Experimental study on flashover voltage characteristics of different arresters at high altitudes and construction of correction models

The unique atmospheric conditions in high-altitude regions significantly affect the external insulation performance of electrical equipment, and existing altitude correction methods struggle to accurately reflect the flashover characteristics of arresters. This study conducts lightning impulse discharge experiments on rod-rod, rod-plane, and adjustable-gap arrester models within an altitude range of 487–4800 m, systematically analyzes the variation law of flashover voltage with altitude, and constructs correction models. Experimental results show that flashover voltage decreases in a power-law manner with increasing altitude, with significant differences among models due to electric field structures and gap-valve element coupling effects: The rod-rod symmetric model exhibits stable discharge statistical characteristics but higher altitude sensitivity for long gaps; the rod-plane asymmetric model shows a faster rate of flashover voltage decrease due to electric field non-uniformity; the adjustable-gap arrester model, through the gap-valve element coupling mechanism, demonstrates a more stable growth trend of correction factors with altitude, effectively reducing design deviations. Pressure characteristic indices n and correction coefficients K for each model are obtained via least squares regression fitting. The adjustable-gap model shows excellent engineering adaptability under long gaps, ensuring insulation reliability while avoiding excessive correction. The research results provide critical data support for the insulation coordination design of arresters in high-altitude transmission lines and promote the engineering application and optimization of correction models.