Investigation on dielectrical and space charge characteristics of peek insulation used in aerospace high-voltage system

Because of the insulation issue in the high-voltage system of spacecrafts, the dielectric and space charge characteristics of polyether-ether-ketone (PEEK) insulating material are studied in this paper. The electric conduction, trap parameters and space charge characteristic of PEEK, especially the space charge distribution after 50 keV high-energy electron radiation, are measured and analyzed, respectively. From the test results, a low DC conductivity (similar to 10(-16) S/cm) and an activation energy of 0.1-0.2 eV are estimated. It indicates that the conductivity is insensitive to the temperature. In addition, a deep chemical trap (2 eV) is evaluated in the PEEK sample. The slight space charge accumulation and the high threshold field for charge injection of the PEEK sample are dominated by the pulsed electro-acoustic (PEA) results. Compared to the polyimide sample (PI), the space charge accumulations are lower in PEEK, and the charge dispersions in the PEEK after irradiation are faster than those in PI. Based on the experimental results, it can be inferred that the space charge properties are ascribed to the deep traps. From the microstructure analysis, it can be seen that the benzene ring and carbonyl group in the PEEK chemical structure would introduce deep traps, resulting in a higher injection barrier and less space charge accumulation. The results show that PEEK sample is a superior insulating material, and the excellent dielectric and space charge characteristics are beneficial for application in spacecraft. (c) 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.