World’s First Substation with Eco-Efficient Gas-Insulated Switchgear Commissioned

ABB in August commissioned the world’s first high- and medium-voltage gas-insulated switchgear (GIS) bays that use a new “eco-efficient” gas mixture instead of sulfur hexafluoride, the greenhouse gas that is typically used.

The 170/24-kV switchgear bays were supplied to Swiss utility ewz for a new 3 x 50-megavolt-ampere substation (Figure 5) in Zurich, Switzerland, which supplies electricity to the northern and most populous parts of the city. Located 15 meters underground, the GIS substation replaces an outdoor air-insulated switchgear substation built in 1949, freeing up about 70% of the space occupied by the old substation for other requirements, said ABB.

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5. First of its kind. Swiss utility ewz’s newest megavolt-ampere substation (located 15 meters under this building) in Zurich uses ABB high- and medium-voltage gas-insulated switchgear with new eco-efficient gas. Courtesy: ABB

High- and medium-voltage switchgear is generally installed in power transmission and distribution to help ensure grid reliability, efficiency, and safety. For the power sector, which otherwise uses switchgear throughout its value chain, including for generation, ABB’s breakthrough is significant. The sector has used pressurized sulfur hexafluoride gas for decades for dielectric insulation due to its physical properties. Because it is a greenhouse gas, however, it requires careful handling. This can prove costly, especially when decommissioning aging substations.

The eco-efficient gas is a fluoroketone-based chemical compound developed for switchgear applications in collaboration with 3M. Among its benefits are that its global warming potential is nearly 100% lower than that of sulfur hexafluoride without compromising equipment quality and reliability.

—Sonal Patel is a POWER associate editor.