Possibilities for Voltage Reduction in the Transmission Grid of Serbia Through Reactive Support of Future Renewable Energy Sources

During the process of decarbonizing electricity production in the power system of Serbia, an intensive integration of wind power plants (WPPs) and photovoltaic power plants (PVPPs) connected to the transmission grid is planned. The analyses in this paper assume two scenarios regarding the installed capacities of renewable energy sources (RES) for the reference year 2030. According to the minimalist scenario, a total of 5200 MW is expected to be connected to the transmission grid by 2030, including 3200 MW from WPPs and 2000 MW from PVPPs. The maximalist scenario anticipates the connection of 7100 MW from WPPs and 3500 MW from PVPPs. For both scenarios, technical analyses were conducted to assess the capability of these sources to provide ancillary voltage control services in Serbia’s future power system. The calculations were based on real characteristics of WPPs and PVPPs in terms of their ability to absorb reactive power, as well as on the power production values calculations derived from available meteorological data for the target locations where these sources are planned. Additionally, an estimation of the production profiles of conventional power plants was conducted based on economic criteria while considering the need for balancing services. The calculations were performed on Serbia’s transmission grid model for a future state using DIgSILENT PowerFactory software. The analyses included the impact of reactive power absorption with the maximum available capacity of prospective RES on voltage reduction at all 400 kV and 220 kV transmission grid nodes.