Modern home appliances contain sensitive electronics, making these devices vulnerable to power surges. Since it is not possible to eliminate them, reliable protection is necessary. Unfortunately, its organization is not the responsibility of the housing and communal services service, so you have to deal with this issue yourself. Fortunately, purchasing protective devices is not a problem today. Before moving on to the description and principle of operation of such devices, we will briefly talk about the reasons that cause voltage surges and their consequences.

What is voltage drop and its nature?

This term refers to a short-term change in the amplitude of the power supply voltage, followed by restoration close to the original level. As a rule, the duration of such a pulse is calculated in milliseconds. There are several reasons for its occurrence:

1. Atmospheric phenomena in the form of lightning discharges can cause an overvoltage of several kilovolts, which is not only guaranteed to damage electrical appliances, but can also cause a fire. In this case, it is easier for residents of high-rise buildings, since organizing protection from such predictable phenomena is the responsibility of electricity suppliers. As for private houses (especially with air inlet), their residents should deal with this issue on their own or contact specialists.
2. Jumps during switching processes when powerful consumers are connected and disconnected.
3. Electrostatic induction.
4. Connecting certain equipment (welding, commutator motor, etc.).

The figure below clearly demonstrates the magnitude of the lightning impulse (U gr) and switching impulse (U k) in relation to the rated network voltage (U n).

To complete the picture, mention should be made of long-term increases and decreases in voltage. The cause of the first is a line fault, as a result of which the neutral wire breaks, which causes an increase to 380 volts (to be precise). No devices will be able to normalize the situation; you will have to wait until the accident is resolved.

Long-term voltage drops can often be observed in rural areas or holiday villages. This is due to insufficient power of the transformer at the substation.

What is the danger of fluctuations?

In accordance with acceptable standards, deviations from the nominal value are allowed in the range from -10% to +10%. During surges, the voltage can significantly go beyond the established limits. As a result, power supplies household appliances are subject to overload and may fail or significantly reduce their service life. With high or long-term differences, there is a high probability of ignition of the wiring, and, as a result, a fire.

Low voltage also threatens trouble, especially the compressors of refrigeration units are critical to this, as well as many impulse blocks nutrition.

Protective devices

There are several types of protective devices that differ in both functionality and cost, some of them provide protection to only one household appliance, others – to all those in the house. We list the well-proven and most common protective devices.

Network filter

The simplest and most affordable option for protecting low-power household equipment. It has proven itself to be excellent at surges up to 400-450 volts. The device is not designed for higher impulses (at best, it will take the blow on itself, saving expensive equipment).

The main protection element of such a device is a varistor (a semiconductor element that changes resistance depending on the applied voltage). It is this that fails when a pulse exceeds 450 V. The second important function of the filter is protection against high-frequency interference (occurring during operation of an electric motor, welding, etc.) that negatively affects electronics. The third element of protection is a fuse that trips during a short circuit.

Filters should not be confused with ordinary extension cords, which do not have protective functions, but are similar in appearance. To distinguish them, just look at the product passport, where full specifications. The absence of such should in itself raise suspicion.

Stabilizer

Unlike the previous type, devices of this class allow you to normalize the voltage in accordance with the nominal one. For example, by setting the limit within 110-250 V, the output of the device will be a stable 220 V. If the voltage goes beyond the permissible limits, the device will turn off the power and resume its supply after the operation of the electrical network is normalized.

In some cases (for example, in rural areas), installing a stabilizer is the only way to increase the voltage to the required level. Household stabilizers come in two modifications:

• Linear. They are designed to connect one or more household appliances.
• Trunk, installed at the entrance to the electrical network of a building or apartment.

Both the first and second should be selected based on the load power.

Uninterruptible power supplies

The main difference from the previous type is the ability to continue supplying power to the connected device after the protection has tripped or a complete power outage. The operating time in this mode directly depends on the battery capacity and load power.

In everyday life, these devices are mainly used to connect desktop computers, so as not to lose data in case of problems with the electrical network. When the protection is triggered, the UPS will continue to supply power for a certain time, usually no more than half an hour (depending on the characteristics of the device). This time is enough to save the necessary data and shut down the computer correctly.

Modern UPS models can independently control the operation of a computer via USB interface, for example, close text editor(after saving open documents), then turn it off. It's pretty useful feature, if the user was not nearby when the protection was triggered.

