计及内、外部交互模态的电压源型风电场-电网稳定性量化分析

Quantitative Analysis of the Voltage-source-type Wind Farm-weak Grid’s Stability Considering the Internal and External Interaction Modes

目前关于电压源控制的研究大多面向单台风电机组,忽略了机组之间的交互作用。为此,探讨了电压源型风电机组的多机交互稳定性问题,给出了电压源型风电场–弱电网系统小信号稳定性分析与稳定裕度的量化评估方法。同时,考虑风电场与电网及风电场内部机组之间两种交互模态,克服了常规多机稳定性分析不考虑机组之间交互模态的缺陷,提高了多机稳定性分析的精度。此外,该稳定性分析方法能够根据稳定裕度量化指标判断多台机组间的交互模态,并对风电场中稳定性较薄弱的机组进行定位,从而有针对性地优化薄弱机组的控制参数,提高风电场的稳定性。研究结果表明,经过稳定性分析与致稳控制,电压源型风电场能够在短路比接近1的弱电网下稳定运行。基于PSCAD/EMTDC的仿真结果,验证了理论分析的正确性。

At present,researches about the voltage source control mostly do not focus on the interaction between wind turbines but the single wind turbine.Therefore,we discuss the interaction stability of voltage-source-type wind turbines,and put forward a small-signal stability analysis and quantitative evaluation method of the voltage-source-type wind farm-weak grid.Two interaction modes are taken into consideration,which are the interaction between the wind farm and the grid,and the interaction between wind turbines in the wind farm.Shortcomings of the conventional stability analysis method in which the interaction between wind turbines is not taknen into consideration are overcome,which improves the accuracy of wind farm stability analysis.Besides,the stability analysis method can judge the interaction mode among wind turbines based on the stability quantitative index,and locate the wind turbine with weaker stability margin in the wind farm,which can help optimize the control parameters of the weak wind turbine and improve the stability of a wind farm.After stability analysis and stabilization control,the research indicates the voltage-source-type wind farm can operate stably in a weak grid with the short-circuit ratio close to 1.The simulation results based on the PSCAD/EMTDC verify the effectiveness of theoretical analysis.