Analysis of Overvoltage in Renewable Energy Integration Systems During Single-Phase Shortcircuit and Open-Phase Operation Faults

This study investigates voltage characteristics and overvoltage mechanisms in renewable energy integration systems under asymmetric fault. The circuit models for single-phase short-circuit and open-phase operation faults are established, derives analytical expressions for fault voltages, and identifies key factors influencing overvoltage. A photovoltaic (PV) integration system case study demonstrates that: (1) Increasing current limitation during single-phase faults enhances voltage support capability; (2) Reducing negative-sequence reactive current injection and active current output during open-phase operation effectively suppresses overvoltage risks; (3) The phase-locked loop (PLL) phase deviation exhibits an overvoltage amplifying effect during transient oscillations. The theoretical analysis is validated through PSCAD/EMTDC simulations, providing actionable insights for optimizing fault ride-through strategies in renewable energy systems.