Probabilistic Load Flow Calculation for AC/DC Power Grid Based on Polynomial Chaos Approach

In this paper, a new method based on polynomial chaos approach (PA) for probabilistic load flow of AC/DC power grid is presented. First, the steady-state model of the AC/DC power grid is constructed. Then, consider the uncertainty of the wind power, the probabilistic load flow equations are transformed into stochastic nonlinear equations by PA. Galerkin method is used to convert nonlinear stochastic equations into high-dimensional deterministic probabilistic load flow equations. The approximate coefficients of the state variables are obtained by the probabilistic load flow calculation by Newton's method. The example analysis of PS 4–4 system shows that the new method can solve the probabilistic load flow for AC/DC power grid.