Valid values

There are standards and permissible values ​​indicated in the relevant GOSTs and PUE regarding the quality of electricity. According to these standards, the ratio between the currents of the least loaded and the most loaded conductors, in switchboards, should not exceed a value of 30%, and in switchboards – 15%. According to GOST p.5.5, the permissible phase misalignment in the reverse sequence should be 2%, and in zero – 4%.

Causes of the phenomenon

There are several reasons why this action occurs. The main reason when incorrect and uneven load distribution occurs in the internal electrical network is considered when one phase receives an overload. The second and third will work as a result with a large load.

In a network where there is only one phase, the load can also be increased. This happens when a large number of household appliances are included in the power supply. Then the deviation becomes noticeable, as the power goes out and the devices stop working.

Due to the fact that household appliances begin to work incorrectly, this may lead to their breakdown. As a rule, motors are the weak point of most devices in this case. Therefore, they are the ones who failed. Check where the skew is, you can use a special device (clamp gauge), which will help determine which chain is in excess.

What is the danger of phase unbalance in a three-phase network and when does it occur?

The three-phase network has a grounded neutral. It is equivalent to the uneven distribution of voltage in the electrical circuit. But with zero break, one phase takes on the role of neutral. Then the voltage on them can reach 380 volts, and on the rest it will be 127 volts and less.

Danger and consequences of skiing

What is the danger of phase imbalance in the electricity network? Conditionally negative moments can be divided into three groups:

1. Damage to electrical receivers (devices and equipment): damage to them, reduction of their useful life.
2. Damage to electricity sources: mechanical damage, increased energy consumption and reduced life of the source.
3. Consequences for consumers: increased electricity costs, need to repair electrical equipment, and potential injury.

Due to the fact that electricity is distributed unevenly across the conductors, electricity consumption increases significantly in the electricity network. A three-phase network, in which asymmetry is formed, can reduce the life of electrical appliances and household appliances.

If it is an independent power plant, then the oil and fuel consumption in this case increases significantly, and the generator may break. If one phase receives a greater voltage than the other two phases, electrical safety is violated. This can lead to various electrical injuries, as well as to the ignition of household electrical appliances and the wiring itself.

As you can see, the consequences of this phenomenon are significant and its solution and removal can lead to significant material costs. In order to avoid such an unpleasant situation, some measures should be taken in advance.

Protection measures

In order for the three-phase network to operate symmetrically and the voltage on each circuit is normal, special devices must be used. Most often, this leads to the installation of a voltage stabilizer . In everyday life, single-phase devices are used that are capable of protecting electrical appliances and equipment . In industry, a three-phase stabilizer is used, which consists of three single-phase devices. But these protective devices cannot completely eliminate bias, since only one phase is installed for them and only the voltage is equalized in it.

Therefore, a three-phase network cannot completely protect itself from this phenomenon with stabilizers, as well as eliminate its causes and consequences. There are times when these same devices are the cause of uneven and improper distribution of energy. This problem can be fixed thanks to alternative technology, which is able to equalize the voltage in all phases of the circuit.

A three-phase network is protected from asymmetry in the following ways:

• Correct design of the power supply, taking into account possible loads;
• Use devices capable of automatic load balancing;
• Change in the current circuit of the power consumption scheme (if each phase is not pre-calculated for overload);
• In more serious cases it is necessary to change the capacity of consumers.
• Install a special phase and voltage control relay, which cuts off power if it detects an inconsistency (pictured below).

So we examined the danger of phase imbalance in a three-phase network and how to protect yourself from this phenomenon at home. We hope that the information provided will be useful and interesting for you!