Overview the influence of high-speed sand on flashover characteristics of cylindrical insulator

High-speed train running in sand environment will cause strong airflow mixed with sand, which seriously threats the long-term service performance of roof insulators. To study the flashover characteristics of insulator under the above condition, a small size wind tunnel system was established to simulate high-speed sand environment. The influences of several key factors, including airflow speed, sand particles size and sand flux on the flashover voltage of a cylindrical insulator, were investigated. Variation of flashover voltage with the airflow, whose speed covers the running velocity range of high-speed train, was obtained. A minimum flashover voltage was found. Mechanisms of the different factors influencing the flashover characteristics were clarified out, from the aspects of airflow density, trace of the charged particles and convection cooling effect. In the end, research on the effects of sand particles size and sand flux revealed a negative correlation with the flashover voltage. These research results will benefit the service performance of roof insulators in high-speed sand environment.