Experimental measurement of electric field near the insulator string

This paper explores the electric field distribution near a string of six NJ120 high voltage insulators through experimental measurements under various conditions. Using a distributed capacitance method with custom probes connected to an Arduino-based system, tests were conducted on clean and polluted insulators. Pollution was simulated using a tuf-based solution with conductivities ranging from 0.5 to 1.97 mS/cm. Measurements were taken at 13 heights and four distances (1 to1.75 m) under applied AC voltages of 15 to 80 kV. The study also investigates the effects of damaged insulators, placed at different positions (near the high voltage terminal, in the middle, and near the ground), as well as the role of guard rings in improving field uniformity. Results indicate that pollution and damaged insulators significantly increased field intensity, particularly near the high voltage terminal. Guard rings effectively reduced field peaks, with larger radii and optimal placement providing the best performance. These findings contribute to optimizing high voltage insulator design for enhanced reliability.