How to protect your computer from lightning. After a thunderstorm, the Wi-Fi router stopped working. Why, what to do, and how to protect your router from lightning? How to protect your router or modem during a thunderstorm
Even from Soviet times, a tradition has been preserved - in a thunderstorm, turn off everything from the outlets. But what to do with the refrigerator, because thunderstorm weather can last several hours, and during this time it will flow? Or if you have an urgent project and you can't turn off your computer? Or if you are not at home?
Why can't electricity be used during a thunderstorm - or is it still possible?
There are hundreds of reasons to keep your appliances on. Many people do this with the hope that lightning strikes power lines once every 20 years, and this time it will blow over. But why play the lottery if you can protect yourself and safely use electricity. Let's figure out what exactly to be afraid of during a thunderstorm.
The myth that electrical engineering is a lightning magnet
As you know, electrical appliances do not attract lightning. This myth is very similar to the fact that supposedly it is impossible to use mobile phones in thunderstorm weather - this is not true. This statement appeared after in 2006 in the British Medical Journal bmj.com An article was published stating that a mobile phone exacerbates the effects of a lightning strike. But, in the text there is not a word about the fact that mobile phones attract a thunderstorm.
Interesting: the article talked about metal phones. Cases have been recorded when, after a lightning strike, the metal case of the phone became hot and caused serious burns. But, the article was published in 2006, and now smartphone cases are made mainly of plastic, like Samsung and glass, like iPhone. The information in the article is no longer relevant.
After the article was published, newspapers began to massively print headlines like "Mobile phones are dangerous during a thunderstorm." Everywhere it was said that the victims during the strike spoke on the phone or that they had it with them. The topic caused a resonance and began to unwind even more. Thus, this popular myth was born. But, can electrical appliances actually attract lightning discharges?
How electrical appliances affect thunderstorms
In fact, turning off or on household electrical appliances does not affect the thunderstorm in any way. This is due to the specifics of the occurrence of this natural phenomenon. The clouds accumulate a static charge with a force of half a million amperes and a voltage of millions of volts. To discharge such energy, a neutral field is needed that can pass an ultra-high power current.
Only the earth can absorb such energy. The natural barrier between the positive cloud and the negative earth is air, which itself is a dielectric. And as soon as the accumulated charge gains enough power to break through this natural insulation, lightning appears. Most often, an electric discharge goes through raindrops - the path of least resistance, and on the ground it is aimed at high objects: iron pipes, wet trees, lightning rods, etc. The meager electromagnetic field of a smartphone and or other equipment cannot in any way affect the charge of such power.
Technique does not attract lightning bolts, but it may be harmed by them.. To prevent this from happening, she must be protected.
How to protect equipment from thunderstorms?
Contrary to popular misconception, lightning never strikes the wires of high-voltage lines themselves. They fall into the poles wet from the rain and pass through them into the ground. But, a passing ultra-high power discharge creates a strong electromagnetic field. Because of it, a high-power pulse appears in the power line.
What is dangerous impulse discharge?
The electronic pulse moves along the conductor, enters the home network and enters the electrical appliances through the outlet. Because of this all electronics with microcircuits burn out. The impulse discharge burns semiconductor elements (resistors, thyristors, etc.). As a rule, electronics after this is no longer suitable for repair.
For heating electrical appliances, a heavy-duty electrical impulse is not dangerous., since it lasts less than a second and during this time does not have time to heat the metal to dangerous temperatures.
An electrical impulse from a thunderstorm can come to a house not only through power lines, but also through a telephone or Internet cable. In this case, all devices with a wired connection to the Internet will burn out.
A fire due to such a discharge is unlikely to occur, but there is a lot of harm from this. In a fraction of a second, the overcurrent manages to burn electronic circuit boards. In order for there to be a source of ignition, gasoline must be poured onto the board on purpose. This happens only once in a thousand. Nevertheless, electronic equipment is expensive and requires protection.
How to protect yourself from lightning impulse?
For protection, you need to buy a surge protection device (SPD) or, as it is also called, a surge arrester. In order for the charge to completely dissipate, it must pass through several degrees of grounded protection:
- SPD on a column of high-voltage lines - conducts current over 100 kA;
- Class 1 (B) - conducts from 50 kA to 100 kA, is installed at enterprises, office buildings;
- Class 2 (C) - removes from 15 kA to 50 kA;
- Class 3 (D) - conducts from 8 kA to 45 kA.
