The variation of C4F7N, C5F10O, and their decomposition components in breakdown under different pressures

Yuwei Fu,Chi Chen,Tingting Wang,Chuang Wang,Zaiqin Zhang,Bing Luo,Lei Yang

doi:10.1063/5.0055221

Yuwei Fu, Chi Chen + Show 5 more

Open Access

https://doi.org/10.1063/5.0055221

Copy DOI

Abstract

The decomposition characteristics of C4F7N and C5F10O are basic to understand their insulating and arc-quenching performance, and the decomposition products are related to the equipment discharge fault and insulation state. A chemical kinetic model is employed to study the variation of C4F7N, C5F10O, and their decomposition components under different pressures. The results show that the molar fraction and recombination rate of C5F10O are higher than those of C4F7N, and high pressure has larger influence on the molar fraction and recovery rate of C5F10O than those of C4F7N, so C5F10O presents a better molecular recovery characteristic and dielectric strength than C4F7N at high pressures.

Highlights

SF6 is widely used in electrical equipment as an insulation and arc extinguishing medium, its greenhouse effect potential is too high (GWP ≈ 23 500), so it needs to be restricted.1 it has become a hotspot to find SF6 substitute gas and develop environmentally friendly electrical equipment
C4F7N and C5F10O are considered as the potential SF6 alternative gases, and environmentally friendly electrical equipment insulated by C4F7N or C5F10O has broad application prospects in green power grids
The chemical kinetic model, which was fully introduced in the work of Wang,5 is adopted to calculate the variation characteristics of C4F7N and C5F10O decomposition components during the breakdown process

Summary

INTRODUCTION

SF6 is widely used in electrical equipment as an insulation and arc extinguishing medium, its greenhouse effect potential is too high (GWP ≈ 23 500), so it needs to be restricted. it has become a hotspot to find SF6 substitute gas and develop environmentally friendly electrical equipment. In the process of product formation, the high energy electrons and high temperature environment caused by discharge fault act on the gas insulating medium, which makes the electron temperature deviate from the heavy particle temperature, and the relaxation time of the chemical reaction is greater than the characteristic time of particle convection, diffusion, and other transient processes, resulting in the system deviating from the local thermodynamic equilibrium and chemical equilibrium at the same time. Van Brunt revealed the formation mechanism of SF6 partial discharge gas components using a chemical kinetic model, but ignored the non-thermodynamic equilibrium effect, and the chemical reaction considered was not comprehensive, and some rate coefficients were obtained by estimation. Wang used electron density to describe the quantitative relationship between the electron temperature and the heavy particle temperature and used a non-equilibrium chemical kinetic model to study the formation mechanism of SF6 arc fault. The decomposition characteristics of C4F7N and C5F10O are seldom reported, the basic parameters of a chemical kinetic model have been revealed. This work can lay a theoretical basis for environmentally friendly power equipment

CALCULATION METHOD

RESULTS AND DISCUSSION

CONCLUSION