Due to the higher energy cost, increased world demand and growing concerns about climate protection, the easiest and most effective measure is to improve energy efficiency and reduction energy losses. Reactive power flow as a component of apparent power has a significant effect on power factor and energy efficiency. To achieve these objectives, the most effective approach which recently used to the electrical distribution networks is power factor correction (PFC). This paper presents the positive impact of power factor correction (PFC) and different solutions where (PFC) system can be installed on electrical networks will be discussed. And capacitor banks designed for power factor correction at (110/15 kV, 50 MVA Breshna Kot Substation in Afghanistan). By improving the power factor correction of the site from 0.836 to 0.95 the kVA capacity on the distribution transformer (supplying the factory) increases by 12% in Breshna Kot Substation. Analyses of the results prove that (PFC) significantly Raises the energy capacity and efficiency in Breshna Kot Substation, and reduces the electricity cost, energy losses, and causes the voltage to be more regulate and stable.