The growing yearly power demand caused by population increases and economic upswings results in considerable energy losses and voltage instability in the distribution system. This study proposes integrating photovoltaic distributed generation (PV-DG) with the battery system (BS) into the grid to address these issues. Despite the many benefits of PV-DG and BS, improper placement can negatively impact the distribution network's technological aspects. The goal of this study is to enhance the production of grid-tied PV-DG and BS along the distribution network. Firstly, using particle swarm optimization (PSO), the study examines two scenarios according to the grid and general condition of PV-DG constraint to determine the optimal placement and size for the PV-DG system. Next, the BS is utilized to store surplus energy from PV-DG and to supply it back into the grid during peak hour (20:00). The backward-forward sweep (BFS) method analyzes 24-hour energy loss and voltage profiles for each scenario. The 22kV radial feeder of 115/22kV grid substation Osaom in Pursat, Cambodia, is used as a case study. The simulation results demonstrated the optimum location was bus-24, and capacity for PV-DG and BS were 2.34248 MW and 1.243 MWh, respectively, within the loss reduction per year of 19.56% from 1,115.8674 MWh loss (system without proposed method) and acceptable voltage levels of 0.95 p.u to 1.05 p.u. Finally, during the 20-year planning study and purchasing cost of energy (COE) of 0.157 USD/kWh for economic evaluation, scenario 1 was a preferable case in which the project was fully refunded in short periods of 7.75 and 13.12 years of simple payback period (SSP) and discounted payback period (DPP), respectively, with a total profit of 558,396.434 USD of net present worth (NPW). In short, these results demonstrated the advantages of employing the proposed method to create the efficient and dependable MVAC distribution system in Cambodia.