Lightning Protection

Lightning Protection:

Lighting is an electrical discharge in the air between clouds between clouds, between different charge centre within the same cloud, or between cloud and earth. Even through more discharges occur between or within clouds, there are enough strokes that terminate on the earth to cause problems to power systems and sensitive electronic equipment.

Lightning protection methods are

^ü   Shielding and surge arresters

^ü   Transmission line arresters

Shielding and surge arresters:

Shield  wire  and  surge  arresters  play  a  significant  role  for  protecting  overhead

distribution lines. The line with shield wire can reduce the number of flashovers in open ground and number of flashovers than shield wire. The application of surge arresters provides better performance than shield wire.

Provides both shielding and Surge arresters:

^ü   Minimize the possibility of direct lightning strike to bus and major equipments in the substation and hence the outage and possible failure of major electrical equipment.

^ü   Shielding may allow some smaller strokes to strike the bus work and equipment. Even though these strokes may not cause flash over they may damage internal insulation systems of transformer, etc… unless they have proper surge arresters mounted at their terminals.

^ü   Surge arresters will provide coordinated protection from lightning and switching surges.