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Lightning Protection Measures

What is lightning?

Lightning is an instantaneous spark discharge that is created between the negative(-) and positive(+) discharges that are separated and condensed in thundercloud, or between the discharge in thundercloud and discharge on the ground surface, and is also called thunderbolt or ground discharge. About 80% of lightning occurs inside the cloud or between clouds, and only 20% occurs between the cloud and ground surface.

Active thunderclouds constantly repeat these Spark discharge,
and sufficient separation of discharges are occurring constantly.

Positive(+) discharge is widely spread at the upper side of the cloud and
negative(-) discharge is usually distributed at the bottom of the cloud.

Size and nature of thundercloud

Height of the lowest part of thundercloud from ground(km): Summer 1.2/Winter 0.3

Voltage (MV): Summer approx. 102 / Winter approx. 10~102

Electric charge (C): Summer 0.2~(2.5)~20/ Winter 0.1~(3.5)~3x10

Electrostatic energy(kJ): Summer approx. 10°/ Winter approx. 102~102

Structure of thundercloud

The upper part of the thundercloud consists of positive (+) charge and ice crystals, and has cold and dense air.

The lower part of the thundercloud consists of negative (+) charge and waterdrops, and has warm and humid air.

1Intra cloud or cloud discharge: Discharge that occurs between (+) and (-) of the same cloud

2Cloud to cloud to cloud discharge: Discharge that occurs between (+) and (-) of different clouds

3Air discharge: Discharge that occurs between cloud and clear air

4Cloud to ground discharge or ground discharge) Discharge that occurs between cloud discharge and ground discharge

Ascending current

Rain