Application of models of the wind energy conversion system to wind power dynamic analysis

Due to stochastic variation of the wind energy, the wind power connected to the grid is stochastic. As a result, the voltage of the grid, particularly near a wind farm, fluctuates. According to the characteristics of the wind energy conversion system (WECS), a program including the models of the WECS was developed. The dynamic performances of the startup, shutdown, and running processes of the WECS and the front of the gust could be simulated and investigated. In this paper, a typical WECS connected to a large system (infinite bus) was simulated, and the relationships of the short circuit capacity (SCC) with the wind power penetration were investigated. The results showed that the SCC was one of important factors to affect the wind power penetration. The bigger SCC of the network at the WECS connection, the larger the wind power penetration. There was a maximum penetration level of the wind power to a given SCC. If the wind power of the WECS had exceeded a limit, the grid voltage fluctuation would have been in excess of the allowable value of the grid; in a severe case, the voltage would have been unstable.