Performance investigation of
SF6 free Gas Insulated DC Systems

Abstract

To reduce the CO2 emission of electricity generation and transmission, SF6 gas needs to be replaced by more environmentally friendly gas. A solution to replace SF6 in high voltage equipment is the mixture of Fluoronitrile C4F7N with CO2 and O2. In this paper, a choice of insulating gas based on theoretical analysis is mentioned including intrinsic gas properties and also CO2 footprint analysis. Experiments were then realized to verify the thermal and dielectric characteristics of gas mixture in the equipment. Finally, investigation tests were conducted with the actual SF6 design of GIS but filled with the mixture and showed very good performance. The results confirm the feasibility of using C4F7N-CO2-O2 mixture as insulating gas in HVDC GIS.

Caterina TOIGO, Cong Thanh VU, Frank JACQUIER, Alain GIRODET

Presented at MATPOST 2023