Surge protection devices

All of the above devices have a common drawback: they do not have effective impulse protection high voltage. If this happens, it is almost guaranteed to disable such devices. Therefore, the protection must be organized in such a way that after activation it can be promptly brought into working condition. SPDs meet this requirement perfectly. On their basis, a multi-level system for protecting the internal lines of a private home is organized.

One of the accepted classifications of such devices is shown in the table.

Table 1. SPD classification

An example of three-level protection is shown below.

Design features SPD.

The device is a platform (C in Fig. 6) with a replaceable module (B), inside of which there are varistors. If they fail, the indicator (A) will change color (in the model shown in the figure to red).

Externally, the device resembles a circuit breaker, the mounting is the same (for DIN rail).

A special feature of SPDs is the need to replace modules when varistors fail (which is quite simple). The modules are designed in such a way that it is impossible to install them on a platform with a different rating. The only serious drawback is related to the characteristic features of varistors. They need time to cool down; repeated exposure to lightning strikes significantly complicates this process.

Safety relay

In conclusion, we will consider voltage control relays (VCRs); these devices are capable of protecting household appliances from switching pulses, phase imbalance, and low voltage. They cannot cope with lightning impulses because they are not designed for this. Their scope of application is protecting the internal network of an apartment, that is, where providing lightning protection is the responsibility of electric companies.

The devices can be installed in the input panel, directly after the electric meter, for this purpose a DIN rail mount is provided.

In addition, modifications of devices are produced in the form of power extension cords and modules for sockets.

These devices can only perform a protective shutdown of the network; if the voltage goes beyond the specified limits (set by control buttons), after normalization of the electrical network it is connected. Stabilization and filtration are not performed.

Cautions

You should not trust the protection of your home to home-made structures; in domestic conditions it can be problematic to configure the assembled circuit and test its operation in critical modes.

Without practical experience in organizing lightning protection, you should not try to implement it yourself; it is better to entrust this work to professionals. We recommend that you consider this part of the article as informational.

All manipulations with the electrical panel, devices and wiring must be carried out only when the power supply is turned off.

The ignorant may be puzzled: why do we need any kind of surge protection in the network? Practicing electricians have probably eliminated the consequences of this phenomenon with their own hands more than once. So that the text does not become gobbledygook for a non-specialist, let us explain the nature of such leaps.

Reasons for spasmodic pulses in power supply devices:

1. Lightning strikes directly into electrical systems (generators, power lines, transformers). Moreover, lightning can strike nearby. These are lightning overvoltages, their duration is ≈ several tens of microseconds;
2. Switching in the system (necessary for stable operation of the network) often leads to switching overvoltages. Their duration is longer - several hundred microseconds. It depends on the impedance (complex resistance alternating current, active + reactance) of switched circuits. But they do not cause catastrophic destruction, like thunderstorms;
3. Some specific operational states of electrical equipment. Basically, only the skill and coordinated work of energy dispatchers can minimize the duration of so-called temporary overvoltages. Without delving into the physical jungle of processes, we will say that, unfortunately, it is not yet possible to completely avoid them. The duration can reach (according to some sources) 100 seconds.

All of them, despite their nature and parameters, are dangerous, primarily for electronic components of home appliances.

Possible consequences

Timely protection of electrical networks from overvoltage helps to avoid complete failure of both devices and parts of the distribution system. Lightning strikes cause the greatest harm to them. The frequency of lightning strikes and the magnitude of the discharge current depend largely on the terrain. But the method of technical execution of the electrical system is also important.

It is possible to completely protect a section of the network or a group of consumers from pulsed or constant increases in voltage, but not cheap. This is how energy workers balance between operational and economic “scissors.” And all over the world.

Failure of a transformer substation or burnt-out power line wires will not immediately fall financially on the shoulders of the consumer. There's no light for a while, and that's it. It’s a different matter if after the jump the computer or refrigerator died...

How to minimize losses

By breaking through the insulation of components, a voltage surge can cause short circuits. Fires in electrical installations are also common, and it doesn’t take long to lose a house, other than a direct danger to life. Therefore, every electrical installation (all electrical equipment from the panel to the light bulb is what it is) is protected from voltages increased above the norm.

Protection home network from overvoltage is carried out in several interconnected stages, always in a complex and in several ways.

The first is a lightning rod, or more correctly “lightning rod”. High-rise buildings are already equipped with lightning protection for the entire building, except for each individual apartment. Individual house: a lightning rod is the concern of the owners, with reliable grounding, tested by an electrical laboratory, and arresters of various designs.

