基于STATCOM的低压配电网电压不对称系统的电压波动控制研究

Research on Voltage Fluctuation Control of Voltage Asymmetry System in Low Voltage Distribution Network Based on STATCOM

针对低压配电网电压不对称时负载侧电网电压的波动情况,传统的基于瞬时无功功率理论的无功电流检测方法已经不能满足静止同步补偿器(STATCOM)的要求,因此,在补偿不平衡负载时,提出了一种改进的低压配电网电压不对称系统的STATCOM的控制方法。该方法通过产生一个与负载无功电流分量大小相等、相位相反的输出电流来达到补偿的目的。STATCOM采用双环控制,其中内环为电流控制部分,外环为电压控制部分,通过外环控制来使得直流侧电压达到指定值,同时将该信号作为有功电流控制环的控制指令,然后将直接检测出来的负载侧无功电流基波分量作为无功电流控制环的指令,实现快速准确补偿。笔者还利用MATLAB软件进行了仿真研究,仿真结果表明,改进后的STATCOM控制方法能更有效地实现由不对称负载引起的电压波动的抑制效果。

In view of the fluctuation of the load-side grid voltage when the voltage of the low-voltage distribution network is asymmetric,the traditional reactive current detection method based on the instantaneous reactive power theory cannot meet the requirements of the static synchronous compensator(STATCOM).Therefore,when compensating the unbalanced load,an improved STATCOM control method for the low-voltage distribution network voltage asymmetric system is proposed.The method achieves the purpose of compensation by generating an output current with equal size and opposite phase to the load reactive current component.STATCOM adopts double-loop control,in which the inner loop is the cuirent control part and the outer loop is the voltage control part.Through the outer loop control,the DC side voltage reaches the specified value.At the same time,the signal is used as the control instruction of the active current control loop,and then the fundamental component of the reactive current at the load side directly detected is used as the instruction of the reactive current control loop to achieve rapid and accurate compensation.In this paper,MATLAB software is also used for simulation research.The simulation results show that the improved STATCOM control method can more effectively suppress the voltage fluctuation caused by asymmetric load.