Research on the compatibility between eco-friendly insulating medium C5F10O and sealing material EPDM

C5F10O is a promising eco-friendly substitute for insulating gas SF6 in gas insulated switchgear. Existing research has verified the application feasibility of C5F10O in terms of dielectric strength, but the compatibility of C5F10O with the sealing material ethylene-propylene-diene monomer (EPDM) still remains to be tested. In this paper, a 28-day thermal accelerated aging experiment was carried out to study the deterioration behavior of C5F10O/N2 and EPDM under long-term coexistence conditions. The compressive modulus of EPDM and the composition changes of C5F10O/N2 mixture were then determined to evaluate their compatibility with each other. The results showed that C5F10O was significantly decomposed after contacting with EPDM, and the decomposition products mainly included CO, CO2, C3F6, C3F7H and C5F10O, among which C3F6 and C3F7H had the highest concentration. Moreover, in C5F10O/N2 environment, the compressive modulus of EPDM also decreased significantly compared to that in pure N2 environment. Therefore, EPDM has poor compatibility with C5F10O. In the application of C5F10O as an insulation medium, special attention should be paid to the air tightness of the gas chamber, and the maintenance cycle of the sealing material of the equipment should be shortened accordingly.