Research on Zero-Value Insulator Detection Method for Transmission Lines Based on Axial and Radial Electric Field Distortion Characteristics

To address the engineering need for detecting zero-value insulators in transmission lines, this study establishes a COMSOL 3D electric field simulation model incorporating components such as floating-potential field strength meters, insulator strings, conductors, and towers. The research investigates the distribution patterns of axial and radial electric field strengths when measuring a 110kV insulator string containing one zero-value insulator using a floating-potential field strength meter. The results indicate that zero-value insulator causes significant distortion in the axial electric field distribution along the entire string, with a characteristic differential value appearing at the corresponding position of zero-value insulator. The differential value is maximized when zero-value insulator is located at either end (#1 or #7) of the string. The radial field distortion gradient localization curve can identify the position of zero-value insulators from #2 to #7 by detecting the highest point, while the steepness characteristic in the #2–#3 interval distinguishes between #1 and #2 zero-value conditions. The simulation results align with experimental measurements obtained using the floating-potential field strength meter, validating the effectiveness of the differential field distortion analysis and gradient localization method. This research provides theoretical support for online insulator detection technology based on non-contact electric field measurement and offers technical references for developing live inspection systems for transmission line insulators.