IEEJ Transactions on Power and Energy
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
Volume 114 , Issue 10
Showing 1-18 articles out of 18 articles from the selected issue
  • Yasuji Sekine, Toshiyuki Hayashi
    1994 Volume 114 Issue 10 Pages 955-959
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Toshiya Nanahara, Ikuo Kurihara
    1994 Volume 114 Issue 10 Pages 960-963
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Kenji Kaminaga
    1994 Volume 114 Issue 10 Pages 964-968
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Akinobu Murata, Kazuhiko Kato, Sadaaki Shimizu
    1994 Volume 114 Issue 10 Pages 969-978
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, a method is presented to evaluate how effective an electricity generation technology is to mitigate carbon dioxide emissions from the national energy system of Japan, based on the long range systems analysis by MARKAL from 1990 to 2030. The proposed method is applied to several electricity generation technologies including nuclear power generation, renewable energy generation and fossil fueled generation with carbon dioxide recovery. Carbon dioxide emissions reduction potentials of these technologies are estimated as well as their cost-effectiveness both economically and environmentally.
    How these technologies reduce carbon dioxide emissions from the national energy system is studied by breaking their reduction potentials down into a reduction in electricity generation sector and a reduction in the other sectors, and resulting technological changes and energy resources reallocation are discussed.
    Sensitivity analysis is also conducted with respect to the costs of renewable generation systems and fossil fueled power plants with carbon dioxide recovery, nuclear power plant capacity growth rate and energy demand growth rate.
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  • Ryo Sartoh, Eiichi Tanaka, Jun Hasegawa
    1994 Volume 114 Issue 10 Pages 979-987
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In electric power systems, to improve economy and reliability, it is necessary to forecast the following day's load curve accurately.
    Load forecasting models based on statistical techniques require a great deal of effort to analyse the complex relationship between load and its determining factors. Furthermore, because such forecasting models are based on averaged values, a large weather variation may result in a large error.
    In this paper, to overcome these issues, a load forecasting model combining an artificial neural network (ANN) with multiple regression analysis is proposed. Therefore, this model is able to reflect nonlinear relationships between inputs (temperature, cloudiness and general weather conditions) and outputs (forecast-ed load values) without analytical effort. To improve the learning characteristics, “dead bands” are introduced into the error values and the computed outputs. Furthermore, various techniques are adopted to overcome problems associated with the fundamental back-propagation method.
    From the simulation results, the effectiveness of the proposed correcting model is confirmed; the dead bands performed stable correction and considerable improvement in accuracy was achieved for the summer period which is normally inferior to other periods.
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  • Takao Kumazawa, Norimoto Tsuzuki, Izumi Arima, Teiji Watanabe, Nobuyuk ...
    1994 Volume 114 Issue 10 Pages 988-993
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The mechanisms for evolution of DC component current have been explained on the behavior of space charge around the tip of water trees. Recently, it was shown that DC component current was closely associated with the water tress linking between inner and outer semiconducting layer. So that, we assumed that the origin of DC component current was present outside the XLPE bulk, and we investigated the influence of semiconducting layer and moisture in it on DC component current. The experimental results indicate that the origin of DC component current is essentially independent of semiconducting layer and water trees. The results also suggest that DC component current arises from the interaction between the moisture in semicon-ducting layer and conductor or shielding layer.
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  • Mitsuo Hasegawa, Kunikazu Inoue, Isao Ueno
    1994 Volume 114 Issue 10 Pages 994-1001
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In various applications of pulsed power technologies, large capacitor bank systems are used to feed high current impulse to different experimental devices. The accidental electric breakdown in one of the capacitors in a parallel connection of the large bank may result in serious damages such as mechanical explosion and oil effusion or fire. In most fast banks, each unit capacitor has an output gap switch, which is expected to decouple the capacitors one another. However, no such special element is adopted usually in the slow bank system, partly because of the economical consideration.
    We have developed a novel and inexpensive protective element for these relatively slow capacitor banks, utilizing a concept of the enclosed type of the fast breakers. The principle of the operation of the protection elements is verified by a simulation experiment. Their practical effectiveness is also successfully demonstrated in the application to the system of the pulsed high magnetic field generator.
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  • Yoshinisa Takahashi, Makoto Hara
    1994 Volume 114 Issue 10 Pages 1002-1008
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    To establish the reliability of the insulating performance of prefabricated-type joints (PJs), dielectric breakdown characteristics of interface insulation were studied.
