An approximate reasoning approach for optimal dynamic dispatch of thermal generating units including auxiliary control

Fuzzy set theory is applied to decision-making in the optimal generation dispatch of thermal generating units. Operational requirements such as unit auxiliary start-up and shutdown create discrete zones of generation output. Plant operators are required to switch units dynamically from one output zone to another in order to keep track of the changing load. The problem arises when making the decision to switch zones for dynamic load dispatch, because of complicated operational conditions. The authors apply approximate reasoning in order to coordinate multiple system requirements and to make effective zone-switching decisions. Membership functions are introduced to measure generation-load balance, fuel cost, and time to stay in a zone. Approximate reasoning using these indices yields information concerning compatibility of output zones. Model analysis is used to demonstrate the flexibility and improved man-machine interface of the approach.