Network overvoltage protection. Protecting household appliances and single-phase networks from voltage surges Do-it-yourself protection against 220V network overvoltage

Currently, the issue of a stable voltage in the electrical network is quite acute. Network organizations are in no hurry to reconstruct and modernize power lines, substations and transformers. Meanwhile, the situation is only getting worse, so voltage fluctuations in our networks are a fairly common occurrence.

Update 11/11/2018.
For those who doubt the installation of a relay to protect against voltage surges for their home or believe in the quality of construction and installation work in modern new buildings. Below is a screenshot of one of the latest.

According to GOST 29322-92 voltage in the power grid of our country should be within 230 V at one phase and 400 V between phases. But if you live in a rural area or near a city, then problems with constant voltage levels are very high, and in the city itself this cannot be ruled out, especially in older housing stock. Voltage surges have a very detrimental effect on electrical appliances in the house. For example, due to low voltage, a refrigerator or air conditioner may burn out (the compressor will not start and overheat), the power of the microwave is greatly reduced, and incandescent lamps glow dimly. Well, high voltage will simply “kill” your household appliances. I'm sure many have heard about "zero burnout" in high-rise buildings, and how entire entrances are taken to workshops to repair household appliances.

The reasons for voltage fluctuations in the network are different:

• Shorting one of the phases to neutral, as a result there will be 380 Volts in the outlet;
• Burnout (break) of zero, if you have a low load at this time, then the voltage will also tend to 380 V;
• Uneven distribution of load across phases (misalignment), as a result, at the most loaded phase, the voltage decreases, and if a refrigerator and air conditioners are connected to it, then there is a high probability that they will break;

Example video showing the operation of a voltage relay

Special devices - voltage control relays - help solve the problem of voltage surges in networks. The principle of operation of such relays is quite simple, there is an “electronic unit” that monitors that the voltage is within the limits specified by the settings and, if there are deviations, signals the release (power section), which turns off the network. All household voltage control relays turn on automatically after a certain time. For ordinary consumers, a delay of a few seconds is sufficient, but for refrigerators and air conditioners with compressors a delay of several minutes is needed.

Voltage control relays are available in single-phase and three-phase types. Single-phase voltage relays disconnect one phase, while three-phase voltage relays disconnect all three phases at the same time. When using a three-phase connection at home, single-phase voltage relays should be used so that voltage fluctuations on one phase do not lead to the shutdown of other phases. Three-phase voltage relays are used to protect motors and other three-phase consumers.

I divide surge protection devices into three types: UZM-51M from Meander, Zubr from Electronics and all the others. I am not imposing anything on anyone - this is my personal opinion.

Voltage relay Zubr (Rbuz)

This device is designed to protect against voltage surges (zero burnout). BISON is produced in Donetsk.

I will note the features of this voltage relay.

Voltage indication on the device - shows the voltage value in real time. This is quite convenient and necessary for assessing the voltage situation in the network. The reading error is low, the difference relative to the Fluke 87 high-precision multimeter is only 1-2 Volts.

Zubr voltage relays are produced for various rated currents: 25, 32, 40, 50 and 63A. The device, with a rated current of 63A, can withstand a current of 80A for 10 minutes.

The upper voltage value is set from 220 to 280 V in steps of 1 Volt, the lower - from 120 to 210 V. The restart time is from 3 to 600 seconds, in steps of 3 seconds.

I set the Zubr voltage relay, the maximum (upper) voltage value is 250 Volts, and the lower value is 190 Volts.

For devices with index t in the name, for example Zubr D63 t, there is thermal protection against internal overheating. Those. when the temperature of the device itself increases to 80 degrees (for example, due to heating of the contacts), it turns off.

Zubr voltage relays occupy 3 modules or 53 mm on a DIN rail and are only single-phase.

The passport and the wiring diagrams for the Zubr voltage relay do not say about current limitations, but in the old documentation it was previously indicated that no more than 0.75 of the nominal one.

