Lightning Protection for Solar Farms

01/04/2023

Introduction:

Lightning is one of the most destructive phenomena of nature. It can cause damage to humans, structures, electrical and electronics equipment. Currently, due to global warOming, the entire world is moving towards Renewable Energy, and Solar Panels are at high risk due to the possibility of destruction by lightning strikes because of its elevation and the wide spread vacant land areas chosen for the installation of such structures. Redesigning or modification of Lightning Protection System post the installation of these structures isn't advisable as it would attract heavy expenses and hence a properly designed LPS as per relevant standards mandatory. Lightning could strike and cause damage to the solar panels either directly or indirectly. External protection of solar panel against direct lightning strikes needs an air terminal to intercept the lightning strike, a down conductor to provide a dedicated path and an efficient earthing system to dissipate the lightning current in to the earth. The internal protection of solar panels needs an appropriate surge protection device to protect these solar panels from getting damaged from a surge current caused due to lightning strikes.

The external lightning protection shall be provided by any of the following two methods.

1) Non-Isolated Lightning Protection System

2) Isolated Lightning Protection System

Non-Isolated Lightning Protection System:

Reference: NBC 2016 Part 8 Clause 11.5.1.7

Air terminal height: less than 0.5m

Positioning method: Rolling Sphere Method

Max. distance between air terminals: 15m

Protected Region: (12X9) m using 2 air terminals.

As the influence of the shadow of Lightning arrestor arrangement on the solar panel could hamper the performance of the entire solar system, the height of the LA should be restricted to less than 0.5m above the solar panel.

Isolated Lightning Protection System:

Reference: NFC 17-102/2011

Air terminal height: > 5m above solar panels

Radius of Protection: 107m

As we said early, the shadow effect of the solar panel arrangement could affect the performance of entire solar panel. So, we will maintain safe separation distance between LPS and solar panel for avoiding those effects. This separation distance between the solar panel and the Lightning Protection System shall be calculated based on the following parameters.