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Customer Success Story

ewz Oerlikon substation, Switzerland

World's first gas-insulated switchgear installation with eco-efficient gas mixture

Hitachi Energy has commissioned the world’s first high-voltage and medium-voltage gas-insulated switchgear (GIS) installation with a new eco-efficient gas mixture as an alternative to sulfur hexafluoride (SF6) gas for ewz, a power utility in Switzerland.

The 170 kV substation deploys the first breakthrough GIS with an eco-efficient gas mixture with a global warming potential (GWP) of less than 1 as an alternative to SF6 gas.

Located in the heart of Zurich, 15 meters underground in a beautifully designed building, it replaces an outdoor air-insulated switchgear (AIS) substation built-in 1949. The new substation takes up only 30 percent of the originally used space, thus freeing up land for other city requirements and enhancing the aesthetics of the cityscape. 

With the deployment of high-voltage GIS with the eco-efficient gas mixture, carbon dioxide (CO2) equivalent emissions can be lowered by up to 50 percent through the lifecycle of the equipment.

Main data
Year of installation 2015
Type of switchgear ELK-14
(eco-efficient gas mixture)
Rated voltage 170 kV
Rated current 1250 A
Rated frequency 50 Hz
Short-circuit current 40 kA