The Editorial Committee is working in planning and editing of the Publication of Power and Energy Society. In this article, activities of the committee of last one year are reported, and recent trend and future problems are also discussed. The process of planning and editing of the publication, and the challenge to reduce the necessary months for reviewing papers are shown. Topics, such as SCI, special issue of English papers, are also discussed.

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Discoveries of high temperature superconducting (HTS) materials have given us a possibility of new superconducting equipments. Many researches and developments bring HTS materials of high quality and cost down. Under these background, Super-ACE national project has started to research and develop the fundamental technologies for superconducting AC power equipments. Super-ACE was founded by METI, being consigned by NEDO in 2000. This paper shows the trends in technology of superconducting electrical HTS equipments to focus power cable, fault current limiter, and magnet, which are subjects of Super-ACE project.

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This paper presents a new approach to optimal voltage and reactive power control based on a genetic algorithm (GA), and attempts to shorten the time of the GA which calculates the control process. For this purpose, a network is decomposed into subsystems by means of region/area information, and the control times of the controller are considered in the voltage and reactive power control. Therefore, some methods which give the control procedure are proposed in the algorithm of GA. The effectiveness of the proposed method is demonstrated by practical 15-bus and 118-bus systems.

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Recently, the world-wide deregulation of the electric power industry is progressing. Further, it is also expected that a lot of distributed generation facilities and energy storage systems will be installed at the end point of the power systems. Therefore, the future power system is required to be able to cope with these various qualities of power in the deregulated situation. The authors have proposed a concept of FRIENDS (Flexible, Reliable and Intelligent ENergy Delivery System) as a new distribution system that copes with a new framework of the electric power business in the near future. The most typical thing of FRIENDS is introducing new equipment; Quality Control Centers (QCC) between distribution substation and customers. In this paper, the authors propose a concrete interior structure and investigate some control ways for realizing unbundling power quality supply and power conditioning using the proposed UPQC type QCC. The effectiveness of the proposed method is confirmed through the instantaneous value analysis using PSCAD/EMTDC.

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We compared the performance of resistive type (R-type) and inductive type (L-type) fault current limiter (FCL) at incoming feeder for consumer system with synchronous generator connected to utility distribution system. We investigated the suppressing effect of FCL on short-circuit current from two viewpoints, i.e., the maximum value of fault current, and the root mean square value of fault current. The effect of FCL were estimated for the current out of consumer and the current at fault point. The introduction of the R-type FCL makes the phase of current out of the consumer system to delay or lead, depending on the recovered output power out of generator. As a result, it was shown that the phase shift have a good or bad influence upon the suppressing effect on the current at fault point. The suppressing effect of the L-type FCL on the current at fault point increases consistently with the limiting reactance.

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Extended chain crystal (ECC) polyethylene subjected to a high voltage exhibits some unique properties. Electrical trees were investigated using a needle to plate electrode system under a lightning impulse voltage, application. The propagation direction of the trees was strongly influenced by the orientation of the ECC polyethylene. When the needle electrode was normal to the orientation, some linear trees with no branches always propagated along the orientation. When the needle electrode was parallel to the orientaion, the tree propagated as a single line without branching along the orientation. The current following tree formation was observed as intermittent sharp pulses in the wave tail of the applied voltage. The number of pulses was dependent on the peak value of the impulse voltage and on the sample's temperature. The tree inception voltage was also dependent on the sample's temperature. These experimental results are represented in the form of an Arrhenius plot for discussion the tree inception process in test samples.

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We have investigated sparkover characteristics when direct lightning hits on power distribution lines to which trees exist in close proximity. In the previous study, negative lightning impulse voltages were used to understand sparkover characteristics when an open wire of overhead distribution line was placed in close proximity to a tree. The rate of sparkover to the open wire or to the open wire via the tree was examined and pre-breakdown phenomenon was observed in detail.
This paper describes experimental results that different voltage waveforms (lightning impulse and switching impulse) were applied under the condition that an open wire was placed in close proximity to a tree. Regardless of impulse voltage waveforms, sparkover occurring directly on the open wire could be seen, even when the height of the open wire is equal to that of the tree or the open wire is about 0.5m lower than the tree. In addition, the progress of an upward leader from the open wire is faster than that from the tree. We investigated the attachment manners when the open wire was placed in close proximity to a log instead of the tree. It was found that the attractive effect of the log was stronger than that of the tree.

