一种通过调整VSC等效输出阻抗来抑制SSR的新方法

A New Approach to Damp SSR by Adjusting Equivalent Output Impedance of VSC

严重的次同步谐振(SSR)会危及电力系统的安全运行。分析和探讨了电压源型换流器(VSC)在近同步发电机侧时,对系统次同步谐振的影响。VSC由一系列的电路元件组成,其等效输出阻抗和其控制参数是与电网交互作用的关键因素。采用复转矩系数法分析了VSC等效输出阻抗对系统阻尼的影响,进一步对VSC做出改善,提高其等效注入电阻以改善系统的阻尼,进而实现抑制次同步谐振的目的。最后给出了时域仿真结果,证明了这种VSC阻抗调整技术能够一定程度的抑制次同步谐振。

Serious subsynchronous resonance （SSR） will threaten the operation of power system.An investigation and analysis is made in this paper of the effect of a voltage-source converter （VSC） on sub-synchronous resonance which is installed near the synchronous generator.The equivalent output impedance of VSC,which is made up of a series of circuit components,and its control parameters are the key factors for interactions with the grid.The effect of the equivalent output impedance of VSC on the damping of the system with the complex torque coefficient method is analyzed,and then,the VSC is further improved to increase the equivalent implanted damping resistance and to achieve the damping subsynchronous resonance.The time-domain simulation proves that the VSC impedance adjustment technology can damp the subsynchronous resonance to a certain extent.