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Wind turbine generation systems (WTs) normally do not have mechanisms to control their output, so that the growth in WT penetration has brought difficulty in the frequency control operation of power grids. This paper presents a frequency adjustment mechanism for the WTs consisting of the following controllers: an active power controller, a governor controller, a pseudo synchronization controller and a pitch angle controller. The governor and the synchronization controllers calculate a correction value to make variability of the WT output in response to its share of power generation. Besides, the pitch angle controller is customized from a viewpoint of relaxing restraint in the frequency adjustment mechanism. By these controllers, the proposed mechanism supplies the frequency adjustability to the power grid in consideration of the actual WT output while effectively suppressing the rapid change of rotor angular speed. Through numerical simulations and discussions on their results, validity of the authors’ proposal is verified.

Higher penetration of renewable energy (RE) generations in power system makes more difficult to keep demand and supply balancing due to augmentation of volatility in RE's generation output. To solve this problem, the authors focus on regulation capacity procurement from consumer's resources. However, utilizing customer's resource must be considered uncertainty of regulation caused by demand variation due to owner's convenience. Moreover, it is necessary to consider voltage fluctuation by regulation in distribution system where many resources are integrated. Therefore, this paper proposes novel operation method utilizing customer's resource with active power regulation and reactive power compensation for providing demand and supply regulation considering uncertainty of owners' convenience and voltage influence on distribution system.

In Japan, PV has been largely installed in distribution system as a clean resource. However, the instability of PV generation leads to the fluctuation of voltage that can’t be ignored, and conventional devices are hard to deal with this problem. Battery storage devices are introduced to suppress the voltage fluctuation. Because battery storage devices with power conditioning system can provide perfect control in PV connected distribution system. Besides large-scale BESS, the increasing penetration of customer-side energy storage devices like Home Energy Storage System (HESS), Electric Vehicle (EV), and etc. in distribution system is also notable. In this paper, the centralized control of energy storage devices for voltage fluctuation suppression is proposed, and the utilization of customer-side energy devices is verified.

Recently, Virtual Power Plant (VPP) has attracted attention for supply-demand balancing capability, but the control methodology for VPP realization is still at a study phase. In this study, VPP is assumed to have many aggregators whereas each aggregator integrates numerous battery resources, and manages a local energy grid like Microgrid. This study presents an allocation method of supply-demand balancing capability by an aggregator considering state of charge (SOC) of battery.

SUMMARY More and more dispersed power sources will be introduced to achieve a low-carbon society. However, many problems may occur as a result of excessive introduction in the current power system. For example, delays or failures of fault detection may occur due to a decline in protective relay sensitivity. This paper proposes a new system of protective relays for distribution lines using section switches with sensors to solve the problem. In addition, experimental results on the proposed system composed of Intelligent Electronic Devices based on IEC 61850 are presented.

Huge numbers of cultural objects were damaged by microorganisms after having been soaked with seawater from the tsunami that followed the Great East Japan Earthquake on March 11, 2011. Among the cultural objects that were damaged, paper-based objects in the tsunami area were severely affected. In the present study, a culture-based analysis and on-site investigations were carried out to determine the extent of the microbial deterioration of paper-based objects (i.e., administrative documents and historical documents). Dark-colored fungi were isolated from black-spotted paper as Stachybotrys chartarum , which was observed to grow significantly in mineral salt medium supplemented with cellulose as the sole nutrient source; growth was shown in 10% NaCl. Two isolates from light red-spotted paper were related to Streptomyces sp. and Myxotrichum sp., respectively. These isolates generated red pigments in the mycelia and on the culture plates. Penicillium -related isolates were dominant in the sample tested, and they showed a higher level of NaCl tolerance. From the results of our on-site investigations, a unique discoloration, mainly black- and light red-spotted alterations caused by microbes, was observed on many paper-based objects that had been left wet for several months. The adhesive tape method applied to the black-spotted and red-spotted areas on damaged documents, Stachybotrys , Chaetomium and Cladosporium , and Actinomycetales bacterium were observed, respectively. With regard to the discoloration found on tsunami-affected paper-based objects, Stachybotrys and Streptomyces sp. seem to be responsible for the black- and red-spotted paper alterations, respectively.

