Lightning strokeelectric currentKill or destroy people, animals, trees, buildings, etc.
The discharge between clouds is harmful to aircraft and has little impact on buildings, people and livestock on the ground, but the discharge of clouds on the ground is very harmful to buildings, electronic and electrical equipment, people and livestock.Once it causesharmCan be called being struck by lightning.
Chinese name
Lightning strike
Foreign name
thunderstroke; be struck dead by stroke of lightning
1. Extremely speaking, the power of striking is incomparable.《Romance of the Three Kingdoms·Shu Annals, Zhang Yi's Biography, "He has always made contributions to planning and conquering wars"Pei SongzhiAnnotate and introduce JinChen ShouThe Biography of the Yibu Jijiu: "If you don't obey, the soldiers will punish you. Although you regret it, it will not help."
2. When lightning occurs, people and animals, trees or buildings are killed or damaged due to the passage of strong current.Lu XunHot Wind - Essays 53: "It's also an elegant thing to learn a few Esperanto words and draw a few flowers. Do we have to envy our peers and declare that fish's eyes are mixed with pearls, and lightning strikes and burns?"[1]
formation
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thunder
One part of the charged cloud layer and another part of the cloud layer with heterogeneous charge, or the charged cloud layer discharges rapidly to the earth.This rapid discharge process produces strong lightning and loud sound.This is the lightning and thunder we see.
Of course, the discharge between clouds is mainly harmful to aircraft, and has no great impact on buildings, people and livestock on the ground. The discharge of clouds on the ground is very harmful to buildings, electronic and electrical equipment, people and livestock.
Generally, there are three main forms of lightning stroke: one is the rapid discharge between the charged cloud layer and a point on the ground, called“Direct lightning strike”。The second isCharged cloudbecausestatic electricityThe induction makes a certain range of the ground bear heterogeneous charges.After the occurrence of direct lightning strike, the cloud electrification disappears rapidly, and some areas on the ground have local high voltage due to large stray current resistance, or due to direct lightning strikedischargeIn the process, powerfulpulse currentThe phenomenon of electromagnetic induction on surrounding wires or metal objects and high voltage resulting in flashover is called“Secondary mine”Or called“Induction thunder”。The third is“spherical thunder”。
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Form of expression
The main form of lightning stroke is lightning.
Lightning strike buildings
When lightning occurs, it usually generates charges. The bottom layer is negative, the top layer is positive, and it also generates positive charges on the ground, moving with the clouds like a shadow.Positive and negative charges attract each other, but air is not a good conductor.The positive electricity rushes to the top of trees, hills, tall buildings and even the human body, trying to meet the clouds with negative electricity;The negative charge dendritic antenna extends downward, and the more downward it extends, the closer it is to the ground.Finally, the negative and positive charges finally overcome the air barrier and connected.The huge current flows from the ground to the clouds along a conductive airway, producing a bright and dazzling flash.The length of a lightning bolt may be only several thousand meters, but the maximum length can be hundreds of kilometers.
Powerful
The average lightning current is about 20000 A (or even more), and the lightning voltage is about 10 to 10 volts (the human body safety voltage is 36 volts). The time of a lightning is about one thousandth of a second, and the average power generated by a lightning is 20 billion kilowatts (the power of a rice cooker is generally less than 1000 watts).
The world's largest hydropower station built by China——Three Gorges Hydropower StationThe total installed capacity of the power station is 18.2 million kilowatts, only one thousandth of the primary lightning power.
Of course, although the electric power of lightning is large, the electric power of lightning current is not large because of the short discharge time, about 5555 degrees at a time.
There are more than 100 lightning phenomena every second in the world, and the total electricity surplus released by lightning in a year is about 1.75 billion kilowatt hours.
If the electricity charge per kilowatt hour is 0.30 yuan, the annual lightning value of the world is 5.25 trillion yuan, which is a huge fortune. But because the lightning time is very short, it is difficult for human beings to capture this kind of electricity;Florida, and ChinaTsinghua UniversityMotor system,Shanghai Jiaotong UniversityHigh voltage laboratories are constantly exploring new dreams for mankind.
