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
128 巻, 8 号
選択された号の論文の10件中1~10を表示しています
解説
  • 美濃 由明, 本田 誠司, 中澤 紳浩
    2008 年 128 巻 8 号 p. 985-988
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    The equipment of hydroelectric power plants has been improving typically by using digital technology and eliminating oil for lubrication and control. According to the investigation executed by the committee of IEEJ, a fault/trouble happened in one equipment in a hydroelectric power plant has decreased to less than once in 5 years due to such improvement and advancement of design and manufacturing technologies. As for maintenance, changing to the condition based maintenance from the time based maintenance has been in progress. Developing diagnostic technologies and the analysis of operating data to understand the condition of the equipment are important.
エッセイ
論文
  • 後藤 聡, 山本 雄史, 杉 剛直, 安永 健, 池上 康之, 中村 政俊
    2008 年 128 巻 8 号 p. 993-999
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    This paper describes a simulation model for a spray flash desalination system which makes freshwater from seawater by temperature difference between warm surface seawater and cool depth seawater. The spray flash desalination system can be modeled by using the energy conservation law and the mass conservation law. Simulation results of the model are compared with the experimental results and it shows the accuracy of the proposed simulation model.
  • 飯岡 大輔, 成田 貴則, 横水 康伸, 松村 年郎, 畠山 法夫
    2008 年 128 巻 8 号 p. 1000-1008
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    Influences of uncertainty in load growth rate and interest rate on total cost of low-voltage distribution facilities was investigated. We assumed that the total cost was composed of initial construction cost, improvement cost and cost of power loss. We also assumed that the distribution facilities were operated for 30 years. Genetic algorithms were used to determine how to construct a cost-effective distribution facilities that did not compromise power quality. Two investment methods were compared. One was that the utility cut down the initial construction cost and improves the initial facilities along with the load growth. The other was that the utility bears the large initial cost without the improvement cost. It was found that the lower cost method depends on the load growth rate and interest rate. It was also found that the influence of uncertainty in load growth rate increases with an increase in the differential between actual load growth rate and expected one.
  • 遠藤 尚樹, 前田 哲彦, 長谷川 裕夫
    2008 年 128 巻 8 号 p. 1009-1014
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    An advanced distributed heating and cooling system utilizing small-scale high performance heat pumps was designed to replace the central heating and cooling system for the AIST laboratory buildings, which have a total floor area of 36,100m2, of which 20,100m2 is occupied by laboratories. In the old system, the total primary energy required for hot water was 44TJ and it was 12TJ for chilled water in FY2001. The new system is composed of small-sized high-performance heat pumps, with an average coefficient of performance (COP) of 3.1. After the reconstruction, the energy consumption was reduced to 37%, and with a total energy saving of 44TJ for one year. And the total CO2 emission is estimated to be 26%, a reduction of 3,000tons of per year. The energy saving is caused by the high performance small-scale heat pumps, the high-performance total system design that takes laboratory into account and the suitable operation of the system.
  • 緒方 修二, 高山 大輔, 浅野 勝則, 菅原 良孝
    2008 年 128 巻 8 号 p. 1015-1019
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    3kV 600A 4H-SiC high temperature flat package type diodes have been developed for use in electricity supply, which are a pressure contact flat package type and include five 6mm × 6mm SiC diode chips. A developed flat package type diodes have the thermal resistance of 0.21°C/W and this value is ten times as large as silicon thermal resistance, because SiC diode chip is smaller than Si diode chip. In order to lower the thermal resistance, it is necessary to increase the number of SiC chips in the flat package because of the difficulty of a making SiC large area chip. SiC pn Flat package diode can realize the same thermal resistance value even at half chip area. The transient thermal impedance is saturated at nearly 1 seconds. On the other hand, the Si diode's transient thermal impedance is saturated at 50 seconds. In the short circuit current flows for 50ms, SiC pn Flat package diode endures the bigger pulse loads than Si diode over Tjmax of 200°C. For example SiC diode endures 2.3 times energy than Si diode at Tjmax of 500°C.
  • 堤 泰行, 小野 征一郎, 江口 美佳
    2008 年 128 巻 8 号 p. 1020-1026
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    A test method of a PEFC single cell with reference electrodes for obtaining correct polarization curves is proposed, where the anode polarization curves of H2/O2 and H2/Air should be approximately equal. Measured anode polarization curves are usually linear to the current density but not ohmic. Leak current between cathode and reference electrode causes voltage shift on the anode polarization curve. In order to obtain the ohmic anode polarization, the measured anode polarization curve should be moved vertically up to overlap with the base point. Configuration of the electrode edge adjacent to the reference electrode gives a significant effect on the anode and cathode potential. Polarization of a electrode which is 0.5mm nearer to the reference electrode than the other electrode does not include the ohmic loss of the membrane. Polarization of the other electrode includes the ohmic loss of the membrane instead.
  • 嶋田 尊衛, 黒川 浩助
    2008 年 128 巻 8 号 p. 1027-1034
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    This paper proposes a new simulation model of lead-acid battery characteristics and a modeling method using step changing current. Battery simulation model is necessary to simulate the photovoltaic systems with batteries. The proposed model considers the nonlinearity of internal resistance and includes 36 constants that can be determined by only 4 cycles of charge/discharge test. This paper clearly reports the measuring method and the modeling procedure of the battery characteristics. The result of verification test using charge/discharge pattern that assumes the photovoltaic system shows 1.0% of mean absolute error ratio of simulated power at 17deg C and 32deg C of battery temperature.
  • 黒澤 潔, 近藤 礼志, 那須川 慎介, 山口 達史, 天野 一夫
    2008 年 128 巻 8 号 p. 1035-1040
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    Fault point locating systems based on surge current detection have recently been used for fast recovery of underground transmission line from the fault. Electromagnetic induction type sensors have mainly been used for detection of the surge current. However they are susceptible to electromagnetic noise which causes unstable system operation. To solve this problem, Tokyo Electric Power Co., Toko Electric Corporation and Fujikura Ltd., by a joint research, have developed a new system that applies optical fiber current sensors.
  • Hironobu Kaneuchi, Toshiaki Yachi, Tatsuo Tani
    2008 年 128 巻 8 号 p. 1041-1046
    発行日: 2008/08/01
    公開日: 2008/08/01
    ジャーナル フリー
    A method for leveling power generation was examined for a power supply system that uses wind power generation for a stand-alone radio base station. One possible method is the conversion of the surplus electric power into hydrogen, which enables stable energy storage that can be later used to produce electrical energy via a fuel cell. In order to efficiently produce hydrogen from wind power, it has been suggested that an electric double layer capacitor (EDLC) can be used as the electric power buffer medium for the system. The effect of EDLC installation to a wind power generation system was examined using numerical analysis. In a system that is constantly converting the generated electrical energy into hydrogen, there is an appropriate load capacity for the hydrogen generator that corresponds to the amount of energy generated. By setting the appropriate capacity and expanding the range of load operation of the hydrogen generator, the electrical charge and discharge of the EDLC are balanced, and the buffer ability improves. As a result, even if the EDLC capacity is extremely small, it is shown to contribute to stabilization of the amount of hydrogen generation. Moreover, a reduction in the hydrogen generator load capacity is observed with installation of an EDLC.
feedback
Top