IEEJ Transactions on Power and Energy
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
Volume 111 , Issue 7
Showing 1-19 articles out of 19 articles from the selected issue
  • [in Japanese]
    1991 Volume 111 Issue 7 Pages 689
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Yoh-Han Pao, Dejan J. Sobajic
    1991 Volume 111 Issue 7 Pages 690-697
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Applications of neural-net computing to power systems in the United States are reviewed from the perspective that neural-net computing is a component of a larger integrated Artificial Intelligence technology. It is clear that conceptual advances have been made in delineating the ways in which neural-net computing can be of service in the operation of power systems. Experimentation, field work and significant involvement on the part of the industry need to be developed, but some beginnings have been reported.
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  • Shinichi Iwamoto
    1991 Volume 111 Issue 7 Pages 698-705
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Takashi Yanagizawa, Shinichi Iwamoto, Tatsuki Okamoto, Hiromasa Fukaga ...
    1991 Volume 111 Issue 7 Pages 706-712
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    It has become more important than ever to observe the partial discharge phenomena to detect insulation deteriorations, because the applied voltages have become higher. So far, we can mesure the quantity of electric charge (q) and occurrence frequency of partial discharge (n) at the same time. However recently it has become possible to mesure not only these two factors but also the phase (φ) at the same time.
    Each electrode model has the specific φ-q distribution pattern. Therefore, in partial discharge diagnosis it is very important to recognize these patterns.
    This paper proposes to apply a neural network theory, specifically the backpropagation method, for identifying electrode types (Tree, IEC (b) and Cigre Method I) and estimating the shape of the cylindrical voids of electrodes.
    The simulation result have confirmed the validity of applfying the back propagation method to the pattern recognition of the electrodes.
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  • Yasuhiro Hayashi, Shinichi Iwamoto
    1991 Volume 111 Issue 7 Pages 713-722
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In recent years, according to the modelling of excellent information processing ability of neurons, it has become possible to carry out pattern recognitions or optimizations with the neural network theory. In this paper, we show how to introduce the neural network theory to the load-flow calculation of rectangular coordinate. A problem which input-output functions have for neural network applications is pointed out, and effects of changes in load patterns and system size are discussed in terms of the optimal multiplier. Results of simulations are shown with the convergence characteristics.
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  • Katsumi Ikenono, Shinichi Iwamoto
    1991 Volume 111 Issue 7 Pages 723-728
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    In this paper, we generalize an online transient stability solution technique using the backpropagation method of the neural network theory. The proposed solution technique can be used for general generator models which include controllers such as AVRs and governors, that have been difficult to deal with for the energy function method. The proposed method also can take into account alterations of network configurations and changes of the number of operating generators. Further, the relationship between input data and effects on the results in the neural network is considered.
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  • Hiroshi Sasaki, Yuhji Fujii, Masahiro Watanabe, Junji Kubokawa, Naoto ...
    1991 Volume 111 Issue 7 Pages 729-734
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper studies the feasibility of applying the Hopfield type neural network to unit commitment problems of a large power system. The unit commitment problem is to determine an optimal schedule of what thermal units must be started or shut off to meet the anticipated demand; it can be formulated as a complicated mixed integer programming problem with a number of equality and inequality constraints. In our approach, the neural network gives the on/off states of thermal units at each period and then the output power of each unit is adjusted to meet the total demand. Another feature of our approach is that an adhoc neural network is installed to satisfy inequality constraints which take into account spinning reserve constraints and minimum up/down time constraints. The proposed neural network approach has been applied to solve a unit commitment problem of 30 units over 24 periods; results obtained were close to those by the Lagrangian relaxation method.
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  • Yoshikazu Fukuyama, Yoshiteru Ueki, Kazuhiro Kaneko
    1991 Volume 111 Issue 7 Pages 735-742
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    For system restoration in a power system, appropriate steps need to be taken in early stages to avoid social damage caused by insufficient power supply. The first step to be taken for restoration is to analyze the fault encountered, which is very important to determine a restoration operation.
    Today, a large number of data are going to be available at the occurrence of fault because of the advanced communication system using digital relays and optical fibers. This system is intended to obtain the data of relays and CBs under operation and the data of voltage and current during the operating time and during the time of prefault and postfault.
