Low voltage protection. Devices for protecting the electrical network in an apartment from power surges and surges

The voltage in electrical networks is rarely a stable value of 220 Volts; most often it fluctuates with an acceptable value of plus or minus 10%. Household and computer equipment can handle 200 or 240 Volts, but if a surge occurs, even if it is a short-term surge, the equipment will most likely fail.

What are voltage surges and why are they dangerous?

First of all, voltage surges occur in typical apartment buildings. Power is supplied through three phases and, with the help of a distribution panel, the current enters each apartment through one working phase and a neutral wire. It is important to note that “zero” experiences the greatest load and what’s bad is that it is common to everyone. Accordingly, when residents turn on many household appliances at the same time, the power grid is overloaded. A common occurrence is the burnout of the neutral wire at the base of the panel. Moreover, at this moment, neighboring apartments become connected in phase and the voltage can jump to 380 Volts, which will inevitably lead to the failure of those devices that do not have sufficient protection.

There are many reasons that can lead to such a situation, but what is characteristic is that they have a common source. Substations that distribute electricity are often morally and technically outdated, and although the equipment is maintained in working order, the question of replacing it has often not been raised for decades. The number of household electrical appliances is constantly growing, and accordingly, the load on substations is increasing. Considering the fact that at the time of their construction the reserve was calculated at a rate of 4.5 kW, the energy consumption at that time and now is a significant difference.

The condition of the electrical wiring also leaves much to be desired. In addition, there is a known situation with would-be repairmen who are able to connect a working electric welder to a common system, which will significantly increase the load on the electrical network, causing other people to experience a situation with an overload on the panel. It’s good if in this case protective equipment is installed, but if they are not there and there was hope for the eternal “maybe”, then the situation with replacing burnt household appliances and a noticeable gap in the budget is extremely high. Fortunately, the market offers a large variety of equipment designed to protect equipment from power surges whenever possible.

What basic means are available to protect equipment from power surges?

It is difficult for an untrained person to understand the types of devices and their purposes, so before purchasing it is important to study the theory in order to have an idea of ​​what exactly needs to be purchased. Modern devices are divided into several types:

• protective relays,
• step-down transformers,
• step-up transformers,
• Surge Protectors,
• multifunctional protection devices,
• circuit breakers,
• network filters.

It is worth taking a closer look at the purpose and capabilities of each device in order to have a good idea of ​​the overall picture of providing protection against voltage surges.

Safety relay

It is an automatic device that is triggered when exposed to voltage changes in the network. It disconnects the electrical circuit from the network in the case when the control microcontroller registers an increase in voltage levels compared to the established normal values. The load is automatically connected back to the circuit when the voltage readings return to normal.

The user sets its value independently, using the control system, and in the future the controller is guided by this value. Since the relay is not capable of withstanding loads above 8 kW, while figures for apartments sometimes reach 25 kW, the protective relay is used in conjunction with a circuit breaker, which serves as the main protection.

A good example of such a device is the VP-16AN relay from the manufacturer DigiTop, which is essentially an individual adapter that can protect an electrical appliance directly connected to it from short circuits and overloads. The cost of such a device is $12

Step-down and step-up transformer

The main purpose of transformers, which are static converters of electrical energy, is to change the alternating current voltage. These devices operate under alternating voltage conditions and have several inductive windings connected to each other. Depending on the current voltage ratio, transformers are divided into step-up and step-down:

• In a step-up winding, the primary winding is characterized by a low voltage and fewer turns, and the secondary winding, on the contrary, is high. As the name suggests, this device increases voltage and is used to transmit electricity over long distances.
• In step-down, on the contrary, the primary winding shows a high voltage and a larger number of turns, and the secondary winding is low. Transformers of this type are used to distribute incoming electricity to consumers.

Typically, a transformer of any type is used both as a step-down and step-up transformer when they are started by applying voltage in the opposite direction. In this case, the downgrade will become an upside, and vice versa.

According to their design, transformers are divided into two types:

• oil,
• dry.

The first type has a tank containing transformer oil. It serves as a good insulator and at the same time a coolant for the magnetic core with windings. As a rule, these types are more often used in substations.

