Capacitor placement plays an important role in distribution system planning and operation. Optimal capacitor placement can result in system loss reduction, power factor correction, voltage profile improvement, and feeder capacity release. To achieve these benefits to the utmost extent under various operating constraints, distribution engineers are required to determine the optimal locations, types, and sizes of capacitors to be placed and control settings of switched capacitors at different load levels.

A Particle Swarm Optimization (PSO) based approach is used to achieve optimal capacitor placement in radial distribution systems. Discrete nature of capacitors and different load levels are all taken into consideration in the problem formulation. Mathematically, the capacitor placement problem is a non-linear  constraints. Most conventional optimization techniques are incapable to solve this hard combinatorial problem, whereas PSO algorithm is more suitable. The proposed solution method employs to search for optimal locations, types, and sizes of capacitors to be placed and optimal numbers of switched capacitor banks at different load levels. The proposed approach has been implemented and tested on various IEEE test system with promising results.