Zubr voltage relay wiring diagram

Currently, manufacturers claim that the relay can be connected at its nominal value. If the rating of the Bison is less than the rating of the input circuit breaker, then you need to use a voltage relay - a contactor - in the connection diagram.

Relay warranty Voltage Zubr the manufacturer gives whole 5 years! Has very good reviews from colleagues - forum members. And just like Meander on the MasterCity forum there is a Zubra representative who is not afraid to communicate publicly. And by the way, it is indicative from the example of UZM and Zubr that representatives of manufacturers of quality products are not afraid to communicate on forums.

Video about voltage relay Zubr

Update (06/07/15). Currently, the Zubr voltage relay is sold in Russia under a different name Rbuz (the word Zubr is backwards).

This is due to the fact that in Russia the Zubr trademark is registered with another manufacturer and only the name of the relay has changed, but all the components remain the same.

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UZM-51M. The protection device is multifunctional.

Currently, UZM-51M has proven itself to be reliable and easy to connect.

UZM-51M is designed for current up to 63A, occupies 2 modules on a DIN rail (35 mm wide). In the standard version, the operating temperature of the UZM is from -20 to +55 degrees, so I do not recommend installing it in a switchboard outdoors. It is true that there is a range from -40 to +55, but I have never seen such on sale, unless you contact Meander JSC directly.The maximum setting for the upper voltage cut-off is 290 V, the lower threshold is 100 V. The restart time is set independently - this is either 10 seconds or 6 minutes. Can be used in networks with any type of grounding: TN-C, TN-S, TT or TN-C-S.

Connection diagram UZM-51M

Meander produces two more types of single-phase voltage relays - these are UZM-50M and UZM-16. The main difference between the UZM-50M and the UZM-51M is, perhaps, only that in the latter, as we know, you can set the triggering setting independently, while in the UZM-50M the setting is “hard”, the upper voltage limit is 265 V, and the lower - 170 V.

UZM-16 is designed for a current of 16A, so it is installed only on a separate electrical receiver. For example, in order not to wait 6 minutes for the UZM-51 to turn on, the refrigerator can be connected via the UZM-16, on which the turn-on delay is set to 6 minutes, and on the main UZM-51M to 10 seconds.

I set the maximum (upper) voltage value on the UZM-51M to 250 Volts, and the lower value to 180 Volts.

Meander also produces a three-phase voltage relay UZM-3-63, as I wrote above, such relays are used mainly to protect engines.

Good reliable surge protection. The UZM does not need to be connected with a contactor, as is usually done with other voltage relays. The device is manufactured in Russia. UZM warranty is 2 years. What’s important is that Meander’s representative is present on the most popular Mastercity forum, always gives advice on products, and also pays close attention to the comments of forum users, whose comments at one time helped improve the UZM-51M.

An example of installing UZM-51M in a three-phase switchboard for a country house, where UZM is installed in each phase.

Perhaps one drawback of the UZM-51M relative to other voltage relays is the lack of voltage indication. But the difference in price between the UZM and a voltage relay with a contactor allows you to buy and supply a voltmeter separately.

Voltage relay RN-111, RN-111M, RN-113 from Novatek

These voltage relays are manufactured here in Russia. As you can see from the title, Novatek offers three types of voltage relays.

RN-111 and RN-111M are practically the same device in terms of parameters; their main difference is that the RN-111M relay has a voltage indication, while RN-111 does not.

The upper voltage limit is from 230 to 280 V, the lower limit is from 160 to 220 V. The automatic restart time is from 5 to 900 seconds. These relays have a 3 year warranty.

Connection diagram for voltage relay RN-111

RN-111 is designed for small currents up to 16A or power up to 3.5 kW, but to connect a higher load, RN-111 can be switched on together with contactors (magnetic starters).

