Research on Sub-synchronous Oscillation Stability of VSC Converter

摘要

This paper studies the problem of the sub-synchronous oscillation,which caused by the interaction between VSC converter and non-series compensated weak grid.The model of VSC converter at grid side under small signal is constructed.Furthermore,eigenvalue analysis method is applied to analysis the model of oscillation modes,and by calculating damping ratio and correlation factors,the key parameters of sub-synchronous oscillation are presented.It is shown that parameters of phase-lock loop control and the voltage feed forward filter have a significant impact on the characteristic of system sub-synchronous oscillation.Therefore,reasonable optimization of parameter configuration can reduce the risk of the oscillation.Finally,the influence rules of the key parameters are verified via electromagnetic transient simulation.