Lightning is one of the main natural disasters. In summer, thunderstorms are frequent, and lightning flashes across the sky, and the thunderous thunder is even more creepy. According to incomplete statistics, there are about 10,000 casualties per year caused by lightning strikes worldwide. Therefore, it is necessary for each of us to understand the thunderstorm weather safety knowledge and thunderstorm weather precautions. Thunderstorm weather safety knowledge is the basic common sense that everyone should meet. We must widely publicize to avoid unnecessary losses, and to schools, streets, etc. To be popular, safety is above everything else, we must learn to protect ourselves during thunderstorms.
The main features of lightning:
1. short discharge time, generally about 50-100 microseconds.
2. The inrush current is large, and its current can be as high as tens of thousands to hundreds of thousands of amps.
3. The surge voltage is high, and the induced voltage can be as high as 10,000 volts.
4. The release of thermal energy is large, and the local air temperature is raised to several thousand degrees or more in an instant.
5. The impact pressure generated is large, and the pressure of the air can be as high as several tens of atmospheres. Therefore, the lightning electrode has a destructive force.
Direct lightning strikes generally have two forms:
Direct lightning strikes (including lightning strikes and lightning strikes): In the lightning activity zone, lightning strikes directly through the human body, building (structure), equipment and other electrical discharge phenomena caused by ground discharge.
Indirect lightning strike: The so-called indirect lightning strike is mainly the electromagnetic field effect of direct lightning radiation pulse and the lightning current conducted through the conductor, such as lightning wave intrusion, lightning strike, etc., which invade the building, causing damage to buildings, equipment or personal injury.
Objects that are vulnerable to lightning strikes:
1. Lightning "favorite" discharges at the tip. In the thunderstorms, when people walk in the wilderness, or take advantage of iron metal tools, or ride on motorcycles, or just lift a golf club, or hide under the electric poles and trees, it is easy to become a discharge. The object is attacked by lightning.
2. Towering buildings, such as water towers, TV towers, towering billboards, etc.
3. A factory with a large number of metal equipment inside.
4. Isolated, prominent buildings in the wilderness and trees in nature.
5. TV antennas and various metal protrusions on the roof, such as flagpoles.
6. The protruding parts and objects of the building roof, such as chimneys, pipes, solar water heaters, etc., as well as the roof.
Thunderstorm weather must be suspended for all use of electrical equipment, especially the use of communication equipment such as mobile phones, do not hide under the trees, do not hide under the metal buildings, should always learn the precautions of thunderstorms.