Voltage fluctuations (jumps) in the mains, causes and methods of protection. The voltage jumps in the network, what to do and where to complain if the equipment burned out? How to protect household appliances from power surges
I promised to tell you how to protect yourself from a terrible phenomenon called "neutral break". Today we will talk about this. I must say right away that circuit breakers are not capable of protecting against this scourge. Here you need another device - a voltage relay (RN). Here are three copies, the most common on the Russian market:
Actually, what is it, a voltage relay? This is a device that continuously monitors the magnitude of the mains voltage and turns off consumers in the event that the voltage goes beyond the permissible limits, and the faster the PH works, the better. But after the consumers are disconnected, it continues to control the supply voltage and when the voltage returns to normal, the relay will reconnect the consumers to the network. From the previous one, you, dear reader, learned that a neutral break is dangerous because of the uncontrolled "walk" of phase voltages, which is detrimental to household appliances. The voltage relay allows you to protect equipment in this situation.
You will not find high-speed PH from European manufacturers. The fact is that in Europe they are simply not needed. Timely and high-quality maintenance of electrical networks eliminates the nightmare called “neutral breakage”. What can not be said about Russia. Therefore, two of the three devices shown in the photo are Russian-made, and the third is the ubiquitous Chinese. Let's start with him.
Automatic protective module AZM-40A from the company "Resanta"
Resanta is a fairly well-known Chinese manufacturer on the Russian market. It produces a lot of things, including such voltage relays:
I will not bore you with unnecessary talk and will immediately move on to listing the advantages and disadvantages.
Advantages:
1. Low price, about 500 rubles.
2. The absence of any governing bodies. This is important when the relay is installed not inside the apartment, but in the floor electrical panel. There are no "krutilok" - accordingly, no one's playful little hands will be able to drive the relay into an unacceptable mode of operation. But this advantage entails one of the disadvantages.
Flaws:
1. Too wide range of operating voltages - 170 ... 265V. GOST 13109-97 sets the maximum permissible deviations of the supply voltage +/-10% of the nominal, that is, 198 ... 242V. Since our electrical networks do not fit into this range either, it can be expanded to +/-15%, that is, 187 ... 253V. But the range of 170 ... 265V declared by the manufacturer is already too much. And it is impossible to change it, there are no “twists”.
2. Low performance. The declared shutdown time is 1…6s. Why such a scatter is not at all clear. But even if the relay works in one second, delicate consumer electronics can still be damaged.
3. Short delay time before restarting. If there is a short-term "drawdown" of the voltage and the relay is triggered, then it will turn on again after 2 ... 3 minutes. This is clearly not enough. For most household appliances, this is unprincipled, but for refrigerators it matters. The delay before restarting must be at least 5 minutes.
4. Although the manufacturer claims a maximum current of 40A, knowing the Chinese love for savings, I do not advise loading the relay with a current of more than 30A.
5. Experience shows that AZM-40A has one unpleasant glitch. In some cases (not always), during a short-term voltage drop, the relay is activated (disconnects the load), after the set time, the green LED lights up, but the load does not connect. And until you remove the power supply from the relay with the introductory machine, and then turn it on again, this glitch will not disappear. What if it happens in your absence? The voltage has been normal for a long time, but the consumer relay does not connect. In the evening you will come to a leaky refrigerator.
6. Significant dimensions. In the shield, the relay occupies a width of three standard modules, while both Russians participating in today's review are only two modules each. But against the background of other shortcomings, these are already trifles.
Conclusion. So-so device. It can be used when the budget is very tight, but at least you want to protect yourself somehow.
Voltage relay RN-111M from Novatek-electro LLC
Novatek is a serious Russian manufacturer from St. Petersburg. It is engaged in the production of automation, metering devices, etc. In particular, it makes such a relay:
Advantages:
1. Sufficiently high performance (0.2s)
2. Wide adjustment range of upper (230…280V) and lower (160…220V) voltage limits and reclosing time (5…900s).
3. The presence of a convenient digital indicator that displays the modes of operation of the relay and the values of the adjustment settings.
4. Compactness.
Flaws:
There is only one drawback - the low load capacity of the contacts, only 16A. For an apartment, this is clearly not enough. Therefore, RN-111M must be used in conjunction with an additional contactor, and the contactor coil must also be protected by a separate machine. In total, this entire structure will take five modules in the shield, and in terms of money it will cost about 2,300 rubles. True, Novatek also has a RN-113 relay with a load capacity of 32A, but there the price and dimensions are different. Yes, and 32A is also not enough, there is no stock.