In apartments, they often put class D, and in private houses C and D one after the other - for greater efficiency. It is impossible to foresee which power line pole lightning will strike. For example, if this happens nearby, it is highly likely that class D will not protect the network.
Class B is placed at the entrance to high-rise buildings, where wires with a cross section of 25 mm2 or more are brought in. A thinner core cannot pass such a powerful impulse, and it makes no sense to put a high-class spark gap on it.
A household SPD consists of a chemical semiconductor composition that allows ultra-high currents to pass through. A wire is connected to it on one side, and a ground on the other. As soon as an ultra-high power pulse flows through the conductor, the chemical composition passes it through itself into the ground.
To understand that lightning protection has worked, many manufacturers make the composition such that changes color when discharged. This does not mean that the spark gap is disposable. Some brands claim that their models are designed for 2-3 or even more operations.
If the arrester is inexpensive, it is better to replace it after the first operation and not hope for a second time. Moreover, the cost of budget analogues starts from 350 UAH.
Where to put protection?
often put one arrester per power grid - not enough. This is not the only way for an ultra-high pulsed discharge to enter your network. There is also a computer and telephone cable, they also need to be protected.
Internet cable
Often, the provider's Internet cable is routed to power poles. And if suddenly lightning strikes this pole, two impulses will appear at once, which will simultaneously flow into the house through the power grid and the copper-core network cable.
If you had an SPD installed at the input and it removed one of the current pulses, then the second one will burn all the electronics in its path. The router and all computers connected to the Internet via cable will burn, even if they were turned off at that moment. That's why, Internet cable needs a special lightning arrester.
There is no need to install it in high-rise buildings, as providers themselves protect their own equipment. Each Internet node on the floor is already equipped with lightning protection. But there are exceptions to every rule, so check with the provider whether you should put additional protection.
Thunderstorms need to be feared if the Internet is carried out by a copper twisted pair cable, an optical cable does not conduct current.
telephone cable
The situation is similar with telephone lines. They are independent of mains power lines and pass ultra-high pulses through their own cable. If there is no protection and a discharge occurs, all telephone sets will burn out. In a private house, the consequences are not so terrible - one or two phones will burn. But, for example, all telephones and faxes will burn out in the office. And this is a loss of thousands of hryvnia. It is cheaper to put a spark gap worth a few hundred.
In multi-apartment buildings, the operator must protect his own equipment from thunderstorms, but in Ukrainian realities this is not always the case. For example, in the lines of Ukrtelecom it is a lottery, protection costs every other time. It is not uncommon for household appliances to burn out due to the lack of lightning protection in this operator.
Antenna cable
The so-called "Polish antennas" are gradually becoming a thing of the past. Nevertheless, they are still used in Ukrainian villages. Signal receivers are placed on 10-meter masts, most often metal, and the coaxial cable from them is led into the building.
Such antennas are the best target for lightning. After hitting, the current pulse flows into the house and "kills" the TV. Like other equipment, after that it can no longer be repaired. In order not to buy a new "box" after each thunderstorm, better put lightning arrester for antenna cable.
How to protect a network with an electric generator?
Let's assume that you have a generator, in case of power outages or for some other reason. When the light fails, the backup source is turned on automatically through the ATS system. Where in this case to put the arrester?
If the generator is small at 3-5 kW and standing indoors, for example, somewhere in the barn, you can simply install a lightning arrester to the main line in front of the ATS. The probability that lightning will hit the backup source and create an impulse is scanty, rather it will strike the shed itself and provoke a fire. Therefore, protecting the backup line, in this case, makes no sense.
Another situation is if the generator installed on the street. If there is no lightning rod, lightning can get into it, which is likely to disable it. But, this is not all the losses, because an ultra-high current will flow through the backup cable and disable the ATS system.
If during the strike the network was powered from a backup source, then a lightning discharge will fall into it and destroy the electronics included in the sockets.
Install one lightning arrester after AVR - wrong, because it will be "killed" by a discharge from the city network. If you put lightning protection in front of the ATS on the main line, then all electronics will fail through the backup line. Therefore, in this situation, the most appropriate option put two lightning arresters in front of the ATS- to the reserve and the city network.
How to protect your home from thunderstorms?
Lightning strikes on buildings fires. The last sensational incident happened on August 22, 2017, when the blow fell on the building of the Court of Appeal of the Kharkiv region. The fire started from the roof, then the fire reached the second and first floors. The total fire area was 1500 sq.m. And this is not the only such case. Thunderstorms often cause fires in private households.
