How to smooth out voltage surges in the network. How to protect household appliances from power surges. The main causes of power surges in the network

Protection against power surges of household electrical networks, types of protective devices and methods for their installation.

The structural imperfection of electrical networks is the main cause of sudden voltage surges. It is impossible to predict the time of the next drop. The only thing we can do to prevent unpleasant consequences is to secure electrical consumers in our home in advance. In this article, we will tell you how and how to protect the network of an apartment and a house.

What will save you from the jumpdressing up

Protection against voltage surges is possible using different types of protective devices. We'll talk about the most common ones. These are voltage control relays (RN) and household stabilizers.

Surge Protection Relay

Protecting the house from power surges with the help of PH is recommended in cases where the mains voltage is stable and its noticeable surges are rare. RN is a device capable of reading the parameters of the electric current and breaking the electrical circuit at the moment when the indicators go beyond the specified range. After the indicators in the general network are normalized, the device will automatically close the circuit and resume power to consumers. The function of restoring power after a specified period of time (with a delay) built into the 220v home voltage relay helps to extend the life of some household appliances, refrigerators, etc.

PH have small dimensions, relatively low cost and good performance. The disadvantages of PH include their inability to smooth out fluctuations in electrical energy. For maximum protection of all consumers, you will need to install several devices at once.

RN protects the network only from unacceptable power surges and is not designed to protect against short circuits (this function is performed by circuit breakers).

Modern models of launch vehicles are of three types:

1. Stationary relay built into the electrical panel of a house or apartment.

2. Relay for individual protection of one consumer.

3. Relay for individual protection of several consumers.

If everything is practically clear with the operation of the relays of the second and third types, then the first type has a more complex design, and its installation requires certain knowledge. Such devices are mounted at the entrance to the room, so protection against power surges in the network of all home electrical equipment is performed.

PH selection

When choosing a relay to protect the home network, it is enough to know the rating of the electric current that the introductory circuit breaker is able to pass through. If, for example, the capacity of the circuit breaker is 25A (which corresponds to a power consumption of 5.5 kW), then the performance of the RH should be a step higher - 32A (7 kW). If the switch is designed for 32A, then the relay must withstand a current of 40 - 50A.

loa FORUMHOUSE user

For such a case, I took a 40 A relay, with an introductory machine 25/32 (it is the first one, but the setting will increase).

Some people choose the brand of RN based on the total power consumption. This is not entirely correct. After all, a relay capable of withstanding a current of 32A can safely operate both at a load of 7 kW and at much higher power consumption. Only in the second case, it is necessary to integrate a special magnetic contactor into the operating circuit of the PH. But more on that in the next section.

PH installation

The standard scheme for installing the RH in the switchboard is shown in the figure. This is the simplest surge protection.

Work on the installation of the PH should be carried out only with the input switch turned off!

As you can see, everything is simple: the control relay is installed immediately after the electric meter and connected to the phase wire, through which the entire house is supplied with electricity. When jumping outside the set (adjustable) range, the relay disconnects the external power supply from the internal wiring, and protection against power surges is performed in the apartment and in the house.

PH, mounted in the panel of the shield, occupies a minimum of space on the DIN rail.

If the power of consumers of the home network gives a total of 7 kW or more, manufacturers strongly recommend that an additional electromagnetic contactor be built into the operating circuit of the PH. Although, a reliable contactor in the general scheme will never become an extra detail, see the following comment:

Vitichek FORUMHOUSE user

It is better to put a contactor to any relay, although the manufacturers write that the PH can withstand high currents. The contactor has large contacts and less resistance.

This device helps to unload the PH contacts by independently disconnecting the power line from the general network of household consumers. The control relay, at the moment of unacceptable overvoltage, only gives a command to turn off. After that, the electromagnetic coil of the contactor disconnects the power contacts connecting the external and internal networks. The connection diagram in this case will be as follows:

Voltage surge protection system.

Surge protection 220v

In order for the RH to benefit its owner, its operating parameters (voltage tolerance limits and power-up delay time) must be properly adjusted. If one pH is used in the working circuit, then the limits of permissible values ​​\u200b\u200bshould be set, focusing on the characteristics of household appliances that are sensitive to drops. The most sensitive and expensive equipment is audio and video equipment. The range of permissible voltage values ​​​​for it is 200 - 230V.