Dry transformers have passive air cooling and are installed in residential premises and industrial facilities. Air cooling avoids the problem of the oil tank leaking, but this method is less effective.

Roughly speaking, a step-down transformer is necessary in order for 220 Volts to come into the house, taking into account the error. It is unacceptable to immediately supply the consumer with high voltage from the substation, and therefore a transformer is used for these purposes.

Step-down transformers for domestic purposes are not very expensive. The cost of the YaTP-025 model, capable of reducing the input value from 220 to 12 volts, is $30, the model capable of reducing the incoming 380 to 220 will cost more, on average from $130

Voltage regulator

This device is designed to maintain a certain output voltage level. The operation of the stabilizer allows you to protect equipment from unstable power supply and interference, as well as network failures.

Such equipment is used when it makes sense to protect household electrical appliances and computer equipment from power surges and surges. If they occur, the stabilizer will turn off the internal network and the devices connected to it until the voltage value returns to normal.

The use of stabilizers allows you to obtain certain advantages:

• protection against voltage surges and surges,
• elimination of electromagnetic interference,
• short circuit protection,
• protection of telephone lines from breaks and noise on the line,
• lower price compared to other protective equipment.

Modern AC voltage stabilizers, which are used in everyday life, are conventionally divided into the following types:

• mechanical with servo drive,
• electronic,
• relay,
• hybrid,
• compensation,

The models are produced in two versions: single-phase and three-phase, the power is very diverse - from hundreds of watts to several megawatts. An important distinguishing feature of a high-quality stabilizer will be its response to changes in voltage level. As a rule, the response occurs within a few milliseconds. The second important factor in the operation of the stabilizer is its output voltage accuracy. The value should not fluctuate by more than 10% of the nominal value.

The optimal choice of stabilizer models is one that can withstand tenfold overloads and for which there is no need to calculate the power reserve.

Multifunctional protection device

First of all, this device is intended to turn off equipment in the event that the mains voltage exceeds the permissible values ​​of the minimum value of 160 V or the maximum of 280. The device consists of a magnetic relay and voltage control connected together. A protective varistor is also connected to them, which, when high-voltage pulses occur in the network, shunts them to a set safe value. A special feature of this device is the operating mode and actions that the device performs:

• If the voltage increases and goes beyond the permissible limits, the power supply is disconnected. At the same time, a timer starts, which counts down the restart time. If another jump occurs while waiting, the timer is reset to zero and the countdown begins again.
• If there is a low power supply, the protection device starts counting the shutdown delay. If, after a period of time, the voltage level does not return to normal, a shutdown will occur, but if the decrease was short-term, the device will continue to monitor the load level.

This solution allows you to provide good protection against impulses, as well as control the quality of the voltage supplied to the connected equipment.

It is important to remember that UZM is not able to replace other means of protection, therefore it is more often used as a comprehensive solution to the problem.

Circuit breakers

These are one of the most common types of solutions for protecting an apartment or office space from power surges. The switch, which is also called a “machine,” controls the current strength in the circuit, while preventing the occurrence of overcurrents, the strength of which exceeds the permissible value for the wiring. As a rule, they are triggered when connecting a load on the network that exceeds the norm, or during a short circuit.

The device is triggered thanks to the releases used in its design, which come in two types:

• thermal,
• electromagnetic.

Thermal ones consist of a bimetallic plate that clearly responds to changes in the current flowing through it. When excessive heating occurs, the plate releases a special spring, which turns off the machine.

The electromagnetic one has the same principle of operation, with the only difference being that it uses a coil with a magnetic core, which releases the spring when the load is exceeded.

It is best to use circuit breakers in combination with a residual current device, which also controls the leakage current. The RCD is also protected by the machine and is always installed after the safety switch. Such a combination is called a differential machine. The benefit of installing the device is a simpler installation scheme and saving space in the distribution panel.

Network filters

These devices are an extension cord with a large number of sockets and a power button. In fact, it is more often used as an extension cord and a place to connect a personal computer. Thanks to the presence of a varistor, the surge protector is able to protect the electrical equipment included in it and suppresses high-frequency interference.

