Lightning protection of power plant

[SA07]

Hi

We are a power plant. Since construction, lightning rod were installed on the boiler, substation 66 kV, lightning arresters on 66 kV lines and earth cables over 66 kV transmission lines. Over time 2 additional small power plants were constructed. They are not sufficiently protected against lightning.

We want to do a study for lightning protection of the whole site.
Should we first do a study with a company specialist in lightning protection or can we work directly with manufacturers of lightning protection equipment?
If we make a 3D autocad drawing of the whole site and send to the manufacturers will this be ok?

Is the earth network of the whole site required?

Some french companies have told us we must do the following. I do not have exact English translation

ARF : Analyse du Risque Foudre
ETF: Étude Technique Foudre 

analyse: analysis
risque: risk
foudre: lightning
etude: study
technique: technical

Is this the correct way to do it?

During construction, there were many contractors working on site. Due to various reasons, there was not a correct handing over of all documents, etc.

We do not have a wiring for the whole earthing network. Is there a special equipment that is used to determine the earthing network? Or it should be done manually by someone?

We can see earth cable coming out of the ground and connected to earth busbars at various places all round the site. And cables interconnecting all the points.
Thank you

 

[FacEngrPE]

Making a map of a buried earthing network is possible using underground utility location equipment that includes a signal injector. The locator operator marks found items on on the ground with marker paint, and a surveyor follows and makes a map of all of the marks.
In my part of the world this is part of the requirements for developing a pre construction site survey.

This information is a necessary input to a study that will expand your grounding grid, or this map could be made a study deliverable.

Your proposed study approach seems to originate from a document like this

https://france.apave.com/prestation/analyse-du-risque-foudre-arf

which using the browser translator seems to be a generally reasonable approach.

I recommend also reviewing NFPA 780 (useful material can be found here)
and IEC/BS EN 62305 Useful material here

Both codes present a assessment approach.

You might get acceptable results just working with a manufacturer, but usually having a local professional engineer involved gets better and sometimes less costly results.

 

[SA07]

Thank you FacEngrPE for detailed explanation and links