IEEJ Transactions on Power and Energy
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
Volume 143, Issue 5
Displaying 1-16 of 16 articles from this issue
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Paper
  • Shungo Oki, Ryoichi Hara, Hiroyuki Kita, Motoki Akatsuka
    2023 Volume 143 Issue 5 Pages 260-269
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
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    The renewable energy resources, such as photovoltaic generation and wind turbine, are rapidly being integrated. In order to compensate for the variable output and imbalance between actual and scheduled outputs, introduction of a battery storage would be one of the promising solutions. In this paper, we focus on the scheduled operation of a balancing group (BG) consisting of the widely distributed photovoltaic generation with storage battery. BG forming would bring reduction of total imbalance due to cancellation of forecast errors among PV stations, and could enable cooperative usage of battery storages for imbalance compensation. This paper proposes a new battery storages operation scheduling for the BG considering the imbalance risk, which are assumed based on the confidence interval forecast for PV output. Effectiveness of the proposed scheduling method is ascertained through year-basis computational simulation of the BG. Advantages of BG forming is also discussed.

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  • Yusuke Yamashita, Yasuhiro Kodama, Yasuhiro Hayashi, Naohisa Murashita
    2023 Volume 143 Issue 5 Pages 270-281
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
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    The voltage fluctuations that occur locally in the distribution system caused by high penetration of photovoltaic (PV) power generation based on the carbon neutrality strategy have been regarded as one of the serious operational problems. Assuming that larger amount of PV power sources will be connected in the future distribution system, Volt-var control of PV smart inverters is expected. This will enable more flexible and effective voltage control support by provide custom var response. The authors have investigated the effective voltage control of coordination between tap operation of Step Voltage Regulator (SVR) and Volt-var control of PV smart inverters. In our previous studies, we proposed a Volt-var curve determination method for MW-large-scale PV smart inverters connected to medium-voltage to decrease SVR tap operations and minimize distribution losses. However, there are uncertainties such as PV outputs and loads of low-voltage consumers that cannot be completely and individually determined from the measurements of medium-voltage PV smart inverters. In this study, using a detailed distribution line model that reflects actual power measurement datasets of individual low-voltage customers, effects of reduction in distribution losses, reduction in the number of SVR tap operations, and changes in cumulative reactive power output sharing of PV inverters are evaluated through simulation studies to confirm the effectiveness of the proposed Volt-var setting method.

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  • Tomoya Ishizeki, Kazuaki Tsuji, Masafumi Yashima, Tomoyuki Sato, Takuy ...
    2023 Volume 143 Issue 5 Pages 282-289
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
    JOURNAL RESTRICTED ACCESS

    Compared to conventional porcelain insulators, polymeric insulators are easier to work because of their lightness, and have better withstand voltage performance under discharge, rain, and contaminated conditions due to their higher hydrophobicity. Therefore, their application is expected to reduce the size and cost of power distribution facilities, so the introduction of polymeric insulators is being promoted in Japan. On the other hand, the use of polymeric materials for the outer coating raises concerns about their deterioration over time, and clarifying the long-term performance in the contaminated and humid environment unique to Japan is an important issue for practical application. To evaluate the long-term weather resistance of polymeric insulators for distribution lines, Tohoku Electric Power Network Co., Inc. has conducted field tests in the coastal areas along the Sea of Japan. In this study, we developed prediction models of leakage current generation based on meteorological conditions using feed-forward neural networks and verified the effectiveness of the models. And we also evaluated meteorological factors which affect the prediction results with the neural network models.

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  • Hiroaki Maeji, Minoru Kuwata, Koji Fujiwara
    2023 Volume 143 Issue 5 Pages 290-296
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
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    In substation, phase advance capacitors are used to improve the power factor. Series reactors are generally connected with the capacitors to reduce the waveform distortion and suppress the inrush current. The fifth harmonic current usually flows into the series reactors for a high voltage power capacitor. Japanese Industrial Standards provide three types of temperature rise test methods, and manufacturer chooses one of them. However, which test method should be selected has not been examined. In this paper, compare the advantages and disadvantages of the test methods using a prototype reactor.

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  • —Middle Frequency Test—
    Hiroaki Maeji, Minoru Kuwata, Koji Fujiwara
    2023 Volume 143 Issue 5 Pages 297-302
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
    JOURNAL RESTRICTED ACCESS

    In substation, phase advance capacitors are used to improve the power factor. Series reactors are generally connected with the capacitors to reduce the waveform distortion and suppress the inrush current. The fifth harmonic current usually flows into the series reactors for a high voltage power capacitor. Japanese Industrial Standards provide three types of temperature rise test methods. Each test method has its own problems. To alleviate them, we have devised a new test method called “Middle Frequency Test” which uses a meddle frequency between the fundamental and fifth harmonics for excitation. This paper presents an implementation method and demonstrates the usefulness of the proposed test method.

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  • Gaigo Kato, Kazumasa Takahashi, Takashi Kikuchi, Toru Sasaki
    2023 Volume 143 Issue 5 Pages 303-308
    Published: May 01, 2023
    Released on J-STAGE: May 01, 2023
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    We have demonstrated a capacitively coupled Hall-type MHD generator using ECR plasma. To clarify the characteristics of the fabricated MHD generator, we measured the power generation characteristics as a function of magnetic field strength using a DC Hall-type MHD power generation experiment. The results showed that the output power decreased due to magnetic pressure at the higher magnetic field. However, the output power corresponded to the theoretical value at the lower magnetic field. An AC Hall-type MHD power generation experiment was conducted using an AC magnetic field. As a result, full-wave rectification voltage was observed as per theory. Finally, capacitively coupled Hall-type MHD power generation experiments were conducted, and full-wave rectified waveforms were observed as in AC Hall-type MHD power generation. These waveforms were similar to the output waveforms predicted from theory. These results show that the capacitively coupled Hall-type MHD generator is feasible.

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