A new report released by Central Electricity Authority (CEA) observes that a gradual transition to SF6-free GIS technologies can be achieved through a structured implementation approach.
The newly-released “Report of the Committee on Use of Green GIS Technology in Indian Grid” notes that Green GIS technologies, which is sulphur hexafluoride (SF6)-free gas insulated switchgear (GIS), present a promising pathway for reducing environmental impact in the power transmission sector. [The report focuses mainly on use of SF6-free GIS in GIS substations.]
However, what is needed is a structured implementation approach, supported by technology validation, capacity building and domestic capability development. This will lead to a gradual transition from conventional SF6-based GIS to Green GIS.
The report also recommends that the initial deployment of Green GIS technologies be taken up through pilot projects at lower voltage levels, so as to gain operational experience and to validate performance under Indian conditions.
The report also cautions that execution timelines for Green GIS projects may be longer at present due to limited manufacturing base and dependence on imports.
For long-term adoption, development of indigenous manufacturing capability is critical, the report notes. Strengthening domestic manufacturing would help reduce dependency on imports, improve equipment availability, and optimize costs over time. In addition, development of testing infrastructure and standardization framework would support wider adoption and ensure reliability of the technology.
Objective
GIS substations are widely used in the power transmission system due to its compact design, high reliability, and suitability for urban and space-constrained areas. Conventional GIS primarily uses SF₆ gas as the insulating medium, which provides excellent dielectric and arc-quenching properties. However, due to the high global warming potential of SF₆, increasing attention is being given to the development and adoption of alternative insulating technologies at the global level. In this context, Central Electricity Authority (CEA) constituted a technical committee to examine and explore the use of Green GIS in the Indian Grid.
Green GIS Technologies
The report observes that several alternatives to SF6 have been devised by global switchgear manufacturers. These include:
- Fluoronitrile-based gas mixtures (C4-FN + CO2 + O2)
- Vacuum interruption combined with clean air insulation (N2 + O2)
- Mixture of CO2, O2 and N2
Some of the currently available SF6-free GIS technologies are: EconiQ by Hitachi Energy; g3 by GE Vernova; Blue GIS by Siemens Energy; AEROXIA by Toshiba and Hyosung Green GIS, the report notes.
Note: The full report is available on CEA’s official website, and may be accessed using this external link.
Featured photograph (source: GE Vernova) relates to GE Vernova’s SF6-free GIS