What are the lightning hazards and what are the lightning hazards?

When lightning occurs, the voltage of thunderclouds to the ground reaches tens of millions to hundreds of millions of volts, and if it is struck by lightning, it will cause significant ** and property damage.

The main causes of lightning strikes on people or livestock are as follows.

1) Direct lightning strike: The current of lightning flows directly through the body of a person or animal and enters the ground, causing death.

2) Discharge lightning strike: lightning strikes other objects to form high voltage, thereby causing damage to nearby people and animals.

3) Step voltage lightning strike: lightning strikes the earth, due to the current to the surrounding dispersion to form a step voltage, thus causing harm to people and animals.

In addition, lightning can also hit houses, damage equipment, and cause disasters and even disasters. Therefore, effective measures must be taken to carry out lightning protection to reduce the occurrence of lightning accidents.

1. Direct lightning damage.

When lightning strikes directly on the building, the strong lightning current causes the water of the building (structure) to be heated and vaporized and expand, thus generating a large mechanical force, resulting in the burning of the building. In addition, when lightning hits the lightning receiver and the current is poured to the ground along the down wire, the potential to the ground rises, and it is possible to jump to nearby objects, which is called lightning "counterattack", resulting in fire or personal **.

2. Induction lightning destruction.

Induction mine destruction is also known as secondary destruction. It is divided into two types: electrostatic induction lightning and electromagnetic induction thunder. Due to the large gradient of lightning current, a strong alternating magnetic field will be generated, which will cause the surrounding metal components to induce current, which may discharge to the surrounding objects, such as nearby combustibles will cause fire and **, and the wire that is inducted will have a strong destructive effect on the equipment.

Electrostatic induction thunder.

The electric field generated by a thundercloud with a large negative charge will induce a positive charge bound by the electric field on the metal wire. When the thundercloud discharges to the ground or inter-cloud, the negative charge in the cloud disappears in an instant (strictly speaking, it is greatly weakened), then the bound positive charge induced on the road will also lose its binding in an instant, and under the action of electric potential energy, these positive charges will produce a large current impact along the line.

Special attention should be paid to the anti-static problems of flammable and explosive places, computers and their sites.

Electromagnetic induction mine.

Lightning strikes occur near power supply lines or strike lightning rods to produce a powerful alternating electromagnetic field, the energy of which is induced on the line and ultimately on the equipment. Due to the existence of lightning rods, the chance of lightning falling on buildings increases, and the chances and degree of internal equipment being harmed by inductive lightning are generally increased, causing great harm to electrical equipment. Therefore, the lightning rod down conductor should have good conductivity, and the grounding body must be in a low impedance state.

Destruction introduced by lightning waves.

When lightning approaches the overhead pipeline, the high-voltage shock wave will invade the room along the overhead pipeline, causing high current to be introduced, which may cause equipment damage or personal accidents. If there are combustibles nearby, it is easy to cause a fire.

The hazards of lightning are generally divided into two categories: first, the thermal effect and electrodynamic effect of lightning directly hitting the building; The second is the secondary effect of lightning, that is, the electrostatic induction and electromagnetic induction generated by the lightning current. The specific hazards of lightning are as follows:

1. The high-voltage effect of lightning current will produce an impulse voltage of up to tens of thousands of volts or even hundreds of thousands of volts, and such a huge voltage will instantly impact electrical equipment, which is enough to break down the insulation and cause a short circuit in the equipment, resulting in direct disasters such as combustion and **.

2 The high thermal effect of lightning current will release a strong current of tens to thousands of amperes, and produce a large amount of heat energy, and the heat at the lightning strike point will be very high, which can lead to metal melting, causing fire and **.

3. The mechanical effect of lightning current is mainly manifested in the occurrence of **, distortion, collapse, tearing and other phenomena of the lightning struck object, resulting in property loss and personnel**.

4. Electrostatic induction of lightning current can make the conductor of the hit object induce a large number of charges contrary to the nature of lightning, and when the lightning disappears and has no time to disperse, it will produce a very high voltage discharge phenomenon and lead to fire.

5 Electromagnetic induction of lightning current will produce a strong alternating electromagnetic field around the lightning strike point, and the current generated by the induction can cause local overheating of the transformer and cause fire.

6. The intrusion of lightning waves and the counterattack effect of high voltage on the lightning protection device on the building will also cause the power distribution device or electrical line to break and burn, resulting in fire.

