How to protect the network from overvoltage and what is needed for this

main reasons

Most often, overvoltage in the 220 and 380 V network occurs for the following reasons:

1. Break the neutral wire on the supply line. The zero conductor provides voltage symmetry in the phases of the supply network, with different amounts of load in the phases. In the event of a zero break, the voltage in each phase varies depending on the difference in phase loads: in the less loaded phase it increases sharply up to 300 V and more, and in the most loaded phase it drops sharply to values ​​​​less than 200 V. Therefore, without Overvoltage Protection At high voltage household appliances can fail almost instantly, but if the voltage is low the electrical appliances will not work properly. At the same time, there is a high probability of failure of electrical appliances, in the design of which there are electric motors (compressors).
2. Connection error in the electrical panel. If a three-phase input is installed in the house and when connecting a single-phase 220 V wiring line, the second phase conductor is incorrectly connected instead of zero, then 380 V will appear in the outlet instead of 220 V.
3. An impulse voltage occurred due to a thunderstorm entering a power line (which is why it is recommended to turn off all household appliances during a thunderstorm, as well as do lightning protection in the area).
4. Overvoltage switch. In case of an emergency in the electrical network: a short circuit on adjacent lines, a sudden change in load due to the interruption (connection) of a section of the electrical network, and accidents at power plants can be observed. Voltage drops, which, depending on the size, can negatively affect the operation of household electrical appliances.

As you can see, overload in a single-phase and three-phase network affects many factors, including natural ones. Therefore, home wiring must be protected so as not to become a victim of an accident.

Surge protector

In the modern world, there are many different devices for surge protection in the network, which are easy to connect with your own hands. Consider devices used to protect against unwanted power surges.

Among the most useful for use at home and apartment:

1. Balancer . This device converts (stabilizes) the input voltage into a voltage of a certain value. It is important to install a stabilizer if constant voltage drops are observed in the network.
   It should be borne in mind that the stabilizer operates only at voltages that do not exceed the permissible values ​​indicated in its technical characteristics.
   If the current rises above acceptable limits, the stabilizer may fail. Therefore it is necessary to choose a voltage regulator with built-in surge protection, and in the absence of such a function, install a voltage relay for protection. About how to connect a voltage regulator, we told in the corresponding article!
2. Voltage relay . This protective device , unlike MV, does not transform the input voltage. Voltage relay is designed to disconnect household wiring from the electrical network in case of unwanted voltage drops (GOST 3699-82). Minimum and maximum voltage limits are set on the relay, and in the event of a jump above the set limits, the relay de-energizes the household wiring, thus protecting household electrical appliances.
   LV can be made in the form of a modular device for installation in a distribution board (known barrier), built into an extension cord (surge protector with the corresponding function), as well as in the form of an electrical plug (for example, ZUBR). About how to choose a voltage relay we talked in a separate article.
3. Multifunctional protection device (UMM ) . This device can be installed in a switchboard instead of a voltage relay. UZM performs several functions, one of which is the protection of the electrical network from voltage surges. About how the UZM-51M works and how to connect it, we told in a separate article.
   
4. Uninterruptible power supply . Once again, from my own experience, I will confirm its effectiveness. More than ten times, the UPS has saved my computer from a sudden shutdown when the voltage at the electrical panel tripped. The cost of “uninterrupted” is low, so it is absolutely necessary to purchase this option of surge protection in the presence of a computer. In addition, most modern uninterruptible power supplies have an internal stabilizer, which is especially important for computer equipment, which is more likely to be affected by fluctuations than most household appliances.
   
5. SPD.  From impulse voltages (which occur during a thunderstorm and can disable equipment), you can protect yourself by installing an SPD at home. This device is very popular today and is widely used in everyday life and production. More about what SPD is and how it works, we describe in a separate article, we highly recommend that you familiarize yourself with it. It should be noted that SPDs can also be called detainee mounting (OPN) units.
6. Contact the power supply service . The energy supplying organization, in accordance with the electricity supply agreement, is obliged to provide a normal voltage level (within acceptable limits) of the electrical network in accordance with GOST 29322-2014 (IEC 60038: 2009). Therefore, if you constantly have an excessive decrease or, on the contrary, an increase in voltage, you need to contact the supplying organization with a corresponding complaint. Handling a collective complaint is most effective, as individual appeals are usually ignored. Contacting the supplier organization is the only way to solve the problem if you experience a sharp voltage drop, since in this mode it will quickly fail.

After installing the necessary devices, overvoltage protection can be provided in the 220 and 380 V network, after which you can not worry about the fact that household appliances, wiring, and most importantly, your life will be in a dangerous situation.