The probability of hitting depends on many factors: the height of the location, the placement of taller buildings nearby, etc. If the house is on a hill, the probability is higher than if it was somewhere below. Also, if there are higher buildings nearby, it is likely that lightning will hit them.
But, even if the building is in a lowland, the probability of hitting still remains. This may be due to a combination of circumstances. For example, while it was raining, a thundercloud formed just above your house. The impact will be on the roof or the nearest tall tree. To prevent a fire, put lightning rod.
This is a long grounding mast mounted at the highest point of the building. Through it, electricity is diverted to the ground, where a buried metal cube - such a design conducts ultra-high currents better. Lightning rod grounding should be independent and nothing do not touch with network grounding. It is better to spread them to the maximum possible distance.
If the grounding of the lightning rod and the mains come into contact, then the impulse discharge will enter the house through the sockets. Lightning current does not care what to flow - phase, neutral or ground.
When planning a lightning rod, take outdoor network wires away from its ground loop, otherwise a lightning strike will provoke a pulse in nearby conductors.
Use electricity in any weather
If you put modular lightning arresters in a shield, your equipment will be safe. So you can use the Internet on your computer even in thunderstorms and not be afraid that all electrical equipment will “burn out”. The minimum set for a private house costs about 1000 UAH. (may be more expensive, depending on the manufacturer). It includes:
- class C and D lightning arresters;
- lightning arresters for internet cable;
- lightning protection for a telephone line.
This set enough for 10-15 years, and maybe more if your house is not located at the epicenter of the formation of thunderclouds. That's enough to keep you from twitching with every flicker in rainy weather and not running around pulling everything out of sockets when thunder sounds.
We looked at how to protect your home from lightning strikes with a lightning rod, but protective measures are not limited to this. About what else threatens us and how to protect ourselves from these threats, we will tell in this article.
As it was said at the very beginning, the organization of external protection is not enough. We remove only the risks of a direct lightning strike into the house and other objects located on the plot. Unfortunately, a thunderstorm can affect objects that may even be located outside the site. But the result of such exposure is a serious danger to the home. In real conditions, such an impact is more common than a lightning strike directly into a house.
Internal surge protection
The channel through which a hazardous effect can be exerted is external electrical and communication networks. So, if lightning hit, for example, electrical networks even a few kilometers from a country house, the damage can be significant. From the failure of electronic devices and electrical equipment to a real fire. Such an effect is commonly called an impulse overvoltage. It should be noted that in addition to a thunderstorm, such an overvoltage can be caused by other reasons, for example, an accident at a substation.
There are usually two causes of overvoltage caused by a thunderstorm. The first one is the direct hit of lightning into the network, most often electrical. The second is a lightning strike next to the network. The fact is that with such an impact, an electric field arises, and we will get an induced electric current, which causes an overvoltage. Lightning can strike close to the house, and maybe outside the backyard. Hence the conclusion that it may not be possible to protect external networks from such influence, therefore it is necessary to protect the networks directly in the house.
Two important points should be noted. First, for such a protection system to work, first of all, the electrical networks themselves must be performed at the proper level, in particular, a full-fledged potential equalization system must be implemented. The second important point is that there is no universal remedy for surge protection. Therefore, the zone principle is applied, and all protection devices are divided into classes and categories. Class "A" is of no interest to ordinary users, such equipment is intended for installation at substations. For protection of a country house the equipment of a class from "B" to "D" is used.
Home protection
At the entrance to the building, the first level of protection is usually organized. For these purposes, class B equipment is used, its task is to limit the overvoltage to 2.5 kV. Typically, surge arresters are used for such purposes. different types. They are arranged simply, schematically these are two contacts, between which the required gap is set. Under normal conditions, such a gap acts as a dielectric. When the critical value is reached, a breakdown occurs, an arc discharge is formed between the contacts and the overvoltage is extinguished to ground.
Surge arrester for installation at the input
Such arresters are installed at the entrance to the house. This is done in order to avoid affecting the protective conductor and the potential equalization connection. Arresters are open and gas-filled. The parameters of open arresters depend on external influences, such as, for example, air humidity. In winter, the air humidity is lower, but in winter thunderstorms are very rare. Therefore, such an arrester should protect against accidents at a transformer substation. The overvoltage parameters in this case are known, which makes it possible to select the required device. In summer, when thunderstorms are to be expected, the humidity of the air rises, which means that the level of operation of the arrester decreases. At the same time, the arrester chosen on the basis of winter conditions will provide reliable protection in summer as well.
