Decision-making at the design stage of the distribution network significantly affects the change in the indices of uninterrupted power supply to consumers. The main ones are SAIDI and SAIFI. There is no methodological support for determining the predicted values of the power supply continuity indices. The purpose of the study is to develop a methodology for calculating the predicted values of indicators of uninterrupted supply during design. A feature of the technique is the account of the circuit-mode changes in the 0.4-10 kV distribution network section. The introduction of the developed methodology into project practice is relevant and expedient. An important point is the accounting of distributed generation, which has a significant impact on the operating conditions of power supply systems. Local power systems based on distribution generation and networks 0,4-10 kv are becoming widespread, which can serve as the basis for distributed energy and energy transition in Russia. Their appearance increases the efficiency of the energy sector, including increasing the power supply reliability. However, difficulties arise in justifying distributed generation power distribution schemes, the feasibility of measures to create local power systems and the effectiveness of their integration without appropriate research and methodological support. The developed methodology is based on the use of statistical processing methods, expert systems, the SAIDI method. It is aimed at medium and low voltage distribution networks. The methodology makes it possible to compare measures taking into account changes in the structural and functional reliability of the distribution network and regime restrictions. Verification of the methodology was carried out on the example of a section of the distribution network of a residential neighborhood. Comparison of the results obtained by the methodology and in the software ETAP, proved the adequacy of the proposed methodology and the reliability of the predicted values obtained SAIDI and SAIFI.