    This paper presents a hybrid fault analyzing expert system using data based on protective devices and phasor measurement. This system is a combination of an artificial neutral network (ANN) and an expert system. ANN is used to simplify the analyses of current and voltage waveform which are considered difficult due to a fault resistance and a line impedance. Since a fault waveform contains various ambiguous factors because of the natures of fault resistance, load current and others, use of ANN is effective for judgements.
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  • Naohiro Hozumi, Tatsuki Okamoto, Takahisa Imajo
    1991 Volume 111 Issue 7 Pages 743-748
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The Neural network algorithm was adopted to the discrimination of the partial discharge patterns before and after the tree initiation from a needle-shaped void. Phase (φ), discharge amount (q) and discharge frequency (n) were measured for all discharge pulses in the partial discharge measurement period. φ-qand φ-q-n patterns before and after the tree initiation were learmed by neural network, using the back-propagation method. The network which learned φ-q-n patterns showed a good discrimination performance than that leaned φ-q patterns. The discrimination performance decreased when the input pattern was taken from the non-experienced sample. Stable discrimination was possible when the tree length exceeded the void length.
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  • Yoshihito Tamaru, Hiroyuki Mori, Senji Tuzuki
    1991 Volume 111 Issue 7 Pages 749-756
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper presents a method for monitoring power system dynamic stability using the Kohonen neural-net. As far as the eigenvalue calculation is concerned in power system dynamic stability studies, the QR method is widely spread due to the high accuracy. However the method has a drawback that the computational efforts are required as the size of systems increases. Also, the S-matrix method is quite attractive in a sense that the method focuses on the most critical eigenvalue. However, the method has numerical problems in evaluating the most critical eigenvalue. The proposed method makes use of the mapping of the eigenvalue that allows to regard the absolute value of the most critical eigenvalue as a quantitative dynamic stability index. In this paper, the Kohonen neural-net is used to estimate the index. The neural-net has the following advantages: (1) simple algorithm without the teacher's signal; (2) effectiveness for classifying input data; (3) easiness to visually understand classification of input data due to two-dimensional mapping of output neurons. The effectiveness of the proposed method is demonstrated in a three-machine nine-node system.
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  • Hiroshi Uematsu, Hiroyuki Mori, Senji Tsuzuki
    1991 Volume 111 Issue 7 Pages 757-763
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This paper presents an artificial neural-net based method for classifying harmonic loads in power distribution systems. The method is used to identify nonlinear relationship between harmonic loads and harmonic currents that vary from time to time. In recent years, nonlinear loads increase due to advanced technologies in power electronics applications. As a result, it is afraid that the harmonic distortion brings about several problems in power transmission and distribution systems. It is necessary to identify the harmonic loads and take an appropriate strategy so that the harmonic distortion is alleviated. However, this identification problem has not been studied so far due to the complex characteristics. The objective of this paper is to identify the nonlinear relationship between harmonic currents and types of harmonic loads as the first stage to detect harmonic sources. In this paper, a three-layered feedforward perceptron is utilized to classify harmonic loads. The neural network is effective for identifying nonlinear problems that have been hard to solve with the conventional methods. The weights between neurons are determined by the backpropagation algorithm. The proposed method has been successfully applied to several sample harmonic loads.
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  • Taizou Hasegawa, Takashi Betsui, Shuuichi Ohnishi, Yoshihiro Makino, S ...
    1991 Volume 111 Issue 7 Pages 764-770
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    Liquid cooled gas insulated transformer utilizes SF6 gas for electric insulation and C8F16O liquid for cooling. The new diagnosis techniques applicable to such transformers have been developed by using gas and ion analysis.
    Amount and kind of decomposition components generated by over-heating, arc discharge and partial discharge in SF6 and C8F16O are analyzed and investigated. Several kinds of table and plots representing the relation among the amount of various decomposed products are proved to be effective to determine whether the transformer is in good condition or not. Various phenomena can be distinguished by these methods.
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  • Nobuhiro Watanabe
    1991 Volume 111 Issue 7 Pages 771-776
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The earth leakage breaker (ELB) is now widely used as the protective device against accidents and disasters by electric leakage of the low voltage circuit. The earth leakage breakers must have the function to detect the slight current leakage surely and to break the circuit quickly and at the same time high reliability not to perform unnecessary operation (false operation) by lightning surges, etc.
    However, it is reported that in some cases the earth leakage breakers made false operation because of lightning surges.
