Fault Response Regulation Model and Voltage Support Strategy for Inverter‐Interfaced Distributed Generator During Asymmetrical Faults

Abstract

To comply with grid codes, inverter‐interfaced distributed generators (IIDGs) are required to have low‐voltage ride‐through (LVRT) capability. However, their limited overcurrent capability compromises this critical requirement during fault events. This paper proposes an IIDG fault response regulation model with an adjustable virtual impedance, to address the overcurrent risk and fulfill the voltage support requirement during asymmetrical faults. By adaptively adjusting the magnitude of the virtual impedance, the model can precisely constrain the output current within the safe limit. The relationship between the IIDG's virtual impedance phase angle (VIPA) and its voltage support effectiveness is investigated, with the lowest phase voltage at PCC as the support objective. The results indicate that the optimal value for the VIPA cannot be predetermined due to factors such as unknown fault resistance. To address this, a voltage support method is proposed, which performs real‐time optimization of the VIPA to achieve optimal voltage support under various fault scenarios. MATLAB simulation results validate both the theoretical analysis and the effectiveness of the proposed fault control strategy. © 2026 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.