Analytic probabilistic load flow calculation method and system

The embodiment of the invention provides an analytic probabilistic load flow calculation method and system. The analytic probabilistic load flow calculation method comprises steps of obtaining historical data of injection power of a distributed power supply access node; fitting the historical data by using a Gaussian mixture model to obtain a joint probability density function of the injection power; obtaining a second-order approximate expansion equation of a node voltage and injection power corresponding to each component; and performing weighted summation of the probability distribution function of the corresponding target node voltage when the injection power obeys the Gaussian distribution of each component to obtain the probability distribution function of the target node voltage, and solving the probability distribution function of the branch power flow similarly. The method is advantaged in that uncertainty of the output of the distributed power supply is fitted through a Gaussian mixture model, the c