Innovation as a key differentiator: developing more eco-efficient switchgear

2015-08-24 - For decades, sulfur hexafluoride (SF6) has been the predominant insulation medium for switchgear, due to its technical properties. Thanks to years of research, ABB has already developed and deployed multiple alternatives to this greenhouse gas with the aim of lowering environmental impact. The world’s first gas-insulated switchgear (GIS) installation with a new eco-efficient gas was recently commissioned in August 2015, and is a good example of how product innovation, a pillar of ABB’s Next Level strategy, can support sustainability.

“For decades, researchers and scientists have been searching for alternatives that can still fulfil the technical requirements of SF6 but with a lower environmental impact. That is basically our driving force,” says Gerhard Salge, Head of Technology for ABB’s Power Products division. Due to its excellent properties as an electric insulator, SF6 is used extensively as the dielectric medium in high and medium-voltage switchgear. In addition to enabling safe and reliable operation, it has also made it possible to significantly reduce the size of switchgear installations.

However, SF6 is a greenhouse gas and its lifecycle management requires careful handling and can entail substantial costs. As the demand for electricity rises worldwide, especially in emerging countries, demand for switchgear is also rising, prompting the ongoing research efforts to find alternatives to SF6 and mitigate environmental impact.

The use of atmospheric components

One alternative that has been developed and deployed is to use carbon dioxide (CO2) as the insulation medium. While CO2 is also a greenhouse gas, its Global Warming Potential (GWP)* is lower than that of SF6 by almost 100 percent. ABB offers the high-voltage LTA, a scalable platform which uses CO₂ as the insulation and arc-interruption medium for live tank and disconnecting circuit-breakers. A pilot project at 145 kV has been running successfully since 2010 and other installations are also in progress, including one recently completed in Sweden for European utility E.ON.

Another alternative is to use dry air as the insulation gas. ABB has developed a ring main unit (RMU) – called SafeRing Air – as part of its medium-voltage switchgear offering. This is as compact as the traditional SF6 insulated RMU but uses an insulating gas that consists of atmospheric components, thus avoiding intensive use of epoxy materials. SafeRing Air is available for up to 12 kV in circuit breaker and load-break switch configurations and is ideal for use in compact secondary substations, light industry, building and infrastructure applications.

Pioneering another world first – the latest breakthrough

ABB has now achieved another breakthrough with a new alternative to SF6 by commissioning the world’s first high- and medium-voltage pilot GIS installation with a new eco-efficient gas mixture. This fluoroketone-based gas mixture is a chemical compound developed for switchgear applications in collaboration with 3M. Its GWP is almost 100 percent lower than that of SF6, without any compromise on equipment quality and reliability. The GIS bays are installed in a pilot substation in Zurich operated by leading Swiss utility ewz.

Commenting on this breakthrough, Salge adds, “We see technology development and innovation as a key differentiator to maintain and further build on our market and technology leadership. This is one element which demonstrates how we further build on our leadership and it is in perfect alignment with Power Products’ and ABB’s Next Level strategy.”

* GWP: The global warming potential describes how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide. GWP is expressed as a factor of carbon dioxide.

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