Conclusion. A good device, but low load capacity forces the use of additional equipment, which leads to an increase in cost and space occupied in the shield. Can be applied if the next review member could not be acquired.
Multifunctional protection device UZM-51M from CJSC "Meandr"
The Meander company (also based in St. Petersburg) is engaged in the development and production of industrial automation, including the UZM-51M device:
Without exaggeration, we can say that today in the Russian market this is the most "predatory" protection against power surges. Judge for yourself:
Advantages:
1. Wide adjustment ranges for upper (230…280V) and lower (160…210V) voltage limits.
2. The response time is only 0.02s. Great!
3. Load capacity 63A. Enough for any apartment, even the most "fancy".
4. A bonus to the main function (over/under voltage protection) is a varistor surge protection capable of absorbing impulses with energy up to 200J.
5. Compactness. It takes only two modules in the shield. No additional devices (as in the case of the RN-111M) are required.
6. Humane price. At retail, the relay costs a little more than 1900 rubles, and they will sell it to a professional even cheaper, for 1700.
Flaws:
The only drawback and disadvantage you can not name. There is no digital indicator. This does not affect the operation of the device in any way, but somewhat reduces the information content. However, Meander recently announced the launch of the UZM-51Ts model, in which there will already be numbers.
Conclusion. Put everyone!
Light bulbs burn out from power surges, household appliances fail, and even an emergency situation can occur in the apartment wiring. Increased voltage is observed with phase imbalance and other problems on the line. Let's figure out how to protect the electrical equipment of the apartment from overvoltage.
Causes
So, what are the reasons for the excess voltage in the network?
1. Phase imbalance.
2. Impulse overvoltage or so-called. voltage surges.
3. Fluctuations caused by the difference in load at different times of the day or season.
It is worth noting that GOST 29322-2014 says: "the supply voltage should not differ from the rated voltage of the system by more than ± 10%" which for 220V lies within 198-242V.
Phase imbalance
Occurs as a result of complete burnout of the neutral conductor at the input to the house, apartment or from the transformer substation, or a strong deterioration of its contact. In this case, all single-phase consumers, which in most cases are apartments, are connected in series to Ulinear.
Then the voltage between them is distributed according to Ohm's law, where the resistance R is the reduced resistance of the load connected in the apartments. In simple terms, where few devices are connected and they are low-power, the voltage will be high, and where powerful heaters are connected, it will be low.
By the way, when zero burns out at the input, such a phenomenon as “two phases in sockets” is characteristic.
surge voltage
Often occur as a result of turning off powerful electrical appliances or a group of them. Welding works also belong to the same reason, most often this happens in the private sector, when some home master once again decides to “weld” the gate or fence.
Also, surges in the supply network can occur due to poor contact on the overhead power line (OHTL),
Due to weather conditions such as wind, blizzard, heavy rain, thunderstorms can also "jump" the voltage. This is due to their impact on the overhead power lines.
Seasonal or daily fluctuations
At different times of the day, voltage fluctuations occur due to the fact that the load changes, for example, in the evening, when people come home from work, they turn on electric stoves, heaters and other electrical appliances, the current increases and, as a result, voltage drops occur, and at night, when everyone is asleep and the load decreases - the voltage can, on the contrary, be increased.
In the summer, voltage can also rise, because electric boilers and other equipment are turned off. Although in cities in the summer there are voltage drops due to the fact that air conditioners start working everywhere.
In simple terms, voltage fluctuations are due to the fact that the substation has the ability to adjust the voltage either by switching the wires to the winding taps, or using special systems. So, in order to provide some average voltage level under a certain load, a certain value is set. As a result, when the load is large, it can sag, and when the load is small, on the contrary, it can rise.
Consequences
As a result of prolonged high voltages, high power is generated on heating devices, which reduces the service life. With significant excess, semiconductor and other electronic components of household appliances - diodes, transistors and capacitors of input filters can fail.
The consequences of impulse surges are essentially the same, but the amplitude of the impulses in this case can reach several kilovolts.
Various developments are likely:
Burning fuses of electrical appliances;
Failure of circuit components;
Operation of automatic switches;
In the most negative cases, fires are also possible.
