A Novel Coordinated Control Strategy Between the Grid‐forming SVG Equipped With Supercapacitors and Renewable Energy Gathering Stations to Support Frequency Stability

ABSTRACT Combining supercapacitors and power electronic devices, grid‐forming static var generators (SVGs) can provide dynamic reactive power compensation while providing inertia support to the system, thereby enhancing the stability of renewable energy systems. However, challenges remain regarding the coordination between the inertia support from grid‐forming SVG and the control actions of automatic generation control (AGC) units in renewable energy gathering stations. To address this issue; this paper proposes a coordinated control strategy that accounts for the state of charge (SOC) of supercapacitors, aiming to enhance the inertia support role of grid‐forming static var generators (SVG) in renewable energy gathering stations and achieve their coordinated cooperation with the AGC system. By integrating the millisecond‐level rapid response capability of grid‐forming SVG and the second‐level continuous regulation capability of AGC, this strategy establishes a multi‐timescale active power support system: at the initial stage of a frequency dip, the grid‐forming SVG independently provides rapid inertia support; subsequently, it implements coordinated power allocation with the station‐level AGC while comprehensively considering the SOC of supercapacitors and the energy status of wind turbine units, thereby balancing transient frequency stability and the system's long‐term continuous regulation capability. Finally, a controller‐level hardware‐in‐the‐loop test platform is established for renewable power plants. Tests under typical operating conditions demonstrate the effectiveness and superiority of the proposed strategy, indicating that it can provide enhanced support when frequency fluctuations occur in renewable energy gathering stations.