Impulse Flashover Characteristics of High-Voltage Post Insulators in High Altitude Areas

High-altitude areas present challenges for external insulation design due to the dry climate and thin air. This paper conducts high-voltage flashover experiments on a ceramic post insulator in a multifunctional artificial climate laboratory. Also, to better compare the characteristic of the testing insulator, the same experiments are performed on a reference post insulator which is commonly used in transmission lines. In order to simulate complex climate in different high-altitude areas, air pressure and absolute humidity are adjusted corrodingly. The research includes two types of voltage sources with positive and negative polarities. It is found that the testing insulator has a higher flashover voltage when a negative lightning testing voltage is applied. Besides, the influence of air pressure is studied. Further, a flashover voltage correction function and factor are given in this paper, based on the experiment results and cross comparison analysis on existing high-altitude insulator flashover studies. In conclusion, this paper provides a technical method of external insulation calculation for post insulators in high-altitude area.