Reactive power/voltage control in distribution systems under uncertain environment

A novel method for reactive power/voltage control in distribution systems under uncertain data environment is presented. This is achieved by minimising boundary real power loss or boundary total real power demand while satisfying constraints on boundary bus voltage magnitudes. Such an approach is more realistic and intuitively satisfying as compared with the crisp solution with deterministic data assumption. On-load tap changing facility of the transformer at the substation and the shunt capacitors at the substation and feeders are used as control variables. A truly nonlinear fuzzy distribution power flow is used, in which simultaneous non-statistical uncertainties in load forecast, load model coefficients and network parameters are incorporated. Genetic algorithm is used to solve the problem. In order to demonstrate the effectiveness of the proposed method, results for balanced 30-bus and unbalanced 25-bus and modified 123-bus systems have been obtained.