Protection methods
To protect the apartment from overvoltage, either stabilizers are used that normalize the voltage to a normal level, or turn off the power at critical network parameters.
In this regard, two types of devices can be distinguished:
Regulating (stabilizers or manual LATRs);
Switching (RKN, RN, UZM, etc.).
Let's consider their features separately.
Under the name "voltage relay" on the modern market, there are many devices, ranging from "nameless" China to popular and generally recognized models, so the following can be distinguished:
Operating principle:
There is a built-in relay to turn off the circuit;
Monitors the voltage in the network;
You can set the upper and lower limits for the allowable supply voltages;
When the voltage in the mains becomes more or less than the set limits, the relay will turn off and the protected circuit will be de-energized. It can be either a separate electrical appliance or the whole apartment;
Does not save from impulse surges;
Protects against overvoltage or undervoltage only.
Depending on the model, the device can work as a relay:
Maximum;
Minimum;
Maximum and minimum voltage.
This functionality allows you to provide protection only from high or low voltage, which will reduce the number of failures or shutdowns of the electrical installation. In some cases, reduced values of the supply network are acceptable for operation, and in some cases the opposite is true (for example, electric motors do not “like” low voltage - the torque is greatly reduced and the current increases).
By execution there are:
For installation on a DIN rail in an electrical panel;
According to the number of phases - single-phase and three-phase. When assembling a three-phase shield, you can also use three single-phase voltage relays.
Both versions are equally good - a socket relay can secure a separate device, for example, by installing a device to protect the refrigerator, or a group of devices, for example, a computer connected via an extension cord.
Consider some popular models for DIN rail mounting:
RN-106 or RN-104- models differ only in rated current - 63 and 40 A, respectively. Operation control range for Umin (minimum voltage) is from 160 to 210 V, and for Umax from 230 to 280V. Also, the time after which automatic reclosing will occur (also called AR or turn-on delay) is set - from 5 to 900 s. The device has convenient and intuitive controls.
The wiring diagram is quite standard for similar devices.
RN-111M and RN-113M- this is a voltage relay from the same manufacturer, but more allows you to use it in a larger range of tasks, limit only the maximum or minimum voltage, or both thresholds. The main thing of the 111th and 113th models is the rated current of 16 and 32A, respectively, as well as the RN-113M occupies more than 111M per 1 model in the shield. The rest of its characteristics, like other devices of this type, are similar.
Please note that the power circuit of the device is separated from the executive circuit, and the output is a relay with a normally closed contact, which also allows you to implement a larger number of protective automation circuits.
On the example of RN-113M, the connection diagram can be made in two versions, depending on the function performed (limiting the upper, lower, or both voltage levels). For RN-111M - similarly.
Please note that the voltage relay must be installed in a circuit protected by a circuit breaker (in the QF diagram), since there is no overload protection function in the vast majority of models.
To increase the power that the relay switches, use a contact starter by connecting its coil instead of the load, and the load itself to the KM power contacts.
In short, a mains voltage stabilizer is a device that maintains the same value of the output voltage when the input changes, within the limits established by the design. Adjustment occurs smoothly (servo-driven devices) and with a given step (relay or electronic).
In terms of power, these devices are either low-power - 500 W, to power individual devices, or capable of protecting the entire apartment - with a power of more than 10 kW. By the number of phases - single-phase and three-phase. In the photo below you can see the three-phase model "RESANTA ASN-15000/3-EM", with a power of 15 kW.
Conclusion
Visitors often ask "which is better voltage stabilizer or voltage relay?". This question cannot be answered unequivocally, since these are different devices. But if you install a voltage relay in front of the stabilizer, then you will protect not only the electrical network of your home, but also the expensive stabilizer itself. While both stabilizers and socket voltage relays can be used to protect individual electrical appliances, these devices can also be used in pairs.
Modern life leads to the emergence of an increasing number of complex household appliances, equipment and electronics in our homes and apartments. At the same time, the quality of power supply wants to be the best for various reasons. On the other hand, the industry offers a number of electrical appliances that allow you to solve the indicated problems with your own hands in your own home. Let's get acquainted with them and make our choice.
