How to size the down-leader cable between the Lightning Arrester and Surge counter

[himmelstern]

Hi; I wanted to know how the size of the down-leader cable connecting the Lightning Arrester and Surge (strike) counter Monitor for a HV Substation. I have a 400 kV 20kA Lightning Arrestor supplied with a Surge Monitor.

How is chosen this cable size and their insulation for it? that cable works only in transient state when a lightning discharge occurrs. The magnitude of lightning surge current is huge and their respective voltage; but the duration is in micro-seconds order. So; the requirement here is that the conductor has to withstand the surge thermally as well as mechanically (electrodynamic forces). the same is for the isulation for the conductor; it work in a transient period. How is calculated flashover voltage phenomenafor a cable.

Thanks

[mukhriz]

nice topic

[himmelstern]

I think the solution is on the following attachments.

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

[ionioni]

imo the solution is the one mukhriz told you: to ask them
especially on HV (expensive) area i had no problems with getting the details i needed