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The overpotential resistances and the entropy changes of two kinds of small Lithium-ion secondary batteries, which are the heat source terms for batteries, have been measured by several methods. And the temperature rises and the heat production rates of the batteries were calculated during the discharge cycle by using the measured results, being compared with the experimental temperature rises and the heat production rates. The overpotential resistance was estimated by four kinds of measurement methods, i.e. the voltage-current characteristics of batteries at constant-current discharge, the difference between the open circuit voltage and the cell voltage, the voltage change by the 60 seconds intermittent discharge, and the AC impedance measurement. The overpotential resistance by the voltage-current characteristics is almost the same with the one by the difference between the open circuit voltage and the cell voltage. However, in some cases the resistances by the intermittent discharge and the AC impedance are shown to be smaller than the above two measurements. The entropy change ΔSmeasured by the temperature change of open circuit voltage is shown to agree almost with the measured ΔShy the temperature rise difference between charge and discharge cycle. The cell temperature rises and the heat production rates of the batteries calculated by the overpotential resistances by the voltage-current characteristics and ΔSby the temperature change of open circuit voltage agree well with the measured for two kinds of batteries.

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A new method for operating a stand-alone photovoltaic/wind/diesel/battery hybrid power system is presented. The system, especially its diesel generator, is controlled so that the battery charge is kept at a specified level. The battery is charged when its present charge level is lower than the specified level and discharged when higher. A simulation is carried out over one year using the hourly data of electric load, insolation, temperature, and wind speed at Kamishima Island, Japan in 1996. This method is compared with other methods: a conventional operating method and a dynamic programming operating method. The results show that in regards to the fuel consumption of diesel generator, the proposed operating method is superior to the conventional method although not than the DP method, and the fuel consumption has a minimum if the PV energy is same as the wind energy.

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To improve GIS insulation specifications, it is important to recognize the insulation characteristics under oscillatory overvoltage waveforms occurring in the field. This paper describes investigations of insulation characteristics for double-frequency oscillatory waveforms with various frequencies and damping ratios. As a result, it was obtained that minimum breakdown voltages (Vmin) were irrelevant to frequency changes in the range of experimental condition under same damping condition. On the other hand, Vmin rose with damping ratio rising under same frequency condition. The insulation characteristics at valley of oscillation were investigated with actual breakdown voltages. It was found that the insulation characteristics were treated all-inclusively based on the characteristics of Vmin for damping time.

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PEFC is expected to be the new generation system for residential use. This system supplies electricity and hot water, so this system has capability of energy use saving. In order to introduce this system, however, several conditions must be overcome, for example, equipment cost, gas cost, electric selling and buying cost, and optimum operation pattern etc.
In this paper, we discuss optimum operation pattern for residential heat and electrical demand, energy cost in a year, and economical evaluation of PEFC system. As results of the study, the most economical output is 500W_??_1.2kW for residence. For the 1.0_??_1.2kW PEFC system, load following operation is the most economical, and for the 0.5_??_1.0kW PEFC system, constant rated output operation is the most economical. Key points to pervade PEFC system is that gas cost needs to be reduce to 70-90yen/Nm³ and that PEFC system price must be reduced to 300, 000_??_500, 000 yen/kW.

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Partial discharge (PD) monitoring system by UHF (Ultra high frequency) method has high sensitivity and high S/N ratio. This UHF PD monitoring system is suitable for PD diagnosis of GIS. Calibration technique of highly sensitive UHF sensor was clarified by injecting the artificial PD pulses. PD sensitivity of each sensor was verified and calibrated results were fully satisfactory. PDs were simultaneously measured with both the conventional method described in IEC-60270 and the UHF PD monitoring system by using many kinds of PD sources and various tank sizes. Owing to this measurement, conversion of dBm units in UHF PD monitoring system to pC units (apparent charge) became possible and it was clarified that the conversion' curve was independent of PD sources and tank size. These characteristics were confirmed by the theoretical analysis.

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Evaluation of insulation strength for lightning surge that actually enters into substations is important to estimate insulation reliability of gas-insulated equipment. The standard lightning impulse voltage (1.2/50μs) is used for factory tests. However, the actual lightning surge waveforms in substations are complex and are usually superimposed with various oscillations. Insulation characteristics of SF₆ gas against such complex voltages have not been sufficiently clarified.
This paper deals with gap breakdown characteristics in SF₆ gas under sub-microsecond pulses. Breakdown voltages are lower under a polarity reversal case than under a mono polarity case. The cause of this difference is discussed with a observing discharge propagation using an image converter camera. Moreover the electrode size effect is also discussed.

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