Connection diagram for voltage relay with contactor

This significantly increases the cost, since a good contactor will now cost about 4-5 thousand rubles, you will need a larger number of modules in the panel, as well as a circuit breaker to protect the contactor coil. The above diagram for connecting a voltage relay with a contactor for RN-111 is valid for any other relay, taking into account the features of its circuit.

The RN-113 relay is already more improved relative to the RN-111, the voltage ranges and AR time are the same as those of the RN-111, but the maximum current for which the RN-113 can be turned on is up to 32A or if the power is up to 7 kW.

Connection diagram for voltage relay RN-113

But I would not do this, since the contacts on the RN-113 are weak enough for a wire with a cross-section of 6 mm 2, and this is precisely the cross-section required for a 32A connection.

It is more reliable to connect RN-113 with contactors, without contactors maximum 25A. I don’t use voltage relays from Novatek in my switchboards, so I borrowed the photo from one of the electricians from the Avs1753 forum.

It looks, of course, beautiful, but such a connection takes 3-4 more modules and is twice as expensive in cost as if UZM-51M or Zubr were used.

But what happens with the RN-113 if you connect it without 32A contactors.

Unfortunately, I did not find any information about tests like the UZM-51M and Zubr on the forums.

Voltage relay TM DigiTop

Just like Zubr, these relays are produced in Donetsk. The manufacturer produces several series of devices with protection against power surges.

The V-protector series voltage relay is intended only for protection against voltage surges. Available for rated currents of 16, 20, 32, 40, 50, 63 A in a single-phase version, it has built-in thermal protection against overheating, triggered at 100 degrees. The upper threshold is from 210 to 270 V, the lower one is from 120 to 200 V. The automatic switching time is from 5 to 600 seconds. There is also a three-phase voltage relay V-protector 380, quite compact 35 mm (two modules), but the maximum current in a phase is no more than 10A.

The Protektor single-phase voltage relay has a 5-year warranty, and the three-phase relay only 2 years.

V-Protektor DigiTop voltage relay connection diagram

Digitop also produces a voltage relay and a current relay, VA-protector, combined in one device. In addition to overvoltage protection, the device also provides current (power) limitation. Available for rated currents of 32, 40, 50 and 63 A. All voltage parameters are the same as those of the V-protector. Based on the rated and maximum current, VA controls the load and, if the rated current is exceeded, turns off the network after 10 minutes, and the maximum - after 0.04 seconds. The device display shows both voltage and current. VA-protector warranty is 2 years.

Well, the most advanced of the series of voltage relays from TM DigiTop is the MP-63 multifunctional relay. Actually, everything is the same as with the previous VA-protektor, only MP-63 shows, in addition to current and voltage, also active power.

This MP-63 relay and V-protector were independently tested by members of the forum, the reviews are average.

I tried to cover in my article the most common surge protection devices. Of course, there are still manufacturers of devices for this type of protection, but there is very little information about their use.

Thank you for your attention.

Designed to protect consumer electrical equipment from long-term voltage surges, mainly associated with a break in the neutral wire, disrupting the operating parameters of the electrical network. This is a durable, easy-to-install and operate device.

Important clarifications were made by the Judicial Collegium for Civil Cases of the Supreme Court of the Russian Federation when it reviewed the results of a dispute between several citizens and an energy company. Due to a power surge in the network, people's entire home appliances - refrigerators, televisions, computers and other property - were damaged.
Such situations - voltage drops in electrical networks - are not uncommon, and the damage from a current surge can be quite noticeable for home equipment. Therefore, the explanations of the most experienced judges in the country can be useful not only to professionals considering such claims, but also to ordinary people.

