Insulation Properties of Liquid C6F12O for the Use in Eco-Friendly Transmission Equipment

Abstract

In order to investigate the possibility to use liquid C 6 F 12 O as a SF 6 substitute for environment protection and the influence of C 6 F 12 O liquefaction in gas mixtures on electric field distortion, the insulation and dielectric properties of liquid C 6 F 12 O are tested by AC break down experiments and broad dielectric spectroscopy (BDS). For analyzing and discussing the experiment results, the molecule parameters (e.g. geometry parameters, potential energy, dipole moment) of C 6 F 12 O, SF 6 and main components in insulation oil are calculated by density functional theory (DFT), Becke, Three-Parameter, Lee-Yang-Parr (B3LYP) method, and 6-311g** basis sets. The results show that, the insulation property of liquid C 6 F 12 O is sensitive to electric field strength. And it is about 3 and 0.55 times that of SF 6 (1 atm) and insulation oil respectively, which is mainly attribute to the molecule geometry size. The permittivity e r and tanδ of liquid C 6 F 12 O are about 4 times that of insulation oil, due to its higher dipole moment of 0.79 Debye and lower resistivity. The high e r may lead electric field distortion and flashover easily. Since the higher insulation property of liquid C 6 F 12 O, it may be used as SF 6 substitute in transmission line. Besides, based on its low freezing point, high clean ability, strong flame extinguishing ability and large e r , the liquid C 6 F 12 O still has potential application prospects in power capacitors or circuit breakers at low temperature.