A model of a radial power supply system in MatLAB was compiled to perform the research. The transformer substation is represented by a step-down transformer, the load of the substations in the form of a resistance. Electricity is transmitted to the substations along three power transmission lines. The power center is represented by an ideal source. A reserve source of limited power is connected to the remote substation. We made calculations of the voltage drop in the lines, voltage at the inputs of substations and electricity losses for transit. The study of the radial power supply system was performed in the daytime maximum mode; the minimum load mode was performed at night and in the peak load mode. As a result of modeling the operating modes, the indicators of the classical radial power supply scheme were compared with the indicators of the system when the local generation facilities were switched on during the working shift or during peak hours. Connection of reserve sources allows reducing voltage fluctuations along the line and reducing power losses for transit.