高比例电力电子电力系统过电压(三):直流故障下新能源暂时工频过电压机理OA北大核心CSTPCD

With high share of renewable energy sources and large capacity of DC transmission projects,the problem of overvoltage has drawn more and more attention,which not only restricts the DC transmission capacity,but may also cause large-scale off-grid accidents of renewable energy sources.When the proportion of renewable energy is relatively high,compared with AC equipment,the renewable energy is more likely to face temporary power frequency overvoltage.This paper analyzes the overvoltage of sending end caused by DC fault.First,simplified equivalent circuits of UHVDC for delivery of renewable energy sources and traditional synchronous generators in fault state when HVDC bipolar blocking and HVDC blocks after continuous commutation failures occur are established.Then,based on the phasor relationship,the maximum overvoltage under DC bipolar blocking faults and DC blocking after continuous commutation failure is derived.Further,the influence of the power of HVDC transmission,the active power of renewable energy source,the parameter of low voltage ride through control,the electrical distance from the traditional synchronous generator to the DC converter station,the electrical distance from the renewable energy source to the DC converter station,and other factors on the terminal voltage of the renewable energy source are analyzed.Finally,PSD-BPA simulation software is used for simulation both in minor case and northwest equivalent grid to verify the validity of the theoretical analysis.