阻抗重塑VSC抑制双馈风电场次同步谐振分析与实验OA

Aiming at the subsynchronous resonance(SSR)problem arising when doubly-fed induction generators(DFIG)deliver power through series-compensated transmission lines,this paper improves the current control loop of the voltage source converter(VSC)and proposes an oscillation suppression method based on impedance reshaping.On the basis of conventional centralized oscillation suppression schemes,an impedance model is established for wind farms with parallel VSCs connected to the grid via series compensation.The equivalent impedance theory is adopted to analyze the triggering conditions of subsynchronous resonance.Theoretical analysis indicates that the VSC with impedance reshaping capability can increase the phase margin and improve system stability.Comparative simulations with and without the VSC-based impedance reshaping branch are carried out to verify the effectiveness of the proposed method.By analyzing how feedback signals extracted from different measurement points affect the impedance reshaping performance of the VSC.the optimal input signal of the VSC is determined.Finally,power hardware-in-the-loop(PHIL)tests are implemented on the RT-LAB real-time simulation platform to validate the practical operational performance of the improved VSC control strategy.