In the event of a high-frequency pulse, the resistance of the varistor drops, due to which the excess electrical pulse is converted into heat. This solution will provide additional protection for equipment, but you should not rely too much on the surge protector. Its purchase is advisable primarily as an extension cord; to ensure the safety of the equipment, it is necessary to pay attention to full-fledged protection devices.

Uninterruptible power supplies

Such devices are used primarily for those devices for which a sudden power outage can harm the operations being performed, that is, computers. This equipment is designed to provide uninterrupted power, while thanks to the built-in battery, they are able to ensure computer operation from one minute to several hours.

First of all, they are purchased in order to “gain time” in case of a sudden power outage, which will allow time to save all the necessary data and operations performed on the computer. The internal structure of uninterruptible power supplies is similar to stabilizers, the difference is visible only in the presence of a lead battery.

However, experts recommend purchasing a UPS if it is necessary to save data; in all other respects they are inferior to stabilizers. The main disadvantage of most UPS is switching on at low voltage and insufficient sensitivity at high voltage. In addition, the device cannot be left unattended, so when you stop working on the computer, it must also be turned off. At the same time, the price of a stabilizer and an uninterruptible power supply of the same power differs several times in favor of the first - so the choice is obvious. To save information and safely shut down the computer, budget models priced at $45 or more are sufficient, the operating time of which is estimated on average at 15 minutes - which is quite enough to complete the work correctly.

Voltage drops and surges in existing electrical networks are, unfortunately, not uncommon. To protect against such surprises, special devices are installed at enterprises; installation of such devices in electrical panels of residential buildings is not the responsibility of the housing and communal services.

Why are voltage surges dangerous in the network?

Electrical fires, failure of household appliances and loss of data in damaged computers.

According to Russian GOST, the permissible voltage fluctuation in the network should not go beyond 10% of the nominal value, in other words, the voltage in the outlet should not fall below 198 and rise above 242 Volts, and during surges the voltage can drop to 35 and rise to 400 Volts.

It is necessary to understand that not only increased voltage is dangerous, but also significantly decreased voltage.

Increased voltage causes damage to power supplies, which immediately burn out due to overload or significantly reduce their service life.

Low voltage is less dangerous, but nevertheless, it also often leads to failure of power supplies or refrigerator compressors, etc.

Causes of voltage surges:

Lightning strikes near power lines. During a thunderstorm, it is imperative to unplug household appliances.

Accidents at substations in which high voltage of the order (6-10 thousand volts) reaches the low voltage side.

Burnout or breakage of the neutral wire at a substation and in electrical cabinets is a fairly common reason. As a rule, this occurs due to an incorrect or unreliable connection. When it breaks or burns out, a “phase imbalance” occurs, and in some apartments the voltage rises to 380 V and higher, and in some it drops to 40 V.

To protect household electronics from destruction, and the apartment from fire, special protection is installed. Of course these are additional costs, but they pay off. After all, repairing broken refrigerators, washing machines, televisions and computers entails not only monetary expenses, but also a considerable loss of time.

Currently, there are quite a lot of devices that protect against power surges, and they all differ in both quality and price. Let's take a closer look at the most common and proven ones.

Perhaps this is the most common and affordable protection option. It is used for a separately located electrical appliance and is called “Pilot” due to the brand of the most popular surge protector.

A surge protector can only protect low-power electrical equipment. For example, a computer or an audio system, but it will not save only from small power surges, from significant changes, it will most likely burn out on its own.

The operation of a surge protector is based on three main components

A fuse or fuse link provides protection against short circuits and overload currents.

The notch filter protects against interference generated by the operation of an electric motor, generator or welding machines near your home.

But all the components described above are present only in real surge protectors; in cheap extension cords, a maximum automatic fuse may be present. Therefore, before purchasing, you should carefully study those. a passport for the product, which indicates all the protections present in a particular model. It is worth mentioning that for any surge protector to operate, grounding is required, since all interference and overvoltage are discharged to the ground through the grounding conductor.

If there is no ground loop, then the surge protector turns into an ordinary extension cord.