Question surge protection will always be relevant for any type of residential and non-residential structures. And it doesn’t matter whether it’s a wooden house or reinforced concrete walls of an apartment, a Khrushchev building or a new building. As an experienced electrician, I have seen the consequences of this “phenomenon” several times; it is not a very pleasant sight. This can actually lead to a fire, because... Almost all modern technology is in “standby” mode, i.e. in fact it is always on. You can find out more about overvoltage. So, as for ultrasonic monitoring devices. Reading the excerpt:
"9.22 Checking protection against overvoltage due to a neutral break in a three-phase system
As a result of a neutral break in a three-phase installation system, an overvoltage between phase and neutral may occur. The maximum value of such overvoltage can reach the interphase voltage. An abnormal increase in temperature in an overvoltage load may cause
fire.
AFDDs must contain an additional characteristic that provides protection in this case. The question of such a characteristic is under consideration."
In principle, most of this type of device is equipped with surge protection, which of course is good news.

Multifunctional protection device UZM-50TS designed to disconnect equipment when the mains voltage goes beyond permissible limits in single-phase networks, to protect equipment connected to it (in an apartment, office, etc.) from the destructive effects of pulsed voltage surges caused by the operation of nearby electric motors and magnetic starters connected to the same network or electromagnets, thereby preventing equipment failure and possible ignition with subsequent fire. The device provides control of the network voltage and the reasons for operation.
After power supply or after an emergency shutdown, the device turns on automatically after the mains voltage is restored after a delay time set by the user. The device can be used in networks of any configuration; TN-C, TN-S, TN-C-S, TT. The device does not replace other protection devices (circuit breakers, SPDs, RCDs, etc.).

Overvoltage- these are disturbances in the normal operation of the electrical network associated with an increase in the electric field strength to values ​​dangerous for elements of electrical installations and conductive lines. At the moment of overvoltage, an instantaneous impulse or additional voltage wave is superimposed on the rated mains voltage. Such phenomena can cause damage to insulation and cause a fire; they can pose a serious threat to the performance of equipment, and sometimes to the life and health of people. Overvoltages have different natures. However, modern protective equipment makes it possible to neutralize the consequences of all types of network disruptions.

In domestic conditions (residential apartment buildings), as in most distribution networks, three-phase power is used. The specificity is that the phases are distributed among apartments and have a common neutral conductor. Three-phase power supply is less common. As a rule, you can’t do without it in premium class cottages or apartments with an area of ​​200 sq.m. where the power consumption threshold exceeds 14 kW. Economy and middle class apartments with an area of ​​up to 100-150 sq.m are usually powered by single-phase power: this is three-phase power, in which each phase goes into a separate apartment with a common neutral.

The neutral wire plays the role of a balancer between phases. In other words, if the load between phases is unbalanced, then the neutral wire neutralizes this imbalance. A neutral wire is not needed if the load is uniform, but in practice this does not happen.

The correct operation of household appliances and equipment, as well as their durability, depend on the network voltage, which is standard and regulated by GOST. However, for many reasons it may deviate from the specified parameters, thereby having a negative impact on the service life of electrical products. A voltage relay will help maintain the functionality of the equipment.
The device is controlled by a microcontroller, which analyzes the voltage in the electrical network and displays its effective value on the built-in display. Load switching is carried out by an electromagnetic relay. The permissible shutdown limits and the turn-on delay time are set by the user using the buttons on the front panel. The values ​​are stored in non-volatile memory.
The voltage relay is mounted on a DIN rail and installed in a distribution cabinet for domestic and industrial use. Allows you to control the voltage of a large number of consumers.

QUESTION:

Good afternoon. I purchased a voltage control relay RM17UBE15. I connect phase (L) to A1 (+) and contact No. 11, zero (N) to A2 (-). I see voltage on pin No. 12, whereas during normal operation of the relay I should see voltage on pin No. 14. Voltage settings are set to extended 80<260, замер реального напряжения в сети произвел (223V). Так же наблюдаю мигающую индикацию Un и R, тогда как подобной ситуации нет в инструкции к устройству. Прошу помощи.