On the morning of 6 June 2009, after further investigation and verification by this reporter, it was found that in the lightning strike incident that occurred in Gaoli Community, Ronggui Street, Shunde District, Foshan City, Guangdong Province (4 dead and 2 injured in the lightning disaster in Foshan, Guangdong, of which 3 were killed and 1 injured was from Guangxi), in addition to the three deceased and one lightly injured person reported by this newspaper yesterday, there was also a seriously injured person who was also from Guangxi and came from Shebu Town, Guiping City. The person in charge of the Ronggui Sub-district Office to deal with the aftermath said that the families of the three deceased have rushed to Shunde, and when negotiating compensation, the local ** will provide judicial assistance to the Guangxi dead and injured and their relatives.

Foshan, 4 Jun (ZXS) -- Shunde District, Foshan City, Guangdong Province, reported on 4 June that at about 16 p.m. on 3 June, six people were struck by lightning while sheltering from the rain in a simple shed in a community in Shunde, resulting in four deaths, one serious injury, and one minor injury. It is understood that at that time, a total of five workers and their relatives in the houses under construction, a total of eight people took shelter from the rain in the shed, and six people were struck by lightning on the spot, five fell to the ground, one person was only slightly injured, and two workers sitting on the bed board of the shed were lucky enough to avoid the lightning strike. Three of the dead were from Guangxi and one was a native of Shunde.

At around 16:00 on August 23, 2010, when Mr. and Mrs. Wu and Mr. Chen of Lianxi Village, Jiangwei Town, Wengyuan County, went out to work, the weather changed abruptly, and they went to a pavilion under a big tree by the Lianxi Bridge to take shelter from the rain, and as a result, the three were struck by lightning and died.

Relevant statistics show that in 2009, there were 7,668 cases of disasters caused by lightning strikes in Guangdong, including 34 personal accidents, 28 deaths, 5,113 lightning damage devices of various electronic and electrical equipment, and economic losses caused by lightning disasters of 100 million yuan. Yang Shaojie, deputy director of the Guangdong Provincial Meteorological Bureau, said: "It can be said that lightning strikes are the largest number of meteorological disasters among all meteorological disasters every year.

In 1997, 200 people died in Guangdong a year due to lightning strikes, and later with the increase in lightning protection, the death toll is still in the dozens. ”

Lightning is one of the 10 most serious natural disasters announced by the United Nations, and it is also one of the top 10 natural disasters in China. Since the 80s of the 20th century, with the wide application of electronic information systems in the production, life and work of residents, the losses caused by lightning disasters have become more and more serious. There are 21 provinces, autonomous regions and municipalities in China with thunderstorm days of more than 50 days, and the maximum number of thunderstorm days can reach 134 days.

Thunderstorms in China are mainly concentrated from June to August every year. Every year, three to four thousand people are struck by lightning**, causing property losses of 5 billion to 10 billion yuan.

Lightning usually strikes the spire of the tallest object outdoors, so isolated tall trees or buildings are often the most susceptible to lightning strikes.

1. Tip discharge and lightning rod.

Under the action of a strong electric field, near the place where the curvature of the object is large (such as a sharp, small tip, and a place where the bending is very strong), the isopotential plane is dense, and the intensity of the electric field increases dramatically, resulting in the ionization of the air here and the gas discharge phenomenon is generated, which is called corona discharge. Tip discharge is a type of corona discharge, which refers to the phenomenon of gas discharge caused by ionization of air near the tip.

When a thundercloud passes over, the middle and lower part of the cloud is a strong negative charge center, and the underlying surface under the cloud is a positive charge center, so a strong electric field is formed between the cloud and the ground. In the vicinity of the tip of the ground protrusion such as building spires, trees, hilltop grass, woods, rocks, etc., the isopotential plane will be dense, where the electric field is extremely strong, and the air is ionized, thus forming a tip discharge from the surface to the atmosphere.

The lightning rod is a lightning protection device composed of a metal rod (flash receiver) standing on the roof of a building, a metal down conductor and a metal grounding body. Its function is to attract lightning that may hit the building to it and enter the ground to protect the building. Further research is needed on the mechanism of why lightning rods can protect against lightning.

