IEEJ Transactions on Power and Energy
Online ISSN : 1348-8147
Print ISSN : 0385-4213
ISSN-L : 0385-4213
Volume 133 , Issue 1
Showing 1-27 articles out of 27 articles from the selected issue
Special Issue on Power and Energy 2012, Annual Conference of Power and Energy Society
Preface
Special Issue Paper
  • Kenji Yukihira, Naotaka Okada
    2013 Volume 133 Issue 1 Pages 2-9
    Published: January 01, 2013
    Released: January 01, 2013
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    In Japan, limit values on the harmonic current emitted by customers with 6.6 kV and higher power supplies were specified in 1994. Because the limit values are applied to large pieces of equipment (those drawing currents of more than 20A), they generally apply to three-phase equipment. Most three-phase transformers have a star-delta connection. Many home appliances are considered to be equivalent to three-phase equipment with a delta-delta connection transformer, because single-phase equipment is connected phase-to-phase. This means that the harmonic currents created by three-phase equipment and single-phase equipment can cancel each other out.
    The authors reached the following conclusions by analyzing harmonic voltage and current data measured at the supply points for customers with a 6.6kV power supply. (1) The 5th harmonic voltage in the electric power-supply system in Japan is produced mainly by single-phase equipment. (2) The limit values for customers with a middle- or high-voltage power supply are unnecessary, because the 5th harmonic current generated by three-phase equipment reduces the 5th harmonic voltage. (3) Connecting a reactor in series with the capacitors to improve the power factor is a necessary and sufficient method for suppressing the 5th harmonic voltage.
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  • Ryoichi Komiyama, Yasumasa Fujii
    2013 Volume 133 Issue 1 Pages 10-18
    Published: January 01, 2013
    Released: January 01, 2013
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    This paper evaluates the impact of an extensive introduction of electric vehicle (EV) and plug-in hybrid vehicle (PHEV) on energy supply mix in Japan. Energy consumption in Japan's transport sector has been dominated by petroleum, and CO2 emissions in this sector accounts for twenty percent of Japan's CO2 emissions. Therefore, the deployment of clean energy vehicles, such as EV and PHEV, are expected to play a significant role in tackling with energy security and environmental concerns. For assessing energy and environmental benefits of EV and PHEV, we develop energy system model integrating optimal power generation mix model and vehicle penetration model, considering optimal electricity charging profile of those advanced vehicles. Calculated results suggest that massive EV penetration serves as energy saving measure in Japan's whole energy system, due to significant petroleum reduction exceeding the growth of fuel input into power generation sector derived from significant EV and PHEV penetration. Massive EV deployment is estimated to contribute to CO2 mitigation of the energy system as well. Evaluating CO2 emissions per mileage by automobile, however, carbon emissions per mileage of EV is almost equivalent to that of gasoline hybrid vehicle (HEV) in the case of decommissioning nuclear power plant which eventually causes higher carbon intensity of electricity supply.
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  • Zhuomin Zhou, Tetsuhiko Maeda, Masayoshi Ishida
    2013 Volume 133 Issue 1 Pages 19-25
    Published: January 01, 2013
    Released: January 01, 2013
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    This paper presents capacity planning and economical evaluation of a renewable power system proposed for Okushiri Island, which is a remote island in the southwest of Hokkaido. In this system, the power demand is mainly provided by photovoltaic, wind turbine. Batteries are used as short time energy storage, and a hydrogen storage system (composed of water electrolyzer, hydrogen storage, and fuel cell) is used as long time energy storage. Optimal capacities of these power sources are those meet the required supply reliability, with the lowest cost. As the first step in the capacity planning, mathematical models for characterizing components are explained. The second step is to optimize the capacities of components. The configurations, which meet the required supply reliability with the lowest cost, give the optimal choices. These calculations are carried out with hourly meteorological data and energy demand data of Okushiri Island. As a result, hybrid storage (battery and hydrogen) is the best choice for Okushiri Island when high supply reliability is required. In the range of loss of power supply probability 0.1 to 0, the levelized cost of energy will be about 70-150yen/kWh.
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  • Kenichi Kawabe, Akihiko Yokoyama
    2013 Volume 133 Issue 1 Pages 26-36
    Published: January 01, 2013
    Released: January 01, 2013
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    This research aims at development of new emergency control schemes using FACTS (flexible AC transmission systems) devices and BESSs (battery energy storage systems) for prevention of cascading outages in bulk power systems. In this paper, use of BESSs is studied for the improvement of short-term voltage stability from the view point of the voltage control. Based on the stabilizing control method proposed in our previous research to improve transient stability, a new control scheme is developed taking into account a finding that the short-term voltage stability is closely related to the angle stability. An additional control system that limits active and reactive power absorption from the grid is applied to the stabilizing control system since the electrical power absorption drops the system voltages. Numerical simulations are conducted on two test systems with BESSs to demonstrate the effectiveness of the proposed method for the improvement of both of the transient stability and the short-term voltage stability under severe fault cases such as a grounding fault and a generator trip. The results show the high potential of the BESSs for the stability enhancement.