Uninterruptible power supply (UPS) UPS

Uninterruptible power supplies (UPS) are used to protect computers and other computer and computing peripherals from major power problems: power surges, electromagnetic and radio frequency interference, high-voltage surges, and complete blackouts. At voltages up to 270 Volts, the UPS switches to battery operation, which will allow it to continue operating from several minutes to several hours, depending on the model.

The UPS is selected based on the power of the electrical appliance being protected.

Surge Protectors.

Installing a voltage stabilizer is an ideal option for those who use expensive electronic equipment. Unlike UPSs and surge protectors, a voltage stabilizer constantly normalizes the voltage to 220 Volts. And if the voltage increases to 250 Volts, it will turn off the power supply. After normalizing the voltage in the electrical network, the stabilizer will automatically connect the power supply.

Installation of a voltage stabilizer is possible both for an individual electrical consumer and for the entire network of a house or apartment. In the latter case, the selection of a voltage stabilizer is based on the power of all electrical equipment in the house.

Voltage control relays are installed specifically to protect against voltage surges. Moreover, the relays protect not only from overvoltage, but also from undervoltage. The relay operates fully automatically and restores power supply with a short delay after its input values ​​return to normal. Relays are installed in panels on a DIN rail. Currently, many relay models are produced with indication and the ability to manually adjust voltage limits, as well as load disconnection and connection times.

In any case, if you have difficulties choosing a technical device for protection against voltage surges, it is better to contact specialists.

Materials related

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 an accident on the line, as a result of which the neutral wire breaks, which causes an increase to 380 volts. 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 of household appliances are overloaded 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 for refrigeration compressors, as well as many switching power supplies.

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 (occurs 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, which contains full characteristics. 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 standard. 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 the computer via a USB interface, for example, close a text editor (after saving open documents), and then turn off. This is a rather useful function if the user was not nearby when the protection was triggered.

Surge protection devices

All of the devices listed above have a common drawback: they do not have effective protection against high voltage pulses. 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

Category	Application
B (I)	Provide protection in the event of a direct hit from a lightning discharge through the lightning protection system. Installation location - input distribution device or main distribution board. The main normalizing characteristic is the magnitude of the pulse current.
C (II)	They protect the current distribution network from switching impulses, and also play the role of a second protective level during a lightning discharge. Installation location: distribution board.
D(III)	They provide the last level of protection, in which residual voltage surges and differential overvoltages are not allowed to consumers. In addition, high-frequency interference is filtered. Installation is carried out in front of the consumer. They can be made in the form of a module for a socket, an extension cord, etc.

An example of three-level protection is shown below.

SPD design features.

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).

SPD Finder (category II)

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.

Negative phenomena such as voltage drops in the electrical network occur quite often. They can be caused not only by malfunctions at the transformer substation from which the house is powered, but also by excessive load on power cables. Even more often, a phase imbalance and an increase in current in the electrical network can create a switched-on welding machine in the house next door.

Voltage monitoring relay for protecting household appliances and equipment

Voltage drops

Unstable parameters of the electrical network can be guessed by a number of signs such as flickering of an incandescent light bulb or unstable operation of equipment with electric motors: a hair dryer, blender or vacuum cleaner. There can be many reasons for an unstable energy supply. If we consider the most common ones, we can highlight:

• simultaneous switching on of household appliances during peak hours or switching off electrical appliances powered from one feeder;
• burning, oxidation or breakage of the “neutral”;
• incorrect connection of wires after replacing metering devices or when replacing wiring in an apartment by unqualified personnel;
• lightning discharges on overhead power lines (OHL) (Fig. below).

Damage to overhead power lines by lightning discharges

If the decrease and complete disappearance of voltage does not go unnoticed, since the lighting is turned off and the TV is turned on, then short-term changes in current with overvoltage are a process that is almost impossible to detect.

It would be unfair not to mention such a phenomenon as “neutral break in a three-phase network with an asymmetric load” or the disappearance of “zero” in common parlance, from which not a single user of the benefits of electrification is insured. In such a situation, in addition to the main phase, the opposite phase of the neighbor comes into the 220 V socket through his switched on device or light bulb.