The permissible voltage deviation from the nominal values ​​in domestic power networks is 10% (198 ... 242V). In the case of frequent operation of the PH, these indicators can be taken as a basis by adjusting the relay. However, sensitive consumer electronics in this case are recommended to be protected using portable stabilizers of low price.

DenBak FORUMHOUSE user

Nobody says that it is necessary to turn off at plus or minus 15V. There is a range of maximum permissible deviations of 10%, which most devices must withstand. You need to set, based on this, approximately 190V-250V. Although, with our state of networks, especially in the private sector, everything is expected. So sensible caution can't hurt.

In order to ensure the most reliable protection of all consumers, an electrical circuit with several relays should be used. The working protection scheme, which includes several RH, allows you to divide consumers into groups - in accordance with their sensitivity to overvoltage:

1. The first group includes audio and video equipment (permissible voltage values ​​​​- 200 - 230V);
2. The second category includes household appliances equipped with an electric motor: refrigerators, air conditioners, washing machines, etc. (permissible values ​​​​- 190 - 235V);
3. The third group is simple heating devices and lighting (permissible values ​​​​- 170 - 250V).

Each group of consumers is connected to its own pH. In such a scheme, the operating parameters of each relay are configured individually.

Network protection against overvoltage and surges.

The power-on delay time should be in accordance with the performance requirements of household appliances. For some refrigerators, for example, the recommended delay is 10 minutes.

Protection of a three-phase network using PH

If the power supply to your house is carried out through a three-phase system, then it is advisable to install a separate control relay for each phase.

Three-phase voltage relays are designed exclusively for the protection of the relevant equipment (electric motor, etc.). If such a relay is installed at the input to the dwelling, then a voltage imbalance in one of the phases leads to a de-energization of all single-phase consumers.

Surge Protectors

If there are constant power surges in your house, then the PH will work several times a day, de-energizing the entire house. Therefore, in such cases, a less simple, more expensive, but also more practical way to protect home electronics is recommended. It consists in the use of stabilizers - devices that smooth out voltage surges in the external network, giving out a constant indicator of 220V at the output.

According to the type of connection, two types of stabilizers are distinguished: local (which are connected to the outlet, protecting from one to several consumers) and stationary (connected to the input power cable and protecting all consumers of the home network). Local stabilizers should be used to protect the most sensitive household appliances. They can be operated in conjunction with a stationary launcher.
Stationary stabilizers are complex devices that not only smooth out voltage fluctuations in the entire household network, but are also able to save expensive equipment by automatically turning off the power to consumers when overloaded and reaching critical values.

It is highly recommended to install stationary stabilizers if the voltage value goes beyond 205 ... 235V several times a day (this can be determined using an ordinary tester).

If the light in the house is constantly blinking, and the voltage goes beyond 195 ... 245V, then it is forbidden to use household electrical appliances without a stabilizer!

How to choose a stabilizer

The stabilizer should be chosen based on the total power of domestic consumers. The device must have a decent power reserve.

According to the interstate standard GOST 29322-92, since 2003 in Russia, the voltage standard in domestic industrial power networks must correspond to 230 volts.

However, the actual voltage in the electrical outlets of apartments or private houses often differs significantly from the normalized value. Often there are power surges in the mains, and devices from power surges in the mains can instantly burn out. How to prevent this and where to go, we will consider in this article.

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Causes of power surges in the network

1. The most common cause of power surges is transients that occur every time a consumer is connected or disconnected to the network. The more power the electrical installation is switched, the stronger the amplitude of the voltage surge in the network. Examples: a neighbor connected a home-made "welder". The mains voltage drops, especially when he starts welding. And if you turn off all the electric heaters in half of the apartment building at the same time, then we get a voltage jump in the power grid in the direction of increase.
2. The next most common reason is a break or burnout of the neutral wire. This defect occurs due to an emergency on power lines or with poor quality installation of power supply systems for residential buildings. With such a malfunction, it is possible to increase the voltage up to 380 volts due to uneven distribution of loads on different phases in the mains.
3. Another reason for changing the standard voltage in the network is installation errors during repairs. If a negligent electrician connects the phase of the network to the neutral conductor, then instead of 220 volts, there will be 380 volts in the sockets.
4. The only natural cause of overvoltage in the network is a lightning strike. In this case, the magnitude of the difference depends on the proximity of the impact.