Lightning intensity
Summer, viaThunderstorm cloudHigh voltage electric field in the strong charge area accumulated by layersdischargeAnd the light radiation intensity of arc light can calculate the voltage value of air molecule breakdown.Generally, the distance between dry air and 10000 volt high-voltage electric field is one centimeter. If the humidity of water in the air changes step by step from small to large, the breakdown voltage will also vary from tens of thousands of volts to thousands of volts.Generally speaking, the electric charge layer of strong thunderstorm cloudsGeoelectric fieldThe voltage ranges from 100 million volts to about 1 billion volts.The current generated when the air is broken down is between 30000 and 300000 ampereselectric powerIt is also about 10 million watts, which is only a discharge data of moderate lightning.The discharge period of thunderstorm clouds can be divided into several stages. The first stage occurs in the early stage of rainwater unloading of thunderstorm clouds. The rainfall is very small or close to sporadic rain. At this time, the air humidity is low, and the height of the charged cloud layer to the ground is about 1000 meters or lower. The space it formselectric fieldThe voltage value is relatively high, generally around several hundred million volts.In the later stage, with the increase of rainfall, air humidity and the decrease of the height of the charged cloud from the ground, the electric field voltage generated by it will also decrease.
The strong lightning charge discharge is generally in the early stage of thunderstorm formation, and its discharge intensity is generally reduced from large to small step by step, which is also a gradient change formed with the continuous increase of air humidity and the continuous release of cloud charges.The arc radiation and huge air shock wave generated by strong lightning discharge we usually see are mostly in the early stage of thunderstorm formation.In the early stage of thunderstorm, the air humidity is low, and the breakdown is one centimeterSpatial distanceThe required voltage of 10000 volts is calculated, and the electric field voltage of 1000 meters requires 100 million volts.ThundercloudCharge quantityThe larger the voltage field is, the higher the voltage field will be. In addition, the lower the height of thunderstorm clouds from the ground, thedischargeThe greater the current, this is a proportional relationship.Rainy seasonthunderstormSound is also caused byArc dischargeThe generated air shock wave is amplified and the higher the sound decibel coefficient of thunderstorm is, the greater the electric field discharge intensity of thunderstorm cloud layer is.
After we know the relevant knowledge about lightning, we know lightning protection and lightning protection as well.In the early and middle stages of the thunderstorm, people try to avoid it, waiting for the heavy rain, the increase of air humidity, the completion of the lightning discharge process and after the rain to do your things.Otherwise, being struck by lightning is inevitable.
Impact Introduction
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Beneficial impact
When lightning strikes, the part in the airoxygenBe cataclysmic intoozone。Thin ozone is not only odorless, but also can absorb most of thecosmic raysSo that the creatures on the earth's surface will be protected from the harm of excessive ultraviolet radiation.The high temperature generated in the lightning process can kill more than 90% of the bacteria and microorganisms in the atmosphere, thus making the air more pure and fresh and pleasant.
According to statistics, there will be more than 3.1 billion lightning flashes over the earth every year, with an average of 100 flashes per second.Each time it is discharged, its electric energy is up to 100000 kilowatt hours, which cannot be compared with the largest electric power device in the world.In addition, the atmosphere also contains 78% of free nitrogen that cannot be directly absorbed by crops.When lightning strikes, the current is as high as 100000 amperes, and the air molecules are heated to more than 30000 degrees, which causes the inactive nitrogen in the atmosphere to combine with oxidation and becomeNitrogen dioxide。Heavy rain will dissolve nitrogen dioxide into dilute nitric acid, which will fall to the ground with the rain and combine with other substances to become nitrogen fertilizer that can be directly absorbed by crops.It is estimated that there are 2 billion tons of nitrogen fertilizer "synthesized" by thunderstorms every year in the world.The 2 billion tons of nitrogen fertilizer falling from the sky is equivalent to the total output of 200000 fertilizer plants with an annual output of 10000 tons
Power generation application
Power generation application
along withNon renewable energyWith the continuous consumption of energy, human beings are about to face an energy crisis.All countries are constantly seeking, developing and utilizing new energy.Among them, lightning is a huge energy source.
In ChinaHainan IslandandLeizhou PeninsulaIt is the area with the most intense lightning activity, with annual averageThunderstorm dayUp to 130 days.Lightning is particularly active in all parts of the world.
Lightning has huge energy. On average, there are 100 lightning flashes per second on the earth, and one lightning release about 8000 watt hours of electric energy.Every year, lightning in the world emits about 25 billion kilowatt hours of energy.It produces more energy than all the generators in the United States generate.
