By Brighton Mwarehwa, Offer and Marketing Director, Power Systems at Schneider Electric

Switchgear is everywhere. It is an essential component of the electrical grid, industrial applications, and large buildings.  It would be safe to say there are millions of switchgear products installed across the globe, and of many of these use sulphur hexafluorides (SF6) as an insulating and breaking medium.

SF6 is a man-made gas that has for decades been used in among others medium voltage (MV) switchgear.  As an insulating and breaking medium SF6 has proved its superior capabilities over the years.  It is also inert, non-flammable and non-toxic and allows to reduce the physical footprint of switchgear, due to its insulating properties,

Unfortunately, SF6 comes with a serious drawback, its impact on climate change.  Its global warming potential (GWP) is 23,500 times greater than that of CO2. The GWP metric was developed to compare gasses’ global warming impact and in essence measures how greenhouse gas is trapped in the atmosphere.  In the case of SF6 GWP, we need to consider these implications and transition to more eco-friendly solutions.

Put in layman’s terms, a typical building switchgear installation, has an average of 1 kg of SF6 inside it. If 1kg had to be released into atmosphere, it would have the same potential environmental impact as driving a car for about 200,000 kilometres.

SF6 is one of six greenhouse gasses that have been identified by the Kyoto Protocol as a major contributor to climate change. Also, the European Commission recently proposed to move the electricity industry away from the use of fluorinated greenhouse gases.  

The air we breath

Pure air provides the perfect replacement for greenhouse gases.  Its GWP is non-existent and its environmental safety unquestionable.

We breathe air every day so pure air requires no gas recycling or special handling. The same cannot be said of SF6 or other man-made gases. When an SF6 switchgear unit reaches the end of its operational life, the gas needs to be recaptured, reprocessed, and reused.

It also must be handled within a closed system until the end of its lifecycle to reduce potential leakage and its environmental impact. With pure air, no such concern exists.

Pure Air – advantages aplenty 

Schneider Electric’s MV switchgear using pure air offers the optimal alternative to SF6. It replaces SF6 in switchgear by using an innovative combination of vacuum interruption and pure air insulation, each a tested and trusted technology. 

Moreover, SF6-free pure air switchgear continuously offers compact physical footprint and is operated in the same way as our SF6-based equipment, which means minimum retraining is required.

Importantly end users can obtain pure air by simply filtering ambient air – they no longer have to use expensive, proprietary gasses.  The ROI on pure air MV switchgear is therefore swift and significant.

In a nutshell, pure air in MV switchgear offers the following important advantages:

·         Environmental friendliness; 

·         People safety; 

·         Ease of operation;

·         Compact footprint;

·         Interchangeability with the currently used SF6 switchgear units (eg - SM AirSeT);

·         No need for end-of-life gas recovery; and

·         Long-life expectancy.