Voltage level control in the networkTypes of voltage surges in the power supply network
It is difficult to choose the right surge protection system without knowing their nature and nature. Moreover, all of them are of a natural or man-made nature:
- Often the voltage in the network becomes steadily low. The reason is the overload of an outdated power transmission line (TL), for example, as a result of the mass connection of electric heaters or air conditioners in the corresponding season.
- Under these conditions, the voltage may be too high for a long time with insufficient load.
- It is possible that, with a stable overall power level, high voltage pulses and surges appear in the power supply line. The reason is the operation of a welding machine, a powerful power tool, technological equipment or poor-quality contact in power lines.
- A rather unpleasant surprise is a break in the neutral wire in the 380 V network of the supply substation. As a result of a different load on the three phases, a voltage imbalance occurs, that is, it will turn out to be too low or too high on your line.
- A lightning strike in a power line causes a huge surge of overvoltage, which leads to the failure of both household appliances and the internal wiring of buildings, which leads to a fire.
How plugs and machines protect household appliances
For a long time in our houses and apartments, fuses called plugs remained a universal means of defense against the troubles listed above. They were replaced by modern automatic switches (automatic devices), and reckless people stopped putting "bugs", restoring burnt plugs. Today, in many apartments, circuit breakers remain almost the only means of protection against problems in the home electrical network.
Circuit breakers replace fuses During operation, the circuit breaker trips when the current flowing through it exceeds the value indicated on its body. This allows you to protect the wiring from overheating, short circuit and fire in case of overload. At the same time, the overvoltage manages to disable the electronics, and with a short jump, the machine will not even work.
Thus, a powerful impulse caused by a lightning strike passes through the circuit breaker and can break through the wiring with the consequences listed.
In other words, the machine does not save from increased voltage and its jumps or drops.
Why are SPDs connected to a home network?
Especially for the organization of a system of protection against lightning strikes and the resulting overvoltage impulses, SPDs have been developed - surge protection devices. Note that power lines have certain means of compensating for lightning strikes. Also, in the power supplies of modern electronic devices, there are SPDs of class III.
Modular SPDs for installation in electrical panels However, this is not enough if you live in a private house powered by an overhead power line. The procedure for selecting and connecting an SPD is given in the article. In any case, a lightning rod will help to protect against lightning, which is described in the article "
RCD functions in the power supply scheme at home
In the power supply circuit of a modern house, there is always an RCD - a residual current device. Its main purpose is to protect people from electric shock, as well as to protect electrical wiring from breakdown and leakage, which can lead to a fire. The method for selecting and connecting an RCD is given in a special article.
Single-phase and three-phase RCD Undoubtedly, if an RCD has not yet been installed in your house, this must be done. At the same time, the residual current device saves from voltage drops only to some extent and indirectly.
Protecting electrical appliances with a voltage stabilizer
An electrical stabilizer is a device that maintains a stable voltage at the output when it changes at the input within acceptable limits. The device can have different power and provide a stable power supply to the whole house, or to individual consumers.
Voltage stabilizers of various capacities The stabilizer does an excellent job of correcting slowly changing under or over voltage. Depending on the principle of operation, it compensates for sudden surges or overvoltage impulses to varying degrees.
In modern units, there is a function to turn off the power supply when its level in the network reaches the limit values. After the input voltage returns to the permissible value, the power supply is restored.
In this case, the device does not protect against lightning overvoltage.
Of the devices we have reviewed, the stabilizer is the most expensive. Read the article
Alternative option - voltage monitoring relay in the network
A budget alternative to a stabilizer is a voltage control relay that performs the function of turning off the power supply that we agreed upon when the voltage in the network goes beyond the permissible limits. Depending on the version, the device triggers in case of overvoltage, or it also controls its lower level.
Modular Voltage Relay Options There are relay modifications that restore power automatically when it returns to acceptable limits, or this must be done manually. The most advanced devices provide the ability to set voltage levels at which consumers turn off and the delay time when power returns. For example, the refrigerator must not be plugged in again within five minutes, so as not to damage the compressor. This is the value that can be set on the relay.
Voltage relay ASV-3M must be switched on manually after operation At the same time, the relay does not provide a stable voltage, does not compensate for impulse surges, and does not protect against lightning surges. In other words, this method of protection is suitable in a situation where the voltage in the network is normal, but its rare and significant deviations are possible, including as a result of an accident in the power supply network.
