Lightning and lightning protection technology

According to calculations by scientists, at any given time, on Earth we have about 2000 active thunderstorms. Each average thunderstorm usually lasts 2 to 4 hours and can generate 1000, 2000 discharges to the ground.

People used to say, thunderstorms like a power plant with a capacity of several hundred MW with a voltage of up to billions of V, the power of a lightning strike in a thunderstorm can be used to light a 100W light bulb within 3 months. With such intense intensity, thunderstorms are one of the most dangerous natural hazards to human life and cause huge damage to physical assets.

In 1769, humanity did not know about lightning protection devices like today. A disaster occurred when lightning struck more than 1,000 tons of explosive reserves in an Italian city. The building exploded and killed more than 3,000 people living in the city. Until the first scientist Franklin's discovery of the lightning rod was born, the terrible damage caused by such lightning strikes no longer happened. Since then, although not completely controlled, but the lightning protection devices have contributed to significantly reduce the damage caused by lightning to protect human life. Over 200 years since the appearance of the first lightning rod, lightning protection technology has become more and more complete and effective.

In 2001, Vietnam's electricity industry had about 400 incidents, 50% of which were caused by lightning. Especially on June 4, 2001, lightning broke a 220 KV cutting machine of Hoa Binh Hydroelectric Plant. The incident caused the Northern grid to be disconnected, many power plants were separated from the system. Hanoi and many other provinces have large outages.

What is the nature of thunder phenomenon - lightning - lightning?

During thunderstorms due to strong winds disturbing the clouds, make the clouds charged. When two charged charged clouds are close together, the voltage between them can reach millions of volts. Between the clouds there is a phenomenon of sparks and we see a lightning bolt. A few seconds later we hear the explosion, it's 'thunder' (the speed of light is faster than the speed of the sound so we see the lightning first). If a charged thundercloud cloud comes close to the ground to empty areas, meeting an object of height like trees, shovel pickers . there will be a phenomenon of sparks between the cloud and the ground. . That is the phenomenon of lightning strikes.

The most effective method of lightning protection is lightning rod. High-rise buildings must install lightning rod.

The principle of lightning rod structure is simple: People attach to the roof of a house with an iron bar with a pointed tip pointing up to the sky. In the lower part of the iron bar, people welded iron wire as ground wire (using non-ferrous 0.04) to connect to the wet soil and bury it deeply. If a high-rise house has to do many lightning rod, welding wires together.

In areas where lightning strikes often occur, they must be planted with lightning rods. People use a wooden pillar or cement pillar about 5 - 6 m high. At the top of the welding pillar a sharp iron bar pointed up to the sky. The iron bar tail section is grounded (using non-0.04 iron) in theory, a lightning rod can protect a cone space with a radius equal to the height of the column. A place with a lot of lightning should plant a lightning rod system, each about 20 - 30 m apart. Ground wire is welded according to a deep buried system.

When it rains, thunderstorms should quickly return home, do not stay in the rain under a big tree or where there is a high risk of being struck by lightning; Do not walk outside if not necessary. The circuit breaker must be disconnected because if lightning strikes the line, it will follow the conductor into the house. The radio antenna must be removed from the machine in order to prevent fire and lightning damage and dangerous for viewers.