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Gas-Insulated Lines

Grid Solutions > HV/MV Equipment > Gas-Insulated Substations > Gas-Insulated Lines > g³-GIL

Gas-Insulated Lines
SF₆-free g³ Gas-Insulated Lines
For electrical networks up to 420 kV
Better for the grid, better for the planet
  • SF₆-free with g³, GE's game changing alternative to SF₆ as insulating medium enables a reduction of 99% of global warming potential
  • First-in-class gas sealing system
  • g³-420 kV GIL is a dual gas busbar system also compatible with SF₆. It allows TSO to still use SF₆ while being ready for up-coming regulations.
  • Improved tightness thanks to sealing length divided by 2 compared to previous version
Field-proven experience
  • Design grounded with 50 years of experience acquired with SF₆ gas insulated lines
  • g³ gas–insulated lines were the World first 420 kV SF₆-free GIL on the market (2015) and the first g³ product available on the market
  • Since then, some 10 sites – 5000+ meters
Smart grid features
  • Full-digital monitoring (BWatch and PDWatch monitoring devices)
Gas Masses Comparison

Positive impact of 100 meters SF₆-free GIL

g³ GIL app

Calculate the CO2e reduction of my project with GE's g3 CO2 equivalent calculator

g³ gas GIL Specifications

Voltage kV 362 420
Frequency Hz 50/60 50/60
Withstand voltages, to earth
- Short-duration power-frequency
- Switching impulse
- Lightning impulse

kV (peak)
kV (peak)


Continuous current A 4,000/5,000 4,000/5,000
Short-time withstand current kA 63 63
Peak withstand current kAp 170 170
Temperature °C -30 -25/-30


Sellindge Substation

NATIONAL GRID, UK - Sellindge Substation
230 m of 420 kV GIL, 63 kA, 4000 A
The world first SF₆-free g³ GIL


SSEN TRANSMISSION, UK - New Deer Substation
1020 m of 420 kV GIL, 40 kA, 4000 A
The longest SF₆-free g³ GIL in operation

Sellindge Substation

SP ENERGY NETWORKS, UK - Kilmarnock Substation
177 m of 420 kV SF₆-free g³ GIL, 63 kA, 4000 A