China Electric Power Research Institute, Beijing 100192, China

The heterogeneous development of the generation structure in the new power system has led to a sharp increase in the risk of large-scale blackout accidents under high-power active power shortages, posing significant challenges to the safe operation of power grid frequency. Considering the frequency regulation potential of large-scale wind farms in the northwest Gobi Desert and other arid areas and the output mode of large-capacity DC transmission, a frequency emergency control strategy for AC/DC hybrid power grids considering the frequency regulation capability of wind power in the sending-end power grid is proposed. When the frequency of the receiving-end power grid reaches the first-round operating value of low-frequency load shedding, the wind power of the sending-end power grid urgently provides the active power support to be transmitted to the receiving-end power grid through the ultra-high voltage direct current line. Firstly, a dual-layer active power allocation structure and active power allocation coefficient for wind power clusters are proposed, and a coordinated active power control algorithm for wind farms based on frequency characteristic identification is proposed. Secondly, the capacity-weighted average method is used to aggregate the parameters of the established multi-machine system frequency response (SFR) model, establishing a simplified SFR model. Then, based on this model, the power grid frequency characteristics are quantitatively analyzed from both time-domain and frequency-domain perspectives, respectively, and the relationship between power grid frequency characteristics and frequency regulation control parameters under the frequency emergency control strategy is evaluated. Finally, simulation analysis is conducted based on a power transmission system in the Gobi Desert and other arid areas in northwest China and the IEEE 2-area 4-machine system, and the simulation results verify the effectiveness of the proposed frequency emergency control strategy.