The contacts of the gas-filled spark gap are isolated from the external environment, and the container is filled with an inert gas under low pressure. Such devices have stable parameters, although they are more expensive.
Line protection
If for the whole house the voltage limit of 2.5 kV may be justified, then for individual house lines it is excessive. Therefore, the next frontier is needed, which will protect separate lines. Unfortunately, there is an opinion that simple automata are enough for protection. This is a dangerous delusion. The thing is that the machines have a slightly different purpose - they protect against emergency situations on the line, for example, a short circuit. But, from external influences, they can not protect.
To protect the lines, varistors are used, these are class “C” devices that protect against surge voltage up to 1.5 kV. A varistor, or semiconductor resistor, is most often produced in a ceramic version. In normal mode, they have a resistance of units of GΩ, that is, there is practically no current flowing through them. When the critical voltage value is reached, the resistance drops sharply to tens of ohms, with a further increase in voltage, the resistance only decreases, so the discharge is extinguished to the ground. For house networks (voltage 220/380 V 50 Hz), the critical voltage value is 470-560 V. Varistors are installed in switchboards for each line that needs to be protected.
Protecting a Specific Device
The last line of defense is the protection of a particular household appliance. For these purposes, class "D" devices are used. This is especially true for electronic equipment that is sensitive to power surges. Well-known uninterruptible power supplies for computers, and even network filters, can have built-in protection of the required level.
Usually, each device is not protected from such jumps - for some household appliances, such jumps do no harm, the cost of others is simply much lower than the organization of such protection. For example, it's easier to replace an incandescent light bulb than it is to protect it from occasional power surges. In the same case when protection is required, there are devices that allow you to protect even a separate outlet. Most often, this is a spark gap already familiar to us, however, designed for a lower critical level of impulse overvoltage. Varistors can also be used, also specialized.
It is important to remember that without organizing the protection of the upper levels, and this is the protection of the house and lines, it is still not worth hoping for reliable protection of a particular device.
Street electrical networks
With electrical networks, we practically figured it out. Only the last case remains. The methods described above are designed to protect internal networks from overvoltage that is generated in the external network. But overvoltage can also occur in the internal network itself. This happens, for example, when you need to connect to electrical network outdoor devices. For example, this could be street lighting or an anti-icing system.
In such cases, the output of electrical networks outside the house must be organized as a separate line. And as an additional protective device, a spark gap is installed, similar to the one installed at the input to the house.
Protection of low-voltage networks
In a modern house, in addition to electrical, there are also low-voltage networks. Inside the house, they do not require protection from a thunderstorm. But in the event that such networks are displayed outside the house, then protection is necessary. An obvious example is a television antenna. A direct lightning strike is very likely. Other low-voltage networks can also be brought outside the house. For example, to connect to a home computer network, two separate buildings. And it is possible that such a network will be laid to control automatic irrigation or to organize video surveillance. If you lay the cable underground, then there will be no direct lightning strike. However, if we recall the inductive shock, it becomes clear that this will not protect against surge voltage.
DIN rail protection device for low-voltage networks
To protect low-current networks, both arresters and varistors can be used, of course, with the appropriate parameters. But the equipment using such networks is very sensitive to overvoltage, therefore, combined devices are more often used, which contain both a gas discharger and a varistor.
Low-voltage network protection device of free installation
Protective devices are placed in low-current shields, on DIN rails. Unless, of course, SCS (structured cabling) is organized in the house. If not, then free-standing devices are used, such small boxes designed to be mounted on the wall. It is convenient that devices can be designed for several channels at once, usually no more than four.
Now the reader knows everything about protecting his country house from a thunderstorm. It remains only to implement this knowledge in life.
Vadim Zhigulevsky, rmnt.ru
With the advent of spring and then summer, we all rejoice in the warmth, rain and even thunderstorms. May thunderstorms... After which the sun appears and everything turns green. But today we will talk about how a thunderstorm can affect a router, or a modem. If you have already encountered this problem, and your Internet stopped working after a thunderstorm, or does not work at all wifi router Let's try to figure out what can be done in this situation. I will also tell you how to protect your router during a thunderstorm so that it remains safe and sound.
