In modern life, electrical energy is massively used, which is delivered to the place of its consumption (to the points of connection of the load) through the electrical network. The parameters of this network, which determine the quality of the supplied electricity directly from the consumer, are standardized by various standards.
In Russia, such a regulatory document is GOST 32144 as amended in 2013, which:
- replaced the previously used interstate (for a number of CIS countries) standard GOST 13109, which had been in effect since 1999;
- determines the parameters of the general-purpose electrical network;
- applies to networks with voltages up to 220 V up to 110 kV.
General characteristics of the document
The standard contains definitions of standardized parameters, specifies their numerical values and acceptable limits of changes.
The strength of the standard is its depth in terms of the list of standardized characteristics.
All possible changes are additionally classified into continuous and accidental. The latter is especially important for developers of power supplies for electronic devices for various purposes, since modern electronic equipment is very sensitive to various impulse noise.
Reference annexes containing the classification of failures and short-term interruptions in the supply of electric current, which allows you to correctly calculate the parameters of uninterruptible power supplies nutrition.
Slow voltage changes
Regarding the voltage of the most interesting household networks for most consumers, the current GOST standardizes the nominal
- 220-volt single-phase voltage;
- 380 volt voltage for three-phase networks.
Possible deviations from the nominal values in terms of the so-called slow changes, determined by the work load changes, are normalized in relative form (parameter δU in Figure 1). δU should not exceed 10% of the rated voltage. It is indicated that the nominal voltage is 220 or 380 V, as well as any other that was agreed with the consumer. The interval at which the change is fixed within 10% is set equal to one week.
The case of going beyond the permitted 10% deviation to the higher side is considered overvoltage, and to the lower side - a failure, Figure 2.
Rapid voltage changes
In terms of rapid changes that:
- caused by abrupt changes in the load when connecting or disconnecting various consumers;
- have a duration not exceeding one minute,
rationing also occurs in a relative form. Given the greater danger of the short duration of abrupt changes, the magnitude of voltage fluctuations is limited for 5% of them, however, a 10% short-term change during the day is permissible without specifying the number of such events. In fact, we are talking about an approximately 20-volt deviation up and down from the usual 220 V.
In contrast to slow changes, in which the voltage usually remains sinusoidal, with fast changes, significant deviations from the sinusoid, which requires a special setting of the relative deviation, Figure 3
In the case of exceeding the 10% limit, rapid changes refer to overvoltages and dips, regardless of the duration of being outside the specified limit.
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