Do n’t run when you encounter a high -voltage wire when you fall to the ground. The standard life -saving posture is so funny

Written Wen Qijun

The high -voltage wire is dangerous. Don't touch it if it's okay. Don't touch it if you have anything. This is common sense. But if the high -voltage wires fall on the nearby ground, what should you do at this time?

Remember four words: absolutely don't run. At this time, there is only one walking posture that allows you to save your life. Today we will learn the correct operation when there is a high -voltage wire next to it.

Error demonstration. Image source: Elektroschutz in 132 Bildern

High -voltage electricity is closely related to our daily life and industrial production, which can be said to be the "blood" of human society.

The power station and the substation are transmitted with a transmission line of 60,000 to 500,000 volts. In the substation, the voltage of high -voltage electricity will be reduced, and then transported to millions of households. Generally speaking, the voltage of high-voltage wires on the street is between 4-25 kV.

This H -shaped transmission line is a relatively old transmission system. There are more in old communities. The voltage of the transmission lines at high places is high. The bottom is the communication line. Image source: hsseworkd

The danger of high -voltage wires is self -evident. Once electric shock, the heat generated when the current pass through the human body will burn the organ, and the current may also cause cardiac arrest. But what many people don't know is that there is a "enchantment" near the high -voltage wire, and the "enchantment" is actually very dangerous.

When the high -voltage wire is directly or indirectly exposed to the earth, the potential of the contact point (you can simply understand the voltage) is fainted to the surroundings like a water wave. The higher the potential closer to the contact point, the more dangerous. This potential is called Earth Potential Rise along the contact point to the surroundings, which is equivalent to expanding the hazards of high -voltage wires.

The power level rose when the wire was directly exposed to the ground. Image source: Western Power

How big is this "enchantment" in this high voltage area?

If a 60,000 -volt high -voltage wire falls to the ground, then the contact point is the center of the circle, and the circular range with a radius of 10 meters is as dangerous as the high -voltage wire. If you don't want to shock, keep it from the contact point for at least 10 meters. If it is a higher -voltage high -voltage wire, the range of this circle is even larger.

Of course, if there is anything that can conduct electricity (such as branches) in this area, it will also become as dangerous as high -voltage wires and can generate electric shocks to the human body.

The power level near the substation rises. Image source: wikipedia

In the field of electrical engineering, the harm of rising land potentials has long been well known. Many international organizations have protection standards with elevated land potential. For example, the relevant standards of the Society of Electronics Engineers (IEEE) are IEEE STD. 80-2000. The U.S. Professional Safety and Health Agency (OSHA) also attributed land potential to "Known Hazard" and proposed corresponding management and disposal regulations.

So, what should I do at this time in case of a high -voltage wire in the nearby?

Once again, don't run at this time, running is dead. In accordance with the provisions of the U.S. Professional Safety and Health Agency, there are only two correct approach at this time: it is best to stay in place. If you have to leave, you need to take the "geisha", that is, the legs are rubbing each other Go, move a few centimeters each time, and your feet cannot leave the ground.

Movement methods in the area of ​​the ground power level: geisha. Picture source: scga

Why is this? The physical knowledge of middle school tells us that the current is caused by poor potential. Because if there is a difference between the two points between the human body, then the person will pass the power.

In the field of power safety, the two -step potential difference is called Step Potential. In the area of ​​the ground power level, the greater the steps, the greater the steps, the easier it is to be split.

Step potential. Picture source: scga

Imagine that one leg of a person stepped on the contact point of 60,000 volt high -voltage electricity and the earth, and the other leg was beyond 10 meters. Can't avoid it, unless you are Xiaozhi, don't try it.

Conversely, reducing the possibility of "pickup pickup" can be reduced, which is also the principle of "geisha step": keeping both feet always contact and moving with legs to reduce the difference between the two feet.

In addition to the stringing potential, another danger is called Touch Potential. It refers to people standing on a low -potential ground, and at the same time, the body is exposed to high potential objects. For example machine. Of course, at this time, the current will go from your feet to a low -electricity land from your feet.

Contact potential. Picture source: scga

The principle of contact with the potential sounds simple, but if you really encounter such a situation, what should you do? For example, when you are sitting in a car where you contact a high -voltage wire?

This is the second important suggestion.

At this time, the most critical self -rescue measure is not to try to leave the car. Because as long as you stay in the car, the body does not contact the low -electricity land, the current will not produce, you are safe.

The U.S. Professional Safety and Health Agency suggested that if you have to abandon the car to escape, then the best posture is to merge both feet, with both hands close to the body, and at the same time, it plays ions like a ruler. The purpose of this is to make you do not touch the earth at the same time when you leave the car. Escape the correct posture of electric vehicles: ruler bomb. Picture source: scga

Of course, after leaving the car, you will use the previously learned geisha.

Speaking of which, you may think that as long as high -voltage wires are in contact with the ground, it is dangerous, but in fact, such things will happen because of artificial settings: the zero wire of most high -voltage transmission lines is grounded, that is, Unicom with the Earth.

In other words, if the zero wire does not go ground, then standing on the ground while the fire of the high -voltage wire will not shock. But does such a system exist?

Yes, it is called floating group, or suspended ground. The zero line of the floating ground transmission system is not grounded, and the purpose of doing so is to safely and the electromagnetic interference generated by the current circuit generated by the ground.

Image source: wikimedia

Since floating ground looks safer than grounding, why do we usually use this transmission system?

The reason is that the voltage of floating ground is not stable, especially when the user switches electrical appliances. When the electrical appliances are turned on and off, over -grounding may occur, which may occur to damage the electrical appliances. Therefore, floating ground is mainly used in large factories, as well as places that cannot be grounded, such as on the plane.

After seeing the safety position and floating ground near the high -voltage wire, the careful child may issue a question: Since the neutral ground ground ground of the general transmission line, then I can directly treat the ground as the scorpion?

There is indeed such operations. This kind of transmission system that uses the ground directly as the zero line is called Single Wire Earth Return Systems. Sometimes, it is not the earth, but the water body as the zero line. Of course, such a system has high requirements for the insulation of the fire line, otherwise the Pikachu is really running away.

The single -line circuit transmission line in the Cruag National Park in Mozambaka Barbara District. Image source: wikipedia

Obviously, the main reason for treating the earth as the zero line is to save the cost of manufacturing and laying the zero line, so most of the single -line circuit is mostly used in areas with scarce smoke and isolated electric fields.

In 1981, a single -line circuit transmission line was built between Betley in Alaska and Napaka. Some developing countries also use such systems as the main transmission facilities, such as Laos, Mozambique and South Africa. Stepping on the ground of these countries a little bit crispy, it may not be an illusion.

Cover source: Mathias Putze/European Stork Village Network

Reference materials:

https://docs.qq.com/doc/dvgxoeglxymttrhv

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Source: Take the science home

Edit: Lezi Superman

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