Flashover characteristics and altitude correction of railway insulators at high altitude and polluted areas

The reduction of electrical performance of railway insulators at high altitude and polluted areas affects the safe operation of the railway. A lot of studies have been carried out on transmission line insulators at home and abroad, but whether the results can guide the design of railway insulators has not yet been determined. This paper takes the railway insulator QBG-25/16 as the research object, experimentally studied the lightning impulse and AC pollution flashover characteristics of the railway insulator under low air pressure, analyzed its insulation configuration under high altitude and pollution environment, and finally proposed its altitude correction method. The results show that the flashover voltages of the insulator decrease in a power function as the air pressure decreases, and decrease in a power function as the salt deposit density increases, and the air pressure influence characteristic index and pollution influence characteristic index are related to voltage type, air pressure and salt deposit density. The tested insulators do not satisfy the requirements for insulation strength at certain high altitude and polluted areas. Finally, the altitude correction method for railway insulators is given. The results of the study provide guidance for the selection of external insulation for electrified railway systems at high altitude.