Multi-time scale coordinated control strategy for frequency regulation of doubly-fed wind turbines

Aiming at the problems of system inertia reduction and frequency modulation capacity reduction caused by large-scale wind power replacing some traditional generators, a multi-time scale coordinated control strategy of doubly-fed wind turbines and traditional synchronous units jointly supporting the system frequency is proposed, so as to improve the system frequency stability and rationally utilize frequency modulation resources. According to the frequency modulation reserve capacity of traditional synchronous units and disturbance power, the system frequency modulation demand in different scenarios is analyzed, and the multi-time scale coordinated control strategy to actively support frequency of doubly-fed wind turbines is proposed. And based on the reserve capacity of traditional synchronous units, the frequency modulation dead zone value of doubly-fed wind turbines is designed, so that it can adaptively switch the inertia support and primary frequency regulation for different scenarios, and realize the full use of the frequency modulation reserve capacity of traditional synchronous units while giving full play to the rapid response ability of doubly-fed wind turbines. The frequency dynamic response characteristics of doubly-fed wind turbines with additional frequency active support control are analyzed, which further proves its superiority. Finally, the large-scale wind power grid-connected system simulation model is built based on RTLAB real-time digital simulation platform, which verifies the effectiveness of the control strategy in this paper.