双馈风电场等值阻抗模型在高频振荡研究中的适用性分析与评价

Analysis and Evaluation of the Applicability of Doubly-fed Wind Farm Equivalent Impedance Model in High Frequency Resonance Research

目前在对风电场高频振荡的研究中,风电场普遍采用等值阻抗模型,然而对于等值阻抗模型在高频段的适用性需要进一步分析与评价。针对这一问题,该文以双馈风电场为例,首先建立风电场中包含双馈风电机组、链路出口处电缆与风电机组间集电线路的链路详细高频阻抗模型。然后,采用常规等值方法聚合风电场,获得等值高频阻抗模型。进而,在同一链路不同风电机组之间控制延时、电流内环控制参数、网侧滤波器等关键参数存在差异的场景下,采用振荡频率相对误差、高频段相位均方根误差两个指标综合评价等值与详细风电场高频阻抗模型的一致性,并研究考虑与忽略风电机组间集电线路对等值高频阻抗模型适用性的影响。结果表明,风电机组间集电线路对风电场等值高频阻抗模型的适用性有较大影响;然而,在考虑风电机组间集电线路的影响后,同一链路不同风电机组的关键参数存在差异时对风电场等值高频阻抗模型的适用性影响较小。最后,在PSCAD/EMTDC仿真平台上搭建双馈风电场的仿真模型,通过仿真验证理论分析的正确性。文章所得结论可以为研究规模化风电场高频振荡现象提供等值模型的适用性参考依据。

In the current studies on high frequency resonance of wind farm,the equivalent impedance model is generally used for wind farm.However,there is a lack of analysis and evaluation of the applicability of the equivalent impedance model in the high frequency band.In order to solve this problem,this paper establishes a detailed high frequency impedance model of the wind farm,which includes doubly-fed wind turbines,cables at the exit of the links and collector lines between wind turbines.Then,the wind farm equivalent high frequency impedance model is established by aggregating the wind farm by means of conventional equivalent method.Furthermore,this paper evaluates the consistency between the equivalent and detailed high frequency impedance model of wind farm with different key parameters such as control delay,current inner loop control,grid-side filter of different wind turbines on the same link,and studies the influence of considering or ignoring the collector lines between wind turbines on the applicability of the equivalent high frequency impedance model,based on two indexes:the relative error of resonance frequency and the root mean square error of high frequency phase.The results show that the collector lines between wind turbines have a great influence on the applicability of high frequency equivalent model.However,the difference of key parameters of different wind turbines on the same link has little influence on the applicability of high frequency equivalent model after considering the influence of collector lines between wind turbines.Finally,this paper establishes the model of doubly-fed wind farm on the PSCAD/EMTDC simulation platform and verifies the correctness of the theoretical analysis.The conclusions of this paper can provide a reference basis for the applicability of the equivalent model for the study of high frequency resonance in large-scale wind farms.