The danger of increased mains voltage is obvious - electrical appliances fail, do not withstand, from cheap incandescent lamps to expensive computers and TVs.
What is the danger of low voltage?

IMPORTANT! The most vulnerable electrical installations to undervoltage are those that incorporate motors. With a lack of electromotive force, the starting torque of the motor is significantly reduced (especially for asynchronous motors), they are not able to overcome the resistance of the attached mechanisms. The motor overheats and its windings burn out. The danger of such an outcome is most likely in compressor units (for example, refrigerators or air conditioners).

Protecting the power grid from power surges: how to prevent power surges and possible damage from them

How to avoid power surges in the network? Fortunately, there are both technical and organizational measures to protect electrical networks from power surges.
Technical measures include:

• Using a voltage stabilizer. This device allows you to compensate for jumps in one direction or another. The best models give out a stable voltage of 220 volts (± 5%) even with network fluctuations from 140 to 260 volts.
• Installation of a relay that disconnects devices from the network at extreme voltage changes. Such relays will protect household electrical installations from failure. When the network stabilizes, the relay resumes power to the connected devices.
• Installation of uninterruptible power supplies (UPS). Such a measure will allow you to maintain the serviceability of household appliances even with a complete short-term power outage. The UPS uses built-in rechargeable batteries, which provide power in the event of a power outage. They are mainly used for working with computers. Such devices will protect against both low voltage and power surges.
• Device for reliable lightning protection of residential buildings.

Organizational measures include:

• switching off devices before repair and electrical installation work and switching them on to the network only after checking the output voltage
• switching off especially sensitive devices from the socket in case of lightning hazard

Unfortunately, it is not always possible to protect your equipment from network problems in a timely manner.

Can the damage caused by a power surge be repaired?

What to do in case of power surges and is it possible to compensate for damage to damaged household appliances? It is possible, the approximate procedure is as follows:

Important! If a power surge occurs in your presence, call the emergency services immediately, report the incident and request that the report be registered. Call the emergency team, which will be able to fix the fact of a malfunction in the power supply on the spot. In the future, this measure will serve as evidence in court.

1. Determine who is responsible for the damage. As a rule, this is one of two organizations:
   electricity supply company;
   home electrical service company.
   To complete this item, you must write a statement to both organizations and demand a response indicating the reasons for the network problems. The organization has 30 days to submit a response.
   To determine the causes of damage, companies can create special commissions or involve third-party experts who will conduct an examination of the state of power supply networks and failed equipment. One copy or a copy of the examination report is sent to the applicant.
2. Take damaged household appliances to a service center and request an opinion on the causes of the failure and the possible cost of repairs. An expert damage assessment can be done. The cost of this service must subsequently be included in the claim.
3. Send a written complaint to the person responsible for the damage claiming damages. Attach copies of expert opinions, inspection certificates to the appeal.
4. If the guilty organization (or a specific person) refused, or did not respond at all to the appeal within 30 days, then the next step is to go to court with a statement of claim on the basis of Article 17 of the Federal Law “On Protection of Consumer Rights”. Another option for this action is to apply to the prosecutor's office with a request to protect the violated rights. In this case, the prosecutor will draw up the claim.

It happens that a specific person (for example, a neighbor) who independently carried out repairs and violated the rules for installing or operating electrical installations becomes the culprit of causing harm.

If the culprit of the damage was an electricity supplier, then the statement of claim indicates a reference to Article 309, Part 1 of Article 539 of the Civil Code of the Russian Federation, Part 1 of Article 547, Articles 4, 7 and 14 of the Federal Law "On Protection of Consumer Rights".

If the culprit is a company that maintains engineering networks at home, then refer to the violation of Articles 309 of the Civil Code of the Russian Federation, Articles 4, 7 and 14 of the Federal Law "On Protection of Consumer Rights", paragraphs 49 and 51 of the "Rules for the provision of public services to citizens", paragraph 5.6 of the "Rules and norms for the technical operation of the housing stock”, paragraph 7 of the “Rules for the maintenance of common property in a residential apartment building”.

