A stochastic response surface method for probabilistic evaluation of the voltage stability considering wind power

In order to accurately describe the influence of the random factors in power systems on the voltage stability, to obtain the probability distribution of load margin or critical active power, and to determine the probability of voltage instability under a certain load level, a probabilistic evaluation method of voltage stability based on a stochastic response surface method was proposed. The stochastic response surface method was applied to transform the problem of probability evaluations to the deterministic problem, and the interior point method was applied to solve the deterministic problem. The randomness of the wind farms out powers and the uncertainty of loads were considered in the model. This paper used the orthogonal transformation technique to deal with the correlated wind speed of different wind farms, and analyzed the correlation of wind speed effects on the critical power probability assessment. The comparison of the calculation results of the stochastic response surface method and the Monte Carlo method on IEEE 118-bus and 300-bus systems indicate that, the stochastic response surface method requires smaller amount of computation and keeps high accuracy. © 2012 Chinese Society for Electrical Engineering.