Voltage relay for low-power consumers There are versions for the protection of individual consumers in the form of an extension or a monobloc with a plug and socket. These devices are designed for a load current of 6-16A. Similar devices in a modular design are mounted on the electrical panel.
The relay of the modular type can have at the output a switching group of contacts, normally open contacts, as well as two separate groups of normally open or normally closed contacts. This allows you to implement different options for power management of consumers.
Wiring diagram for connecting a voltage relay in a 220V network The wiring of the modular type voltage relay can be done according to the illustration above. In any case, the device is connected after the input machine. The neutral wire is connected to the N terminal, and the phase wires are connected to the normally open relay contacts.
To protect a more expensive device, its rated operating current is selected one step higher than the value indicated on the body of the input machine. For example, if a 40A automatic machine is installed in front of the relay, a device with a nominal value of 50A is selected.
If a device with the required operating current is not available, or is too expensive, it can be replaced by a voltage relay with a minimum load parameter. At the same time, a contactor of the required power or a starter is connected to its output, which supplies voltage to consumers.
Voltage relay connection diagram using a contactor The wiring of the voltage relay paired with the contactor is shown in the diagram. In this example, the voltage relay itself is also connected after the input machine, counter and RCD. The phase wire from the output contact of the relay is connected to the terminal of the control winding of the contactor, and the neutral wire (protruding part of the housing) is connected to its second terminal. The power phase and zero are supplied to the contactor output terminals (the far part of the case) from above, and the wires of the phase and zero of consumers are connected from below.
If there is a normal voltage level in the network, the control relay closes the output contacts and supplies power to the contactor winding. He, in turn, closes the output contacts and supplies power to consumers. If there is no voltage in the network or if it goes beyond the permissible limits, the circuits are sequentially broken and the load is turned off.
Wiring diagram for several voltage relays in a single-phase network In some cases, it is convenient to use several voltage relays for different types of consumers. At the same time, for the most expensive electronic consumers, such as computers, you can set the allowable input power range within 200-230V using the appropriate relay.
Household electrical appliances with electric motors, such as a refrigerator or a washing machine, can be set to a voltage range of 185-235V. Consumers such as iron, heater or water heater can be powered by 175-245V. The relay's internal timers can be configured to vary the power-up delay time.
How the phase control relay works in a 380V network
A three-phase voltage relay can be installed in a 380V network. This makes sense if the house has three-phase power equipment.
Connecting a voltage relay in a 380V network In this case, the relay is activated when there is a voltage deviation on any phase and disconnects the load on all three lines. In the absence of 380V consumers, it is more convenient and cheaper to connect three separate voltage relays. In this case, we get three groups of 220V consumers, for which different voltage limits and delay times can be set.
Voltage relay connection diagram for each phase in a 380V network What does IPB protect against?
The main task of an uninterruptible power supply (UPS) is to provide consumers with electricity in the absence of voltage in the network. Most often, this device is used to power computers. Although the UPS provides 220 volts for a short time, it is possible to save the information and turn off the computer. It is relevant to use an uninterruptible power supply when using a small-sized power plant for uninterrupted power supply at the time of its launch.
Common uninterruptible power supply Obviously, the use of the IPB is functional if a voltage relay is installed in the power supply network of the house. When using a battery of sufficient capacity, a gas boiler can be connected to an uninterruptible power supply. A 60 Ah battery is enough to provide a 160W boiler with a voltage for about a day.
A double conversion UPS works with wide input voltage variations, but is very expensive.
Probably, in most cases, for domestic purposes, it is more practical to use an inexpensive uninterruptible power supply and a voltage stabilizer or relay at the same time.
How a network filter can help
Most often, household surge protectors are made in the form of an extension cord. Thus, several units of household appliances can be connected to it at once. Filters differ in the number of outlets and cable length. Usually the device is equipped with its own switch with indication of power supply. The filter may have individual power switches for each outlet.
Popular Network Filters A number of models have protection against short circuit and overload. The total load current of devices of this kind does not exceed 6-16A. The actual filter of such devices consists of several capacitors and inductors. Thus, protection of electronics from low-power and short pulses of hindrances is provided. The latter can be created, among other things, by household appliances connected to the home network.
Everyone, at least once, but faced such a problem. And for many, unfortunately, power surges (its increased / underestimated ratings, phase imbalances) in the home electric / network have become commonplace, and we no longer pay special attention to this if they are not too large. But the equipment (especially imported) is very sensitive to such shortcomings in the power supply - the same heating boilers.
