Fast evaluation of probabilistic total transfer capability considering multiple wind farms

Before the rapid growth of wind power, most bulk power system uncertainties came from system contingencies and load fluctuation. However, when large numbers of wind farms are introduced, the stochastic nature of the wind farm output under system normal state calls for a new probabilistic framework for system operation and evaluation, which captures the uncertainty of wind and corresponding transfer constraints of the system. Total transfer capability (TTC) is a measurement of the system's maximum power transfer capacity from a set of source buses to a set of sink buses. In this paper, we propose a fast probabilistic TTC evaluation method that incorporates the less predictable nature of wind farms. The proposed method returns the probabilistic TTC as a random variable that follows a certain distribution derived from wind farm output distributions using power transfer distribution factors. Our proposed method solves the probabilistic TTC in an analytic way. Results from the IEEE 118-bus test case demonstrate the efficiency and accuracy of the proposed method.