At the same time, the voltage in the network increases above 300 V. If, due to short-term surges of current, plugs on the electric meter can, at best, “fly out”, fuses burn out, or incoming circuit breakers turn off, then an increase in voltage above 300 V poses a real threat to the home equipment.

Triggering of incoming circuit breakers due to increased voltage in the network is not enough. Increasing the potential significantly above the nominal value can damage turned on household appliances: refrigerator, computer, washing machine and TV. As a rule, such breakdowns due to fluctuations are not covered by warranty, and expensive equipment must be repaired at your own expense.

Surge protection

The best way is to reconstruct the power supply system and audit the connections on each switching device. But practically this is not feasible.

There are several reliable methods for preventing an apocalypse in the power supply of your home, which any owner can do. The measures taken will allow you to keep expensive household appliances in good working order, these include:

• purchasing household voltage control relays (VCRs) or multifunctional protection devices (UPDs), and installing them in the electrical network according to the connection diagram immediately after the incoming circuit breakers;
• supplying power to household electrical appliances in the network after a voltage stabilizer;
• use of an uninterruptible power supply (UPS).

RKN and UZM

A reasonable solution for protecting electrical circuits from high current would be to use a voltage control relay (VCR) or a multifunctional protection device (UPD). The principle of operation of these devices is quite simple: the built-in microcontroller continuously monitors the incoming voltage in the network and turns off the power supply to the apartment, house or office if it differs from the previously set value, either up or down. Moreover, the measurement occurs even after the power supply has been completely turned off, and switching on is performed automatically after the voltage returns to the set range after the expiration of time, which is also set manually.

Voltage monitoring relay with indicator light

Thus, these devices will protect the consumer from both low and high potential, and power will be supplied only after the network has been stabilized.

Voltage relays allow you to select the time delay before power supply in a wide range - from 10 seconds to 6 minutes.

For refrigerators and air conditioners, restarting after an emergency stop should occur no earlier than after 5 minutes. This is due to the operating principle of compressors. In addition, compliance with operating conditions will significantly extend the life of electrical appliances.

This type of surge protection is installed in the electrical panel on a 35 mm wide DIN rail.

The advantages of using RKN and UZM are:

• optimal ranges for setting the maximum and minimum voltage;
• disconnection from current overload and short circuit;
• response speed is about 0.2 sec;
• sufficient load capacity - from 25 to 63 A;
• powerful contacts and overheating protection;
• compact dimensions and easy installation;
• information display showing current network voltage readings.

Voltage Control Relay Models

RMM

A similar principle of operation is the minimum and maximum voltage release (PMV). This device monitors the incoming voltage, and in the event of a low or high value, it turns off the circuit breaker to which it is connected.

The release is turned on manually by pressing the “Return” button.

Circuit breaker with built-in trip unit IEK

The advantage of the RMM is its compactness, simplicity of design and affordable price. The disadvantage is the lack of automatic restart, and, as a result, spoilage of food in a switched off refrigerator or defrosting of the electric heating system in winter.

When installing voltage control relays and other automatic means of protecting the electrical network from surges, strict compliance with the Safety Rules for the operation of consumer electrical installations (PTBEEP) is required.

This equipment is a relatively expensive, but no less reliable option for protecting your home network from surges. It is “able” to constantly provide the output voltage in the set range, regardless of what oscillations occur on the primary winding.

When choosing the type and power of a voltage stabilizer for your home, you should take into account the technical characteristics and the total electricity consumption of all simultaneously turned on devices.

Automatic voltage stabilizer with informative display

The advantages of stabilizers are:

• long service life;
• accuracy and speed with increasing current;
• constant voltage value.

The main difference from voltage stabilizers is the presence of rechargeable batteries in uninterruptible power supplies (UPS). Therefore, the devices can not only maintain the voltage in the required range, but also ensure continuous operation of household appliances without emergency shutdown for some time.

The cost of uninterruptible power supplies is quite high and depends on the type of rechargeable batteries (AB) and the technical parameters of the device.

Uninterruptible Power Supply (UPS)

UPSs are most often used to protect individual appliances and household appliances, such as personal computers (PCs), televisions and refrigerators, which are more sensitive to high or low voltage.

How to protect yourself. Video

This video shares tips on how to protect connected devices from power surges.

