Optimization of electrical power distribution systems is becoming crucial with the significant increase in electricity demand due to population growth and industrial development. PT PLN (Persero), as the main electricity provider in Indonesia, faces major challenges in distribution efficiency, especially regarding power losses which reach approximately 10% of the total distributed energy. This research aims to optimize the distribution network configuration at PLN Mempawah Customer Service Unit to minimize power losses using the Particle Swarm Optimization (PSO) algorithm. The research method involves modeling the distribution network using DigSILENT PowerFactory software, power flow calculations with the Newton-Raphson method, and PSO simulation to determine the optimal location and capacity of capacitors. Seven alternative capacitor configurations were analyzed, and the results show that PSO simulation is effective in reducing power losses. Alternative 5 showed the highest efficiency, reducing power losses from 0.42 MW to 0.34 MW, or about an 80.952% reduction, with the placement of three 315 KVar capacitors at strategic buses (MW 0002 MJ, MW 0016 MJ, MW 0006 MJ). The fast and stable convergence of PSO in certain alternatives demonstrates the algorithm's effectiveness in finding optimal solutions. Factors such as load profile, network topology, line impedance, technical data accuracy, and operational constraints greatly influence the optimization results. This research contributes to the development of electrical engineering science and provides practical recommendations for PLN to improve the efficiency and reliability of its electricity distribution system.