IMPORTANT: To make it easier for the judge to make a decision in your favor, add evidence of neighbors who have fallen into a similar situation to the statement of claim.

Summing up the article, it should be noted that it is easier to take measures in advance to protect home equipment from power surges than to waste time and nerves in the courts.

Voltage relay necessary to protect the electrical network from power surges. At present, the issue of a stable voltage value of the power grid is quite acute. Grid organizations are in no hurry to reconstruct and modernize power lines, substations and transformers. In the meantime, the situation is only getting worse, so voltage fluctuations in our networks are quite common.

For those who still doubt the installation of a relay for protection own housing or believes in the quality of construction and installation work in modern new buildings. Below is a screenshot of one of the latest, where the author writes that he has in the new building "burnt out zero".

According to GOST 29322-92 voltage in the power grid of our country should be within 230 V in one phase and 400 V between phases. But if you live in a rural area or close to a city, then problems with a constant voltage value are very high, and this should not be ruled out in the city itself, especially in an old housing stock. Voltage fluctuations are very detrimental to 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 oven is greatly reduced, and incandescent lamps shine dimly. Well, high voltage will simply “kill” your household appliances. I'm sure many of you have heard of "burning out zero" in high-rise buildings, and how entire entrances are carried to workshops to repair household appliances.

The causes of 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.
• Burn-out (break) of zero, if you have a low load at this time, then the voltage will also tend to 380 V.
• Uneven load distribution over the phases (skew), as a result, the voltage decreases in the most loaded phase, and if a refrigerator and air conditioners are connected to it, then there is a high probability that they will “burn out”.

An example of a video showing the operation of a voltage relay

To solve the problem of power surges in networks, special devices help - voltage monitoring relays. 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, in case of deviations, signals the release (power unit), which turns off the network. All household voltage monitoring 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 single-phase and three-phase. Single-phase voltage relays disconnect one phase, and three-phase - simultaneously all three phases. With a three-phase connection in everyday life, single-phase voltage relays should be used so that voltage fluctuations in one phase do not lead to disconnection of other phases. Three-phase 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 rest. I do not impose 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 to assess the situation with the voltage in the network. The error of indications is low, the difference relative to the high-precision Fluke 87 multimeter is only 1-2 Volts.

Zubr voltage relays are produced for various rated currents: 25, 32, 40, 50 and 63A. The device at 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 increments of 1 Volt, the lower value is from 120 to 210 V. The re-closing time is from 3 to 600 seconds, in increments of 3 seconds.

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

For devices with an 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 rises to 80 degrees (for example, due to heating of the contacts), it turns off.

The Zubr relay occupies 3 modules or 53mm on a DIN rail and is available in single phase only.

In the passport and the given connection diagrams of the Zubr, it is not said about the current limits, but in the old documentation, it was previously indicated that it was not more than 0.75 of the nominal.

Zubr voltage relay wiring diagram

Currently, manufacturers claim that the relay can be connected at face value. If the value of the Zubr is less than the value of the introductory machine, then it is necessary to use a voltage relay in the connection circuit - a contactor.

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

Update (07.06.15). Currently, the Zubr voltage relay is sold in Russia under a different name Rbuz (the word Zubr is the opposite).

This is due to the fact that in Russia the Zubr trademark is registered for another manufacturer and only the name of the relay has changed, while all components have remained the same.

.

UZM-51M. The protection device is multifunctional.

UZM-51M is designed for current up to 63A, it occupies 2 modules on a DIN rail (width 35 mm). With a standard version, the operating temperature of the UZM is from -20 to +55 degrees, so I do not recommend installing it in a shield on the street. True, there are also from -40 to +55, but I have not seen such on sale, if only to contact Meander CJSC directly.The maximum setting for the upper voltage shutdown is 290 V, the lower threshold is 100 V. The re-closing time is set independently - it 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.

Wiring 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, perhaps, is only that, as we know, the latter, as we know, can be set to operate independently, and in the UZM-50M, the setting is “hard”, according to the upper voltage limit - 265 V, and according to lower - 170 V.

UZM-16 is designed for a current of 16A, so it is placed only on a separate electrical receiver. For example, in order not to wait 6 minutes until the UZM-51 turns 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 of 250 Volts on the UZM-51M, and the lower value is 180 Volts.

