Multi-Objective PSO-Based Capacitor Allocation for Loss Reduction and Voltage Enhancement

Electric power distribution systems often experience active power losses and voltage drops, especially in radial networks with long feeders and high reactive power demand. Improper reactive power compensation can reduce operational efficiency and voltage quality; therefore, optimal capacitor bank allocation is required to determine suitable installation locations and capacities. This study aims to optimize the location and size of capacitor banks in the IEEE 33-bus radial distribution system using Multi-Objective Particle Swarm Optimization (MOPSO) to reduce active power losses and improve the voltage profile. The proposed method uses two objective functions, namely minimization of active power loss and minimization of total voltage deviation. The IEEE 33-bus system is first simulated under the base-case condition without capacitor banks to obtain the initial voltage profile, minimum voltage, and active power loss. Then, MOPSO is applied to search for the best capacitor placement and sizing while considering voltage and capacitor capacity constraints. The optimization results show that the optimal capacitor banks are installed at bus 15 with a capacity of 1405 kVAr and bus 30 with a capacity of 935 kVAr. After capacitor installation, the active power loss decreases from 1618 kW to 1031 kW, representing a reduction of 36.28%. The minimum bus voltage increases from 0.913 p.u. to 0.961 p.u., while the total voltage deviation decreases from 1.708 p.u. to 0.807 p.u. These results indicate that the proposed MOPSO-based capacitor allocation method effectively reduces power losses and enhances the voltage profile of the IEEE 33-bus distribution system.