Probabilistic Load Flow Analysis for Power System Containing Wind Farms

Abstract

The power grid containing wind farms is analyzed by AC probabilistic load flow. By using the method of the combination concept of Cumulants and Gram-Charlier series expansion theory, the DC probabilistic model is extended into AC probabilistic model, in which a three-parameter Weibull distribution is adopted to describe the random variation of wind speed, meanwhile the asynchronous wind turbine generator is treated as PQ node, then a probabilistic model of wind turbine generator is built. Based on the built model the calculation of IEEE 118-bus system is carried out, and then the probabilistic distributions of nodal voltages as well as the probabilistic distribution of branch load flow are obtained. The variation of nodal voltages and branch load flow before and after the connection of wind farms with power grid is compared.