To make the final choice, you should contact a specialist who can select the most suitable device depending on individual conditions and technical capabilities. But it is worth noting that installing a voltage control relay is the optimal and inexpensive way to protect your home from force majeure situations.

It is important to understand that surge protection is a wise investment that can protect your home appliances and property from unwanted consequences.

The magnitude of the voltage deviation in a household network is regulated by GOST 32144-2013. It states that the increase or decrease in voltage should not exceed 10% of the rated value. Failure to comply with GOST requirements leads to failure of household appliances. Household electrical appliances are designed to operate in the range of supply voltages that are mentioned in GOST. Exceeding the voltage threshold of 242V causes electrical appliances to operate in a critical mode, overheating, failure of electronic components, and insulation breakdowns occur. The consequence of this is equipment failure and even fire.

Fire is a consequence of increased voltage

Signs of increased network voltage

1. Often fail lamps.
2. Incandescent and halogen lamps shine brighter than usual.
3. Light intensity changes periodically.
4. Unusual behavior household appliances at work.
5. Unexpected reboot the computer or turning it off.
6. Malfunctions consumer electronics.

If the voltage goes beyond the permissible limits, household electrical appliances must be turned off immediately. If the situation regularly repeats, contact the sales company.

Reasons for increasing network voltage

1. Phase imbalance. AC networks are three-phase. The voltage between each phase and zero is 220 V. When designing the electrical wiring of a house or holiday village, consumers (apartments or private houses) are distributed equally among the phases. But this does not mean that the load will be divided equally between phases. The difference in consumption leads to a redistribution of voltage values ​​across phases: where less is consumed, there is more voltage. Most often this factor manifests itself in rural areas.
2. Zero interruption of the power supply network. This is an emergency mode of network operation that must be eliminated immediately. As a result of an accident with a zero break, the voltages are redistributed even more than in the case of phase imbalance. If in the first case, in the absence or with minimal load of one phase, the voltage on it is increased, then in the second case it will approach 380 V! As a result, in a few seconds, all household appliances that were not lucky enough to be working at the time of the accident will die. Then litigation begins with the network organization for damages, because its task is to audit contacts and monitor their condition. A re-grounding loop helps smooth out the consequences of a zero break in the network, but the further the substation is from the consumer with the loop, the less effective it is. Within the city limits, it is impossible to create a personal grounding loop.
3. Lightning strikes close to consumers cause a short-term increase in voltage in their electrical wiring. In modern networks, the design necessarily provides for surge protection, but old networks do not have it and are therefore vulnerable.
4. Errors during installation or repair. Inexperienced or inattentive electricians may, when working in the panel, either connect two phases (380V) to the consumer, or forget to connect the neutral wire in place (case of a broken neutral). Therefore, if you have any doubts about the electrician’s qualifications, do not trust him with the job.

Methods of protection against overvoltage

• 1. Installation of voltage control relay. When the voltage in the network increases, it will turn off electrical appliances and save them. When the voltage returns to normal, the relay will turn them back on. Among the voltage control relays, there are two groups: for connection to a socket and for installation in a distribution panel. In the first case, one consumer is protected, in the second – all electrical equipment in the house.

• 2. helps protect the equipment connected to it: computer, TV, router – from minor overvoltages in the network. It smooths out only impulse effects and does not change the voltage value. Remember: not everything that is called a “surge protector” actually is one; sometimes ordinary extension cords with a block of sockets are sold under this name. They do not contain any filling that acts as protection against interference, surges and overloads. Buy only surge protectors from reputable companies.

• 3. Stabilizer protects equipment without disconnecting it from the network. When the input voltage changes in the operating range, it outputs 220 V. But when the input voltage exceeds the threshold value, it turns off. This additionally provides protection against zero loss. The stabilizer does not protect against surge voltages.

• 4. Uninterruptible Power Supply (UPS) performs all the functions of a stabilizer and surge protector, but when the voltage is turned off or its value increases above the permissible value, it switches to powering the load from the battery.

• 5. SPD— surge protection device. Protects electrical equipment from overvoltages caused by nearby lightning strikes.

Surge protection device