The continuous increase in power demand, as well as urbanization, needs a high quality and reliable power supply system. However, the existing passive electrical power distribution system faced a number of challenges as a result of those which can’t meet the increasing power demand in a reliable and secure manner. The most critical problems in power distribution system performance are poor voltage profile, power loss. This type of problem can be minimized by integrating optimally placed and size of Photovoltaic distributed generation (DG) with the existing distribution system. Optimal placement and sizing of DG sources have profoundly impacted on the system losses and voltage profiles in a distribution network. This research paper proposed a methodology for optimal placing and fixing the issue of the size of DG units in the distribution system to minimize the real power loss, reactive power loss and improve the voltage profile by using Hybrid optimization methodology of grey wolf optimizer and particle swarm optimizations (GWO-PSO) methods. The study has been carried out on the Kombolcha distribution system on the feeder-3 which has 131 buses. The selected feeder has been modeled and load flow analysis has been simulated using the Backward-Forward Sweep (BFS) method implemented in MATLAB for evaluation of power loss and voltage profile of the feeder. From the existing system, three different scenarios are formed and analyzed independently. Namely Scenario I: Base case Scenario II: Only Type- 1 DG and Scenario III: Only Type- 3 DG. From BFS load flow result of the existing system, the total active and reactive power loss are 506.9256 KW and 303.5537 KVAr respectively and one hundred-nineteen (90.84%) of buses are below the minimum standard level. From the simulation result in scenario III the proposed algorithm gives higher improvement in feeder performance. For example, percentage reduction in active power loss is 87.1769 %, 90.993%, 91.712 % and 93.011 % when integrating 1-4 DG respectively. And also, 87.1769%, 90.068%, 91.712 % and 93.011 % reduction in reactive power loss. From scenario -III integrating 4DG gives good performance improvement in the feeder. Generally, type -3 DG has good performance in minimizing loss and improving voltage profile than type-1 DG. The cost-effectiveness of the proposed solution was also analyzed and the payback period has become nearly six years. Key words: GWO, Hybrid (GWO-PSO) optimization, Power loss reduction, PSO, Voltage profile improvement