The consequences (not to mention the discomfort) can be the saddest - from incorrect operation, or even breakdown of household appliances to the fire of electric / wiring. So what to do if sudden voltage drops in the mains become frequent?
Not knowing what the "ailment" can be caused by, it is pointless to look for healing remedies from it. All abrupt changes in the voltage rating are caused by natural or man-made factors (including emergency situations that are extremely difficult to predict). What is meant?
Substation instability
This is more typical for areas of old buildings.
Initially, the power is calculated for a certain load with some margin. But will it be enough for the long term? After all, people are gradually settling in, apartments (private houses) are filled with household appliances, there is a change of owners, the purpose of buildings, and so on - it is impossible to take into account everything. As a result, energy needs are increasing. And the existing power transformer, due to its design features, is no longer able to provide them. This is rarely taken into account, and power engineers are practically not involved in the modernization of substations (and this is the property of resource-supplying organizations) - it is too expensive, and does not promise profit.
Wear and tear of equipment
This applies to both the power Tr itself and power lines. The process is quite natural, and there is only one way to get rid of power surges - reconstruction.
One-time outages
It is enough to decommission several fairly powerful consumers (at the same time stop their work), and surges in the network cannot be avoided. This is typical not only for areas in which there are any industrial enterprises, but also for high-rise buildings. If the lines and switchboard equipment are worn out, then in the evening, with a massive shutdown of the light and modern powerful household appliances (for which the wiring in old houses was not originally designed), power surges are more than likely.
Zero break
Such a fault somewhere on the line (substation) is unlikely. The main reason for the jumps is the intervention of a person who does not have the slightest idea about the organization of the en / supply of buildings and structures. For houses, there are three typical power supply schemes, so before engaging in any independent reconstruction, you should clarify which one is implemented in a particular building.
In practice, various "homemade" try to do everything on their own. Most of our houses start up 1 phase and zero, but here. It must be connected to modern devices, especially powerful ones. Here are some craftsmen, without contacting the Criminal Code, trying to solve this problem on their own, not knowing all the features of the common house scheme. The result, as a rule, is the same - burning out the common neutral wire. The most common cause of power surges in apartment buildings.
Line accidents
Their unsatisfactory condition in some areas is only one of the reasons. Strong gusts of wind, icing of wires and their subsequent sagging (or even breakage) - all this leads to short circuits, mechanical damage on the track.
Ground Loop Disturbances
This may be the same breakage of the conductor, loosening of the contact, its oxidation. In apartment buildings, such malfunctions can be caused artificially by the already mentioned “homemade” ones. Not knowing the scheme and wiring of the cores, they often confuse "zero" with "ground".
Poor quality of installation work
This applies both to the organization of the power supply of private buildings, and to high-rise buildings. Often, for the restoration (alteration) of the electrical wiring in the apartment, the owners attract low-skilled specialists (acquaintances, “knowledgeable” neighbors, and so on). What did they connect, how, to what? And if they climb into the access shield, then everyone can feel the consequences.
Incorrect operation of household appliances
If the model is powerful, then it alone is enough to cause surges in the power grid. This happens in devices that are not equipped with various circuits, power / power regulators (or when they fail). This happens only periodically, when such a product (for example, an oven) is connected to the network, which is why it is often called a “flickering effect”, a “floating” malfunction.
In addition, there are a number of reasons that are not systematic (especially permanent) in nature - welding work near the house (in the entrance), turning on a powerful heater in an adjacent area, a lightning strike, some kind of natural disaster, and so on.
What to do
In the house
- Power powerful household. devices (for a PC, the latter are required). Each product has its own, individual device. First of all, this applies to those that are operated intensively or continuously for a long time. For example, heating boilers, dishwashers.
- Install protective devices on the line - AB, RCD or differential automata. As a rule, they are placed in apartment (access) shields. There are other product options - surge protectors, special switching (protective) blocks.
- Check all devices for correct operation. It is not difficult to do this, it is only necessary to alternately supply mains power to them and fix voltage drops (if any). The simplest indicator can be an ordinary Ilyich light bulb, so when testing the technique, you should turn on the light in the room.