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  • Suresh Chand Verma, Yoshiki Nakachi, Yoshihiko Wazawa, Yoko Kosaka, Ta ...
    2013 Volume 133 Issue 1 Pages 37-44
    Published: January 01, 2013
    Released: January 01, 2013
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    This paper proposes estimation methods of short circuit current using phasor measurement unit (PMU) measurements (phasors). The methods follow the basic notion of representing the source side of a power system by an equivalent circuit with a voltage behind back impedance, and employ a set of voltage and current phasors measured at substations during the normal variation of loads in their estimation. In order to improve the estimation accuracy of the proposed methods, the concept of using the changes between the consecutive phasors is introduced. Furthermore, to make the methods applicable to the real world system, a reference phasor concept to remove the effects of system wide frequency variations and a filtering process to filter out the outlier phasors, are proposed and implemented. The validity and effectiveness of the proposed methods were checked and confirmed using experiments and field tests.
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  • Shinya Sekizaki, Mutsumi Aoki, Hiroyuki Ukai, Shunsuke Sasaki, Takaya ...
    2013 Volume 133 Issue 1 Pages 45-55
    Published: January 01, 2013
    Released: January 01, 2013
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    In Japan, in order to reduce greenhouse gas emissions, Photovoltaic generation (PV) is being focused on recently. According to Japanese governmental policy, a large amount of PVs will be introduced into the distribution system in the near future. However, the output of PV depends on weather conditions and climate may change rapidly or randomly. As a result, voltage in distribution system with many PVs will fluctuate; nevertheless, distribution network operator must keep voltage in network within adequate range determined by law. By contrast, Step Voltage Regulator (SVR), which is located on distribution line to control voltage, has time delay to operate against voltage change. Hence, SVR could cause voltage deviation from adequate range when a large amount of PVs are connected to network. From this point of view, several novel equipment that control voltage flexibility such as Static Var compensator (SVC) and Battery are being noted lately. Although, this kind of device using power electronics technology is usually expensive, and huge cost is necessary to introduce these devices into many distribution systems in which there are lots of PVs. For this reason, it is necessary to control voltage with established device such as LRT (Load Ratio control Transformer) and SVR over the next 10 or 20 years, but these devices have several issues such as voltage deviation in case that there are a lot of PVs. The authors focused on SVR and analyzed the cause of voltage deviation by SVR. By analyzing several cases, the authors found the causes of voltage deviation and effective control method of SVR. In proposed method, it can realize to both reduce the cost and keep voltage within adequate range even if there are a lot of PVs in the distribution system.
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  • Yoshiharu Okumoto, Naoto Yorino, Yutaka Sasaki, Yoshifumi Zoka, Toshih ...
    2013 Volume 133 Issue 1 Pages 56-63
    Published: January 01, 2013
    Released: January 01, 2013
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    In this paper, we explain how the N-1 security will be difficult to keep up and propose the countermeasure under high-penetration of PV in the future. It is a fact that no effective methodologies exist to analyze the N-1 security quantitatively in relation to PV penetration. In order to overcome the present situation, we propose a solution for the subject by using the concept of Robust Power System Security as a new evaluation index for quantitative analysis. The followings are shown that (1) the relation between PV penetration and the N-1 security is clearly trade-off, (2) installation of storage batteries is effective to enhance the N-1 security and (3) power system operators will be able to monitor the N-1 security condition directly by visualizing this concept. The effectiveness of the proposed method is demonstrated through simulations using a three machines model system.
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  • Naoto Ishibashi, Tatsuya Iizaka, Ryoko Ohira, Yosuke Nakanishi
    2013 Volume 133 Issue 1 Pages 64-71
    Published: January 01, 2013
    Released: January 01, 2013
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    This paper presents an insolation forecasting method using numerical weather forecasting data and a confidence interval estimating method. It is planned to introduce photovoltaic (PV) system on a large scale into the power system in order to achieve the low carbon society. Thus, it is necessary to forecast the insolation and evaluate the confidence interval in terms of power system operating and planning. This paper proposes the insolation forecasting method by Partial Least Squares (PLS) and the confidence interval estimating method considering the forecasting error distributions. PLS handles multicollinear data among input variables in order to construct proper forecasting models. The proposed method can estimate continuous confidence intervals by linearly-approximating for representative values of some weather conditions extracted features from forecasting error distributions. The effectiveness of the proposed method is demonstrated using numerical weather forecasting data and actual data observed by Japan Meteorological Agency. The proposed method by PLS can forecast the hourly insolations more accurately than conventional multiple regression equation. Moreover, the proposed method can evaluate continuous confidence interval.
