Why install a lightning rod on the roof of a very high building

How lightning rods protect buildings.

Modern high-rise buildings have lightning rods at the top, and lightning rods are designed according to the principle of tip discharge. The lightning rod was invented by the American scientist Benjamin Franklin after the famous kite test. Tip discharge refers to the electric charge that gathers on one tip to a certain extent, which can ionize the surrounding air and cause discharge.

The lightning rod is the tip conductor installed at the highest point of the building, the large metal needle we see, which passes through a thick copper cable to the ground. One end of the ground is buried in damp earth at a certain depth, or connected to a metal plate buried in the ground to keep it in good electrical contact with the earth. The main function of the lightning rod is to prevent the occurrence of lightning sparks, the lower part of the thundercloud is usually negatively charged, so that the electrons on the lightning rod are repelled to the ground, and the tip of the needle has a large number of positive charges, these positive charges are put into space by the tip of the lightning rod, which can produce a slow neutralization effect and avoid violent spark discharge, so as to protect the safety of the building.

If the building is subjected to an electric shock, the charge will also be safely channelled underground along the copper cable.

Of course, it is lightning protection, and things in high places are easy to lead mines.

Of course, it's lightning protection, and if there's lightning, it's going to send electricity to the ground, and if it's not, then the lightning is going to go straight upstairs.

Thunder strikes high places"Habit"

If you want not to be hacked, you have to press the lightning rod.

An American ** invented called.

Franklin.

Dear, why are high-rise buildings not equipped with lightning rods? Answer: The reason is that the use of "cage lightning protection net" has more advantages than the traditional Franklin lightning rod, and is the most widely used lightning protection technology in modern buildings.

The latest Olympic stadium view basically adopts a "cage lightning protection net". In the case of the Bird's Nest, the lightning protection design cleverly uses the Bird's Nest's huge metal roof panel to act as a lightning receiver. Therefore, the lightning receiver of the bird's nest is a huge "lightning protection surface."", and all its "steel and iron bones" constitute a cage lightning protection net.

This huge cage protects the nest, and when lightning arrives, the current is quickly drawn into the ground along the "highway" of steel bars and steel plates. In addition to direct lightning strikes, in recent years, there has been an increasing number of lightning accidents in high-tech equipment, because the internal electronic equipment has a very low withstand voltage and is very afraid of induced lightning (that is, the lightning pulse generated by thunderclouds on various metal pipes and lines of the building will threaten the safety of personnel and various electrical equipment in the building). Therefore, induction mines have become the focus of modern lightning protection.

The measures taken are to have a good grounding and wiring system for all kinds of equipment in the building, as well as a safe distance, and install corresponding lightning arresters or take shielding measures according to the conditions of various lines. For example, in some public buildings, heating equipment, water supply and drainage pipes are connected to a copper wire; The flooring of the computer room or the language room is made of special flooring materials. These are set up for lightning protection.

Summary. Electrified clouds, first of all, run from top to bottom, and install a lightning rod at a high place, the electricity in the cloud will be discharged first, and when the house comes into contact with the cloud, there will be basically no or only a small amount of electricity without danger.

Why is there a lightning rod on the roof? Eight reasons.

Electrified clouds, first of all, run from top to bottom, in a high place to install a lightning rod to talk about the cover, will first release the electricity in the cloud, and when the house touches the cloud, there will be basically no or only a small part of the electricity without the danger of stuffiness.

A reason is probably more than 50 words.

Not too much. Lightning Rod Principle In thunderstorms, we sometimes see some towering trees knocked down by lightning, while some surrounding towers, high-rise buildings and other high-rise buildings are safe and sound. These towering trees are also charged with a large amount of electricity due to the induction of the clouds with the scattered charge of the big filial piety orange, and when the accumulated charge is too much, the tree is knocked down Under the same situation, the high-level building is safe and sound, I am afraid it is thanks to the lightning rod On many towers, there is a thing made of metal, shaped like an embroidery needle, and the needle is upright, which is a lightning rod So, why does this thing that looks like an embroidery needle and does not look amazing have such a great effect and can "avoid lightning"?

In fact, the lightning rod should be called "lightning rod" is appropriate In the thunderstorm weather, when there is a live cloud above the high-rise building, the lightning rod and the top of the high-rise building are induced a large number of charges, because the lightning rod needle is pointed, and when the electrostatic induction, the tip of the conductor always gathers the most charge In this way, the lightning rod gathers most of the charge The lightning rod and these charged clouds form a capacitor, because it is sharp, that is, the area of the two pole plates of this capacitor is very small, and the capacitance is very small. That is to say, it can hold very little charge and it gathers most of the charge, so when there are more charges on the clouds, the air between the lightning rod and the clouds is easy to be broken down and become a conductor In this way, the charged clouds and the lightning rod form a pathway, and the lightning rod is grounded The lightning rod can guide the charge on the clouds to the earth.

The number of words is too much, probably more than 20 times.

You can use the key needs directly on it.

It was you who gave me a brief summary, and I wrote it directly in the future.

Well. Sorry for the trouble, I don't need it now, thank you.

Thumbs up, thanks.

First of all, distinguish the two lightning protection situations of lightning rods:

1. The tip of the lightning rod is concentrated with a different charge due to electrostatic induction, and the tip is discharged, which is neutralized with the electric phase in the cloud to avoid the occurrence of fierce lightning, which is one aspect of lightning rod can avoid lightning.

