An Efficient Hybrid Approach for Volt/Var Control in Distribution Systems

This paper presents an efficient hybrid approach for volt/var control in distribution systems, with switching limits on taps and shunts. Since the problem is nondeterministic polynomial hard and combinatorial with huge solution space, metaheuristic techniques, despite being computationally expensive, have been used. The proposed approach combines the strengths of a gradient technique and a metaheuristic technique. In the first phase, the primal-dual interior point method (PDIPM) treats the discrete variables as continuous. These are then discretized using PDIPM-based sensitivities. These two solutions provide heuristic bounds on controls which are used in the second phase by a metaheuristic algorithm. The bounds aid in limiting the number of controls´ combinations. Results for two systems have been obtained which ascertain the potential of the proposed approach over the conventional metaheuristic technique. These also indicate approximately 30-35 times increase in speed with the proposed algorithm compared to the conventional one.