Analytical method is to establish the reliability mathematical model of power system according to the random parameters of power system components, and get the indexes of the system through numerical calculation. Because the analytical method adopts strict mathematical means, the calculation results are highly reliable. However, its computational complexity increases exponentially with the increase of system scale, so the analytical method is generally only suitable for systems with small network scale and strong network structure. That is to say, when there are few component failures with great impact and the number of components is not too large, analytical method can give full play to its advantages of clear concept and accurate model. However, for large power systems, or when there are many factors to be considered in the model, the research process of analytical methods will become very complicated.

Monte Carlo simulation method is to represent the probability parameters of each component in the system with corresponding random numbers on the computer, simulate the actual situation of the system on the computer, and estimate the required indicators according to the observation of this simulation process for a period of time. its