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  • Masato Takahashi, Hiroyuki Mori
    2013 Volume 133 Issue 1 Pages 72-78
    Published: January 01, 2013
    Released: January 01, 2013
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    In this paper, a new method is presented to predicting PV generation output. The method makes use of a hybrid intelligent system of EPSO (Evolutionary Particle Swarm Optimization) of meta heuristics and GRBFN (Generalized Radial Basis Function Network) of artificial neural network (ANN). GRBFN is an extension of RBFN in a sense that the center and the width of the radial basis functions are determined by the learning process although the conventional RBFN does not update them through the learning process. EPSO is used to evaluate better the weights between the hidden and the output layers because it is useful for solving nonlinear optimization problems from a standpoint of global optimization. In particular, EPSO has advantage to adjust the algorithm parameters with the evolutionary strategy to make the search process more diverse by the replication. In addition, DA (Deterministic Annealing) clustering that corresponds to a global clustering technique is employed to evaluate the initial solutions of the center and the width so that the performance of GRBFN is improved. Furthermore, the weight decay method is utilized at the learning processes to avoid the overfitting to learning data since the conventional methods are inclined to provide erroneous results due to overfitting to complicated time series data of PV generation output. The proposed method is successfully applied to real data of a PV system.
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  • Yoshiaki Yoshida, Hirokazu Suzuki, Koji Fujiwara, Yoshiyuki Ishihara
    2013 Volume 133 Issue 1 Pages 79-90
    Published: January 01, 2013
    Released: January 01, 2013
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    When distributed generators (DGs) such as photovoltaic (PV) systems spread widely in distribution systems, it is important to quickly prevent islanding operation caused by power system fault in order to ensure electrical safety. So far, the various islanding protection methods have been used practically. But, the conventional active systems tend to increase the detection time, because mutual interference occurs due to asynchronous state between active signals. On the other hand, the new active islanding detection system that is called “frequency-feedback system with step-injection”, also has possibility of extending the detection time in so called non-detection zone. So, we propose a novel islanding-prevention method by harmonic injection synchronized to exciting current harmonics of the pole transformer. We have carried out the experimental study by using the prototype inverters equipped with the proposed method. We were able to show the feasibility of detecting the islanding-operation quickly and reliably, even if the islanding state is in non-detection zone. According to the experimental results, it was demonstrated that mutual interference does not occur due to synchronous state between active signals, and also shown that the proposed method is applicable to the islanding detection system under clustered installation of PV systems.
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  • Takeyoshi Kato, Shinsuke Kumazawa, Nobuyuki Honda, Masakazu Koaizawa, ...
    2013 Volume 133 Issue 1 Pages 91-98
    Published: January 01, 2013
    Released: January 01, 2013
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    In order to estimate the total power output fluctuation of high-penetration photovoltaic power generation system (PVS) by using the data of limited number of points, the smoothing effect around individual observation point should be taken into account. Based on the transfer hypothesis, this study proposed a low-pass filter to estimate the spatial average irradiance fluctuation characteristics taking the smoothing effect around observation point into account. First, by using the irradiance data observed at 18 points in the Nobi plain, we confirmed that the fluctuation characteristics of spatial average irradiance can be estimated by using the characteristics of single point irradiance when the radius of equivalent circle area is smaller than 30km. Then, by formulating the relation between the area size and the fluctuation cycle from which the random fluctuation factor begins to increase, we developed a low-pass filter to take the smoothing effect around observation point into account. Finally, we demonstrated that the spatial average fluctuation characteristics can be estimated successfully for various area sizes within the radius of 20km by applying the dedicated low-pass filter according to the area size.
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  • Toshiharu Tada
    2013 Volume 133 Issue 1 Pages 99-105
    Published: January 01, 2013
    Released: January 01, 2013
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    This paper discusses a new method of calculating temperature distribution and a theory of thermal conduction in waves. Temperature distribution is calculated by evenly dividing its distribution, and applying a new style formula of thermal resistance that is proportional to the volume, moving heat source and a numerical analysis method that substitutes differentials for infinitesimals, such as for thermal resistance per divided layer. The theory of thermal conduction in waves is shown to be reasonable, because it agrees with the actual conditions when reflection ratios are applied to it.
