The Third and Fourth EU Energy Packages, as well as the Energy Strategy of Ukraine “Safety, Energy Efficiency, Competitiveness” until 2035, define the development of electricity production using renewable energy sources among the priorities of the energy sector. In this situation, the decision-making process on the integration of renewable energy sources into the electricity supply system is of particular importance. The article develops a fuzzy model for assessing the risks of connecting (integration) renewable energy sources to the power supply system. The toolkit, based on logical rules, allows modeling various connection options. The data obtained can then be used to set requirements for the parameters of the electrical installation at the stage of issuing technical specifications to the customer. The modeling results demonstrate the adequacy of the developed knowledge base and the possibility of using it to develop a methodology for the controlled and efficient connection of renewable energy sources to the power grid.