With the expansion of overhead transmission lines， there has been an increasing number of high-capacity， extra-high voltage， and long-distance transmission line sections， making crossover transmission lines a more common occurrence. The electrical safety gap of crossover lines has become a critical factor affecting the safety of power grid lines. Therefore， a general expression for the spatial configuration of overhead conductors in three-dimensional space was constructed on the basis of a catenary model， and the critical segment method was employed to calculate the minimum electrical gap value within the lines. Then， by integrating the Unity3D engine with the minimum gap calculation program， virtual simulation was conducted， the layout effects of crossover sections under different parameter settings and the locations of flashover faults in the lines were demonstrated by using tower and conductor models in three-dimensional space， and based on the virtual simulation of electrical gap， the minimum gaps under different line parameters were solved. Simulation results indicate that the line crossover angle and the line icing have significant influence on the minimum gap of the lines， validating the effectiveness of the critical segment method and virtual experiments.