A Frequency and Duration Method for Adequacy Assessment of Generation Systems With Wind Farms

This paper proposes a frequency and duration method for the adequacy assessment of generation systems with wind farms (WFs). Based on Markov chains, reliability models for WFs, conventional generators, and load are developed and represented as the corresponding probability-frequency distribution functions (PFDFs). The failures of wind turbines and the uncertainties and correlations of wind speeds are considered and incorporated into the reliability modeling of WFs. With the proposed method, the implementation of the reliability modeling of large WFs becomes simple. Moreover, for a generation system with WFs, not only probability-based reliability indexes, such as the loss of load probability and the expected energy not supplied, but also frequency-based reliability indexes, such as the loss of load frequency and the loss of load duration, can be calculated analytically and efficiently using the PFDFs. An optimal decision-making model for determining the clustering number of random states is proposed to improve the credibility of stochastic process modeling of Markov-chain-based random variables. The tests on two modified IEEE-RTS79 grids with WFs demonstrate the rapidity and validity of the proposed method.