Overvoltage protection is a power supply feature that shuts down equipment when the voltage exceeds a specified setting. Overvoltages can occur at the source or in distribution networks and last only a few milliseconds, but even such a short-term manifestation of electromagnetic effects on household appliances is destructive, especially for electronic equipment containing semiconductor components.

Causes of emergency situations in the household electrical network

The main factors of overload in the 220 and 380 Volt network:

• thunderstorms and lightning are the highest energy phenomena on Earth;
• improper operation of equipment and low level of qualifications of power grid personnel;
• violation of safety rules when operating electrical installations, as a result of which the consumer will not have 220 V, but 380 V or less than 110 V;
• spark of static electricity;
• neutral wire break;
• surge voltage due to a thunderstorm hitting a power line;
• current surges in the network due to the simultaneous activation of a large number of devices and equipment.

Consequences of network overvoltage

Exposure to overvoltage conditions can completely damage electrical equipment, cause device malfunctions, lead to fires, and sometimes even explosions. In terms of the number of cases, the second place in the country is occupied by fires caused by overvoltages in the network, when the current instantly increases to hundreds of thousands of amperes, a huge amount of heat is suddenly released in electrical wiring or devices, followed by ignition of their insulation or plastic products.

Voltage surges have a detrimental effect on all household electrical appliances; they can only be protected by using a special surge protection device.

Types of protective devices

To combat network voltage surges, there are many different devices that are easy to install yourself. The products help to most effectively protect your home and loved ones from emergency situations caused by network overvoltage.

There are several types of surge protective devices:

1. Voltage stabilizer - controls the size of the mains voltage.
2. An uninterruptible power supply (UPS) is a device for emergency maintenance of equipment when the main source is turned off, designed on the principle of a backup battery. A UPS is still different from an autonomous power system, as it provides lightning protection by powering the device from battery energy. The emergency operation time of the UPS is very short (a few minutes), but this is enough to start another source or properly disconnect devices from the network.
3. A circuit breaker is an electrical device with functions similar to that of a fuse. Network overvoltage protection of the simplest circuit breakers is provided by a solenoid, which is activated by an excessive increase in current. Small circuit breakers are widely used instead of fuses to protect electrical systems in homes and apartments.
4. A surge filter is a protective device with a built-in electronic circuit for protecting against pulsed, low- and high-frequency network interference by smoothing it out.
5. Nonlinear surge suppressor (SPL) - a device that protects equipment from switching surges and lightning, is the best means of protection.
6. Transformers (step-down and step-up) - change the voltage to operating voltage when there is a regular voltage drop or rise in the network, which is why the devices cannot function at full capacity.
7. Residual current devices (RCDs) are the most common means of protecting people from the danger of electric shock when touching live devices and equipment, as well as protecting against fire caused by leakage currents. Other means of protection cannot perform these functions, since they only respond to network overload.

Sources of impulse noise

Pulse interference (IP) is created by an instantaneous voltage surge in the electrical network with an amplitude of more than 4-6 thousand V. IPs come in the form of a single or multiple (pack) of alternating pulses. This is the most common “disease” of electrical networks and causes irreparable damage to electronic components of household appliances. IP protection - powering equipment using surge protectors. Other electrical equipment protection systems are practically not configured to protect against IP, and therefore cannot provide it.

There are different sources of IP:

1. Natural sources - lightning strikes close to power grids (aerial or underground), coverage area up to 20 km.
2. Man-made sources - switching processes during the period of operational control of power transmission systems (on/off) and emergency situations at transformer substations.

According to operational data, the most common IP is of a man-made nature, which can be explained by the level of deterioration of networks and the high consumer load.

Equipment safety classes for IP protection

Depending on the pulse power, IP protection equipment is divided into classes:

• lightning protection - 0 (A);
• entrance panel for structure I (B);
• electrical panels for premises - II (C);
• equipment according to GOST-III (D).

