In this paper, distributed power supply and electric vehicle charging load are studied in depth, and the distributed power supply output model and electric vehicle charging load prediction model are constructed, which are integrated into the power system balance calculation model. In the framework of traditional power balance calculation, flexible calculation method is introduced for improvement, a new power system model is constructed, and a new power system power balance method based on flexible calculation is proposed. The application of the flexible calculation method in power systems is understood through the flexible balance calculation and example study of typical regional power grids.The variation interval of the load flexibility parameter in region A is [20350, 25000] MW, and the minimum value on the left side of the flexibility inequality (24524.6) is larger than the maximum value on the right side (23875.6), which realizes the flexible balance.The annual load of the power system of province Z is dominated by the summer and winter as the The annual load of the power system in Province Z is peaked in summer and winter, and troughs in spring and fall. The daily load basically shows the pattern of “double peaks and double valleys”. The UHV DC corridor in Province Z delivers power according to the 100/75 curve, with 100% capacity in January, July, August and December, and 65% capacity in other months. The UHV AC channel delivers power on a 100/70/55 curve throughout the year. Photovoltaic output is large in spring and small in winter, and the maximum output in a day is around 13:00. Wind power output is large in winter and small in summer, with large output at night and small output during the day.
