Fuzzy Expert System Application to Under Voltage Load Shedding

摘要

Under voltage load shedding (UVLS) is a partial solution to voltage security problems, since voltage dependency of the load has tremendous influence in voltage security. To counter act imbalance between load demand and generation, under frequency load shedding has been applied by almost every utility and grid operator for a long time. Therefore controlling the voltage level at this local load center may be a good option to keep the voltage security within its limits which is not possible in under frequency load shedding. Our studies show that in a large inter connected power system it will be difficult to implement UVLS because of change in load demand pattern also due to different topology load duration curves will not help in a violated environment. So a knowledge based intelligent tools like fuzzy - expert system will eventually helps to reduce errors in judgment for load shedding and also increases the speed of decision making. Using intelligent load shedding techniques, the task of decision making will be independent of human operator and will be based on rules and knowledge base. Since the implementation of the under voltage load shedding is based on particular mode or characteristics of power system, the fuzzy - expert system approach is considered most appropriate for under voltage load shedding for large power systems to improve voltage security.