For this reason, we can plan to develop a safe and effective method to convert the lightning interception with instantaneous high energy into a kind of utilization that can be used by human beings.The main principle is to convert electricity into heat, use heat to evaporate water to generate steam, and promote steam turbine power generation.
We can lead lightning down through the following three schemes:
1. Use the hydrogen balloon to pull the fine steel wire into the high altitude to ignite the mine
2. Use small rockets to lift off and detonate mines
Then, we lead the lightning to a certain resistance, so that after it is heated, it can use heat energy to generate electricity or heat objects.
In addition to power generation, heat at different temperatures can also be used for refrigeration, industrial drying, industrial thermal processing, greenhouse heating for planting, domestic hot water, bathing, soil heating, seawater concentration and fresh waterdistillation。
It is especially suitable for coastal and someIsland area。
It provides a more simple and easy to implement method.
harm
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Disaster introduction
Lightning strike
There are millions of lightning flashes in nature every year,Lightning disasterIt is one of the ten most serious natural disasters announced by the United Nations International Decade for Disaster Reduction.The latest statistics show that the losses caused by lightning have risen to the third place of natural disasters.There are countless casualties and property losses caused by lightning strikes every year in the world.According to incomplete statistics, the number of casualties caused by lightning strikes and negative effects of lightning strikes in China each year is 3000~4000, and the property loss is between 5 billion yuan and 10 billion yuan.
Thunder and lightning disasters cover almost all walks of life.One of the negative effects of the rapid development of modern electronic technology is the reduction of its ability to withstand lightning surge.withlarge-scale integrated circuitMeasurement, monitoring, protection, communication, computer network and other advanced electronic equipment as core components are widely used in power, aviation, national defense, communication, radio and television, finance, transportation, petrochemical, medical and other fields of modern life, integrated with large CMOSelementThese electronic devices generally have weak tolerance to transient overvoltage and overcurrent. Transient overvoltage will not only cause misoperation of electronic devices, but also cause greaterDirect economic lossAnd broad social impact.
Hazard type
Direct lightning strike
The charged clouds discharge violently to a point on the earth, which is called direct lightning strike.Its destructive power is very great. If it cannot be poured into the earth quickly, it will cause serious damage or damage to objects, buildings, facilities, people and animals in the discharge channel - fire, building damage, electronic and electrical system destruction, and even endanger the life safety of people and animals.
Lightning wave invasion
Lightning does not discharge directly in buildings and equipment itself, but discharges cables laid outside buildings.The lightning wave or overvoltage on the cable is almostlight speedSpread along the cable line, invade and endanger the indoor electronic equipment andAutomatic controlAnd other systems.Therefore, our electronic equipment and control system may have been damaged before hearing the thunder.
Induced overvoltage
Lightning strikes occur near equipment, facilities or lines, or lightning does not discharge directly to the ground, but only between clouds.Lightning releases electric charges and induces overvoltage on power and data transmission lines and metal supports of metal pipes.
When lightning strikes a building with lightning protection facilities, lightning waves along the lightning arrester on the top of the building (lightning stripLightning conductor、Lightning protection networkorLightning arrester）. In the process of releasing the downlead to the earth, a strong transient magnetic field will be formed around the downlead, which may cause interference to electronic equipment, data loss, malfunction or temporary paralysis;In serious cases, it can cause component breakdown and circuit board burning, which will paralyze the whole system.
The system parameters are changed due to the operation of circuit breaker, heavy power load, input and removal of inductive load, system short circuit fault and other changes in the internal state of the system, resulting in the conversion of electromagnetic energy in the power system, thus generatingInternal overvoltage, that is, switching overvoltage.
Although the amplitude of switching overvoltage is small, its probability is far greater thanlightning induction Overvoltage.Experiments have proved that whetherInduced overvoltageOr internal switching overvoltageTransient overvoltage(or called transient overvoltage), which will eventually endanger electronic equipment in the form of electrical surge, including destruction of printed circuit wiring, premature aging of components and insulation, shortening of life, destruction of database or misoperation of software, making some control components out of control.