    Using two types of electrodes, which simulate the interface configuration in actual 275 kV PJ, AC and impulse BDSs, together with long-term performance of the interface, were evaluated under various conditions. Among the many factors which would influence the insulating characteristics of the interface, the effect of the silicone oil layer, as well as the applied external pressure, were examined. It was determined that the BDSs were greatly influenced by silicone oil appllication, by the applied interface pressure, and by the pretreatment of the surface of XLPE insulation. On the basis of the result of experiments, the functions of the silicone oil layer in the insulation interface of the PJ were examined.
    The authors concluded that the thinner silicone oil layer in the insulation interface is favorable for the establishment of the insulation interface of the PJ.
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  • Kei Ohtsuka, Makoto Nishida, Takakazu Hirano
    1994 Volume 114 Issue 10 Pages 1009-1015
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper deals with instability of a SVC control system, which compersates reactive power of loads using measurements of voltage and reactive power of the loads. It is found that the SVC control system is characterized by meeting a bifurcation point followed by its instability before the loads reach the so-called nose point. This fact is proved by an invesigation based on the bifurcation theory, and is also supported by simulation studies on an example power system. Motivated by the bifurcation theoretic investigation, a SVC control system using a reference voltage pattern is proposed, which does never bring to such instability.
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  • Atsushi Akisawa, Yoichi Kaya
    1994 Volume 114 Issue 10 Pages 1016-1021
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Although co-generation is regarded as one of the most effective energy conservation measures to cope with the global warming problem, it is necessary to balance electricity demand with heat demand. If the supply of extra electricity to outside consumers is allowed, then co-generation plants can work at high efficiencies. In that sense, wheeling, which enables co-generators to send extra electricity through the transmission lines of utilities, is expected to contribute to the improvement of energy efficiency.
    In this study, the behavior of co-generators with and without wheeling is modeled from the view point of maximizing the welfare of the co-generator. Solution optimization is determined by Kuhn-Tucker's condition. The optimal solutions for given electric price conditions show that the behavior and marginal values of electricity and heat strongly depend on the heat-to-electricity ratio of the co-generation. These solutions also clarify the conditions under which wheeling becomes active or inactive, and under which co-generation is operated or electricity is purchased. Furthermore, the effect of wheeling on increasing energy efficiency is presented in a numerical example.
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  • Hitoshi Kakimoto, Takehiro Hayasi, Hirosi Handa, Kenzi Yukihira, Yukio ...
    1994 Volume 114 Issue 10 Pages 1022-1028
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper describes the development of Automatic Fault Point Locating and Sectional Isolating System. This system locates a single-line-to-ground fault point at each pole by using ground-current-sensors and isolates the faulted section by controlling pole switches with no outage of unfaulted sections.
    The ground-current-sensor is connected to the line between allied earth terminals of pole devices and grounded conductor. It detects a ground fault current of more than 0.64 amperes that is determined so as to avoid an unexpected operation by stray-current but to detect the fault current certainly and sends out a emergency signal with time delay of 0.1 seconds.
    Sectional isolation starts when both the emergency signal from the sensor and relay operation signals from substation are received and ends within a feeder circuit breaker's tripping time of 1.5 seconds.
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  • Katsuhisa Yoshimoto, Keiichiro Yasuda, Ryuichi Yokoyama, Hideo Tanaka, ...
    1994 Volume 114 Issue 10 Pages 1029-1037
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The aim of transmission expansion planning is to determine which right-of-way to construct new lines in order to meet the future forecasted load in the most economical way. This problem has been solved by the mathematical programming techniques, which require considerable computational efforts, or by successive planning based on sensitivity analysis, which find a single non-optimal solution. It is difficult to plan the economical and reliable expansion due to its discrete and combinatorial nature. Although another method that has efficiency for combina-torial problems is the neuro-computing, this approach obtains poor solutions while it saves computational efforts. The most desirable approach for this planning problem can find many good solutions in reasonable time, because experts of planning will easily plan the economical and reliable expansion according to these solutions.
    This paper presents an approach for solving transmission expansion planning based on neuro-computing hybrid-ized with genetic algorithm. This approach generates suitable initial states, which include past information, of neural networks utilizing genetic algorithm. Mingling neuro-computing and genetic algorithm, the proposed ap-proach can find many good solutions in reasonable time making full use of their merits. Computational examples show the effectiveness of the proposed approach by comparison with conventional approaches.