We all know well that lightning and thunder can damage various electrical appliances. It is not uncommon for situations when televisions, refrigerators, computers and other equipment that is connected to the mains burn out during a thunderstorm. So, routers and modems are very sensitive to lightning strikes. They can suffer both due to a power failure or get hit through an Internet cable that is connected to the WAN port. Moreover, it seems to me that most often the router receives a discharge precisely over the Internet. This is because these cables are laid anyhow and are not protected from lightning in any way.
In this article:
- How a thunderstorm affects a router or modem, and how it can harm them.
- What to do if the Internet and / or the router stopped working after a thunderstorm.
- How to protect the router (modem) during a thunderstorm.
Why is the router afraid of thunderstorms?
As I wrote above, there are two reasons. Apart from a direct lightning strike on the router 🙂
- Voltage surge in the mains. In this case, most often the power supply of the router burns out. But the board itself can also suffer. There are cases when, after such a power surge, the power supply becomes very hot, or even melts. The router may generally stop responding to the connection to the mains, or only the power indicator will light up. It happens that all the indicators are constantly on. This already depends on the specific model and indicates some kind of hardware failure.
- The occurrence and transmission of a discharge through an Internet cable. As a rule, the Internet cable is laid from house to house, and is not protected from lightning strikes. If the provider has not taken care of protecting their equipment, then during a thunderstorm it can be severely damaged. Moreover, all routers and computers (network cards) to which a network cable is connected suffer. Since a discharge passes through it. In the best case, only the WAN port, or the network card on the computer, burns out. At worst, the router board burns out completely, or motherboard and other computer components.
It should be noted that not only lightning can cause harm. Most often, during a thunderstorm, a strong wind rises, which can close the power line, knock down a tree on it, etc. This will entail a short circuit, which can also disable electrical appliances connected to the network.
What to do if the Internet and Wi-Fi router do not work after a thunderstorm?
First you need to determine what is the reason. There may be problems on the side of the equipment of the provider itself, or something with your modem, router, or computer. Or maybe both.
Perform all actions only after the thunderstorm is completely over!
Be careful, the router's power supply may be hot or damaged!
Let's look at the different options:
1 Turn on your router and pay attention to the indicators. If they do not light up at all, only Power (power) is on, or all indicators are constantly on, then most likely the router is out of order. In this case, there are several options:
I did not consider the case when the router obviously burned out. The case of the device itself, or the power supply, began to melt, smoke went up, etc. There, it seems to me, the reason and solutions are clear even without my advice.
2 The router is working, there is a Wi-Fi network, but there is no Internet connection. "Without internet access." Most often this happens for two reasons:
Here are some breakdowns. First of all, determine the reason why the Internet stopped working after a thunderstorm. Problems with the provider, or with your equipment. If you have something, then see how the modem or router works. What indicators are on. Check WAN port operation.
How to protect your router or modem during a thunderstorm?
A few tips on this subject:
- As soon as clouds begin to gather outside the window and it smells like a thunderstorm, unplug your router from the mains, unplug the cable from the WAN port and hide it in a closet :). I'm serious. The best way– turn off the router completely. Don't forget to unplug your internet cable. Moreover, I advise you to turn off computers and other equipment. Just unplug them.
- Connect the router through a normal network filter. In most cases, it really helps. Such a filter is not expensive, and the effect of it may not be bad.
- It is even better to connect the router through a voltage stabilizer. I understand that these are additional costs, but if you have problems with the mains voltage, or you live in a place where lightning likes to fly, then buying a stabilizer may be the only solution. Although, if there is a strong discharge, then the stabilizers also burn.
Write in the comments how you protect your equipment from such natural phenomena. And have you had to deal with problems in the operation of the router, or the Internet after a rain with beautiful lightning.
Increased thunderstorm activity in the summer season makes it necessary to take measures to protect against the destructive effects of the strongest lightning discharges. You can protect yourself from powerful discharges of natural electricity with the help of modern electronic means, such as voltage stabilizers and arresters. There are options for lightning protection for a wide variety of equipment traditionally used in everyday life (including network routers and other communication elements).
Lightning protection of electrical networks
A direct lightning strike into a house is fraught not only with the threat of causing direct damage to the structure, but also leads to the formation of strong electromagnetic fields and induced currents. These physical effects cause large voltage spikes that can damage any equipment that is connected to household power during a thunderstorm. Routers, network switches (switches) and computers are especially often affected by thunderstorms. With the direct impact of discharges on the electrical wiring, the wires can melt, a short circuit occurs, often leading to a fire.
