Lightning electromagnetic pulse disaster analysis

In recent years, with the development of high technology, the use of various types of electronic computer systems has increased. In computers and other electronic devices where lightning and multi-destination devices are installed, faults and damage caused by lightning electromagnetic pulses are a common type of failure. Even in low-lying areas, due to the integrated circuit board of computer equipment, especially MOS integrated circuits (metal-oxide-semiconductor circuits) and operational amplifiers, memory pointing amplifiers and other circuits, it is also sensitive to very low lightning overvoltages. Lightning electromagnetic pulses often cause damage to such circuits.

Lightning electromagnetic interference is mainly transmitted to the victim by two methods. One is conductive coupling. Lightning interference is coupled to the input of the electronic device through various wires, metal bodies, resistors, inductors, and capacitors, and then enters the device. It is also possible to couple the common ground impedance to the common power supply. The other is radiation coupling. The lightning electromagnetic radiation is coupled to the antenna of the electronic device and the cable device through the space in the form of an electromagnetic field. Lightning interference is one of the main causes of computer hardware damage, and it is also one of the root causes of damage to communication system equipment. Because the lightning induced overvoltage wave generates thousands of volts of induced overvoltage on the communication line, it is harmful to the equipment.

In order to improve the efficiency of computer information exchange and achieve the sharing of information resources, computer systems have gradually become networked in recent years. Computers in different regions and countries have been used in networking. In computer networks, microwave trunks are often used to transfer information. The soaring effect of towering microwave towers has greatly increased the probability that computers will be harmed by lightning.

According to the relevant research data from the United States, the New England region of the low-lightning region has caused computer failures in the region once every two years, while in the high-lightning region of Florida, computer failures occur as many as six times a year. According to the analysis of relevant data in our country, the "leaking" effect of the microwave tower near the computer room has increased the computer's failure rate and damage rate by several dozen times.

Signals and images received by satellite earth stations are sometimes relayed through television relay stations. Most television relay stations were built on the top of the mountain. In recent years, accidents involving lightning transmission by television relay stations have frequently occurred. Under normal circumstances, the probability of direct lightning strikes on relay towers and computer rooms is small. Most accidents are caused by lightning electromagnetic pulses via cable and signal line input devices.

With the development of modern telecommunication business, more and more long-distance electronic devices are connected and computer networks are connected. These connecting wires receive electromagnetic radiation as antennas. With the extension of the line, the signal is attenuated, but the perturbation signals formed by the lightning electromagnetic pulses are not attenuated over the connecting wires erected in urban and rural areas. Some metal casings of electronic devices are replaced by plastic casings, and the shielding effect of lightning electromagnetic radiation is weakened. All these factors are the causes of recent lightning damage caused by electronic devices.

According to statistics, in recent years, the average annual loss of electronic equipment caused by lightning and pulse destruction has reached hundreds of thousands to several million yuan, and has increased in recent years. According to statistics, there are an average of approximately 1 million lightning strikes per year in Germany. Each year, damaging electronic equipment causes an average economic loss of about one billion marks. France has an average of about 2 million lightning strikes per year. The average annual economic loss caused by lightning disasters amounts to hundreds of millions of francs, and the global annual lightning strikes report losses of about one billion US dollars.

Many scientists in China and abroad are conducting extensive research and exploration on the mechanism of thunder and lightning electromagnetic pulses, and put forward effective protective measures.