Numerical Simulation of the Discharge Dynamics of C₄F₇N-N₂ and the Influence of Buffer Gas

Due to the greenhouse effect of SF
₆
, the search for new environmentally friendly substitute gases has become an urgent task for the electrical industry. In this article, we have employed a 2-D fluid model to study the characteristic of streamer discharges in the C
₄
F
₇
N-N
₂
mixture. The discharge process and insulation performance of the C
₄
F
₇
N-N
₂
mixture with different C
₄
F
₇
N content are compared under the same conditions. In a5.07% C
₄
F
₇
N-N
₂
mixture, the streamer expands continuously and reaches the top boundary quickly. In 7% and 13.1% C
₄
F
₇
N-N
₂
mixture, the streamer is gradually stagnated in the simulation domain. The streamer radius shows a decreasing trend, and a low electron density area appears behind the streamer head as the streamer moves forward. The streamer discharge simulation in 50% SF
₆
-50% N
₂
is also performed to compare its insulation performance to the C
₄
F
₇
N-N
₂
mixture. The results show that the discharge is suppressed more heavily in 13.1% C
₄
F
₇
N-N
₂
than in 50% SF
₆
-50% N
₂
. The influence of buffer gas is studied by comparing the discharge process in C
₄
F
₇
N-N
₂
and C
₄
F
₇
N-CO
₂
with 13.1% C
₄
F
₇
N content. It is found that the discharge is more easily to a breakdown in C
₄
F
₇
N-CO
₂
than that in C
₄
F
₇
N-N
₂
in our simulation configuration. The simulation provides a way to optimizing the buffer gas ratio of new environmentally friendly gases from a microscopic perspective.