Voltage protection device. Protection against overvoltage in the network. type of relay for protecting household appliances and equipment. Uzip or relay

I promised to talk about how to protect yourself from a terrible phenomenon called “neutral break.” Today we will talk about this. I’ll 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 that are most common on the Russian market:

Actually, what is it, a voltage relay? This is a device that continuously monitors the voltage of the supply network and turns off consumers when the voltage goes beyond acceptable limits, and the faster the LV operates, the better. But after disconnecting the consumers, it continues to monitor 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 broken neutral is dangerous due to the uncontrolled “walking” of phase voltages, which is detrimental to household appliances. A voltage relay allows you to protect equipment in this situation.

You will not find high-speed launch vehicles 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 break.” The same cannot be said about Russia. Therefore, two of the three devices presented in the photo are Russian-made, and the third is the ubiquitous Chinese. Let's start with it.

Automatic protective module AZM-40A from Resanta

Resanta is a fairly well-known Chinese manufacturer on the Russian market. It produces a lot of things, including the following voltage relays:

I won’t bore you with unnecessary talk and will immediately move on to listing the advantages and disadvantages.

Advantages:

1. Low price, approximately 500 rubles.

2. 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 “twists” - accordingly, no one’s playful hands will be able to force the relay into an unacceptable operating mode. But this advantage also 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 value, that is, 198...242V. Since our electrical networks do not fit into this range, 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 stated shutdown time is 1...6s. Why there is such a spread is not at all clear. But even if the relay operates in one second, delicate consumer electronics may still be damaged.

3. Short delay time before restarting. If a short-term voltage drop occurs and the relay operates, it will turn on again after 2...3 minutes. This is clearly not enough. For most household appliances this is not important, but for refrigerators it matters. The delay before switching on again must be at least 5 minutes.

4. Although the manufacturer claims a maximum current of 40A, knowing the Chinese love for saving, I do not recommend loading the relay with a current of more than 30A.

5. Experience shows that the 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 required time the green LED lights up, but does not connect the load. And until you remove the power supply from the relay using the input circuit breaker and then turn it on again, this glitch will not go away. What if this happens in your absence? The voltage has been normal for a long time, but the relay does not connect consumers. In the evening you come to a leaking refrigerator.

6. Significant dimensions. In the panel, the relay occupies a width of three standard modules, while both Russians participating in today’s review have 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 really tight, but 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. It also makes the following relay:

Advantages:

1. Quite high performance (0.2s)

2. Wide range of adjustments of the upper (230...280V) and lower (160...220V) voltage limits and restart time (5...900s).

3. The presence of a convenient digital indicator that displays the relay operating modes and the values ​​of the adjustment settings.

4. Compactness.

Flaws:

There is only one drawback - the low load capacity of the contacts, only 16A. This is clearly not enough for an apartment. Therefore, the RN-111M must be used in conjunction with an additional contactor, and the contactor coil must also be protected by a separate circuit breaker. In total, this entire structure will take up 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 the price and dimensions are different. And 32A is also not enough, there is no reserve.

Conclusion. Not a bad device, but the low load capacity forces the use of additional equipment, which leads to an increase in cost and space taken up in the panel. Can be applied if the next review participant was unable to be purchased.

Multifunctional protection device UZM-51M from Meander CJSC

The Meander company (also from St. Petersburg) is engaged in the development and production of industrial automation, including the UZM-51M device:

Without exaggeration, we can say that today on the Russian market this is the most “predatory” protection against power surges. Judge for yourself:

Advantages:

1. Wide ranges of adjustment of the upper (230...280V) and lower (160...210V) voltage limits.

2. Response time is only 0.02s. Great!

3. Load capacity 63A. Enough for any apartment, even the most sophisticated one.

4. As a bonus to the main function (overvoltage/undervoltage protection) there is varistor surge protection, capable of absorbing pulses with energy up to 200J.

5. Compactness. The shield occupies only two modules. No additional devices (as is the case with the RN-111M) are required.

6. Humane price. At retail, the relay costs a little over 1,900 rubles, and will be sold to a professional even cheaper, for 1,700.

Flaws:

The only drawback cannot be called a drawback. 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, which will already have numbers.

Conclusion. Give it to everyone!

How to protect home electronics and equipment from power surges and surges.

Changes in mains voltage have always existed. The reasons are various: the switching on and off of powerful loads (especially in single-phase networks), the operation of a welding machine nearby, a phase-to-phase short circuit (usually on overhead power lines), a break in the neutral wire (usually in old high-rise buildings and “Khrushchev” buildings and not only), an electromagnetic pulse, the accompanying lightning discharge causes the appearance in an overhead power line, at a distance of several kilometers, of voltage pulses with an amplitude from hundreds to several thousand volts, a duration from units to thousands of microseconds, etc.

