Damping Torque Analysis of a Power System Integrated with PMSG-based Wind Farm for Low-Frequency Oscillation Mitigation

Gradually increasing penetration of inverter-connected generators is radically changing the structure of the power system and posing significant challenges to its stability. This article extends the damping torque analysis (DTA) theory to investigate the damping effect of grid-connected permanent magnet synchronous generators (PMSGs) on power system low-frequency oscillation (LFO). The dominant oscillation mode is first obtained by calculating the participation factors of the studied system. A reduced model of PMSG reflecting the properties of dominant modes is then proposed for LFO analysis. On this basis, the impact of PMSG on system damping characteristics can be assessed with the explicit expression of the damping torque coefficient, which guides the parameter tuning of the grid-connected converter. Case studies of a PMSG integrated power system have been conducted to verify the reduced PMSG model and the results of DTA.