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  • Masatugu Amano, Hiroyuki Takazawa, Tadayosi Tanaka
    1994 Volume 114 Issue 10 Pages 1038-1043
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Global environmental problems such as global warming and the effect of acid rain are becoming more and more serious in the years to come. One of methodologies for solving this problem is to use harmless energy resources. Ocean energy is also one of such energy resources. From such a viewpoint, we are conducting study on OC-OTEC system, which is one of ocean thermal energy conversion technologies. In this system, steam driving a turbine is generated in an evaporater and condenses in a condneser after going throrgh a turbine. However, Steam evaporating rate in an evaporator is affect-ed by fluctuation of surface sea water temperature and ambient pressure. Therefore, it is necessary to define dynamic characteristics of evaporator to gain constant power output. In this paper, we analyzed how evaporation rate is affect-ed when surface sea water temperature and ambient pressure change, and we make clear that dynamic characteristics of evaporator is affected by fluctuation of ambient pressure than that of surface sea water temperature.
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  • Kaoru Endoo, Yoshito Uwano, Kiyoto Hiraishi, Toshiyuki Oonuma, Ryuuji ...
    1994 Volume 114 Issue 10 Pages 1044-1049
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Large power transformers using perfluorocarbon liquid have advantages of high dielctric strength, excellent cooling ability, and nonflammability.
    To make the transformer more compact, it is very important to improve insulation material.
    Recently, we succeeded to develop the new type of aramid insulation paper which has no fluff on its surface to avoid field concentration.
    In this paper, outline of the developed paper and the experimental results of insulation strength on turn-to-turn and inter-coil models are described.
    It was found that the developed new aramid paper makes insulation strength increase 1.2(turn-to-turn case) to 1.7 (inter-coil case) times of the existing insulating paper.
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  • Akira Asakawa, Shigeru Yokoyama, Yousuke Hashimoto
    1994 Volume 114 Issue 10 Pages 1050-1058
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Recent lightning protection design has been considered against not only induced overvoltages due to nearby lightning hits, but also overvoltages due to lightning direct hits on power distribution lines.Electric power companies are both expanding conventional protection methods such as overhead grounding wire and surge arresters, and developing new protection equipments with a Zinc-Oxide surge divider.In order to get effective protection method, it is important to study the relation between protection method and lightning outage ratio of a power distribution system.From the above point of view, authors developed the program which can calculate lightning outage ratio due to both lightning direct hits and indirect lightning hits. Moreover this program can consider interval of lightning protection equipment, grounding resistance, flashover voltage of the insulator, and characteristics of surge arresters at will. In this paper, detail of the developed program and comparison of calculated outage ratio according to lightning protection methods are described.
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  • Akihiro Ametani, Yuki Kasai
    1994 Volume 114 Issue 10 Pages 1059-1065
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The paper proposes a simplified model to deal with a distribution system which involves a number of nodes and branches due to earth wire grounding at every some ten meters. The grounding, which is a typical boundary condition, is combined with the shunt admittance of a distributed-parameter line, and thus a distribution line with a number of the earth wire groundings is represented by an equivalent homogeneous line.
    The input impedance evaluated using the proposed model agrees with the accurate input impedance. Transients on a distribution system are calculated using the proposed model and the results show a satisfactory accuracy compared with the accurate solutions. By this approach, a computation time step of a transient is greatly increased and therefore a CPU time and a memory required are greatly reduced. The proposed model is expected to be very efficient to carry a transient analysis on a distribution system.
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  • Yuuki Watanabe, Shohei Kato, Azuma Mochizuki, Eichi Zaima
    1994 Volume 114 Issue 10 Pages 1066-1072
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    It is investigated surge characteristics of a miniature transmission tower model with power lines and overhead ground wires experimentally. The Lightning path from the tower to sky is simulated by a current delay line of which the velocity is a several tenth of the light velocity. Experimental results show that the surge voltage in the tower is not very much affected by the upward current velocity, and the voltage between the tower arm and the power line decreases from the upper line to the lower one.
    We obtained a higher surge impedance of the tower without overhead ground wires than that of the one with wires. The transient mutual coupling factor between the overhead ground wires and power lines estimated from the results shows small values, about a fourth of the conventional values that is used in an analysis of a slow front wave surge.
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  • Yasuyuki Goto, Katsuhiro Ichiyanagi, Keisuke Yasui, Katsunori Mizuno, ...
    1994 Volume 114 Issue 10 Pages 1073-1074
    Published: September 20, 1994
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Download PDF (922K)
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