Active power losses and the maximum penetration of PV in the MV distribution grid: Case-study of Pleiku, Vietnam

Vietnam is the country with the highest solar energy development rate in Southeast Asia thanks to the government’s attractive mechanisms and policies over the past decade. The installed capacity of solar power has increased dramatically from 105 MW in 201S to 16,504 MW by the end of 2020. This drastic increase has brought both positive and negative impacts to the power system; besides the positive impacts in terms of economics and the environment, many negative impacts have also been recorded in numerous studies related to power quality and system stability. This study was conducted to verify one of the most important impacts of high penetration level of photovoltaics (PV) into the power system, namely the impact on system’s active power loss; meanwhile, a power flow analysis model is used in combination with different PV penetration scenarios to find the maximum penetration limit where the voltage violations occur. A case-study was conducted for a medium voltage (MV) branch of Pleiku City power grid, Gia Lai Province, Vietnam using the ETAP power system analysis software. The results showed that an appropriate increase in PV penetration will help reduce power losses in the power system. When the penetration rate exceeds 135% of the system power, the reverse power flow resulting from the high penetration level of PV will lead to a large number of losses.