Lightning strike into a lightning rod in a private house

But it's not just lightning that causes TVs to go silent. The “zero” has burned out - the voltage has jumped in some phases due to their distortion. One thing absolutely guarantees against all “electronic troubles” - disconnecting from the network. But how often do we use it? And it is not always possible to turn off the power to the same refrigerator in time.

Ways to protect your home network

Thunderstorm protection is discussed above. But it still won’t provide a complete guarantee against failure of home assistants. Same with other types of power surges. The reason is the “delicacy” of microelectronic components of complex household equipment.

Conventional protection devices: “automatic machines”, RCDs, (not to mention “traffic jams” - fuses) simply cannot keep up with the surge in volts. This prompted both “homemade” radio amateurs and professionals to develop new, fast-acting devices.

Modern network surge protection - a new generation circuit - switches off the load instantly. 4 circuit solutions that eliminate the need to repair or purchase an SBT when the quality of the supplied electricity changes: SPDs, stabilizers, voltage relays and an overvoltage sensor (OHS) + RCD.

• . The effect is achieved by using semiconductor components. The speed is orders of magnitude higher than traditional electromechanics. Such a network protection circuit breaker (SPD) is differentiated into 3 classes (according to IEC standards):
  1. It will protect against direct and indirect lightning strikes and compensate for the potential of the entry point into the building. The device is located at the input, most often the main switchboard of the building.
  2. Eliminates the inevitable side effects of lightning strikes and eliminates residual voltage. Installed after surge protection devices of class I.
  3. They are placed between auxiliary switchboards and end consumers, possibly in sockets. For the most sensitive consumers, their own SPDs can be installed.

When choosing and installing an SPD if there is a lack of special training, it is best to contact specialized organizations or consult with an experienced electrician.

Surge protection device (SPD)

• Stabilizers do not require installation. Below 150 or above 260 V? – block and disconnect from the network. Has the voltage returned to normal? - we turn on again. The displays that many models are equipped with will help you “monitor” the status.

Stabilizer for protection against power surges

• . Device → relay → socket - this is how the voltage relay is turned on. There are relays installed on switchboards and protecting the entire apartment “electronics” en masse.

Types of voltage relays

• DPN+UZO: the overvoltage sensor issues a command if the parameter is invalid actuator devices protective shutdown. The network is de-energized.

All protective assistants are mounted on the DIN rail of the shields.

In contact with

Today, each of us has a huge number of expensive electrical appliances installed in our apartments. And of course you want to always have “stable” 220 Volts in the sockets, so that the equipment works properly and is protected from overvoltage.

But in reality, everyone has had unpleasant moments at least once in their life, and it was not even you who were to blame for them, and not the quality service of electrical equipment by energy grid companies.

Only after this do most users think about whether it is possible to protect themselves and protect themselves from these moments, while incurring minimal costs. Everyone gets out to the best of their financial capabilities. Buy sources uninterruptible power supply on expensive equipment, voltage stabilizers or mounted stationary ones in an electrical panel. At the same time, in order to do this, you need certain knowledge.

What to do if there is no space in the panel, but there is no desire to invite an electrician or redo the wiring? In this case, a voltage relay in the socket will help you. Here is a comparison table of the two most common brands:

Let's take a closer look at each of them.

Voltage relay for socket RN-101M

It is produced by the famous Russian company Novatek-Electro.

Device specifications:

Very frequent overvoltages in the 220V network occur precisely when electricity is turned on at the substation after a long period of inactivity, caused by various reasons (scheduled repairs or repair of damage after short circuit). This has an extremely detrimental effect on the operation of household appliances such as a refrigerator. By connecting it not directly, but through a socket-type relay RN-101M, you can set the restart time.

What it is? This is the time after which the relay itself will turn on after voltage is supplied to the apartment. For RN-101M it can be set from 5 to 900 seconds. Thus, voltage will be supplied to your device after all transient processes, without the risk of failure of the motor or other elements.

In addition, a surge protector is mounted inside the device. It protects electronics from high-voltage network interference. And for protection against overloads there is an internal circuit breaker for current up to 15A. In general, this is not a socket, but a whole complex of protections in a miniature case.

There is a button in the upper left part of the body automatic protection from overload. When the machine knocks out, to turn on the relay, the button must be pressed down, like the old automatic traffic jams in the meter panel.