Today, the most effective and cheapest way to preserve household electrical appliances is to “press” and “turn off”, i.e.:

• Squeeze impulse voltage surges to a safe value.
• Turn off the electrical equipment of the apartment when the voltage goes beyond the permissible values.

To do this you need:

1. At the input of the voltage control device, it is necessary to install a powerful varistor for the appropriate voltage, with an absorption energy of at least 200 J and a permissible pulse absorption current of at least 4000A.
2. To protect against overvoltage or undervoltage, a voltage control device with an overvoltage response threshold of 250...270V and a voltage reduction threshold of 160...170V must be installed in the apartment input panel (immediately after the meter), with a response time of no more than 0.5 s and with automatic return when voltage is restored with a delay of 1..3 minutes. The permissible current of the device contacts must be no less than the maximum current consumption of a modern apartment - 25...40A (5.5...8.8 kW).

The multifunctional protection device UZM is designed to protect equipment connected to it (in an apartment, office, etc.) from the destructive effects of powerful pulse voltage surges caused by electromagnetic pulses of nearby lightning discharges or the activation of nearby electric motors, magnetic starters or electromagnets connected to the same network, and also, to turn off equipment when the mains voltage goes beyond the permissible limits (170 - 270V) in single-phase networks. If the neutral wire breaks or is connected incorrectly (for example, to two phases).

The equipment turns on automatically when the mains voltage is restored to normal, after the restart delay has expired.

UZM does not replace other protection devices (circuit breakers, RCDs, etc.).

V (rated load current 16A), it is possible to adjust the thresholds, while the thresholds are fixed.

Operation of the device from increased voltage UZM-50M, UZM-51M, UZM-16:

When the supply voltage is applied, the device maintains a readiness time of 10 seconds, while the indication does not work, and then the green indicator begins to blink indicating the countdown of the turn-on time delay t1. If the voltage is within acceptable limits, the load is connected to the supply voltage and the green and yellow indicators light up. It is possible to quickly connect the load manually by pressing the “TEST” button.

ATTENTION: Do not use manual mode in case of network emergency. If you try to turn it on manually in emergency mode, the device will not allow you to turn on power to the load.

In operating mode, the device controls the supply voltage.

When powerful voltage pulses appear in the network, the built-in varistor shunts them to a value that is safe for the equipment.

Two-color indication operates in different modes:

When the voltage increases and approaches the upper shutdown threshold, the red indicator begins to blink and when the voltage goes beyond the permissible limit, the built-in relay turns off, while the yellow indicator turns off and the red indicator is constantly on. When the voltage returns to normal, the countdown of the on-time delay t1 begins, and the green indicator begins to blink after the end of the countdown, the load is connected to the supply voltage network (if during the countdown of time t1 the voltage goes outside the permissible limits, the time countdown t1 is reset).

When the voltage drops to the lower shutdown threshold, the green indicator flickers and when the voltage goes beyond the permissible limits, the shutdown delay time t4 begins to count, and the red indicator begins to flash; after the end of the countdown t4, the load is disconnected from the network, while the yellow indicator turns off and the red light comes on with a frequency of 2 seconds.

When the voltage returns to normal, the countdown of the on-time delay t1 begins, and the green indicator begins to flash after the end of the countdown, the load is connected to the supply voltage (if during the countdown of time t1 the voltage again goes beyond the permissible limits, the countdown t1 stops and is reset).

If the load is forcibly disconnected from the network by pressing the “TEST” button, the two-color indication indicates this by alternately turning on the red and green indicators.

Pressing the “TEST” button again returns the product to operating mode.

ATTENTION: If the load is turned off with the “TEST” button, the device remains in the off state even after the supply voltage is removed and applied. You can turn on the relay only by pressing the “TEST” button again.

If necessary, you can change the turn-on time delay t1 (10 sec. or 6 min.) for this:

Manually use the “TEST” button to turn off the internal relay

Then press and hold the “TEST” button (the “norm-failure” indicator goes out) until the indicator starts flashing. If it flashes in green, then time t1 is set to 10 seconds, if in red, then time t1 is set to 6 minutes.

Release the “TEST” button and the internal relay will turn on.

Diagram of operation of the protection device UZM-50M, UZM-51M:

Specifications:

To protect computers and office equipment, we recommend using surge protectors to protect against impulse noise from the electrical network and uninterruptible power supplies (UPS) to protect equipment from electrical faults by switching to battery operation.

