Direct lightning stroke poses a severe threat to low-voltage overhead distribution grids with low insulation levels, as it easily induces lightning-related faults, such as conductor breakage. Accurate simulation of lightning overvoltages is therefore critical for designing targeted lightning protection measures and reducing fault occurrence in low voltage distribution grids. In this paper, we simulated the overvoltage of low-voltage overhead distribution grids under different configurations using the Partial Element Equivalent Circuit (PEEC) method, which was validated against triggered lightning test benchmarks. Simulation results indicate that overvoltages at the line start or central pole exhibit rapid pre-peak rise and polarity reversal decay, which can easily cause electrical equipment faults. Whereas the line end exhibits post-peak oscillation and residual voltage due to terminal arrester action. Return stroke current parameters were accurately modeled, with strong linear correlations between overvoltage and current peak. This method effectively simulates direct lightning overvoltage, supporting lightning fault protection and electrical equipment safeguarding within low-voltage distribution networks.