Improved VSG Scheme of WPPs for Frequency Regulation of Power Grid

Abstract

In this paper, an improved virtual synchronous generator (IVSG) scheme of wind power plants (WPPs) is proposed to provide better grid frequency support during inertia response (IR) and primary frequency regulation (PFR) stages than WPPs with conventional VSG control (WPPs-VSG). Because the analysis for different power imbalance conditions is different, only the condition when power consumption is larger than power generation is discussed in this paper for its difficulty of control. For WPPs-VSG, the input power of VSG depends on the wind turbine (WT) rotor speed and its value decreases when the stored energy in WT is released during grid frequency response stage. Then the output power of WPPs-VSG is smaller than expected and the frequency support capability of WPPs-VSG is weakened, too. For WPPs with IVSG control (WPPs-IVSG), the input power of VSG is maintained constant during IR and PFR stages and WPPs-IVSG can provide expected power to the power grid. What's more, by implementing the PFR function with zero response time, the grid frequency response of the WPPs-IVSG is better. The effectiveness of the proposed WPPs-IVSG is verified by simulation results.