How often did appliances burn in your apartment? Have you ever wondered why this happened? Perhaps it would be more correct to initially take care of protecting your equipment from such situations, because in our life they are far from uncommon. In the secondary stock, the electrics are in a deplorable state and you cannot count on the fact that you will not be spared by a power surge. Given the state of our city power grids, power surges are a common occurrence. It’s just that today it was insignificant and you didn’t notice it, but tomorrow the equipment burned out and you’re unlikely to find the last one.

We are often hired by service organizations to replace driveway electrical systems and input switchgears. We saw enough horrors in the houses that it would take too long to tell, and there was no point in it. General household electrical systems do not provide any means of protection, only the TP contains terrible inserts that are triggered when it is generally too late. The only thing that saves them is the cable itself, going from the house to the transformer substation.

How to protect yourself and the equipment in your apartment from such a situation. The equipment is often expensive, and its internal protection is not designed for operating conditions in Russia. Indeed, in civilized countries, the electricity supplier itself will not allow an overestimated or underestimated voltage value to reach the consumer, turning off the power until the causes of the malfunction are determined. In our country, consumers suffer first and foremost and suffer without a chance of justice. During my time working in such houses, I have not heard a single case where a tenant sought compensation, and first of all we have to communicate with the tenants. Subsequently, many of them became our clients and we helped organize protection against such situations.

Only after experiencing expensive equipment repairs do people understand that it is much cheaper to immediately purchase and install protection than to throw up their hands later and look for those to blame.

How can you protect yourself from such situations?

One of the most common and inexpensive devices is the voltage control relay. They are produced by a lot of organizations in different form factors, but we are most interested in the modular version for installation in the input panel. After all, it is better to initially assemble and sleep peacefully than to later try to add devices to a shield in which there is not even room for them.

There are, of course, voltage control relays that are available in other types and can be used directly with expensive equipment; they are plugged into the outlet before the consumer and protect only him.

They can be divided into the following types

The most important thing to remember when choosing a voltage control relay, no matter in what form you buy it, is not to trust cheap fakes. Before purchasing, you need to consult with specialists and find out whether this device really performs its functions, because you most likely will not be able to check it in a store, and at the time of a power surge it will be too late to check it. Russian roulette is not for us. We will protect it competently.

When should you pay attention to the fact that something is wrong with the electrical network?

• The very first thing that will let you know about this is incandescent lamps. When voltage surges occur, they begin to change their brightness and burn out quite often.
• household appliances that contain any electric motors. This includes a hair dryer, washing machine, blender and much more. When there is a power surge, electric motors, like light bulbs, react immediately. They begin to work intermittently. You can also determine it by noise, which is not typical for this device.
• Some electrical appliances in the apartment begin to malfunction and may periodically turn off randomly.

If you notice what is happening in your apartment, you should seriously think about protecting your electrical equipment.

A voltage control relay is installed in the input panel after the input circuit breaker and power is taken from the voltage control relay for distribution to the group circuit breakers. Very often you can find a wiring diagram when the protection relay is connected through an additional contactor. This diagram is very correct. The main thing is to protect both the contactor itself and the relay with a properly selected circuit breaker.

This work is best entrusted to competent specialists because incorrect connections in the water shield can also lead to emergency situations. And by purchasing a finished product with a guarantee, you minimize this possibility.

The voltage control relay needs to be configured before starting. Depending on the version, the adjustment is made either with a screwdriver - the maximum and minimum permissible values ​​​​are set, like on a watch, at which the device will not turn off the voltage. If the device is digital, then using the corresponding buttons we set the values ​​we need.

A time delay is also set after which the device will try to turn on again. After this time, from several seconds to several minutes, the device will turn on again and if the value still does not meet the specified standards, it will not allow it to enter the network. This will continue until the voltage in your network returns to normal.

The only drawback of this device is that until the voltage stabilizes, you will not turn on anything in the apartment because the device will turn off the load. The load is switched off instantly as soon as the voltage goes outside the permissible limits. But this is the principle of operation of the device and its purpose - not to allow dangerous voltage to enter our apartment.

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

Fire is a consequence of increased voltage

Signs of increased network voltage

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

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

Reasons for increasing network voltage

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

Methods of protection against overvoltage

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

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

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

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

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

Surge protection device

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

Voltage monitoring relay for protecting household appliances and equipment

Voltage drops

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

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

Damage to overhead power lines by lightning discharges

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

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

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

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

Surge protection

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

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

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

RKN and UZM

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

Voltage monitoring relay with indicator light

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

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

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

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

The advantages of using RKN and UZM are:

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

Voltage Control Relay Models

RMM

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

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

Circuit breaker with built-in trip unit IEK

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

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

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

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

Automatic voltage stabilizer with informative display

The advantages of stabilizers are:

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

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

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

Uninterruptible Power Supply (UPS)

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

How to protect yourself. Video

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

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

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