Capacitor placement, replacement and control in large-scale distribution systems by a GA-based two-stage algorithm

This paper presents a two-stage algorithm tailored for capacitor placement, replacement and control of general, large-scale, unbalanced distribution systems. The first stage of the proposed algorithm consists of a GA followed by the second stage which consists of a sensitivity-based heuristic method tailored for the capacitor placement, replacement and control problem. The two-stage algorithm is designed to take advantage of the merits of each technique. The GA is employed to find neighborhoods of high quality solutions and to provide a good initial guess for the sensitivity-based heuristic. The heuristic uses the sensitivity of real power loss to reactive power to quickly and locally improve upon the solution provided by the GA with less computation than by allowing the GA to continue. The two-stage algorithm was implemented in the C programming language and tested for a 292 bus unbalanced system with single, two and three-phase branches and grounded and ungrounded portions of the network with promising results.