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PuckSR t1_j6t1g6h wrote

Quick explainer: They use sulfur hexafluoride because it prevents arcing.

In electrical equipment, you are always worried about an arc forming at switches. You mitigate this by putting space between the two points. This is true for all electrical equipment, even the light switch in your house. The distance an arc can occur is based on the conductivity of the medium. Air is the medium typically used. But with really high-voltage equipment, you need very large gaps. Alternatively, you can use something different than air. That is where hexafluoride comes into use. It allows us to make much smaller equipment for high voltage, because it is less conductive and therefore needs far less spacing.

The alternative to using hexafluoride are:

  • bigger equipment
  • alternative gases, which are more expensive and more hazardous

Both of those things cost money, so the utility industry hasn't been in a big hurry to fix it. But there is no reason we couldn't use an alternative if it was mandated.

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mooseyontheloosy t1_j6u8w4z wrote

Third alternative: solid dielectric devices, often coupled with vacuum interrupters. Also typically more costly, and introduce some operational/safety concerns (e.g., SF6 and air-insulated switches often have visible gaps, which are desired - and in some cases required - for utility operations. Vacuum interrupters are fully encapsulated, so the open gap is not visible.)

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kruger_bass t1_j6trb0l wrote

The biggest problem would be find a gas that do all that and isn't so problematic for greenhouse effect.

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PuckSR t1_j6u6bf7 wrote

Or just build slightly bigger switchgear and use nitrogen

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jkjm24 t1_j6zeekv wrote

I know Schneider electric has developed LV-MV switchgear that is SF6 free using air under presser insulation and vacuum interruptors in their Aireset range, working with them currently and the airset stuff is definitely picking up more and more over the SF6 stuff as companies look to brand themselves more sustainable and better for the environment, don't know about Hv switchgear much though

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