Effect of Material and Creepage Distance on the Flashover Characteristics of Insulators under HEMP

Insulators, as the most common and widely used electrical components in the operation of power systems, play an important role in the mechanical support and electrical insulation of transmission lines. So, it’s necessary to conduct experimental research on the flashover characteristics of line insulators under HEMP (High-altitude Electro Magnetic Pulse). Based on the PCI-E500-5kA pulse current injection source, a test platform for pulse current injection on insulators was established. The effects of different materials and different creepage distances on insulators under HEMP flashover were studied through the constructed test platform. Key parameters such as the 50% flashover voltage, flashover time, flashover duration, and volt-second characteristics of seven types of insulators (LXP70 glass insulator, FPQ1-10T composite insulator, U40BP ceramic insulator, U70BP ceramic insulator, PQ1-10T ceramic insulator, P-6T ceramic insulator, and P-10T ceramic insulator) were obtained. The experimental results demonstrated that in the HEMP conduction environment, line insulators would experience flashover at the tail of the pulse, and the flashover delay was in the range of several thousand nanoseconds. The ability of glass materials to withstand HEMP pulses was relatively weaker compared to ceramic materials. Insulators with smaller creepage distances had smaller 50% flashover voltage values in the HEMP environment.