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

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 made in Russia. Warranty for UZM 2 years. Most importantly, Meander's representative is present at the most popular Mastercity forum, he always advises on products, and is also attentive 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 in the UZM-51M relative to other voltage relays is the lack of voltage indication. But the difference in price between the UZM and the voltage relay with a contactor allows you to buy and install a voltmeter separately.

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

These voltage relays are produced in Russia. As you can see from the title, three types of voltage relays can be purchased from Novatek.

The RN-111 and RN-111M are practically the same device in terms of parameters, the main difference between them is that the RN-111M relay has a voltage indication, while the 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 sec. These relays have a 3 year warranty.

Connection diagram for voltage relay RN-111

RN-111 are 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).

Voltage relay connection diagram with contactor

This significantly increases the cost, since a good contactor will now cost about 4-5 thousand rubles, you will need more modules in the shield, as well as an automatic machine to protect the contactor coil. The above diagram for connecting a 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 the 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 of the RN-113 are rather weak for a wire with a cross section of 6 mm 2, and it is this cross section that is necessary for connecting to 32A.

It is more reliable to connect RN-113 with contactors, without contactors for a maximum of 25A. I do not use Novatek voltage relays in my shields, 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 modules more and is twice as expensive in cost than if UZM-51M or Zubr were used.

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

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

Relay

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

The voltage relay of the V-protektor series is intended only for protection against voltage surges. It is produced for rated currents of 16, 20, 32, 40, 50, 63 A in a single-phase version, has a built-in thermal protection against overheating, which operates at 100 degrees. The upper threshold of operation is from 210 to 270 V, the lower threshold is from 120 to 200 V. The automatic switching time is from 5 to 600 sec. There is also a three-phase relay V-protektor 380, quite compact 35 mm (two modules), but the maximum current per phase is not more than 10A.

The Protektor single-phase voltage relay is guaranteed for 5 years, for the three-phase relay only 2 years.

V-Protektor DigiTop Voltage Relay Wiring Diagram

Digitop also produces a voltage relay and a current relay VA-protektor combined in one device. In addition to overvoltage protection, the device also provides current (power) limitation. They are produced for rated currents of 32, 40, 50 and 63 A. All voltage parameters are the same as for V-protektor. According to 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 one - after 0.04 seconds. The instrument display shows both voltage and current. Warranty for VA-protektor 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 the previous VA-protektor, only MP-63 shows, in addition to current and voltage, also active power.

This MP-63 and V-protektor relays were independently tested by members of the forum, 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 kind of protection, but there is very little information about their application.

Thank you for your attention.

Voltage fluctuations in the household network are not uncommon. The reason may be the actions of the energy company, breakdowns, overloads, other force majeure circumstances. For many technical devices in a room and apartment, even minor jumps are fatal. To minimize the consequences, you need to know how to secure housing and what to do after: where to file a complaint, for compensation, and more.

Definition of the term

Equipment breaks down due to power surges

A power surge is a short-term significant drop in electricity that goes beyond safety standards. In Russia, jumps within +/- 10% of the nominal value for 7 days are considered acceptable. For example, for a standard 220V outlet during the week, the normal values ​​​​are from 198 to 242. There are three types:

• longer than a minute - a long deviation from the norm;
• less than a minute - short-term fluctuations;
• impulse overvoltage (electricians call "throws").

Appliances and wiring can "burn out" regardless of the causes and type of energy surge. After “throws”, the quality of the resulting voltage deteriorates significantly. If the voltage in the house jumps constantly, you need to look for the cause, install protection, stabilizers, limiters.

The main causes of power surges in the network

Various events can lead to a sharp change in the voltage level - from technical issues to weather conditions. In many cases, it makes no sense to look for "guilty people", but some are directly dependent on the work of the company that provides the building with electricity.

Thunderstorms

A lightning strike in a power line causes a strong overvoltage in the network

In the old days, during rain and thunderstorms, all equipment was disconnected from the power supply, the sockets were removed from the network. The household equipment did not have security sensors, so the action was appropriate. Today, most devices have safety modules that protect against power surges and sudden changes.

