Summary
In the past decades, SF6 technology has enabled reliable, compact, and scalable gas-insulated high-voltage equipment for the power grid. The high global warming potential of SF6 has been recognized while the impacts of climate change have become increasingly evident. Reducing equivalent carbon emissions to limit global warming and achieving net-zero carbon emissions is a globally imperative subject to increasingly stringent legislation, regulation, and financial incentives. In this context, gas-insulated high-voltage equipment owners require solutions that minimize the use and emissions of SF6 for new and existing installations.
Read more Read lessIn recent years, the development and deployment of SF6-free solutions for gas-insulated highvoltage equipment at transmission voltages has progressed considerably. Substituting SF6 in installed equipment with a design life of circa 50 years can dramatically reduce damaging emissions cost-effectively by avoiding the costs of continually improving SF6 management for aging assets and/or early asset replacement. To deliver these benefits, retrofill concepts have been developed and fully qualified. SF 6 is replaced on-site with a gas mixture of nitrogen (N2), oxygen (O2), and fluoronitrile (C4-FN), with the high-voltage equipment staying in place. The new mixture has about 99% reduction of
CO2 equivalency compared to SF6. The first 420 kV retrofill gas insulated lines have already been in operation since 2021.
In this paper, we will present an extended development that goes beyond 420 kV GIL to include other 420 kV GIS components, such as disconnectors and earthing switches and 550 kV GIL.
The expanded scope of the retrofill further reduces CO2 equivalency compared to retrofill 420 kV GIL. We are now achieving around 75% reduction of SF6 on average substations and driving eco-efficient solutions for the existing installations. Possible further developments for retrofill in GIL and GIS are under consideration.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | B3_12281_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Switzerland |
| Study committees | |
| File size | 589 KB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
BERNER Pascale - Hitachi Energy Switzerland; CHRISTEN Dennis - Hitachi Energy Switzerland; JORGE Teresa - Hitachi Energy Switzerland; PACHLATKO Samuel - Hitachi Energy Switzerland; STEINEMANN Karin - Hitachi Energy Switzerland; STOECKLI Marcel - ELECTROSUISSE / CIGRE Switzerland NC Secretary
Keywords
SF6 alternatives, GIS, GIL, transmission, disconnector, earthing switch, C4-FN, fluoronitrile, gas handling, retrofill, installed base, gas-insulated switchgear, gas-insulated line
