This paper first establishes a 3D simulation model of a 110 kV porcelain insulator and calculates the impact of insulators with zero values at different positions on the spatial electric field of the insulator string. Subsequently, a spatial electric field measurement experiment under operating frequency voltage was conducted in a laboratory setting. The research findings indicate that when a zero-value insulator is located on the conductor side or the crossarm side of the insulator string, the degree of spatial electric field distortion is greater than when it is positioned at the center of the string. Based on the simulation and experimental results, the paper proposes a criterion for zero-value spatial electric field characteristics for each insulator in a 110 kV porcelain insulator string. The validity of the detection method is verified by defining a coefficient for the variation in the spatial electric field strength of the zero-value insulator string. The conclusions drawn in this study can provide valuable references for non-contact detection of insulators in transmission lines.