This paper presents a heuristic constructive algorithm to solve the discrete capacitor size and allocation problem in distribution systems. Initially the discrete nature of the capacitor allocation problem is mitigated by using a sigmoid function in the [0,1] interval which is incorporated into the optimum power flow (OPF) through modifications in the power flow equations. The proposed algorithm uses the primal-dual interior point technique to solve the OPF problem. Finally, the sensitivity obtained by sigmoid function which is weighted by the reactive loading of the distribution system, determines step by step the location, size and number of capacitors to be installed in the distribution system. The proposed technique is applied in two distribution systems. The results obtained are compared with the ones obtained using the genetic algorithm.
Optimal Capacitor Allocation; Heuristic Constructive Algorithm; Sigmoid Function; Interior Point Technique