The Basic Philosophy and Improvement on Reliability of Electric Power Systems in Japan

An outline of the electric power system and the present status of power system failures in Japan where "wide area coordination" is adopted, are described. To increase the reliability of the electric power system, it should be simple, streng, and flexible in its arrangement and also easy in its operation. Thus it is essential that it be composed as a well-balanced, powerful, and living system. According to this concept, an intensive study has been made on the system reliability, especially from the viewpoint of equipment and also of operation. Ten typical approaches to improve the system reliability in Japan are shown. The economic aspect, which is most important in improving the system reliability, is now under study. A comparison of the amount of investment with the expected profit is being undertaken.