Ground potential counterattack
If lightning strikes buildings or facilities with lightning protection devices directly, the ground potential of the grounding grid will be raised by tens of thousands or hundreds of thousands of volts within a few microseconds.The highly destructive lightning current will flow from the grounding part of various devices to the power supply system or various network signal systems, or break through the ground insulation and flow to the power supply system or various network signal systems of another facility, so as to counter damage or damage electronic equipment.At the same time, in the absence ofEquipotential bondingHigh potential may be induced in the lead circuit ofSpark dischargeRisk of.
Prevention and treatment
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Emergency points
Lightning strike
Hot weather and thunderstorm in the morning increase the probability of electric shock accidents.Electric shock accidents are very easy to happen in summer. For one thing, because the weather is hot and rainy, and the human body secretes a lot of sweat, it is easy to conduct electricity when using electrical appliances;In addition, due to the increase of thunderstorms, lightning protection should also be paid attention to outdoors to avoid electric shock accidents.
Pay attention to closing doors and windows, and indoor personnel should stay away from metal objects such as doors and windows, water pipes, gas pipes, etc.
Turn off household appliances and unplug the power plug to prevent thunder and lightning from invading the power line.
When you are outdoors, you should avoid in time and do not stay in the open field.When there is no place to hide in the open field, try to find a low-lying place (such as a pit) to hide, or squat down immediately to reduce the height of the body.
Keep away from isolated trees, towers, power poles and billboards.
Immediately stop outdoor swimming, boating, fishing and other water activities.
If many people live outdoors, do not squeeze against each other to prevent current conduction after being struck by lightning.
Expert tips
Installation of lightning arrester
Lightning protection devices must be installed on tall buildings to prevent lightning disasters.
Try to take less showers in thunderstorms,solar heaterUsers must not take a bath.
Indoor prevention
In thunderstorm weather, if you are at home, you should also pay attention to the prevention of lightning disasters. The most scientific method is to install lightning arresters at home. If you do not install lightning arresters at home, you can do this:
1. When it thunders, the first thing to do is to close the doors and windows, leave the metal water pipe entering the house and the sewer pipe connected to the roof.
2. Try not to dial or answer the phone, or use the phone to access the Internet. Unplug the power supply, telephone line, TV antenna and other metal wires that may lead to lightning strikes.
3. Do not use solar water heater for bathing in thunderstorm weather.
4. Do not connect the iron wire used for drying clothes and bedding outside the window or at the door to prevent the iron wire from causing lightning.
5. Do not stay in isolated bowers and grass sheds for a long time, pay attention to avoid wires, do not stand under the light bulb, and it is better to cut off power or do not use electrical appliances.
Outdoor lightning protection
1. In thunderstorm weather, do not stand, but squat down to lower the height, and put two feet together to reduce the harm caused by step voltage.
2. Don't stand under the big tree, and don't touch the big tree, because the wet trunk has become a lightning device, and then it should be 5m away from the big tree.
3. Do not stay at the water edge and depression, do not stand on the roof, the top of the mountain, or close to other conductive objects. You should quickly go to the dry room to shelter from rain. If you cannot find a house, you should go to the nearby mountains or under the rocks to shelter from rain.
4. Do not hold metal articles to stay in the thunderstorm, and the metal articles taken with you should be placed 5m away;It is not suitable to take an umbrella or carry a badminton racket on the shoulder in a thunderstorm.
5．Thunderstorm weatherWhen going out, you should wear rubber shoes, which can play an insulating role. It is also not suitable to drive a motorcycle and ride a bicycle. People will not be attacked by lightning when they are in a car. Because the closed metal conductor has a good lightning protection function, you should be careful not to put your head and hands out of the window.
Lightning rescue
Main symptoms:The skin is burned, and the tympanic membrane or internal organs are cracked,ventricular fibrillation, cardiac arrest, breathing
Muscular paralysis.
First aid measures:
1. The wounded shall lie flat and loosen the buttons, bra, belt, etc.
3. Hand guidance or acupuncture in the middle of people, ten Xuan,Fountain, Mingmen and other acupoints.
4. Send to hospital for first aid.
Lightning incident
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On the morning of April 3, 2016, in the Jin'an Fuyuan cemetery area of Anyi County, Jiangxi Province, a citizen was struck by lightning while sweeping the tomb, causing one death and three injuries.[2]
The most in the world
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The air around lightning strikes is the hottest place on the earth.In a fraction of a second, the air is heated to about 30000 º C (54032 º F), or about five times higher than the visible surface of the sun.Guinness
