takuma Miyake, Yoshihiro Arata, Tatsuya Sakoda, Masahisa Otsubo, Yasuf ...
    2011 年 131 巻 6 号 p. 530-531
    発行日: 2011/06/01
    公開日: 2011/06/01
    ジャーナル フリー
    Application of polymeric materials for housing of outdoor insulators is expected to rapidly increase in the near future. However, the lifetime and the aging deterioration, owing to environmental conditions, are concerned. To understand the long-term reliability of the insulation performance of polymeric materials, the salt fog tests were performed on the polymeric insulators made of ethylene vinyl acetate (EVA) and silicone rubber (SiR). The hydrophobicity was also evaluated. The samples which 11 years have passed since the installation were taken away from an actual distribution system in the region where pollution condition was comparatively severe. The results indicated that the polymeric insulators had enough insulation performance.
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