- Carefully inspect the power cabinet in the entrance. If one of the neighbors did work in it (this is noticeable at least on new wires) - there is already a topic for conversation. Perhaps the reason for the jumps that have appeared is incorrect or poor-quality installation of the circuit section.
Outside home
Check if any construction (repair) work is being carried out in adjacent areas. Power surges can be caused not only by turning on the welding machine, but also by the operation of powerful installations - pumps, concrete mixers, and the like. If so, then changes in the nominal value in the network are a temporary phenomenon, and power engineers are not responsible for this. So, it is useless to make claims against them.
After inspecting the area (if no obvious reasons have been identified), you should contact your management company (DEZ, ZhEK, HOA) with a request to send an electrician. The goal is to measure the voltage at the input to the apartment and find out whether the quality of the service provided meets regulatory requirements. Many articles still refer to the old GOST, although there is already a new document - No. 54149, which was put into effect on January 1, 2013. It describes in detail all the requirements for mains voltage and permissible deviations from the nominal value (jumps).
If violations of at least one of the points are detected, the measurement results should be activated. With this document, you can already go to the power engineers. Since the voltage drops are caused by reasons beyond the control of the owner (that is, they are outside his home), and the resource supply organization does not take action, there is reason to appeal to the consumer protection law.
In this case, upon the provision of a service that does not meet the requirements of regulatory documents. And if, due to shortcomings in the en / supply, there was a breakdown of complex household appliances, you can safely file a lawsuit in court. But this is another topic that requires separate consideration.
By the way, one of the functions of housing inspections (which not everyone knows about) is precisely to check the quality of services provided in the housing and communal services sector. Before suing, you can write a statement to this organization.
Power surges (jumps) have existed for a long time, but recently this problem has become more and more relevant for our country. This is due to the constant increase in electricity consumption.
If until the 90s all household appliances consisted of a TV, refrigerator and tape recorder, now every apartment has a lot of powerful and at the same time sensitive household appliances (computers, air conditioners, freezers, microwave ovens, washing machines, video and audio equipment, etc.). which is connected to the network almost all the time.
The result of a voltage drop in the mains may be the failure of a part of household appliances installed in the apartment and connected to the network at that moment. In the vast majority of cases, the reason for the failure of household appliances is an overvoltage in the network.
After consumer appliances burn down, people start asking questions: How could this happen? What is the reason? How to avoid? And perhaps the main question Who is to blame?
Why do surges occur in the network
There are several reasons. Let's highlight the most common:
1 . Let's start with the fact that not only you alone (your apartment or house) are connected to the AC power supply, but many consumers like you, which is important, and many more industrial and construction facilities. It would seem, what impact can one house have on the power grid? Definitely a minor impact.
And if, at the same time as you, a thousand consumers turn off their equipment, especially high-power ones (electric kettles, water heaters, microwave ovens, air conditioners, washing machines), then we get a kind of overvoltage, you all noticed voltage drops in the evenings, this is noticeable by incandescent lamps.
But do not be afraid, it will still be less than the permissible GOST and all your equipment will continue to work in normal mode.
Another thing is that if an entire plant or construction site is turned on / off at the same time. Imagine what a "jump" voltage will happen!
This option is possible in areas where the infrastructure is associated with a large factory or large construction. Then it is possible that your equipment will fail.
2 . The most common reason for the residential sector - these are neutral wire breaks.
You all know the deplorable state of electrical transformer substations, input devices to the building and storey switchboard entrances, most often due to the lack of a serving electrician or his illiteracy.
Periodically, it is necessary to carry out preventive repairs in electrical switchboards, which, in principle, is not done, therefore, over time, bolted connections weaken, the reliability of electrical contact deteriorates, which can lead to burnout of the supply wires.
The neutral wire (blue) burns out much more often, which leads to the appearance in your outlet group of a voltage above the permissible level due to uneven power consumption.
The figure shows that during normal operation, the voltage between any phase wire (red) and zero (blue) is always approximately 220 volts, the current goes from phase to zero, and the voltage between the phase wires is 380 volts. At the moment of breaking the neutral wire, the current will flow between the phases, i.e. there will be an overvoltage in the sockets up to 380 volts, it depends on the power of the electrical appliances connected at that moment.
For example, an electric kettle is turned on in one phase, and a light bulb in the other phase, and a TV in the third phase, when the neutral wire disappears (burns out), the voltage between the phases 380 Volt appears on your household appliances. The power that the electric kettle consumes will pass through the lamp and the TV, the light will dry brightly, and the TV will probably smoke.
