Hello all,

I have a query regarding arc flash assessment in GIS. If I can get help with it, please.
1. How do we perform arc flash calculations for higher voltages, for GIS applications such as 66 kV GIS and 400 kV GIS? This is the area where people go for a routine inspection - once in 3 months.
2. Although some software tools use Lee's formula to calculate the arc flash calculations for higher voltages, is it appropriate to use Lee's formula for GIS.
3. Shall we use a risk assessment approach for 66 kV and 400 kV GIS applications.
Thanks and regards.

The Lee equations were a good first attempt back in the 1980's however they greatly overpredict at higher voltages. In fact, the 2018 Edition of IEEE 1584 no longer references the Lee equations. There are a few alternatives: The 2023 National Electrical Safety Code has tables based on fault current and voltage to determine PPE ratings. Arc Pro is a commercial program by Kinectrics in Ontario that is referenced in the NESC and OSHA 1910.269, ETAP has a model for arc flash above 15 kV as well.

Quite a few options but I would avoid the Lee equations based on what we have learned over the past several decades.

Thank you very much for your reply, I appreciate your quick response.

Best regards,
Rupali

What energized work is done with a GIS? Does it involve exposed energized parts?

I was wondering that myself but answered based on energized work above 15 kV

Thank you very much for your response.

There are no exposed energised parts, it is a standard enclosed 66 kV Gas insulated switchgear in an offshore windfarm project. The project is still at the design stage, hence make/model is not yet decided. People will not carry out any work during the energising condition, however, they will have an access to the GIS room for a normal routine inspection. Maintenance work will be only carried out only when it is de-energised.
There will be another GIS in the room that may be energised while maintenance is carried out on another de-energised GIS.

I would also appreciate it if there are any papers/literature available on this subject.

Many thanks.

Best regards,
Rupali