On the right is a digital indicator. Below it is an LED that records the state of the load (on-off). And adjustment buttons: minimum, maximum voltage and AR time.

Be careful with refrigerators and other compressor equipment. For them, you cannot set a threshold lower than that allowed by the factory instructions. So if you don’t have it, try to find it at least on the Internet.

In addition, the automatic restart time delay for refrigerators and air conditioners must be at least 4 minutes.

Also, do not forget about the error of the device. For example, you found in the documentation that the electronics on your equipment can safely operate at a maximum of 255 Volts. Long work at 256 Volts and that’s it – death to the device.

You set the setting on the relay in the socket to exactly 255 V, while forgetting that the stated error of the relay is up to 3 Volts. At night, the voltage in the network for a long time exceeds 258 V; this often happens during the hours of minimum load. The relay did not sense it due to an error and did not work, thereby burning all the electronics.

Preparing for work

Plug the relay into the socket. Use the adjustment buttons to set the minimum, maximum voltage and AR time. In this case, the set value will be displayed on the indicator screen. That's all, the voltage relay is ready for use. You can use it to plug the plug of the protected equipment into the socket.

Operation of relay RN-101M

If everything is normal, then the voltage level in the socket is displayed on the display and the LED lights up green.

When a sudden surge occurs, the relay automatically turns off the voltage in the outlet. The LED will no longer light up, and the display will display the increased voltage value in flashing mode. After normalizing the parameters, the indicator starts counting down in seconds, which you set before turning on the load. And upon completion, the relay supplies voltage and returns to normal mode.

If the voltage is normal, but there is an overcurrent, the internal circuit breaker is triggered. The button snaps off, the LED starts blinking, and the voltage value in the network is still lit on the display. First, find out what caused the shutdown, remove the plug from the relay and press the button, turn on the machine. After this, wait a few minutes for the thermal protection element to cool down and turn on the load again.

To prevent the relay from triggering falsely, for example, every time the refrigerator is turned on, there is a short-term voltage drop for a few tenths of seconds, a fixed delay was provided in the relay. Even when the voltage drops smoothly and evenly, the device will not turn off immediately, but after 7 seconds. If there is a deep and sharp drawdown (below 145V), the shutdown will occur in 0.12 seconds.

If the specified parameters are exceeded, there is no longer such a long delay, since there is a greater likelihood of equipment failure. And the relay will turn off the power in the socket after 1 second (with a smooth rise). When jumping, the shutdown time is also 0.12 seconds.

The device is absolutely functional in all sockets, even with a grounding conductor, even without it.

The price of a voltage relay for an RN-101M socket is on average 1,700 rubles. But for this price you get three protective devices instead of one!

Voltage relay Zubr R116y

Zubr R116y is another popular relay model that performs the function of protecting against overvoltage of a 220V network, but from a different manufacturer. Also designed to be easily plugged into a power outlet.

Important note: the device must not be connected after a UPS (uninterruptible power supply) as this may damage it.

Its characteristics are as follows:

It is advisable to connect a load of no more than 75% of that indicated in the passport through the relay socket (rated current 16A, power 3000VA). Why is this so? The fact is that with increased voltage, the power of the same equipment increases.

For example, you connected a 3 kW air conditioner through a relay. But this is its power at a voltage of 220V. And if the upper threshold for shutdown is set to 260V, then the power of the same air conditioner at the time of shutdown will already be 4.19 kW. And when such a load is disconnected, the relay may not withstand it and burn out. To correctly calculate the power allowed for connection, use the formula:

Main differences from RN-101M:

• ⚡ Limits are adjusted using buttons, which is subjectively more convenient than miniature rotating knobs
• ⚡ faster response time in case of overvoltage
• ⚡ wider range of minimum voltage settings (from 120V)
• ⚡ there is a function to disconnect the load without removing the plug from the socket
• ⚡ there is an adjustment for voltage readings on the display

• ⚡ no overload protection
• ⚡ no protective filter against impulse noise
• ⚡ more heat-loving (the minimum temperature for normal operation is from -5, versus -25 for the RN-101M)

Setting up the voltage relay Zubr R116u

The initial (factory) settings of the response limits are as follows:

• ⚡ Umin=198V
• ⚡ Umax=242V

In general, the recommended limits are + - 10% of the considered standard of 220V. Although according to the new rules (GOST 29322-2014) today the standard is 230V!

