Question about lightining arresters....?

Question

Givin that lightning arresters help protect live wires on power lines from lightning strikes, what method of lightning arrester installation would be more economical and effecient in protecting damage to the power grid from lightning strikes?.....

Fewer lightning arresters installed on few poles but are larger and can handle more lightning capacity?

or

more lightning arresters installed on more of the poles but smaller and can handle less lightning capacity?

Answer 1

The number and rating of arresters is determined by the equipment being protected and the probability of overvoltage events.

We do use a variety of techniques and configurations, depending on local practices and experience.

But, here's a fundamental point to realize:  It is very difficult to apply arresters in parallel and get them to share discharge current consistently proportionately.  Usually, the weakest, lowest rated arrester gets blasted while the rest of them loaf along.

Also, note that flashover of air-insulated systems, like overhead lines, don't usually result in significant damage.  But, other insulation systems, such as underground cables, transformers, motors, etc. must be protected, so the arresters are applied adjacent to this equipment.