Probabilistic Load Flow Calculation For Power System Based On Two Point Estimate

There are many uncertain factors in power system operation, such as the random fluctuations of load, the outage changes of generator, the fault in equipment, the outage of new energy sources such as wind power generation changes with the climate, etc. When we analyzed power system planning and operation conditions, deterministic methods are still used, in the process of which statistics and calculations are needed for many possible events, the calculated quantities is too much and the computation time is too hard to bear, and this method is difficult to reflect the integral operations of the system. So, the research on analysis of probabilistic load flow which was able to consider the affect by uncertain factors is very necessary.This paper studies the probabilistic load flow calculation method based on the point estimate method. First, I did load flow calculation and analysis on IEEE-14nodes system respectively by the method of this paper and Monte Carlo Simulation, and verified the validity of this paper.Then this method was used in the probabilistic load flow calculation of system integrated with wind farms, it builds the probabilistic model of generator, load and wind farm, and through the probabilistic load flow calculation,the probability distributions of node voltages and branch load flow are obtained, and the influence of wind power was analyzed by comparing the power system unconnecting wind farms.On this basis, this paper calculated the probabilistic dynamic flow which considering the frequency fluctuation based on point estimates, the random disturbance affect on the system frequency and the system adjusts the generator and load automatically according to the change of frequency after the disturbance is wholely considered in this paper, it can simulate the actual situation after the system disturbance, and the probability distribution results of system state parameters will be more realistic and reasonable.