Research on Probabilistic Power Flow of the Distribution System Based on Cornish-Fisher

DG based on wind energy system (WES) has the probabilistic output power relied on natural conditions, the traditional deterministic load flow is not a suitable tool for the analyzing and maintaining distribution system. Aiming at this problem, this paper applies a probabilistic power flow (PLF) method to evaluate the influence of distributed generation with WES. Firstly, the probabilistic model of WES is established which considers the relationship between output power of WES and wind velocity. Secondly, instead of the conventional Gram-Charlier expansion, the model of combined cumulant and Cornish-Fisher expansion is applied to calculate the PLF. This model has the more convergence for on-Gaussian probabilistic density function. Lastly, the IEEE 34 distribution system with the modification by injecting the WES to some nodes is tested. The results show that the method in this paper is efficient and reasonable.