Lightning Protection

Lightning

Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions in the atmosphere or ground temporarily equalize themselves, causing the instantaneous release of as much as one gigajoule of energy.

A lightning strike or lightning bolt is an electric discharge between the atmosphere and the ground. They mostly originate in a cumulonimbus cloud and terminate on the ground, called cloud to ground lightning

A Lighting Protection System (LPS) is the system that provides a means by which a lightning discharge may enter or leave earth without passing through and damaging personnel, structures such as buildings and electrical equipment. A Lightning Protection System does not prevent lightning from striking. It provides a means for controlling energy and prevents damage by providing a low resistance path for the lightning. They LPS has been categorized into four classes (Level - I, II, III, IV). The class of LPS used for the structure is selected corresponding to the Lightning Protection Level (LPL) required for that structure. LPL is determined by carrying out the risk assessment as per IEC 62305-2. The four corresponding LPL (I, II, III, IV) are based on fixed minimum and maximum lightning current parameters for each level.

A lightning protection system consists of three parts-

(a) intercept a lightning flash to the structure (with an air-termination system),

(b) conduct the lightning current safely towards earth (using a down-conductor system), and

Indian Standards for Lightning protection & Earthing-