When you turn it on for the first time and normal operation relay - the green LED lights up and the voltage readings in the socket are displayed on the display.

If you are not satisfied with the factory settings, you can set your own limit values. Press the plus button to set the upper voltage threshold, and press the minus button to set the lower voltage threshold.

A quick press of the middle button will show what voltage (high or low) caused the relay to turn off last time.

To set the AR (reclose) time, press the middle button 2 times. After that, use the + and – buttons to increase or decrease the time in seconds from 3 to 600.

Voltage control relay Zubr R116y has load disconnect function without removing the appliance plug from the socket. To do this, press the middle button for a long time (up to 6 seconds), the word OFF will appear and the relay along with the load will turn off. To turn it on, repeat the same procedure.

Another advantage of the relay is the ability to correct the voltage readings that are displayed on the display. If you are sure that your voltmeter or multimeter shows the correct values, but the relay is “lying” by a few volts, then you can adjust these values ​​to the correct ones. Press the middle button for 9 seconds (until the word PoP appears), and then use the + and - buttons to adjust the voltage to the desired result.

When the PRG inscription suddenly appears on the screen, do not be alarmed - it is the overheating protection that has tripped. Most likely there was a bad contact in the socket. Because of it, the relay began to heat up, and since it has protection against overheating at contact temperatures above 80C, it worked, preventing a fire. For further operation, the relay must cool down to a temperature of 60C, and by pressing any of the buttons, it will start again.

The cost of the Zubr R116y voltage relay in online stores starts from 1,400 rubles.

To summarize, if you need surge protection for any individual device, a socket voltage relay is the best option. No costs for calling an electrician, no alterations with wiring.

But if you simultaneously need protection for several electrical appliances (refrigerator, TV, computer, air conditioner), then you need to look towards a standard relay installed in the panel, since this option will cost several times less.

Although the supply of electricity to apartments and houses is regulated by law, residents should not fully rely on the relevant services to provide the required quality of electricity. If expensive electrical appliances fail due to power surges, it will be almost impossible to receive compensation. And since problems with power lines are not uncommon, it is worth taking measures on your own that will help protect household appliances from breakdown. To do this, you need overvoltage protection, which can be provided by installing an appropriate device in the network - a protective relay, a sensor with an RCD or a voltage stabilizer.

Acceptable electricity parameters

The voltage rating indicated on all household electrical appliances is 220V, but in real life this value is not always stable. This is taken into account in the manufacture of modern devices, and they can operate stably with voltage fluctuations from 209 to 231V, as well as withstand a spread from 198 to 242V. If small differences in potential differences were not provided for by the design of household appliances, they would break down constantly. More significant deviations lead to network overload, and this reduces the operational life of the equipment.

To smooth out voltage fluctuations and ensure the safety of devices, it is enough to install a stabilizer. Overvoltage (the so-called sharp jump in potential difference) is much more dangerous for electrical engineering.

Types of overvoltages

Overvoltage can last for both a short and quite a long time. It can be caused by a lightning strike during a thunderstorm or switching caused by a substation problem. To protect against them, an SPD (surge protection device) is connected to a 220 or 380 Volt network (domestic or industrial). Its automatic operation helps to protect the line when exposed to, for example, a powerful lightning discharge, from which a voltage stabilizer cannot save.

Visually about the SPD in the video:

A lightning strike results in the appearance of a powerful electromagnetic pulse, under the influence of which electrical potentials arise in conductors located near the discharge site, and a sharp voltage surge occurs. It lasts only about 0.1 s, but the magnitude of the potential difference is thousands of volts.

It is clear that when such voltage enters household and production networks the consequences can be very severe.

Overvoltage due to switching

This phenomenon can occur when devices that produce a high inductive load are connected to or turned off in the line. These include power supplies, electric motors, as well as powerful tools, powered from the network.

This effect is due to the laws of commutation. An instantaneous change in the current value in the solenoid, as well as the potential difference across the capacitor, cannot occur. When a circuit with such a load is connected or opened, the appearance of an electric potential caused by self-induction and switching processes is noted at the point of contact.

The transient process is always accompanied by a surge of voltage, which has the opposite polarity to the input. The small capacitance of the conductors in the network causes a resonance that lasts a short time and causes high-frequency oscillations. At the end of the transition process they fade out.

