As we all know, lightning is extremely destructive, its voltage is as high as millions of volts, and the instantaneous current can be as high as hundreds of thousands of amperes. The destructive consequences of lightning strikes are reflected in the following three levels:

① Equipment damage, casualties;

②The service life of equipment or components is reduced;

③ The transmitted or stored signals and data (analog or digital) are interfered or lost, and even cause the electronic equipment to malfunction and temporarily paralyze or the entire system stops.

Ⅰ. Direct lightning strike: Lightning strikes directly on the camera in the open air, causing equipment damage or lightning strikes directly on the overhead cables, causing cable damage. The damage caused by this lightning strike is more serious, but the probability of occurrence is relatively small.

Ⅱ. Induction thunder: also known as secondary thunder, it is divided into electromagnetic induction and electrostatic induction. When a lightning strike flashes down in the nearby area, a strong transient electromagnetic field will be generated around the passageway where the lightning strike is implemented. The monitoring equipment and transmission lines in the electromagnetic field will induce a large electromotive force. This phenomenon is called electromagnetic induction; when there is a charged thundercloud, it will be induced on the buildings and transmission lines under the thundercloud. The opposite charge, this phenomenon is called electrostatic induction. The equipment damage caused by induction thunder is not as large as the damage caused by direct lightning strike, but the probability of occurrence is very high, accounting for more than 80% of modern lightning accidents.

Ⅲ. Lightning intrusion wave: When the power cord, signal transmission line or other metal cables of the monitoring system are struck by lightning or are induced by lightning, the lightning wave will invade the equipment along these metal wires/conductors, resulting in high potential difference and damage to the equipment.