    It is one of the important tasks to investigate the false operation of the earth leakage breakers by lightning and to examine the preventive countermeasures in view of the stable supply of electricity.
    In this paper, the mutual relationship between quantity of electric charge of the impulse current which passed through the earth leakage breakers and occurrence of false operation was experimentally examined and the processes to the false operation were basically analyzed.
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  • Tetsu Shioiri, Hiroshi Murase, Mikio Okawa, Iwao Oshima, Satoru Yanabu
    1991 Volume 111 Issue 7 Pages 777-783
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    An experiment is carried out to investigate the influence of electrode surface oxidation on the vacuum breakdown characteristics, and the cleaning effect of heating treatments. An X-ray photoelectron spectroscopy is used to analyze the change of gas absorption on the electrode surface with the heating treatments. This analysis aims at identifying cleaning effect on a copper electrode surface.
    With an increase adsorbed gas, the breakdown voltage decreases. With an increase on the temperature of heating treatments, the adsorbed gas is likely to be removed and the breakdown voltage increases. The oxidation degree of copper surface (Cu2O, CuO) is strongly dependent on the exposure time to the air. With an increase in the temperature of the heating treatment, the copper becomes more deoxidized. This indicates that the heating treatment in vacuum provides substantial cleaning effects on the electrode surface.
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  • Naoto Nagaoka, Kyoko Yoshida, Akihiro Ametani, Takashi Karasaki
    1991 Volume 111 Issue 7 Pages 784-790
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    The wave-propagation characteristic of a cable installed within a tunnel is investigated. The transient characteristic of the cable system differs from that of the directly buried cable system. The characteristic is heavily dependent on the distance between the-cable and the tunnel wall and the physical parameter of the tunnel. From the investigation, a modeling method of the cable system installed within a tunnel is proposed.
    A field measurement of transient sheath voltages of a 275kV crossbonded cable system is carried out. Numerical results obtained using the proposed model agree well with the field test results, and the accuracy of the modeling method proposed in this paper is confirmed.
    The effect of the circuit parameters, such as inductance of the sheath bonding wire and the equivalent capacitance of the sheath protection arrester, are studied based on the calculated results.
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  • Terukazu Sekiguchi, Masayuki Okazaki, Tsuginori Inaba, Naoki Ikeda, To ...
    1991 Volume 111 Issue 7 Pages 791-797
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    This report describes a by-pass device which was developed in order to make a more precise current coordination in low-voltage distribution lines. The principle of this device is the use of electromagnetic repulsive force caused by the short-circuit current and its practical performance was confirmed by actual tests.
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  • Shingemitsu Okabe, Tsuruo Yorozuya, Eiichi Zaima, Susumu Nishiwaki, Ma ...
    1991 Volume 111 Issue 7 Pages 798-806
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
    It is not easy to measure arc voltage of reignition high-frequency current at the time of small-current interruption by a high-voltage circuit breaker because arc voltage is much lower than circuit voltage, and the phenomenon is the high-frequency one. There have been few reports on this type of measurement. This paper mainly describes the measuring methods for the above-mentioned arc voltage. The arc voltage was measured by employing a 300kV SF6-gas circuit-breaker model in an experimental circuit simulating reignition at the time of reactor-current interruption. Arc resistance and arc conductance were obtained from the measured arc voltage and current. These arc resistance and arc conductance offer the data necessary for clarifying and analyzing reignition surge and high-frequency arc extinction phenomena.
    Several methods were employed to measure high-frequency arc voltage. (1) An insulating spacer was utilized as a voltage divider. (2) Clippers were installed for measured signal output. (3) Zero-line shift of voltage-divider output at the time of circuit-breaker reignition was controlled and utilized. (4) Errors due to voltage-divider characteristics included in the original measured waveforms and errors of voltage drop due to stray inductance were corrected. (5) For the above-mentioned correction, a microprocessor was utilized to effect differentiation, integration, and other calculations on waveforms. (6) Signals were optically transmitted.
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  • Mamoru Matsuoka
    1991 Volume 111 Issue 7 Pages 807-808
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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  • Tomonobu Senjyu, Katsumi Uezato
    1991 Volume 111 Issue 7 Pages 809-810
    Published: July 20, 1991
    Released: December 19, 2008
    JOURNALS FREE ACCESS
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