Abstract Asymmetrical faults in the grid can lead to voltage drops at the grid-connected points, and in serious cases, there is also a risk of cutting the machine. The traditional voltage support strategy is easily affected by the output of the units and cannot support the voltage flexibly. To address the above problems, an optimized strategy for boosting voltage performance is proposed under asymmetrical faults in the power grid. Firstly, the voltage support principle under asymmetrical fault is analyzed, and the voltage support equation is derived. Then, based on the above equations, an optimal voltage support strategy under asymmetrical faults is proposed by taking the operation requirements of grid-connected standard voltage as the objective and considering the peak current and active power fluctuation amplitude as the constraints. Finally, the effectiveness and flexibility of the above strategy are validated by simulation.