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Recently, the worldwide deregulation of the electric power industry is progressing. Further, it is expected that a many distributed generation facilities and energy storage systems will be installed at the end point of the power systems. Therefore, the future power system must be able to cope with these various qualities of power in the deregulated situation. The authors have proposed the FRIENDS (Flexible, Reliable, and Intelligent ENergy Delivery System) concept as a new distribution system that copes with a new framework of the electric power business in the near future. The most typical aspect of FRIENDS is the introduction of new equipment; Quality Control Centers (QCC) between distribution substations and customers. In this paper, the authors propose a concrete interior structure and investigate some control methods 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. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 26–38, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10243 [ABSTRACT FROM AUTHOR]

The authors have proposed FRIENDS as a concept of the future electric power system. In order to realize FRIENDS, it is necessary to design the concrete interior structure and control scheme of the Quality Control Center (QCC) which is to be installed between distribution substation and customers. Hybrid-type transfer switches are assumed to be installed on the high-voltage side of the QCC to realize network reconfiguration. Some devices for handling power quality are also assumed to be installed on the low-voltage side to realize customized power quality. In this paper, a novel control scheme for shutoff of the thyristor switches by the power quality handling devices is proposed and the effectiveness of the proposed scheme is investigated through momentary analysis using PSCAD/EMTDC. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(1): 32–41, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10077 [ABSTRACT FROM AUTHOR]

This article provides information on a study that proposed a preventive control strategy for an integrated security monitoring and control system. There are two categories underlying the preventive control problem: dynamical and statical. Information is presented on the P-Q decomposition used in the study. The objective functions of each sub-problem are discussed, as well as the effectiveness of the proposed technique in reducing operating costs.

Online monitoring and preventive control of a power system are receiving increased attention in recent years. Contingency analysis provides the basic data for these purposes and the development of fast contingency analysis method is strongly desired. The article proposes a more accurate method for contingency analysis. The method stimulates a given fault conditions by injecting hypothetical power. These variations of amplitude and phase angle of each node voltage, which are produced by the injected power, are calculated using prefault coefficient matrix. The non-iterative method is effective for reducing the computing time whether it may be based on ac or dc method.