How long the overvoltage will last and what its magnitude will be depends on the following indicators:

• Load inductance.
• Instantaneous value of the potential difference during switching.

• Capacity of connecting electrical cables.
• Reactive power.

Danger of overvoltage

Since the wire insulation is designed for a voltage significantly higher than the nominal value, breakdown most often does not occur. If the electric pulse operates for a short time, then the voltage at the output of power supplies with a stabilizer does not have time to increase to a critical value. The same applies to ordinary light bulbs - if the sharply increased voltage quickly returns to normal, then the spiral does not have time not only to burn out, but even to overheat.

If the insulating layer cannot withstand the increased voltage and its breakdown occurs, then an electric arc appears. In this case, the flow of electrons penetrates through microcracks that have arisen in the insulation and goes through the gases that fill the resulting tiny voids. And the large amount of heat generated by the arc contributes to the expansion of the conductive channel. As a result, the current increases gradually, and the circuit breaker trips with some delay. And although it only takes a few moments, they are quite enough for the electrical wiring to fail.

What devices provide network surge protection?

An electrical line surge protection circuit may include:

• Lightning protection system.
• Voltage regulator.
• Overvoltage sensor (installed together with the RCD).
• Overvoltage relay.

Separately, it is necessary to say about uninterruptible power supplies, through which computers are most often connected in home networks. This device is not intended to provide surge protection. Its function is different: in the event of a sudden power outage, it works like a battery, allowing the user to save information and calmly turn off the PC. Therefore, it should not be confused with a voltage stabilizer.

Operating principle of protective devices

To protect against electrical impulses caused by lightning, a lightning arrester is installed together with an SPD. And you can protect the line from the flow of electrons, the parameters of which do not correspond to the operating characteristics of the network, using special sensors, as well as overvoltage relays.

It should be said that both the DPN and the relay differ in principle of operation and purpose from the stabilizer.

The task of these elements is to stop the supply of electricity if the value of the difference exceeds the maximum threshold specified in the technical data sheet of the protective device or set by the regulator.

After normalizing the parameters of the electrical line, the relay switches on independently. DPS for line protection should be installed only in conjunction with a residual current device. Its task is to cause a current leak when a malfunction is detected, under the influence of which the RCD will trip.

Visually about the voltage relay in the video:

The disadvantage of this circuit is that it needs to be turned on manually after the voltage returns to normal. In this regard, a voltage stabilizer compares favorably. This device provides an adjustable time delay for current delivery if it is triggered by excessive voltage. The stabilizer is often used to connect air conditioners and refrigeration units.

Long-term overvoltage

Long-term overvoltages very often occur due to a break in the neutral conductor. Uneven load on the phase conductors causes phase imbalance - a displacement of the potential difference towards the conductor with the heaviest load.

In other words, under the influence of an uneven three-phase electric current, voltage begins to accumulate on the neutral cable, which does not have grounding. The situation does not return to normal until a repeated accident completely puts the line out of action or a specialist fixes the problem.

If the neutral wire in the electrical outlet breaks, the voltage will change in accordance with the load, which users who are not aware of the problem will connect to different phases. It is almost impossible to use a faulty circuit, even if a good stabilizer is included in the power line. The fact is that network parameters, regularly going beyond the stabilization limits will lead to the device constantly turning off.

You can see clearly about the zero break and what needs to be done about it in the video:

Lack of voltage (sag)

This phenomenon is especially familiar to people living in villages and villages. A dip (sag) is a drop in voltage below the permissible limit.

The danger of sagging is that many household appliances are designed with several power supplies, and a lack of voltage will cause one of them to turn off briefly. The device will react to this by displaying an error on the display and stopping operation.

If we are talking about a heating boiler, and the malfunction occurred in winter, then the house will be left without heating. Connecting a stabilizer will help avoid this situation. This device, having detected a sag, will increase the voltage value to the nominal value. A stabilizer can save the situation, even if the network voltage drops due to the fault of the transformer substation.

Conclusion

In this article, we explained why network surge protection is needed, what devices provide it, and how to use them correctly. The recommendations given will help readers understand the causes of mains voltage failure, as well as select and install a device to protect the electrical network.

Protection against overvoltage in the network is a very important measure, which will not only extend the service life of electrical wiring, but will also ensure the safety of its operation during power surges. If it occurs in the electrical network and there is no appropriate protection, household appliances fail, and this, in turn, is fraught with fire. Next, we will look at the main causes of overvoltage, as well as devices that will protect electrical wiring from the harmful consequences of this phenomenon.

