关键词: 经验Copula函数, 非线性相关, 概率潮流, 三相配电网, 前推回代法

Abstract:  ABSTRACT：   Due to the nonlinear correlation of wind powers, it is of significance to consider the wind power nonlinear in the probability load flow of distribution network, especially in the aspects of security, reliability and economy of the system. In this paper, a method for calculating probability load flow of distribution network is proposed, based on the empirical copula function of wind power. Compared with the traditional methods, such as the methods based on Gauss distribution and t distribution, the samples of wind power generated by proposed method has better performances on approximating the wind power characteristics. The mathematic model of distribution network power flow with wind power is formulated. Also, the treatment methods for the PQ nodes, PV nodes and PQ （U） node are introduced. The forward and backward substitution method is applied in calculating the power flow of distribution network. Finally, the proposed method is applied to the probabilistic load flow calculation of the pure radial distribution network and the weakly meshed distribution network, comparing with the results of no correlation and liner correlation. The results indicate that the proposed method can obtain better results, which provides more accurate reference information for the operation of power system. 

Key words: empirical Copula function, nonlinear correlation, probabilistic load flow, three-phase distribution network, forward and backward substitution method