The compatibility between environmental-friendly insulation gas C4F7N with alumina and zinc oxide: A comparative study

Abstract

C4F7N has showed much importance as one of the most promising environmentally friendly gases to submit SF6 in power industry, due to its good dielectric strength and environmental characteristics. Zinc and aluminum are both frequently-used metal material in GIS as construction and coating. Since the presence of water and oxygen, which is hard to avoid during manufacture and operation, the metal may be oxidized. Meanwhile, Aluminum oxide has been widely used as insulation materials, of which the stability when exposed in C4F7N is very important for the long-term stable operation of electrical equipment. Therefore, the compatibility between insulation gas C4F7N with alumina and zinc oxide need to be carefully verified for the engineering application of the novel gas. In this article, the compatibility was studied by both thermal compatibility experiments and density functional theory calculation. The thermal ageing test were performed, and the scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) analysis were used on the solid powders. In the meantime, the adsorption energy, total charge transfer, density of states and electron density difference of the gas molecular on solid surface were calculated to evaluate their interactions. The results demonstrate that C4F7N shows certain compatibility with the two metal oxide.