考虑阻抗双解现象的可控串补模式切换控制方法

可控串联补偿(thyristor controlled series capacitor，TCSC)的模式切换对电力系统的稳定控制具有重要意义。TCSC阻抗双解现象的存在对其模式切换提出了更高的要求，单一改变触发角的方法无法实现模式切换。在考虑阻抗双解现象影响的基础上，提出了一套相应的TCSC模式切换控制方法。通过强制晶闸管支路电流与线路电流同步，实现由容性区到Bypass模式的切换；在由容性区到感性微调模式切换的过程中提出了晶闸管条件触发的方法，即当线路电流和电容电压满足同向条件时晶闸管才触发导通。同时为及时向切换控制提供线路电流同步信号，提出了一种预测电流过零的新方法。数字仿真及动模实验结果表明，提出的切换方法能使切换过程平稳迅速，且动态特性良好。

Mode-switching Control Method of TCSC Considering Dual Impedance Phenomenon

The mode-switching control method of thyristor controlled series capacitor (TCSC) is of great importance to power system stability. The switching control method becomes more complex because of the dual impedance phenomenon of TCSC. There is no way to realize mode-switching only by changing firing angles. Considering the influence of dual impedance phenomenon, a set of mode-switching control methods is proposed. By means of forced synchronization of current in thyristor branch with the line current, the mode switching from capacitive mode to Bypass can be implemented. In the switching strategy from capacitive mode to inductive veriner mode, a method of thyristor conditional firing is put forward. The thyristors will be fired and conducted on condition that both line current and capacitor voltage are inphase. To provide synchronization signal of line current for switching control in time, a method to forecast the zero-crossing point of the current is given. Simulation and experimental results show that the proposed switching methods can make the switching process fast and possess good dynamic performance.