In recent years, renewable energy system such as Photovoltaic generation system (PV) is widely introduced in distribution system. On the other hand, voltage deviation due to voltage fluctuation and unbalanced voltage caused by PV becomes serious problem. In order to mitigate those problems, the Combined type Dynamic Voltage Regulator (C-DVR) which consists of a step voltage regulator and AC chopper is the effective device. C-DVR can regulate line voltage continuously and quickly. This paper shows the effectiveness of C-DVR by the numerical simulation. KeywordsDynamic voltage regulator, AC chopper, Voltage control, Photovoltaic generation system.

With the increasing the number of Photovoltaic generators (PV) connected to distribution system (DS), several concerns such as rise and sudden change of voltage on distribution line are growing in Japan. Step Voltage Regulator (SVR) is well known as the one of voltage control equipment used in current DS. Meanwhile, SVR cannot regulate rapid voltage change because SVR has time delay against variation of voltage. In contrast, Static Var Compensator (SVC) is the effective device to control voltage changed rapidly. However, since the cost of SVC with large capacity is expensive, it is important to reduce the capacity of SVC in order to increase the introduction of SVC into power system. From this background, the novel control method of SVR using solar radiation information to reduce the capacity of SVC is proposed in this paper. The effectiveness of the proposed method is confirmed by numerical simulation with real time simulator.

In recent years, power quality in distribution system becomes to be greatly concerned. There are two power quality problems greatly. One is the voltage rise, the other is harmonics voltage. The voltage rise in distribution system is caused by leading current from Static Capacitors (SCs) which are widely installed at receiving points by consumers to improve power factor. Especially, the voltage rise is caused in light-load time, because of the excessive amount of SCs. On the other hand, the harmonic voltages are caused by nonlinear loads such as power electronics devices. Since harmonic currents from nonlinear loads flow through the line and transformers, the voltage is distorted. To improve those problems of power quality, Hybrid type Power Quality Conditioner (HyPQC) is proposed. HyPQC is consist of the power electronics converter and LC circuit, it could compensate the reactive current and harmonic currents from loads. In order to use for practical application, the experimental test should be performed. From this background, this paper presents the control algorithm to compensate the reactive current and harmonic currents in case of changing the loads. The simulation and experimental results are also presented using the proto type model.

In recent years, it has been very important to adequately keep power qualities such as voltage and imbalance and so on. Especially the imbalance of voltage on distribution system may increase in the future by increasing electrified houses. Therefore it is necessary to decrease imbalance of voltage all the time in cooperation with electric power company and consumers. The high voltage consumers usually install static capacitors (SC) in order to improve power factor at receiving point. In this paper authors propose the method that these SCs in consumers are controlled in order to decrease the imbalance of voltage on distribution line. By the proposed method, single phase SCs are installed and the amounts of these SCs are decided in cooperation with several consumers that the proposed method is installed. The effect of the proposed method is confirmed by numerical simulation. Furthermore the effective scheme for introducing the proposed method to consumers is studied in this paper.

第Ⅱ部 研究会「大学共同利用機関の歴史とアーカイブズ」 第2章, 青木睦［国文学研究資料館 アーカイブ系］

In recent years, the voltage rise at the end of distribution line and the increase of harmonic voltages has become to be greatly concerned because of extreme expansion of distributed generation (DG) systems and excessive amount of static capacitors (SCs) for improving power factor. For compensating leading current and harmonic currents from consumers, the hybrid type of power quality conditioner was proposed. The proposed system consists of a LC series circuit, a series transformer and a self-commutated converter in order to reduce the capacity of the converter than the conventional type of static synchronous compensators (STATCOMs) and active filters (AFs). This paper presents SC bank quantity control to expand the range of the compensating current and DC bus voltage control of the converter in the hybrid type power quality conditioner. In this study, the performance evaluations for the proposed conditioner in terms of the control of the harmful currents are presented by the various simulations.