电压型虚拟同步发电机控制策略下的双馈风电机组阻抗及次同步振荡特性

Impedance and Sub-synchronous Oscillation Characteristics of Doubly-fed Induction Generators with Control Strategy of Voltage Virtual Synchronous Generator

针对双馈风电机组(doubly-fed induction generators,DFIG)经串补送出系统存在次同步振荡(sub-synchronousoscillation,SSO)的问题,以电压型虚拟同步发电机(virtualsynchronous generator,VSG)控制策略下的DFIG 为研究对象,首先基于三相静止坐标系建立了其阻抗模型,推导了机组正、负序阻抗解析式;其次搭建了PSCAD/EMTDC模型,对理论推导阻抗特性和频率扫描结果进行了对比验证;最后基于奈奎斯特稳定判据定量分析了VSG 控制策略下的DFIG 经串补送出系统SSO 特性,通过仿真验证了所建立模型和稳定性分析结论的正确性。研究结果为SSO 的抑制提供了参考。

Aiming at the problem that sub-synchronous oscillation (SSO) is observed in doubly-fed induction generators (DFIG) connected to series-compensated transmission system, the DFIG with control strategy of voltage virtual synchronous generator (VSG) was taken as research object. Firstly, its impedance model based on three-phase stationary coordinate system was built, and the positive and negative sequence impedance analytical formulas of DFIG were deduced. Then, the impedance model of the DFIG was built on PSCAD/EMTDC platform, and the results of theoretical derivation and frequency scanning were verified by comparison. Finally,the SSO characteristics of DFIG connected to series-compensated transmission system with control strategy of VSG was analyzed quantitatively based on Nyquist stability criterion. The correctness of the established model and stability analysis conclusion was verified by simulation. The study results provide reference for suppression of SSO.