目前,许多风电场中安装了大量的双馈异步风电机组,其中应用了大量的电力电子设备,不可避免地在工作过程中产生谐波.当双馈风电机组检修后重新并网时,与风电场中其他正处在不同工作状态的双馈风电机组之间会产生谐波干扰.为研究此问题,首先分析双馈风电机组在不同工作状态下的功率流动情况及造成双馈风电机组之间谐波干扰的原因;之后,在Matlab中根据瞬时无功理论对双馈风电机组之间产生谐波干扰的过程进行仿真,总结出相关规律,即在亚同步发电状态下的双馈风电机组与超同步发电状态下的双馈风电机组之间由于功率流动会造成谐波干扰,并且随着超同步发电状态下风电机组数量的增多,产生的谐波干扰也随之加剧.
DFIGs with many power electronic equipment have been widely used in wind farms,which will cause harmonics.Especially,some reconnected-to-grid wind generators after maintained and repaired will cause the internal harmonic interferences with other wind generators in different working conditions.According to the theory of instantaneous reactive power and wind power generation,power flows and harmonic interferences between DFIG-based wind power generators in sub-synchronous condition and hyper-synchronous condition are studied and simulated by Matlab.The result shows that the internal harmonics are just caused by the power flows between the generators in different conditions,and the increase in the number of wind generators will exacerbate the harmonic interferences.