Substation Lightning Protection

Most important thing about lightning: it always strikes the highest point. Make sure your lightning conductor is located well above your substation and that you have a very good earthing point for it to discharge to.

Lightning does not always strike the highest point. Lightning seeks the easiest path to ground. If you do not have a good path to ground from your highest point, lightning could very easily strike at a lower point.

Hi

Thanks for the reply

Yes it is already low and we have checked touch and step voltage criteria

We have

Angle method for Lightning

Rolling sphere EGM

I need some guidance in rolling sphere if some one can provide suitable height and strike radius information

We started using the "Rolling Sphere Method" of designing just before I escaped from the T&D and switchyard gulag about 20 years ago.

I found this introduction on the web:Surge protection

Glad to have people with huge experince so that we can learn something

Rolling sphere is currently in use by many companies but it is still a mystery

dont know why

Still the question is unanswered

I recently did a pretty in-depth study for two clients experiencing repeated lightning-caused failures. One of the issues I encountered was that the failures of concern appeared to have been caused by "positive" lightning (clouds having positive charge, sucking electrons from the ground), which typically occurs on the trailing edge of the storm rather than the leading edge (something that is not uncommon in this part of the world). After a significant search of available information (on line and off), consultations with industry experts, studying American and Japanese experiments involving "induced lightning" (i.e., firing tethered rockets into thunderheads), I can say with absolute certainty:

Still, the question is unanswered...

If you would be interested in the study I prepared for my clients, send me your e-mail via PM and I will send the document to you...