# Analysis on Temperature Distribution and Current-Carrying Capacity of GIL Filled with Fluoronitriles-CO2 Gas Mixture

• Chen, Geng ;
• Tu, Youping ;
• Wang, Cong ;
• Cheng, Yi ;
• Jiang, Han ;
• Zhou, Hongyang ;
• Jin, Hua
• Accepted : 2018.04.25
• Published : 2018.11.01
• 43 10

#### Abstract

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.

#### Keywords

Gas-insulated transmission line;Fluoronitriles-$CO_2$ gas mixture;Thermal field calculation;Current-carrying capacity

#### Acknowledgement

Supported by : Central Universities