一种抑制连续换相失败的定关断角加速控制方法OA北大核心CSTPCD

There is a problem of continuous commutation failure(CCF)of an LCC-HVDC transmission system caused by an AC fault on the inverter side.Thus this paper first analyzes the variation of electrical quantity and control quantity in the recovery process of the first commutation failure(FCF),and clarifies that improper cooperation between constant current(CC),constant extinction angle(CEA)and current error control(CEC)in the recovery process is an important cause of CCF.After the asymmetrical fault,the DC second harmonic current caused by the AC negative-sequence current will lead to the delay of the control switching point and increase the risk of CCF.Based on this,a constant extinction angle acceleration(CEAA)control method is proposed,one which can enhance the coordination effect of controllers.This method can adaptively switch according to the commutation recovery process.It uses the extinction angle deviation to dynamically adjust the CEA command,realizes the control switching in advance,and reduces the influence of improper control after switching.At the same time,the method reduces the harmonic current by the notch filter.This can reduce the adverse effect of controller switching by reducing the firing angle wave.This method can improve the coordination effect between controllers,thus improving the ability of a DC system to resist CCF.The correctness of the theoretical analysis and the effectiveness of the optimization method are verified in the CIGRE model.