Optimal capacitors sizing in distribution feeders using heuristic search based node stability-indices

A novel approach to size and locate capacitors in distribution feeders is presented in this paper. The proposed heuristic approach is formulated as a maximisation of a single objective function. This objective function includes both power loss reduction and capacitors investment costs. In this method where the capacitor optimal sizes and locations are decoupled, node stability indices are used to suitably select the capacitor probable locations. The capacitor initial sizes are determined while deriving the objective function subject to some constraints. The usually used voltage constraint has been substituted by a new one made on the reactive branch currents for which positive values (over-compensation) are allowed to improve voltage profile as well as the cost and power loss reductions. The developed algorithm has been implemented on several test systems and the obtained results have been compared with those of authors having used fuzzy logic and other heuristic search methods.

► Optimal capacitor sizes are determined using a two-stage efficient heuristic method.
► Appropriate capacitor locations are identified using nodes stability-indices.
► Over-compensation is allowed to improve the voltage profile, the economic return as well as power loss reduction.