静止同步串联补偿器控制方式及特性研究

基于dq同步旋转坐标系建立静止同步串联补偿器(static synchronous series compensator，SSSC)的数学模型，采用电压外环电流内环的双环控制实现对SSSC的控制。基于IEEE次同步谐振第1标准测试系统，考虑仅由固定电容提供串补及其中部分由SSSC提供串补的2种补偿方案，利用测试信号法计算2种补偿方案下发电机组的次同步阻尼特性，并进一步分析SSSC在次同步频率范围内的阻抗特性。研究表明：次同步频率下串有SSSC支路的阻抗特性与串有等值电容支路的阻抗特性相似，但SSSC所呈现的容抗小于固定电容的容抗，且SSSC还呈现较大的电阻分量。因此，串有SSSC的系统次同步谐振点将偏移，且谐振点附近的负阻尼大大减小，这将有利于缓解次同步谐振(subsynch- ronous resonance，SSR)。

Stuty on Control and Characteristcs of Static Synchronous Series Compensator

The mathematic model of a static synchronous series compensator (SSSC) in dq reference frame was founded and a double-loop control was presented in which an inner loop adopting current control and an outer loop adopting voltage control were included. The IEEE first benchmark model was adopted and two series compensation schemes were considered: the line was compensated by the fixed capacitor only and by an SSSC as a part of the total compensation. Then the subsynchronous resonance (SSR) damping characteristics of the studied system were investigated by the test signal method. Furthermore, the impedance characteristics of the SSSC in subsynchronous frequencies range were studied. The results show that in subsynchronous frequencies range the transmission line compensated by the SSSC causes a resonant impedance effect similar to that caused by the fixed capacitors. But the value of the capacitive reactance exhibited by SSSC is smaller than that of the fixed capacitors and the additional resistance component is exhibited by SSSC. So the resonant point of the combined system is shifted and the electric negative damping around the resonant point is reduced greatly. Such is helpful to mitigate the SSR.