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  • Kenta Kajita, Kohta Miyagawa, Yoshihiro Baba, Naoto Nagaoka, Akihiro A ...
    2013 Volume 133 Issue 1 Pages 106-113
    Published: January 01, 2013
    Released: January 01, 2013
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    The type-C constrained interpolation profile (CIP) method has been applied to analyzing lightning electromagnetic fields. The CIP method is one of the finite-difference methods. Differently from the finite-difference time-domain (FDTD) method, however, it considers not only electric- and magnetic-field values at each discretized points in a working space but also their spatial-derivative values there. Therefore, in principle, it can compute fields accurately even when a relatively coarse grid and a relatively large time increment are used. In section 2 of this paper, a numerical procedure for computing electromagnetic fields in a three-dimensional space using the CIP method is presented. In section 3, the type-C CIP method is applied to computing electric fields in a uniform grid, which are generated by a lightning return-stroke current wave propagating upward along a vertical straight channel located on flat perfectly conducting ground, and the CIP-computed waveforms are compared with the corresponding waveforms computed theoretically and using the FDTD method. In section 4, the method is applied to computing lightning electric fields in a nonuniform grid, and a similar comparison is made.
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  • Hiroki Kojima, Takafumi Suzuki, Naoki Hayakawa, Masahiro Hanai, Hitosh ...
    2013 Volume 133 Issue 1 Pages 114-120
    Published: January 01, 2013
    Released: January 01, 2013
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    A metallic particle defect seriously degrades an insulation performance of gas insulated switchgear (GIS). Therefore, the estimation of risk of the metallic particle is important to maintain the reliability of GIS. In this paper, based on a partial discharge (PD) mechanism, we suggest a novel method to estimate the metallic particle defect using PD properties, which are the minimum instantaneous voltage of positive PD extinction, the instantaneous voltage of negative PD inception, and the negative PD pulse number from PD generation characteristics of applied voltage phase.
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  • Michio Hirose, Toru Iwao, Motoshige Yumoto
    2013 Volume 133 Issue 1 Pages 121-128
    Published: January 01, 2013
    Released: January 01, 2013
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    Gas tungsten arc welding (GTAW) is a high quality and productive joining technology. The tungsten inert gas (TIG) welding which is one of the GTAW has been used as a high quality joining case. Because the inert gas is used as a shielding gas, the arc is not contaminated by surrounding gas. Therefore, this joining process is very clean to join the materials. However, the weld defects are occurred, such as lack of penetration and overlap because of low heat transfer to the anode. Some researchers have researched the weld defect. However, the view point of radiation loss has not been researched. Especially, the TIG welding is contaminated with metal vapor from anode material. In this case, the heat transfer to anode is affected by radiation emitted from metal vapor, because of the net emission coefficient emitted from metal vapor is very high. In this paper, the radiation loss of gas tungsten arc welding affected by current increment is elucidated. When the current increases, the heat transfer to the anode increases, and then the contamination ratio of metal vapor increases. When the contamination ratio of metal vapor increases, the arc temperature changes, and then the heat transfer to the anode changes. Therefore, that energy balance of heat transfer to anode and radiation loss should be considered in the TIG welding. As a result, the radiation loss increases with increasing the current. When the metal contamination ratio and its distribution change, the radiation loss changes. In addition, the current increase to 300A, the radiation loss is saturated. Therefore, the radiation loss is obtained by the complex condition between the current, temperature, metal contamination distribution. And the heat transfer to the anode is affected by this radiation loss.
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  • Eriko Mitsuyasu, Toru Iwao, Motoshige Yumoto
    2013 Volume 133 Issue 1 Pages 129-136
    Published: January 01, 2013
    Released: January 01, 2013
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    The arc lighting to obtain the environment to evacuate, save the life, keep the safety and be comfortable are focus on. The lack of radiation intensity and color rendering spectrum is problem because of inappropriate energy balance. This paper elucidates the improvement of color rendering spectrum with control of spectrum affected by scandium vapor mixed with argon arc. The temperature with keeping the color rendering increases with increasing the contamination ratio of metal vapor because of x, y chromaticity diagram. In addition, the volume increment of low temperature region; periphery of the arc is effective for the color rendering. The radiation power increases with increasing the metal vapor even if the temperature is low. Especially, the maximum radiation power with metal vapor is 10 times as high as that without one. The radiation power increases with keeping the color rendering and the radiation power increases when the appropriate temperature is chosen under consideration of x, y chromaticity diagram. The improvement of color rendering spectrum is expected by the control of balance between the broad continuous spectrum of argon and line spectrum of scandium with temperature distribution derived from current increment and/or arc pinch.
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