Technical trends on on-line DSA, applications in Japan

The difficulty of siting power plants in suburban areas makes it necessary for Japanese power utilities to build new power plants on sites far from urban areas in a maldistributed way. Moreover, due to requirements for reducing electricity costs, utilization of transmission line systems is getting heavier. Even today, it is not exceptional in Japan to find a transmission line to deliver power exceeding 10% of the network capacity, and this situation is expected to become even worse in the future. Thus, measures to maintain stability in the event of a serious line fault or bus fault have become more important. To cope with such stability problems there are two major approaches using dynamic stability analyses in Japan: (1) behavior assumption type approach based on pre-fault calculations; and (2) behavior prediction type approach based on a post-fault calculation. These two approaches are discussed