In order to prevent the possible consequences of a thunderstorm, it is customary to use special technical means. They limit the voltage and reduce the effect of electromagnetic interference. These lightning protection devices include:
- special arresters;
- voltage stabilizers in the network;
- surge arresters OVR and other similar devices.
Please note that the functions of a pulse arrester and a limiter are combined in a number of modern electrical appliances, so their division into separate types is purely arbitrary.
Types of stabilizers
Stabilizers, as a rule, are used to protect networks from sudden surges in the supply voltage caused by power outages or poor quality. However, in certain situations, these devices are able to protect electrical networks from lightning that strikes during a thunderstorm.
There are three types of voltage regulators:
- the simplest regulators of the "LATR" type;
- relay type systems;
- triac stabilizers.
To protect electrical networks from thunderstorms, only fast-acting samples of the second and third types of stabilizers are used, which provide the required speed of response to a lightning discharge.
Additional Information. For protection against natural electricity, industrial stabilizers with lightning protection, equipped with a special discharge unit, are best suited.
At the same time, devices based on triacs, operating on the principle of key switching of power circuits, are most preferable. The only drawback of such stabilizers is the high cost.
Arresters (surge arresters)
The use of limiters as an element of protection of electrical equipment is currently widespread, which is explained by their relatively low price and efficiency. Three modifications of these devices are known, each of which is assigned its own class, similar to the characteristics of network circuit breakers (classes B, C and D, respectively).
Devices of the first class maintain the efficiency of power circuits by diverting dangerous pickups to the ground. The device is made in the form of a modular design with a hermetically built arrester that responds to overcurrents.
Such a block is installed in the switchboard in the input cable (before the electric meter) and provides protection against the transfer of dangerous pickups to the PEN protective conductor. Devices of this class are installed at industrial facilities, in government agencies and institutions, as well as in buildings that are part of large residential complexes.
Arresters of the second type (class C) are completely similar in their functionality to those discussed above, with the only difference being that they can also operate from ordinary switching, accompanied by current surges in the mains.
And, finally, class D devices are designed to protect individual consumers connected to a given electrical network from thunderstorms. They are installed directly in the user's power sockets, protecting the wiring from surges.
With the help of such built-in devices, it is possible to protect the computer from a thunderstorm, as well as to ensure the uninterrupted operation of the router in the apartment.
Telecommunications protection devices
Despite the fact that coaxial cable networks are highly resistant to external force fields, they are quite vulnerable under certain conditions (most often during a thunderstorm). The situation is similar with the so-called "twisted pairs", which also need protection from strong electromagnetic pickups and overvoltages.
To eliminate all these threats, the industry has developed devices called "GZ-RS485-T", which protect a two-wire twisted pair, both from pickups and from secondary electrostatics. The efficiency of this class of equipment is ensured by shunting interference to the ground bus or automatic channel shutdown.
It is also necessary to touch upon the issue of the security of satellite communication lines. When organizing the operation of such channels with the professional name "satellite" (SATELLITE LINE), surge protection is also provided with the help of special equipment.
As a result of the May thunderstorms, it was necessary to revise the burnt equipment, and although the damage was not so great financially, the failure of some equipment violated the well-established comfort of living in one's own house. So I decided to turn to experts in my field, consult and expand the protection system.
Initial data: house, 3 phases (15 kW per house), grounding with a 3 m long pin, autonomous electrical system based on solar panels
The photo shows the result of a short circuit from the side of the 10 kV line. The protection did not work at the regional substation. This is how the introductory shield looks from the 0.4KV side. The IEK 100A machine could not break the arc between the jaws. Next along the line was MAC HYBRID 9kW 48V. We escaped with a slight fright: the varistor was changed in the inverter, after which the MAC came to life, however, the RS232 port stopped working normally. That is, a serious accident at the substation, which burned out a 100 Amp automatic fuse, affected the inverter only with a burned-out varistor and errors on the controller, and all other functionality of the device was preserved, like all the equipment connected after it - praiseworthy work.
And below in the photo is the metering station from the side of 10 kV
This accident did not happen in my house, but these photos were handed over to me by specialists from the MicroART company. At one time I decided to switch to equipment Russian manufacturer for his hybrid solar-grid electrical system and described these devices and.