Main causes

Most often, overvoltage in a 220 and 380 Volt network occurs for the following reasons:

1. on the supply line. Neutral conductor ensures voltage symmetry across the phases of the supply network, with different load values ​​across the phases. In the event of a zero break, the voltage in each phase changes depending on the difference in load between the phases: in the less loaded phase it increases sharply up to 300 or more volts, and in the more loaded phase it sharply drops to values ​​​​below 200 V. Therefore, without overvoltage protection In this case, household appliances may fail almost immediately, and in this case, electrical appliances will not work correctly. At the same time, there is a high probability of failure of electrical appliances that contain electric motors (compressors).
2. Connection error in electrical panel. If the house has a three-phase input and when connecting a single-phase 220 V wiring line, the second phase conductor was mistakenly connected instead of zero, then 380 V will appear in the socket instead of 220 V.
3. A pulse voltage occurred due to a thunderstorm entering the power line (which is why it is recommended to turn off all household appliances during a thunderstorm, as well).
4. Switching overvoltages. In the event of emergency situations in the electrical network: a short circuit on adjacent lines, abrupt changes in load due to disconnection (connection) of a section of the electrical network, accidents at power plants, voltages may be observed, which, depending on the magnitude, can negatively affect the operation of household electrical appliances .

A visual example of the action of overvoltage

As you can see, single-phase and three-phase networks are influenced by many factors, including natural ones. Therefore, it is imperative to protect your home wiring to avoid becoming a victim of an accident.

Surge protection devices

IN modern world there are many various devices for protection against overvoltage in the network, which is easy to connect with your own hands. Let's consider devices that are used to protect against unwanted voltage surges.

Among the most useful for use in the home and apartment are:

1. . This device converts (stabilizes) the input voltage into a voltage of a given value. It is important to install a stabilizer if there are constant voltage drops in the network. It should be borne in mind that the stabilizer only works at a voltage that does not exceed the permissible values ​​indicated in its technical specifications. If voltage surges occur above permissible limits, the stabilizer may fail. Therefore, it is necessary to have built-in overvoltage protection, and in the absence of such a function, install a voltage relay for protection. We talked about that in the corresponding article!
   
2. . This protective device, unlike the MV, does not convert the input voltage. designed to disconnect home wiring from the electrical network in the event of unwanted voltage surges (GOST 3699-82). The minimum and maximum voltage limits are set on the relay, and if a surge occurs above the set limits, the relay de-energizes the household electrical wiring, thereby protecting household electrical appliances. The RN can be made in the form of a modular device for installation in a distribution panel (the well-known Barrier), built into an extension cord (surge protector with the corresponding function), and also in the form of an electrical plug (for example, ZUBR). We talked about this in a separate article.
   
3. Multifunctional protection device (UZM). This device can be installed in a distribution panel instead of a voltage relay. The UZM performs several functions, one of which is protecting the electrical network from voltage surges. We talked about this in a separate article.
   
4. Uninterruptable power source. Again, I can confirm its effectiveness from my own experience. More than ten times, the UPS saved my computer from a sudden shutdown when the voltage relay in the electrical panel was triggered. "Bespereboynik" has low cost, so it is extremely necessary to buy this type of surge protection option if you have a PC. In addition, most modern uninterruptible power supplies have a built-in stabilizer, which is especially important for computer equipment, which is the most susceptible of all household appliances negative impact changes. For information on how to choose a UPS, read our article:.
   
   
5. SPD. From impulse voltage(occur during a thunderstorm and can damage equipment) you can protect yourself by installing an SPD in your home. This device is quite popular today and is widely used both in everyday life and in production. We described in more detail about how it works in a separate article, which we strongly recommend that you read. It should be noted that SPDs can also be called modular SPDs (SPDs).
6. Contacting the energy supply service. The energy supplying organization, in accordance with the electricity supply contract, is obliged to ensure a normal (within acceptable standards) voltage level of the electrical network in accordance with (IEC 60038:2009). Therefore, if you constantly have excessively low or, conversely, increased voltage, then you need to contact the supply organization with a corresponding complaint. It is most effective to address a collective complaint, since individual complaints are usually ignored. Contacting the supplying organization - the only way solution to the problem if you experience strong voltage drops, since in this mode any MV will quickly fail.
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