TSO perspectives on 40 years of GIS evolution, SF6 alternatives strategies and technical specifications recommendations

During the last 40 years, Gas Insulated Switchgear technology has evolved. The years 2020’s, will see another major turn in the GIS evolution with a new type of technology using alternative gas to SF6. The four authors are employed from four different TSOs (Hydro Quebec, RTE, Terna and Statnett). Even though each company have different requirements (type of network, frequency, layout, architecture, and climatic environments), all four have a long history with GIS products, and share many similar problematics as well as common understanding of technical requirements. The paper will first be describing the evolutions of GIS through the last 40 years. Footprint evolution, gas mass and gas pressure evolutions, interface compatibility, leakage rate evolutions and gas compartment issues are presented and discussed. End-user issues related to the complexity to gas compartment and mechanical work in a vicinity of a close barrier fully pressurized, as well as non-intrusive diagnostic methods, are described. Reflections on the consequences of using SF6 alternatives are presented by the authors. Finally, the last chapter of this paper highlights the authors companies' requirements and recommendations regarding type testing and routine tests. The four authors also present companies' objectives and visions on how the grid decarbonization road maps will be implemented. Example on how to evaluate different SF6 free solutions are discussed. Concrete plans and actions to address the reduction of greenhouse gas emissions from authors companies' activities are described with the corresponding time frame.