I had the following case: during a thunderstorm, lightning struck my substation or nearby, as a result of which the protection at the entrance to the house worked out. The result of that thunderstorm was a burned-out battery charger connected to the network at the time of the thunderstorm, a blown ventilation automation relay (the relay was powered from the line that was supported by the same charger), and the Hybrid 4.5 kW inverter MAC started flashing and stopped generating. After a thunderstorm, restarting all systems brought the house back to power, the inverter started without problems, and I thought about seriously protecting the home electrical network.
A bit of theory
During a thunderstorm in an ordinary apartment or office building, the protections installed by the stationary power supply must work out. In a cottage village, village or cottages, protection, as a rule, is limited to dug-in grounding at the substation and a fuse that disconnects the entire network from work. Moreover, according to the connection rules, grounding must also be installed on every second pole and separately on the final one, where the subscriber house is connected. Having walked through my village and examined more than fifty pillars, I did not find a single grounding, that is, I can only rely on myself.
The second "killer" factor is induced electricity. During lightning, there is a fairly powerful burst of EMP, and the house wiring is, in fact, a large antenna. The closer the lightning, the greater the likelihood of a power surge in the internal network. This phenomenon is constantly faced and continue to face the installers of brownies local networks when switches without grounding, during a thunderstorm, burn out in whole chains.
So, we need to protect ourselves from an external impulse that can come from a substation and from an internal surge that can happen with lightning near the house.
Practice
Lightning rod
If your house is located on a hill, far from any buildings and is the highest point on the ground, then it is better to take care of a lightning rod. The device is reliable, but it is necessary to clearly calculate the coverage area. There are a lot of materials on the net on this subject. I will only say that the action of a lightning rod spreads in a cone from the highest point to the ground. To "cover" the whole house, it is necessary to install either two lightning rods with a metal cable between them, or one, but quite high. If the grounding of the lightning rod is made separately from the general grounding, then it is necessary to apply a potential equalization system.
Extracts from INSTRUCTIONS FOR LIGHTNING PROTECTION OF BUILDINGS AND STRUCTURES RD 34.21.122-87:
“It is allowed to use all recommended grounding electrodes as grounding conductors for lightning protection
electrical installations, with the exception of neutral wires of overhead power lines with voltage up to 1 kV. „
“2.5. To exclude the entry of high potential into the protected building or structure, but underground
metal communications (including electric cables for any purpose)
direct lightning strikes should be, if possible, removed from these communications to the maximum distance,
admissible according to technological requirements. „
Entering the network into the house
The danger of high voltage input is terrible not only in a thunderstorm, but also when the wires on the poles overlap or there is a large phase imbalance. A common thing for rural power networks, when the phase voltage can be 180, 200 and 240 V. GOST allows power supply with a voltage deviation of up to 10% (to be exact, then + 10% and -15%) from the norm of 220 V, that is, from 187 to 242 V. But not all supplied equipment can withstand such voltage drops. For normal protection, it is best to use voltage stabilizers. Moreover, there are three-phase and single-phase stabilizers. Most often, three single-phase stabilizers will work better than one three-phase, if only because the simplest devices monitor the voltage in one phase and the change (increase or decrease) in the voltage occurs in all three. Simplified: when the voltage rises from 180 to 220 V, the voltage on the other phase will increase from 210 to 250 V, which is fraught with equipment. Therefore, tracking each of the phases will be more reliable. In addition, there are several types of stabilizers:
- Relay
- Triac
First has a high accuracy of voltage setting, since the motor slides the carrier along the windings and sets the desired voltage. Pros: low price, high accuracy of output voltage. Cons: low response rate to power surges, physical wear and tear of mechanics
Second has an increased switching speed of the transformer windings, but since the power can reach a dozen or more kW, the relay contactors wear out and sooner or later can stick, which will lead to sad consequences. Pros: affordable price, sufficient switching speed. Cons: insufficient reliability due to the use of mechanical relays.
Third the most interesting type, but also the most expensive. The use of powerful keys allows you to instantly respond to changes in the input voltage and switch the transformer windings. There is simply no physical wear, as well as sticking of contacts. In addition, switching occurs when the sine passes through zero, so jumps are also excluded. Pros: high response speed, no physical wear. Cons: high price.
For myself, I chose a more expensive, but also more reliable option, a 6 kW CH-LCD “Energy” triac-controlled stabilizer. Since I already have a 4.5 kW inverter, which can deliver up to 7 kW at the peak, it was decided to choose a stabilizer with a rated power of 6 kW and the ability to output up to 7.4 kW at the peak.