It is believed that the tip of the lightning rod discharges, neutralizes the charge accumulated in the thunderstorm cloud, and plays a role in eliminating electricity. But in recent years, by calculating the amount of discharge at the tip, it is far from being able to neutralize all charges.

2. Human lightning protection.

People who are outdoors when thunder and lightning are thundering and lightning should follow four principles in order to protect against lightning strikes.

One is that the human body should lower itself as much as possible so as not to be directly hit by lightning as a protruding tip.

Second, the contact surface between the human body and the ground should be reduced as much as possible to prevent damage caused by "step voltage". The so-called stepping voltage is near the lightning strike point, a large potential difference between the two points, if the two feet of the person are very separated, respectively contact the two points far apart, then the two feet will form a large potential difference, there is a strong current through the human body to cause people to be injured.

Third, do not go under isolated trees and near tall buildings without lightning protection devices, and do not hold metal bodies high above your head.

Fourth, do not enter the water, because the water body conducts electricity well and is easy to be struck by lightning. In general, you should go to a lower place and stand or crouch with your feet together to reduce the chance of encountering lightning.

If you are indoors during the lightning period, do not go near the window, as far away as possible from the electric lights, **, the lead of the outdoor antenna, etc.; In buildings without lightning protection devices, contact with chimneys, water pipes, heating pipes, steel columns, etc. should be avoided.

3. Top 10 methods of outdoor lightning protection.

The following rules should be observed outdoors

1) Fire and **. The high-temperature arc, secondary discharge, huge lightning current, and ball lightning intrusion of direct lightning discharge can directly lead to disasters and mines; Impulse voltage breakdown of insulation and other damage to electrical equipment can indirectly lead to disasters and damage.

2) Electric shock. Cumulus clouds can directly electrocute people by discharging electricity, secondary discharge, ball lightning strike, and lightning current to the human body. Electrical equipment insulation damaged by lightning strikes can also cause people to be electrocuted.

3) Destruction of equipment and facilities. The high voltages and currents generated by lightning strikes can cause damage to important electrical installations, buildings and other facilities.

4) Large-scale power outages. Large-scale power outages can occur when power equipment or power lines are damaged.

Lightning damage is attribute damage, and unlike ordinary damage, it can trigger the chain of iron cables, and has a defense-breaking effect on vine armor. The thunder attribute cards are thunder kill and lightning, and the generals who can cause thunder attribute damage are, Zhang Jiao, Zhang Liang, God Liu Bei and so on.

The hazards of lightning are: personnel, destroying buildings, power supply and distribution systems, communication equipment, causing forest fires, causing computer information system interruption, storage, oil refineries, oil fields, etc.

More than 2 3 victims of lightning were attacked outdoors. Two of them out of every 3 people survived. Eighty-five per cent of those killed by lightning were women, ranging in age from 10 to 35. Most of the deceased took refuge in thunderstorms under trees.

Thunderstorm weather lightning protection recommendations:

1. Stay indoors and close doors and windows, and those who work outdoors should take refuge in buildings.

2. Reduce the use of ** and mobile phones.

3. It is not advisable to use televisions, stereos and other electrical appliances without lightning protection measures or insufficient lightning protection measures, and it is not suitable to use faucets. 44. It is not advisable to enter temporary shantytowns, sentry boxes or low-rise buildings without lightning protection facilities.

5. Do not touch antennas, water pipes, barbed wire, metal doors and windows, building exterior walls, and stay away from live equipment such as wires or other similar metal devices.

6. Do not stand on the top of a mountain, the roof of a building or close to an object with high conductivity.

7. Do not dispose of flammable materials contained in open containers.

8. Do not swim or engage in other water sports or activities, should not play outdoor ball games, in case of thunder and lightning, immediately leave the water and other open venues, and find a place to hide.

9. When it is impossible to hide in a building with lightning protection facilities in the wilderness, you should stay away from trees and masts.

10. It is not advisable to play umbrellas, hoes, shovels, badminton rackets, golf clubs, etc. on your shoulders in an open field.

1. The hazards of lightning are: personnel, destroying buildings, power supply and distribution systems, communication equipment, causing forest fires, causing computer information system interruption, storage, oil refineries, oil fields, etc.

2. More than 2 3 of the victims of lightning were attacked outdoors. Two out of every 3 of them survived. Eighty-five per cent of those killed by lightning were women, mostly between the ages of 10 and 35. Most of the deceased took refuge in thunderstorms under trees.