Power System Long-Range Decision Analysis Under Fuzzy Environment

In long-range power system planning, the states of power systems are not known precisely. To find an optimal alternative of a project, usually the states of the system and associated utilities are assumed to be statistically known. In applying the statistical decision theory, the decision maker tacitly equates the system imprecision or fuzziness with randomness and neglects some of the criteria of merits of alternatives that ought to be considered for optimal decision because of unavilability of data. It is the contention of this paper to emphasize the need for differentiation between randomness and fuzziness. By fuzziness is meant a type of imprecision which is associated with fuzzy sets (1). A systematic approach for decision making in a fuzzy environment is presented in this paper. The use of linguistic variables and fuzzy algorithm in decision analysis of long-range projects will provide an approximate and yet effective tool for analyzing the behavior of future systems which are complex or too ill defined at the time of planning.