You can read in detail about the features of the operation of these stabilizers and what kind of stabilizers there are in general.
Well, I was interested in taking it apart and seeing what was inside.
The opening of the stabilizer showed
As can be seen from the photo, the stabilizer uses a toroidal transformer, which, with the same dimensions as the W-shaped one, has greater efficiency and less weight. The transformer itself was made in Tula, and the stabilizer was designed and assembled in Moscow. Thus, we can safely declare a completely Russian production, which was managed to organize and maintain in the company MicroART.
So, I insured against subsidence and voltage growth in the range of 125-275 Volts, but what if there is a sharp voltage surge that goes beyond these limits? The inverter somehow showed me 287 V in phase, after which it went into protection. But apply 380 V to it and it will simply burn out, like the stabilizer. I wanted to protect expensive equipment. Some kind of release was required, which, at threshold voltages, would turn off the external network. It is better to be left without a network than to repair or change burned-out equipment later. The output was found - the mains voltage control relay UZM-51M1.
This device is designed to ensure the operation of one phase, while you can manually set the upper and lower voltage thresholds at which the relay will operate. The shutdown time is about 20 ms, which is a very good indicator. At the same time, small drawdowns or some overvoltage will not cause an instant shutdown, but a shutdown timer will start. When the parameters return to normal, the relay will independently connect the load to the network. So, home devices are protected from surges and surges in the external power grid using a voltage control relay and a stabilizer. In the event of a mains failure, the inverter starts to work. But what if the external network is already disconnected, lightning strikes nearby and the house wiring works like an antenna?
Internal network protection
We will proceed from the fact that all sockets have the correct wiring, the grounding is done properly and the excess charge flows into the ground. But a power surge in the internal network easily destroys all equipment, since all protections are for defense against external surges. But there is nothing from internal interference. With this thought, I turned to MicroART engineers when I was picking up the stabilizer and they recommended me a “Lightning and interference protection device” - SPD.
This is a kind of arrester, which, when a critical voltage appears between the phase and the ground, passes a pulse through itself, sending it to ground. That is, during a thunderstorm, when lightning strikes nearby and the voltage in the home network rises to several kilovolts along the phase wire relative to the ground and exceeds a certain value, this SPD will simply release the entire charge into the ground. Therefore, it is placed in front of the inverter, with one end connected to the phase and the other to ground. It is worth considering that the discharge can be significant, so you should not save on the cross section of the ground wire, otherwise the resistance of the wire may turn out to be critical and not have time to transfer the impulse to the ground.
This is how the connection to the external network and the generator is made: 
I have already mentioned that I have an off-grid solar-powered system. A serious impulse can also come along the wires coming from the solar panels, disabling the solar controller, and behind it the inverter. Therefore, I also hung an SPD on each of the wires from the solar panels.
Generator protection
In the most emergency case, when there is no external network, the sun is not visible, and the batteries have already run out, all autonomists have a backup option - a gasoline / diesel generator. It will allow the home network to function, work itself as a powerful tool, and even recharge the batteries. I described a similar redundancy topology in my material. The problem with this connection is that most generators produce extremely unstable and “noisy” power. Sometimes inverters or chargers simply cannot work with such power. To suppress interference, there is a special surge protector. You can get by with a standard "pilot", but it is usually designed for power up to 2-3 kW, and more is often consumed from the generator. So, I also found an EMI (electromagnetic pulse) filter: EMI suppression line filter.
It can withstand power consumption up to 11 kW, which is enough to power an entire house if there is a powerful generator. It has a through connection and a separate ground pin.
Results of the work carried out
The result of one thunderstorm and small losses was a rethinking of the methods of protection, both from external energy collisions and from internal ones. In addition, the security of all electrical appliances in the house has increased, both from voltage drops and from sudden surges and impulses. In addition, autonomy has increased due to the connection of the generator through a filter, which guarantees a stable charge of the batteries and the normal operation of the inverter.
As a result, the electrical system has changed. Before: 
So it became AFTER installing protection:
The generator wiring diagram is quite simple. Any of the wires is combined with the existing ground and zero brought into the house. The second wire after that becomes the phase. It is important to choose a switch that will prevent the simultaneous short circuit of the generator phase and the phase from the substation.
The first start of the whole system looked like this:
