What are the structures and principles of the four lightning protection devices?

As follows:

(1) Lightning rod

Lightning rods are generally made of galvanized round steel or galvanized welded steel pipes. It is usually installed on the frame, pillar or building, and its lower end is welded to the grounding device through down conductors. Since the lightning rod is higher than the protected object and directly connected to the earth, when the leader of the thundercloud approaches, the electric field intensity between it and the thundercloud is the largest, so the path of thundercloud discharge can be attracted to the lightning rod itself and passed through the down conductor and The grounding device safely discharges the lightning current into the earth to protect the protected objects from direct lightning strikes.

The protection range of a lightning rod is expressed by the space it can protect from direct lightning strikes. The lightning rod protection range is calculated according to the method specified in GB50057-1994 "Lightning Protection Design Code for Buildings".

(2) Lightning protection wire

Lightning protection wires are installed on overhead lines to protect overhead lines or other objects (including buildings) from direct lightning strikes. Since the lightning protection wire is both overhead and grounded, it is also called an overhead ground wire. The principle and function of lightning protection wires are basically the same as lightning rods, and their protection range is calculated according to the method specified in GB50057-2000 "Lightning Protection Design Code for Buildings".

(3) Lightning protection belts and lightning protection nets

Lightning protection belts and lightning protection nets are generally used to protect taller buildings from lightning strikes. Lightning protection strips are generally installed along the perimeter of the roof, 100mm to 150mm above the roof, and support a distance between cards of 1m to 1.5m. In addition to being installed around the roof, the lightning protection net is also connected vertically and horizontally with round steel or flat steel to form a net on the roof when necessary. Lightning protection belts and lightning protection nets must be reliably connected to the grounding device through down conductors.