However, electricians recommend turning off the computer, TV. When thunderclouds form, the lightning discharge reaches billions of volts. Modern protection systems reduce the risk of a direct blow to electrical wiring, but do not completely eliminate it. Cables in sleeping areas suffer more often. Such lines are laid as you like, sometimes in violation of the rules. Routers, switches, a computer with a hard drive and a monitor, and other network equipment can break down.

Atmospheric overvoltage

A situation similar to a thunderstorm - a difference in voltage accumulates in the atmosphere, a lightning discharge occurs. If the blow hits directly into the electrical installation or in its immediate vicinity, a sharp voltage surge will occur in the networks. Low-power installations burn out first of all.

Distinguish between inducted (next to the block) and direct throw. In the second case, in addition to a power surge, mechanical breakdowns occur - racks and overhead line supports split. For household appliances and appliances, there is a danger in each case.

Technogenic reasons

Power surges

Most often, the causes of sharp drops are technical problems and the human factor. At home and in production, they do not always monitor the maximum load of the network and connect a lot of devices at the same time, which causes a surge in electricity. Unprotected devices will burn. Other similar situations include:

• Overload at a transformer substation - most of the projects were formed more than 30 years ago and were not designed for the current amount of electricity consumed.
• Accidents on power lines and cable networks - occur due to the general condition of wires, equipment and bad weather conditions.
• Malfunction or poor contact with the neutral wire.
  
• Problems on the intra-house part of the electrical wiring (violations during laying, poor-quality or faulty equipment).
• Being close to large industrial and other facilities (shopping centers, workshops, and the like) with high power consumption - when the equipment is turned on and off, a sharp voltage drop occurs on neighboring networks as well.

There are many reasons for power surges. If the house or premises are at risk, you should take care of additional protection of electrical equipment in advance.

Possible consequences



TV power supply after a lightning strike in a power line

A power surge means a short-term sharp change in the level of electricity in the network. For household networks of 220 Volts, the limits are from 198 to 242 Volts (within 10% of the nominal value). First of all, electrical appliances with minimal or no protection “suffer” from drops.

The most dangerous are the drops from thunderstorms and lightning entering electrical installations. The difference in such cases can be up to several kilovolts. With a heavy load, relays and other devices do not have time to work.

Breakage of zero (contact) causes the combustion of household devices in most cases. The voltage level reaches 380 volts (more often - 300-320). This amount is enough to bring equipment out of action.

Protection methods



Voltage relay

It is impossible to completely eliminate the possibility of drops. If power surges are constant, there are several options to secure expensive household appliances. It can be used for most known types of devices.

Voltage control relay

The device helps to solve the problem of sudden power surges in the network. In case of deviation from the set values, the device turns off the equipment. After the voltage supply reaches the established norm, the relay starts the supply of electricity again.

This method helps out only in some situations - a break in the zero contact, a city transport cable (tram, trolleybus) getting on the power lines. When struck by lightning and during periods of atmospheric overvoltage, the device is almost useless.

You can install it yourself by following the step by step instructions.

Uninterruptible power supplies

These devices are not protective, but together with them they help to avoid burnout of devices, but not to remain in complete isolation until the normal voltage level is restored. Providing electricity to the entire house or apartment is impractical and economically inefficient. It is enough to connect a separate section of wires (for example, for lighting).

The choice of uninterruptible power supplies is influenced by the total number of devices in the room and the required amount of energy. Devices are divided by the maximum amount (value) of current.

Surge Protectors

If the voltage jumps in the apartment (throws, jumps, etc.), it is recommended to use special stabilizers. The maximum effect is given when the input voltage "sags". They help with weak surges in the network, but they cannot cope with strong impulses (for example, a lightning strike). Electricians recommend use in tandem with a relay.

Lightning surge protection



Protection of an overhead power line against atmospheric overvoltage

Atmospheric overvoltage and lightning are the cause of burnout of household appliances. You can avoid unpleasant consequences if you install special voltage limiters at the input. It is especially important to use devices in private homes. Without protection against lightning surges during bad weather conditions, it is necessary to disconnect all home devices from the mains (pull out from the socket), turn off the lights.

These devices protect only in the event of high voltage surges. With small power outages, they are useless.

