VOLTAGE ± 5%

If during the day to measure the mains voltage, the voltmeter each time will be different. This is due to you can enable or disable individual power consumers, changing mode of operation (in accordance with the work schedule of production, process flow, etc.), that is, change the values of loads that cause instability of voltage in the networks.

 

It would seem, what’s the difference — 220 To the network or, say, 250? Meanwhile, all consumers, both household and industrial, designed to operate at a strictly determined value of the supply voltage. Any deviation from this value lead to a drastic reduction of the service life of electrical equipment, reducing its effectiveness.

 

For example, increasing the voltage by 10% from the funeral service life of filament lamps is reduced by almost 70%. And if the voltage drops by 7% the process of annealing of workpieces of non-ferrous metal in a foundry of the plant lasts for 5 hours. instead of the estimated three. As a result, annual damage from lengthening process, is a thousand.

 

No less insidious invisible enemy wielding in our own apartment where you work different appliances. Take, for example, television. If due to the increase in the filament voltage of the lamps, the temperature of the cathode will increase by 3%, reduced by about half their lifespan. And first of all go down the tube.

 

Permissible limits of voltage fluctuations in electrical networks is strictly regulated by GOST 13103-67 most consumers are ±5%- current requirements make it increasingly necessary to limit such strict limits. In practice, however, to remain within the boundaries of these parameters is very difficult.

 

Mains is a complex, networked dynamical system with a mixed load and with varying voltage levels at various points. Therefore, the voltage often adjust every single end user or group of consumers. But the controls are very complicated and expensive. For example, a device for switching the terminals of the transformer operating under load depending on the power of the latter is 3-9 thousand RUB Quite obvious that such devices can only install PA major substations. And even then directly from the consumers of network stability will be unsatisfactory.

 

There is another factor greatly influencing the level of voltage. We are talking about the so-called asymmetry of stresses caused distortions of the three-phase system at different load phases. It is almost impossible to connect a single-phase to three-phase power consumers of the network is strictly evenly so that every phase, every moment of time accounted for the same load. The slightest inequality of loads causes a voltage drop in one phase and increasing in the other.

 

The energy around the world are constantly exploring the problem of maintaining constant voltage in electric networks. In our country, for example, greater attention is given to improving their configuration. Created theory and methods of voltage control using the capacitor banks, synchronous compensators, booster transformers, induction regulators, etc. In Czechoslovakia and in France just did: expanded the limits of permissible voltage deviations in the power consumers. In East Germany and in the United States to change the voltage widely used, especially in rural areas, small induction regulators with blocks of automatic control. Mounted on poles next to the house, they are automatically within the specified limits maintain tension household power.