Surge protection device (SPD)

There are SPDs - varistors and arresters of various designs, usually having indicators that signal a shutdown. Varistors have certain disadvantages: after operation they must cool down, which reduces the level of readiness of lightning protection in the event of repeated lightning strikes. They are mounted on a DIN rail, so they are easy to replace if necessary.

Overvoltage protection and reliability of use of the device depends on the efficiency of grounding with equal potentials TN-S or TN-CS, separation of the protective and 0-wires. SPDs are installed with a step of 10 m along the cable, which ensures the calculated sequence of operation of the SPD.

On overhead lines, SPDs are installed from arresters and fuse-links, in the common house panel - varistors CL. I, II, and on the floors - III class. If additional protection is necessary, sockets are equipped in the form of network extension cords.

220 volt surge protection device for home

Overvoltage protection 220 V is a task that you will have to solve yourself: think with your head and assemble the protection with your own hands. Modern household and computer equipment operate safely from 190 to 240 V. A voltage surge creates devastating consequences for equipment when the voltage instantly increases significantly and drops sharply.

The most common causes of overvoltage:

• simultaneous switching off/on of a large number of devices;
• 0-wire damage;
• lightning strikes power lines;
• wire breakage by an external object;
• violation of the wiring diagram in the switchboard.

The industry produces a large list of devices that can reliably provide protection from overvoltage of a 220 V network, and household appliances from damage and high network parameters:

1. VKN (voltage control relays) are installed when voltage drops are a rare occurrence. RKN - a device that turns off the electrical circuit when the potential difference changes and turns it on when the network parameters are normalized, must have its own power exceeding the total power of the connected equipment.
2. DPV (voltage drop sensor) is triggered when the potential difference changes. The DPN causes a current leak, which is detected by another machine - the RCD, which also turns off the network.

Surge Protectors

For normal operation of electrical equipment, the voltage must be maintained in the range from 190 V to 240 V. Protection against surge voltages occurs when permissible parameters are exceeded, for example, caused by welding work performed near the house, or the appearance of a short circuit current in the general house electrical network. In this case, the stabilizer instantly turns off the electricity. After stabilizing the network, the protective device independently supplies voltage to the consumer’s devices.

Network filters

If the filter cannot cope with the interference, it turns off the power with a built-in fuse. Surge protection is used for household multi-level computer networks. A surge protector circuit provides one of the simplest, cheapest, and most effective methods of surge protection. This usually involves a regulated output and a protected circuit or load. SFs operating on the basis of a transistor control the output current and voltage. The protection device shuts down the equipment when the voltage exceeds a preset value.

Surge protection using arresters

Lightning, quasi-stationary and switching overvoltages affect the performance of electrical equipment. The main protective devices are RV (valve arresters) and surge arresters (non-linear surge arresters). The reliability of their operation depends on:

• Selecting the number of devices, their parameters and location.
• Internal surge protection of the arrester itself, which is not protected from this type of impact.
• Tested under normal conditions, they should not break through.

Surge arresters (varistors) consist of a resistor and a spark gap connected in series. This connection scheme changes characteristics in a humid environment, so they are hermetically sealed. This type of arrester operates silently and does not emit gas or flame.

The phenomenon of overvoltage in our networks is not uncommon; power supply systems are outdated, as they are not designed for the modern increased standard of living of consumers. Inflated electricity consumption loads are destroying worn-out networks, causing power surges to occur more and more frequently.

To summarize, it should be said that surge protection methods, of course, are designed to protect equipment and people from high voltage damage, but do not provide a 100% guarantee. During thunderstorms and switching phenomena in the network, the best protection is always to completely disconnect expensive equipment from the power grid.

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. This depends on the impedance (complex resistance to alternating current, active + reactance) of the 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.

Protecting your home network from overvoltage is carried out in several interconnected stages, always in a complex manner 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: circuit breakers, RCDs, (not to mention plugs - 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 voltage 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, if the parameter is invalid, sends a command to the actuator of the residual current device. The network is de-energized.