Where to complain and how to compensate for the damage

Initially, a complaint and a claim for damages are submitted to the company with which the contract is concluded. At the same time, it is necessary to describe in detail what happened and why this particular company is considered to be guilty. Issues on collective appeals are resolved faster than on individual ones. Therefore, in apartment buildings, it makes sense to cooperate with neighbors and submit one requirement. Necessary contacts - addresses, telephones, details - are indicated in the contract (often found in receipts for payment).

Immediately after the incident, it is necessary to call electricians to record the fact of damage and draw up an appropriate act. Take burnt devices for examination - you should get a written confirmation of the cause of the breakdown of the devices. Copies of the act and the expert's conclusion are attached to the written claim to the energy company. If management refuses to pay damages, consumers can apply to the court. You can draw up a competent claim on your own according to the samples on the website of the court or with the help of a lawyer.

In this article, we will analyze in detail, how to protect yourself from power surges and drops in a household electrical network.

Power surges are especially relevant for the old housing stock, where the wiring is already old, in some places completely dilapidated, the connections are loose, and the neutral wire often burns out. And this, in turn, leads to the fact that in some apartments the voltage drops below the permissible level, while in others, on the contrary, it rises abruptly and can reach almost 380V.

A sharp increase in voltage leads to the fact that household appliances simply burn out and fail. And a decrease in voltage below an acceptable level is especially dangerous for household appliances, which include electric motors: refrigerators, air conditioners, washing machines, etc. Reduced voltage leads to an increase in starting currents in electric motors, which can ultimately lead to damage and failure of their windings .

In order to protect the wiring and devices connected to it, special devices are used - voltage monitoring relay. They are also called overvoltage relays, as well as overvoltage and undervoltage relays, or simply "barriers".

Let's take a closer look at the principle of operation and connection diagrams of these devices using the DigiTOP voltage relay as an example.

I will not dwell on the technical characteristics in detail, if necessary, you can find it on the Internet. I will briefly mention the most important.

The relay circuitry measures the effective voltage value and when the upper setting is exceeded, or when the voltage becomes less than the lower setting, the relay opens its power contact, disconnecting the phase, thereby opening the external supply network from the internal wiring.

The left button with the down arrow adjusts the lower voltage threshold (default 170V). The right up arrow button adjusts the upper voltage threshold (default 250V).

By pressing both buttons at the same time, you can adjust the delay time when the relay is turned on again when the voltage returns to the operating range.

In single-phase 220V networks, two main voltage relay connection schemes are used:

—in the first scheme, the relay contacts directly control the load, i.e. through them flows all the current consumed by electrical appliances connected to the home network;

- in the second scheme, the relay contacts control the contactor winding, and the load is already connected to the network through power contacts, thereby unloading the contacts and increasing the reliability of its operation.

The circuit with the contactor is discussed in detail in the video at the bottom of this article !!!

We will consider the first scheme.

The voltage relay is installed after the meter, usually in. The phase wire from the external power supply (after the meter) is connected to the terminal 2 power contact of the voltage relay. Further through the power contact from the terminal 3 phase is fed into the home electrical wiring network. Zero applied to the terminal 1 in order to power the circuitry of the relay itself. Those. zero is not broken, the relay contacts control only the phase wire.

When the introductory machine is turned on, power is supplied to the voltage relay. If the voltage value is in the operating range, then after a delay time (set using the buttons on the front panel), the relay contacts close and the phase is supplied to the internal electrical network and it is ready for operation and connection of consumers.

Let's assume that there was a power surge and its value exceeded the upper threshold of 250V. The relay monitors this change and, when the upper limit is exceeded, opens its power contact, thereby breaking the phase wire and stopping the power supply from the external electrical network to the internal network of the apartment or house.

This allows you to protect the connected household appliances and other electrical appliances from failure.

When the supply voltage returns to the operating range again, i.e. becomes less than 250V, the voltage control relay, having withstood the set time delay, again closes its power contact and the circuit returns to working condition.

Similarly, there is protection against unacceptable undervoltage.

Since in this voltage relay connection scheme the load is connected directly through its power contact, when choosing a relay, it is necessary to choose a model designed for a current greater than the current of the introductory machine. This will give the necessary margin and protect the relay circuitry in case of switching the maximum load. We do the same for .

Connection diagrams and the principle of operation of the voltage control relay.

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