Lightning is a very destructive natural phenomenon, its voltage can be as high as millions of volts, and the instantaneous current can be as high as hundreds of thousands of amperes. For thousands of years,

Analysis of the necessity of lightning protection grounding project construction

Lightning is a destructive natural phenomenon, its voltage can be as high as millions of volts, and the instantaneous current can be as high as hundreds of thousands of amperes. For thousands of years, lightning has caused countless damage. After the lightning strike, within 1.5-2Km of the lightning strike center, there may be a dangerous overvoltage damage to the equipment on the line. Lightning disasters, like heavy rain and hurricanes, are meteorological (natural) disasters, and they are collectively referred to as the six major disasters affecting social security and economic development along with water, drought, criminal offenses and traffic accidents.

In recent years, with the increasing application of a large number of data equipment and precision instruments, the accidents caused by lightning damage have a trend of increasing year by year. Due to the high concentration of the internal structure of the precision equipment of the communication computer network, the ability of the equipment to withstand voltage and overcurrent is reduced, and it is more vulnerable to lightning damage. The light can cause damage to the interface of computer terminals and communication equipment, interrupt communication, and lose or transmit a large amount of information; the heavy can damage the network host, resulting in network paralysis and impossible work. Computer network systems are susceptible to lightning damage equipment: MODEM (modem), ROUTER (router) SWITCH (switch), HUB, network card, communication card, UPS, computer power supply and motherboard.

Lightning strike protection: it is to introduce the energy of the lightning current to the earth as much as possible through reasonable and effective means, which is to channel, rather than blocking or demining. A complete lightning protection system consists of two aspects: protection from direct lightning strikes and protection from inductive lightning strikes. The absence of any side is incomplete, flawed and potentially dangerous. Generally, we divide it into two parts: external lightning protection and internal lightning protection. By the lightning rod (or lightning belt, lightning protection net), the lead wire and the grounding system to form an external lightning protection system, mainly to protect the building from lightning strikes caused by fire accidents and personal safety accidents; and the internal lightning protection system is to prevent lightning and other forms of overvoltage intrusion into the equipment caused damage, which is the external lightning protection system can not guarantee, in order to achieve internal lightning protection, the building in and out of the protected areas of the cable, metal pipes, etc. installed overvoltage protectors to protect and good grounding.

A. Multi-level hierarchical (class) protection principle: that is, according to the different functions of electrical and microelectronic equipment and different protected procedures and protection layers to determine the protection points for classified protection; according to lightning and the possible channel of operation instantaneous urban hazards, multi-level protection should be done from the power line to the data communication line.

B. External passive protection: Passive protection in the level 0 protected area, that is, external passive protection, mainly lightning rods (nets, wires, belts) and grounding devices (ground wires, earth electrodes). Protection principle: When the thundercloud discharge is close to the ground, it distorts the ground electric field. At the top of the lightning rod (wire), a local electric field intensity distortion is formed to affect the development direction of lightning pilot discharge, guide lightning to the lightning rod (wire) discharge, and then lead the wire through the ground, and the grounding device introduces the lightning current into the earth, so that the protected object is protected from lightning strikes. This is an effective method of anti-direct lightning that people have proved in long-term practice. However, in the past, it was generally believed that the higher the lightning rod was, the better (generally only considered at a 45-degree angle), and the passive discharge lightning rod was used, which had a poor reaction speed, a small range of protection and a small conductivity. According to the requirements of modern development, the lightning rod should choose an active lightning protection device for early discharge, and should be considered from different angles such as 30 degrees, 45 degrees, 60 degrees, etc., to achieve the protection of various lightning strikes, increase the scope of protection and increase the throughput. All exposed metal components (pipes) of the building should be well connected to the lightning protection net (belt, wire).

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