Probabilistic optimal power flow of distirbution system with distribution generation considering corelation relationship

Abstract

Aiming at the optimal power flow problem (OPF) of distribution network, this paper firstly establishes a multiobjective OPF model including the lowest cost of power generation, the minimum pollutant treatment cost and the minimum active power loss. Theconstraints include active power and reactive power flow equation constraints and inequality constraints including the limits of active power output of generations, the upper and lower limits of node voltage, and the penetration limits of distribution generations. Then use the fuzzy set theory to reformulate the multiobjective OPF problem into a single objective nonlinear programming problem. According to the probabilistic OPF of distribution network with random output of related distribution generation (DG) units, this paper adopts Cholesky factorization to handle the correlations between DG units and point estimation method to transform the probabilistic OPF problem a deterministic calculation using the above OPF method. Based on the estimated samples obtained by point estimation method, the statistical characteristics of multiobjective OPF can be obtained. The modified IEEE 33-node system is used to verify the proposed method.