A FUZZY - BASED OPTIMAL REACTIVE POWER-CONTROL

This paper presents a mathematical formulation for the optimal reactiv e power control problem using the fuzzy set theory. The objectives are to minimize real power losses and improve the voltage profile of a gi ven system. Transmission losses are expressed in terms of voltage incr ements by relating the control variables, i.e., tap positions of trans formers and reactive power injections of VAR sources, to the voltage i ncrements in a modified Jacobian matrix. This specific formulation of the problem does not require the Jacobian matrix inversion, and hence it will save computation time and memory space. The objective function and the constrains are modeled by fuzzy sets. Linear membership funct ions of the fuzzy sets are defined and the fuzzy linear optimization p roblem is formulated. The solution space in this case is defined as th e intersection of the fuzzy sets describing the constraints and the ob jective functions. Each solution is characterized by a parameter that determines the degree of satisfaction with the solution. The optimal s olution is the one with the maximum value for the satisfaction paramet er. Results for the application of this approach on test systems revea l its numerous advantages.