Voltage Risk Evaluation Based on Improved Probabilistic Load Flow Considering Intermittent Wind Farm

The randomness and intermittence of wind power have brought a great threat to grid voltage security and new difficulties to voltage security evaluation of power system. An improved probabilistic load flow (PLF) method considering the intermittence of wind power is proposed in this paper. The simplified steady state equivalent circuit iteration of IG in wind farm is considered to compute the base load flow, avoiding the inaccuracy that wind farm is only treated as PQ or PV model. Then combined Cumulants and Gram-Charlier expansion are introduced to attain the probability of voltage violation. The theory of risk assessment is applied to the power system with wind power to make a quantitative evaluation of voltage risk. The paper also provides theory reference to the wind power security penetration. At last, the effectiveness of the proposed method is verified through IEEE 14 Benchmark Model.