变换器短路故障时整流发电机的暂态电流计算

Transient current calculation of rectifier generator under converter short circuit fault

考虑直流变换器侧短路故障时,整流发电机带直流变换器运行可以等效为整流发电机突加RLC负载,其暂态电流计算直接关系到直流故障诊断和保护。通过将RLC负载从直流侧等效至交流侧后,将暂态电流计算等效为同步发电机串联RLC后三相短路电流计算;在得到了暂态电流的表达式后,通过类比同步发电机三相短路电流的初值、终值和时间常数计算,近似得到了暂态电流的解析表达式,并给出了电流峰值和峰值时间。通过仿真验证了该解析表达式的有效性,可以用于对直流故障诊断和保护方法的确定。

Considering the short circuit fault at DC(direct-current)converter side,the rectifier generator with DC converter can be equivalent to the rectifier generator suddenly applied with RLC(resistance inductance capacitance)load,and its transient current calculation is directly related to DC fault diagnosis and protection.When the RLC load was equivalent from the DC side to the AC(alternating-current)side,the transient current was equivalent to the three-phase short circuit current under the condition of the synchronous generator in series of RLC.Through the expression of the transient current,the analytical expression of the transient current was obtained by calculating the initial value,final value and time constant with the method of analogizing the three-phase short-circuit current′s calculating process of the synchronous generator,and the peak value and peak time of the current were given.Finally,the validity of the analytical expression is verified by simulation,which can be used for the improvement of the diagnosis and the determination of the protection way of DC faults.