Flashover characteristics of cylindrical insulator in high-speed sand environment

With the launching of Lanzhou-Xinjiang high-speed railway in Northwest China, high-speed train running in sand environment will cause strong high-speed airflow with sand around it, which seriously threats the long-term service performance of roof insulators. To study the flashover characteristics of insulator under the condition, a small size wind tunnel system is established to simulate high-speed sand environment, the influence of airflow speed, sand particle size and sand flux on the flashover voltage of cylindrical insulator is investigated. Results show that, in pure high-speed airflow environment, the flashover voltage of insulator has an increase-decrease variation trend with the increase of airflow speed. The flashover mechanism is due to the combined effects of airflow blowing effect and airflow density. In sand environment, flashover voltage will decrease obviously which is caused by nonuniformity of electric field, but the decreasing degree will become small with the increase of airflow speed. Sand particle size and sand flux have negative influence on flashover voltage of insulator. These research results can provide theoretical basis for service performance of roof insulators in high-speed sand environment.