3 . The reason is purely human factor, more precisely, the illiteracy of an electrician or the self-confidence of a home master.
The lights went out at home, one of the most common causes phase wire burnout(L1, L2, L3) or zero working conductor(N), You yourself or, having called an electrician, restore the power supply, when connecting, you mixed up the wires by connecting instead of 220V (phase-zero), voltage 380V (two phases), perhaps not even to yourself, but to your neighbors on the floor.
Result, instant failure of all electrical equipment connected to the mains.
4 . Power surges caused by lightning discharges near power lines (TL) occur in areas where overhead power lines are used.
5
. Another reason for voltage drops (surges) is theft of a grounding conductor (grounding) in the electrical risers of floor boards, entrance of a residential apartment building. I've been running into this quite often lately.
As I hope you know, grounding is necessary to protect against electric shock during a breakdown of the insulation of electrical equipment, and in principle everything will work without it.
What "advanced" non-ferrous metal collectors sometimes use is to cut out the grounding from the cable riser of the entrance, this is done very quickly, literally a few seconds on each floor of the house.
Someone will say where is the overvoltage. And the fact that when connecting apartments, three wires are used, phase, zero and ground, the last two (zero and ground) are sometimes confused with each other, so it turns out that when the ground is stolen, if at least two apartments were connected to it on the floor , two opposite phases come to both apartments, between which 380 Volt.
Harm of low mains voltage
A situation is possible when the voltage in the network is greatly underestimated. Which is often found at old construction sites due to the inability of the old wires to deliver the necessary power, as well as the switching by utilities, on purpose, of all riser apartments to the phase of the same name, due to fear of the zero working conductor burning out, which would lead to overvoltage in the network. Reduced mains voltage can damage some household appliances or their functions, for example, a microwave oven rotates a plate, but does not heat up; the washing machine runs non-stop; The most common failure is the failure of the refrigerator compressor, due to the constant on position, even when you are not at home.
Damage to equipment from undervoltage is less common than from overvoltage. You can also avoid equipment failure by using the points from the section "How to deal with overvoltage in the network"
And so we examined the main causes of voltage drops in the power grid, but it’s easier not to get because the equipment has already burned out, then read on.
Who is responsible for the lost household appliances
Paradoxically, despite the fact that the electricity supplier undertakes to provide you with voltage of the established quality, most likely you will not be able to receive compensation for the lost equipment.
This is due to the following considerations.
How can you prove that the reason for the failure of the equipment is an overvoltage in the network, and not a defect in the equipment.
The lack of real control and collection of statistics leads us to the following conclusion. In 99% of cases, you will not be able to receive compensation for lost equipment. it is impossible to prove whose fault this is, as we said earlier, there are many causes of overvoltage, both related to the human factor and force majeure by definition (lightning discharge near power lines).
What to do, is it really every time to throw out the equipment? Of course not. There are methods to deal with power surges.
How to deal with overvoltage in the network
There are several ways:
1 . Reconstruction of electrical networks and maintenance by competent electrical personnel, a very expensive option and only reduces the risk of overvoltage, most often depends on utilities
2 . The use of voltage stabilizers is ideal for those who use very expensive equipment. You connect the network wires to the stabilizer and already remove high-quality voltage from it. The option is very good - there is only one minus - this is the price. The price of a good (quality) stabilizer with a power of 5 kW is over 30,000 tenge.
Accordingly, if you have a large amount of equipment, you will have to spend a tidy sum, but after that (with the right choice of stabilizer), you can be sure that your equipment is reliably protected.
3 . If you work with valuable information on a computer, then choose an uninterruptible power supply (UPS), which is most often used in administrative buildings, but you cannot install an uninterruptible power supply only for office equipment, for all household appliances, also because of the high price and high operational expenses.
4 . A voltage relay is the most affordable option for protecting against voltage surges (surges) in a household and office electrical network.
In Kazakhstan there are such devices:
Single-phase voltage relay RN-113
Single-phase voltage relay RN-111M
Conclusion
In this article, I expressed only my view on the existing problem of voltage drops in domestic and industrial networks. I do not claim absolute truth on all positions. It should be borne in mind that the methods of struggle are fair at the time of writing.
