Because of excellent mechanical properties, thermal insulation and ideal radiation resistance, polyimide (PI) is one of the best choices as a flexible solar backsheet in photovoltaic systems. In this study, accumulation characteristics of surface charge of PI backsheet under temperature-controlled corona polarization were investigated both theoretically and experimentally. In order to investigate the surface charge accumulation of PI backsheet under the effect of different temperatures, finite element method (FEM) was used. The mechanisms by which the temperature influenced accumulation and decay processes of the surface charge of the PI backsheet were investigated. The results show that the carrier mobility of PI backsheet increased in the stages of charge accumulation and charge decay, which then has an indirect effect on the dynamic characteristics of the surface charge. Charge accumulation decreases with the increase of temperature, and both accumulation process and decay process occurred simultaneously. The results of this study provide theoretical support for the modification of PI backsheet. At the same time, a practical theoretical method for modeling and simulating the charge diffusion of insulating PI backsheet under the influence of temperature was explored.
Surface charge accumulation and pre‐flashover characteristics induced by metal particles on the insulator surfaces of 1100 kV GILs under AC voltage
