Effect of Electron Irradiation and Operating Voltage on the Deep Dielectric Charging Characteristics of Polyimide

Space Solar Power Station (SSPS) will operate in geosynchronous orbit. Its operating environment is rather complicated, including space plasma, energetic particles radiation, extreme temperature, and cosmic rays. To reduce power loss, SSPS has to apply high-voltage (HV) power generation and transmission technique. Deep dielectric charging will be a major problem in the design of insulation structure in SSPS. In this paper, the hopping conductivity of polyimide was studied. Hopping distance and hopping barrier height were obtained from surface potential decay analysis. Second, a deep dielectric charging model of polyimide under FLUMIC spectrum electron irradiation was established, in which the hopping conductivity parameters were applied. The effects of electron flux enhancement and operating voltage on the charging characteristics were discussed in four cases, i.e., A) suspended-HV; B) HV-suspended; C) grounded-HV; and D) HV-grounded. When the electron flux enhancement increases, the influence on case A is much larger than the other three cases. When the operating voltage increases, the influence on cases A and B is small, whereas the influence on cases C and D increases fast. Thus, when designing the SSPS, the effect of operating voltage and electron flux enhancement on the insulation system must be carefully considered.