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

In contact with

Voltage surges are common in household electrical systems. Regular failures of network parameters lead to rapid failure of home appliances. And this is already a direct threat to the human body.

Overvoltage is a condition of the electrical network in which the voltage exceeds the operating limits. Permissible range for electrical networks 0.38 kV: 0.198..0.242 for single-phase, 0.342..0.418 for three-phase. Those. the deviation ranges from 5-10% at inputs to consumers.

Causes

Causes of overvoltage in the network:

1. Lightning strikes. At the same time, current flows through the wires, with pulse voltages of several tens of thousands of volts.
2. Operator errors when servicing equipment at supply substations. This happens due to inconsistency in voltage regulation at the substation.
3. Incorrect connection of wires in the switchboard. Occurs when the phase is connected to zero.
4. Violation in neutral. Occurs when a conductor breaks or burns. It is the most common cause of overvoltage in household networks. When a break occurs, phase imbalance does not occur, which causes voltage surges.

Danger for electrical appliances

Household appliances are designed for the presence of power surges exceeding operating values ​​three times (up to 1000 V). If an emergency occurs, the value of the surges may exceed the maximum permissible norms. In this case, overheating of the cables occurs, breakdown of the insulating sheath, and as a result, sparking and fires. Short circuits can occur even in sections of the electrical network without load.

Surge protection

Safety measures include SPDs (surge protection devices).

There are two types:

1. Full. Provides for the installation of devices at the entrance to apartments, as well as in front of each household electrical appliance.
2. Partial. In this case, the devices are installed only in the electrical panel room.

Modern SPD safety measures

Types of surge protection:

• Relay. Performs emergency shutdown of household appliances when the power grid reaches critical parameters and automatic switching on after voltage normalization.

They are used to protect the entire network, as well as for each electrical device separately.

• Surge Protectors - .
• Modern models are microprocessor-based, have a display and a multifunctional interface. Combined use of RCD and DPN (overvoltage sensor). The last device monitors the network parameters, and the RCD performs an emergency shutdown.

Devices intended for:

• monitoring voltage symmetry in household electrical networks;
• preventing load asymmetry;
• correct phase sequence in three-phase networks.

Used in systems with automatic control.

Imported equipment is very demanding on the quality of electrical networks. The lack of proper electricity control measures leads to rapid wear and complete failure of electrical devices. The phase control relay is also designed to stabilize the parameters of the power supply network.

Advantages:

1. work on a microprocessor base;
2. high accuracy of readings and reliability;
3. simplicity of design.

The operating principle is based on the phenomenon of self-return of parameters. When voltage is applied, the device performs control. An emergency shutdown occurs when failures occur.

Installation locations:

• to protect separate equipment or a group of electrical installations directly in front of the outlet;
• for general house protection on the DIN rail of the input distribution device.

If several phases fail at the same time, the device operates without a time delay.

Automatic backup power input device

Reasons for relay operation:

1. phase imbalance;
2. inconsistency in the connection of phase wires;
3. phase cable break.

Types of stabilizers

There are ferroresonant, triac, relay stabilizer electrical devices and servo drive stabilizers.

Ferroresonant

In a transformer-capacitor system, the ferroresonance effect is used. Perform stabilization of parameters in the selected load range. A less common type due to the difficulties of implementation in household power supply systems and high cost.

Advantages:

• operation accuracy;
• long service life;
• performance;
• reliability of operation.

Flaws:

• bulkiness;
• sinusoidal distortion;
• small load range;
• impossibility of working in idle mode and overload.

Triac

The principle of operation is the signal is triggered by a relay type. The circuit is disconnected by triacs.

Advantages:

• upon receiving a signal, stabilizers are capable of rapid switching;
• no noise;
• smooth adjustment.

Flaws:

• overpriced;
• step adjustment.

Relay

Used to protect low-power electrical devices. The device includes a power relay and an autotransformer. When the parameters of the external network change, the relay element is triggered and the windings of the autotransformer are switched.

