Study of the Dielectric Strength of SF6-N2 Mixtures at elevated temperatures

• Published in: 2024 7th International Conference on Energy, Electrical and Power Engineering (CEEPE) pp. 311 - 315
• Main Authors: Zhong, Yao, Yang, Weihong, Xu, Kui, Chen, Peilong, Li, Xin, Yao, Yuyang
• Format: Conference Proceeding
• Language: English
• Published: IEEE 26.04.2024
• Subjects: Boltzmann equation; environmentally friendly; Gases; hot SF 6 -N 2 mixture gases; Industries; Insulation; insulation performance; Ionization; Power engineering; Sulfur hexafluoride
• DOI: 10.1109/CEEPE62022.2024.10586477

Sulfur hexafluoride (SF 6 ) is widely applied in the electric power industry. However, it has also brought serious environmental problems. Since there is no good alternative gas for SF 6 , SF 6 -N 2 is studied in this paper. The insulation performance of 20% SF 6 - 80% N 2 , 28% SF 6 - 72% N 2 , 40% SF 6 - 60% N 2 at different pressure and temperature were studied. The compositions of different ratios of SF 6 -N 2 mixtures under different conditions were obtained by using the minimizing the Gibbs free energy. The electron energy distribution function then was calculated by solving Boltzmann equations. The critical reduced electric field strength was obtained when the effective ionization coefficient was equal to 0. Before 1500 K, 40% SF 6 -60% N 2 had the largest (E/N) cr , 28% SF 6 - 72% N 2 followed, and 20% SF 6 - 80% N 2 had the smallest (E/N) cr . With temperature increasing, the (E/N) cr of gas mixtures decreases rapidly. The (E/N) cr after 2000 K is opposite to that before 1500 K. The research results provide fundamental theoretical data for SF 6 -N 2 post-arc breakdown and are of guidance for SF 6 -N 2 engineering applications and equipment design.