Zoned Oscillation Suppression Method for High-frequency Oscillation in Doubly Fed Wind Farms

After high-frequency oscillation occurs in a certain area of the wind farm, it may affect other areas, leading to large-scale oscillation of the entire wind farm. Taking a domestic doubly-fed wind farm with static var generator (SVG) as an example, the equivalent high frequency impedance model of the wind farm is established. Then, the phenomenon of large-scale oscillation in wind farms caused by high-frequency oscillation in a certain area is studied. The results show that wind farms can be divided into regions by contacting transformers, and the high-frequency oscillation risk of wind farms can be comprehensively evaluated based on the high-frequency stability characteristics of each region. Furthermore, based on the typical passive filter, the parameter design principles and methods are proposed, which can suppress the high frequency oscillation in a specific region and shield the influence of high frequency oscillation in other regions on this region, and the stability margin and high-frequency oscillation absorption ratio can be dynamically adjusted according to the design requirements. The constraint relationship between phase margin and absorption ratio is explored, based on which the optimization method of passive filter parameters is proposed. Theoretical analysis and simulation results indicate that within the target frequency band, the designed passive filter can not only effectively suppress high-frequency oscillations within the protected area, but also effectively shield the impact of high-frequency oscillations in other areas on the protected area.