In large-scale photovoltaic (PV) integration systems using voltage source converter-based high voltage direct current (VSC-HVDC) transmission

the sending end exhibits characteristics such as a wide range of power source distributions and poor resistance to disturbances. During the recovery period following sending end AC short-circuit faults

overvoltage problems can easily occur

threatening system safety. Firstly

the technical scheme and control structure of the 10-million-kilowatt-level PV base transmission system using VSC-HVDC are introduced. The existing fault ride-through strategies for VSC-HVDC and PV inverters are analyzed

and the characteristics of three-phase short-circuit faults in the sending end system are studied. Based on four stages

namely

fault transient

fault steady state

fault recovery transient

and system steady state

the mechanism of overvoltage caused by short-circuit faults at the sending end is revealed. A new AC short-circuit fault ride-through strategy for large-scale PV transmission systems using VSC-HVDC is proposed. This strategy accurately detects AC faults at the sending end by adding a DC over-voltage criterion for PV generation units. Furthermore

a coordinated control strategy is utilized

where the AC voltage control of the VSC-HVDC is harmonized with the power recovery rate of the PV inverter

to achieve smooth ride-through of short-circuit faults. Finally

the effectiveness of the newly proposed fault ride-through strategy is verified using PSCAD/EMTDC.