Different levels of tension, what are they?

Are the 380V electrical outlets three-phase 127V? The World of Electrical shows in this video the various voltage levels taken in Brazil abroad. Understand why there are three-phase 220V and other 127V sockets.

Stress Levels

Brazil is a “fruit salad” in terms of electrical voltage levels. We know that it has 115 Volts, 127 Volts, 220 Volts, 254 Volts, 240 Volts, 230 Volts, 380 Volts, and 440 Volts. Sometimes in the same city, there are three different tension levels, and an example of this is the city of São Geraldo do Araguaia in Pará.

If we go to Aneel’s website, which is the National Electric Energy Agency that draws up the rules for the entire power supply network to work. It is possible to consult the tension levels of each city in Brazil. Note in the image below that in the city of São Geraldo do Araguaia, there are three levels of nominal voltage (254/127 volts), (230/115 volts) and (220/127 volts).

São Geraldo do Araguaia, there are three levels of rated voltage.

With this mess of voltage levels, many people think that the 380 Volt voltage is actually a sum of three 127 Volt voltages. This reasoning is even natural because if we multiply the voltage of 127 Volts by three we have 381 volts which is very close to 380 volts, but in reality, it is not at all!

We will choose another city that has a voltage of 380V, on the Aneel website we will select the state of Piauí and then the city of Arraial. In Arraial, the available voltage is 380/220 Volts. These two voltage values ​​are because one is line voltage and the other is phase voltage.

The voltage available at the camp is 380/220 Volts.

Where the electric voltage is 380 Volts, the second voltage is the phase voltage, which will always be 220 Volts and not 127 Volts. So you can forget this idea that just add the voltage of the three phases of 127 Volts that you have the 380 Volts.

In calculating electrical systems, it is important to consider a root factor of three that is used in the calculation. This value is obtained after applying some more complex mathematical calculations that take into account the angular lag and the peak voltage of the electrical system.

In the case of 220 Volts, which is half of 110 Volts, this means that the system is two phases of 110 Volts forming a 220 Volts. In the cities we looked at on the Aneel website, we did not find the 220 Volt / 110 Volt voltage, but we found a very curious case.

On the Aneel website we selected the state of Minas Gerais, then the city of Além Paraíba. This city is also a “fruit salad” in relation to electrical voltage, we can see the electrical voltage levels in the image below. The first fact to be this “mess” is because Além Paraíba is served by two concessionaires, CEMIG and Energisa Minas Gerais.

Besides Paraíba has four different voltage levels and at three of these levels, the phase voltage is exactly half the line voltage, which is the nominal voltage of (440/220 volts), (240/120 volts) and (230 / 115 volts).

In addition, Paraíba has four different voltage levels ..

In these cases, the line voltage is obtained by transformers that have a tap configuration, in addition to closing the transformer coils differently from other voltages. All of these supply systems are three-phase, that is, there are three phases. And in these cases, the phase and phase voltage is exactly double.

There are many exceptions in the Brazilian electrical system, precisely because it is very large. The following table indicates the levels of secondary voltages provided by the electric energy concessionaires in accordance with ANEEL standards.