2. If the electricity in the cloud accumulates quickly, or a cloud with a large amount of charge suddenly flies, sometimes it is too late to neutralize it in the above way, so there is a strong discharge, and the lightning will still occur. However, because the lightning rod is higher than the surrounding objects, its tip concentrates a charge of opposite polarity to the charge in the cloud, and if the lightning occurs between the cloud and the ground object, the discharge current mainly flows into the earth through the lightning rod. It can be seen that the tip discharge effect of the lightning rod will reduce the possibility of lightning between the ground objects and the clouds, and when it is inevitable, it will bear the blow of lightning itself, and the house and people will be safe.

3. "The lightning rod can guide the charge on the clouds to the earth", in fact, it is the second situation, the detailed process:

Due to the electrostatic induction of lightning on the lightning rod, the lightning shelter generates an additional electric field for the lightning electric field, which distorts the lightning field, thus attracting the discharge path of the thundercloud to the lightning rod itself.

At the same time, due to the electrostatic induction, the charge of the lightning rod body is opposite to the polarity of the charge carried by the lightning, causing the charges to attract each other (opposites attract), so there is a "discharge process" to produce current, because the earth is an infinite scattered fluid, and the lightning trap land needle itself is connected to the earth through the down wire and the generated current is introduced into the earth and neutralized.

4. In dark and humid weather, you can see the corona around the lightning rod before the lightning and hear the sizzling discharge sound, which is the first situation of the lightning rod mentioned above.

5. When the lightning rod transmits the electricity from the clouds to the earth for a moment, you will see lightning on the lightning rod, which is the second case of lightning rod lightning protection.

How lightning rods work:

During a thunderstorm, when charged clouds appear over a tall building, a large amount of electrical charge is induced on both the lightning rod and the roof of the tall building.

Since the lightning rod needle is pointed, the tip of the conductor always gathers the most charge when electrostatic induction. In this way, the lightning rod gathers most of the charge.

The lightning rod forms a capacitor with these charged clouds, and because it is sharp, that is, the area of the two poles of the capacitor is very small, and the capacitance is also very small, which means that it can hold very little charge.

And it gathers most of the charge, so when there is more charge on the clouds, the air between the lightning protection pin and the clouds can easily be broken down and become a conductor.

In this way, the charged cloud layer forms a path with the lightning rod, and the lightning rod is grounded, and the lightning rod can channel the charge on the cloud layer into the earth, so that it does not pose a danger to the high-rise building and ensures its safety.

Types of lightning rods.

Direct lightning rod Special lightning rod Pre-discharge lightning rod in advance.

Direct lightning strike. Special.

It is suitable for microwave communication stations, radar base stations, beacon stations, communication base stations, military bases, radar rooms, bank buildings, astronomical and meteorological stations and other important places in tall buildings.

Pre-discharge. When the lightning rod intercepts the lightning strike, it is connected by the lightning receiver, and through the lightning waveform processing device, there is a 3mm gap between the shell and the central grounding rod to form a coupling capacitor, and the shell is grounded through an inductance coil (the central grounding rod) when the downlink pilot approaches the lightning receiver.

Due to the extremely high frequency, the inductance is in an open-circuit state, and the capacitance is a short-circuit characteristic to the high frequency, so under the action of the coupling capacitor, the electric field strength on the surface of the flash receiver increases rapidly until the avalanche process is triggered, so that the lightning current can be discharged into the ground in an instant, so as to effectively achieve the purpose of lightning protection and safety.

Summary. Houses above 10 meters must be equipped with lightning rods. For larger buildings, several lightning rods are required.

1. The lightning protection project must have the construction qualification and the test report of the local lightning protection center before it can be considered qualified.

2. The protection range of the lightning rod must be calculated according to GB50057 with the rolling ball method to know whether the building can be protected.

3. Because of its small protection range, lightning rods are easy to lead lightning, and now they have been mostly replaced by lightning belts or lightning nets.

4. The construction quality and grounding resistance should meet the requirements of the specification.

5. When lightning strikes, there is an extremely high voltage on the surface of the steel bar instantaneously, and at this time, it is necessary to avoid people and animals approaching, and counterattacks occur, causing injuries.

6. At the same time, a strong electromagnetic field will be generated around the steel bar flash, causing the nearby metal pipelines to be electrified, so all metal pipelines in the home should take grounding measures, and surge protectors should be installed on the power supply and signal lines.

Houses above 10 meters must be equipped with lightning rods. For larger buildings, several lightning rods are required. 1. The lightning protection project must have the construction qualification and the test report of the local lightning protection center before it can be considered qualified.

2. The protection range of the lightning rod must be calculated according to GB50057 with the rolling ball method to know whether the building can be protected. 3. Because of its small protection range, the lightning rod is easy to lead lightning, and now it has been replaced by lightning belts or lightning nets. 4. The construction quality and grounding resistance should meet the requirements of the specification.

5. When lightning strikes, there is an extremely high voltage on the surface of the steel bar instantaneously, and at this time, it is necessary to avoid people and animals approaching, and counterattacks occur, resulting in silver damage. 6. At the same time, a strong electromagnetic field will be generated around the steel bar flash, causing the nearby metal pipelines to be charged and fiercely nucleated, so all metal pipelines in the home should take grounding measures, and surge protectors should be installed on the power supply and signal lines.