Advantages:

• performance.

Flaws:

• step adjustment;
• low response accuracy;
• sinusoidal distortion.

Servo-driven

Arranged according to a rheostat circuit. When the electrical network parameters change, the electric drive moves the moving contacts on the autotransformer winding to the required position.

Advantages:

• high sensitivity of the electrical appliance to violations of network parameters;
• no sinusoidal distortion;
• smooth control.

Flaws:

• low reliability;
• slow response of electronics.

Automatic voltage stabilizer

Work in 220 V networks

Installation is carried out in accordance with electrical safety requirements - without load. Connection to the circuit is carried out directly after the meter. The phase wire connection is broken.

The device has three contacts:

• Zero. The neutral is connected without a break.
• "Entrance". The wire coming from the input machine is connected to this contact.
• "Exit". Connects to the conductor going to consumers.

In the case of a four-pin connection, the circuit is similar. The phase conductors and neutral coming from the main machine are connected by breaking to the stabilizer.

• An inspection must be carried out at least once a year.
• The devices do not produce sounds during operation. Extraneous noise indicates instability of operation.

After installation, a test run is performed - without load. If the network is disconnected, the installation was carried out with errors.

There are portable stabilizing devices. They are a box with a plug and several sockets for connecting electrical appliances. They are adapters between the power supply and the load.

Work in 380 V networks

Operation of stabilizers in 380 V networks:

• Stabilizers must monitor the uniform distribution of current across phases.
• The use of three-phase devices is necessary in cases where electric motors will be used in a 380 Volt network.
• As a rule, all consumers are 220V, so it is advisable to use a set of 3 single-phase stabilizers. If one of the three devices fails, the supply of electricity will not stop, unlike the case with three-phase. Replacing a failed phase will cost 3 times less.

When choosing a stabilizing device, it is necessary to take into account: the cost of the equipment, service life, speed, interface convenience, adjustment device, load characteristics of the household network.

Installation location of protective devices

The devices are installed in specially equipped rooms – electrical switchboards. If this is not the case, then the installation location may be vestibules, storerooms, and utility rooms. The main condition for the room is to ensure high-quality ventilation.

When installing stabilizers in recessed shelves and niches, it is necessary to retreat 10 cm from the walls to prevent overheating of adjacent surfaces. Also, there should be no flammable materials nearby - plastic panels, synthetic curtains, etc.

Selection of stabilizing devices

Selection of stabilizers:

• By network type. For residential buildings with a three-phase electrical network, at least one kit for a three-phase load is installed.

Single-phase is installed for consumers powered from the network

• By power. The characteristics of the device must be one step higher than the load assigned to the consumer. For such cases, the load of all protected electrical installations should be taken into account.

In calculations, the total power is used, taking into account (active and reagent).

• Starting current value. It is taken into account when choosing protective devices such as refrigerators, pumps and others, i.e. those whose circuit contains asynchronous motors. For these devices, stabilizers are chosen with a margin of up to 25%.

To protect electric lighting devices, stabilizers with an accuracy of at least 3% are used. It is from this value that the flickering of lamps can be detected.

It is worth answering the question: is it better to have one stabilizer per home or several for each electrical appliance?

For low-power systems, the installation of one set at the input is suitable. This method of protection is economically justified.

If you intend to use a large number of electrical installations, then it is advisable to install protection on each device or group, taking into account the importance and economic feasibility.

UPSs are used to connect expensive equipment: televisions, refrigerators, computers, etc.

Installing a voltage relay. Video

This video explains how to install a surge protection relay.

When designing the power supply of a residential building, special attention should be paid to protecting the network from overvoltage. The use of comprehensive measures allows you to reduce the risk of an emergency to a minimum. You should also not forget about the basic rules for using and maintaining electrical appliances. This not only protects people’s lives, but also saves money on subsequent repairs and replacement of damaged electrical equipment.