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What is high electrical voltage?

Electrical voltage is the power differential between a point of origin and another destination within the flow and transit of electricity. It is also called potential difference.

Within electrical systems, high voltage is understood to exceed 36 kilowatts (kW). It is used for transporting electricity over long distances, usually from power plants where it is generated up to the substations of the end consumption centers.

The use of high voltage prevents energy losses in the electrical distribution system. Once it arrives at the destination, the energy is transformed to obtain medium and low voltages, as needed.

What is the difference between high, medium, and low voltage?

The electricity used on a daily basis has gone through all the phases of high, medium, and low voltage, from its generation to its consumption. Depending on the voltage and the main function, electrical voltage can be:

  • High: used to transport electricity from generation plants to consumption points;  higher than 36 kV.
  • Medium: used to transport electricity from substations to transformer plants that are close to consumption centers; between 1 and 36 kV.
  • Low: used for electricity consumption in homes. The number of kV varies by continent: in Europe, it is 230 volts, while in America, between 100 and 127 volts are used.

What types of high electricity voltage are used?

The high voltage categories are regulated by each country. The technical conditions, guidelines, safety guarantees, and complementary instructions for the installation and use of power lines are specified depending on the needs and criteria of each region.

European countries have similar regulations. As an example, there are four types of high voltage lines in Spain:

  1. Special category: when the rated voltage is equal to or greater than 220 kV. They are also called standardized voltages when they are between 220 and 240 kV. Its most common use is for transportation over long distances.
  2. First category: the nominal voltage is higher than 66 kV and lower than 220 kV, with standard voltages of between 110, 132, and 150 kV. It is most frequently used for transportation and distribution.
  3. Second category: its rated voltage is greater than 30 kV and equal to or less than 66 kV, with standard voltages between 45 and 66 kV. Its most frequent use is for distribution.
  4. Third category: it is considered close to medium voltage, whose voltage is greater than 1 kV and equal to or less than 30 kV. Its most common use is for generation and distribution to industries and tertiary sectors.

How to handle high voltage safely

All high voltage electrical facilities require electrical control and constant maintenance that enables evaluating their operation and optimal development. Since this energy can have very high voltages, it can only be handled by authorized personnel who are trained to do so.

High electrical voltage is concentrated in large power plants where it is manipulated and modified through transformers. It follows a process of predictive, preventive, and corrective maintenance so that there are no negative failures at the facilities or any other type of risk to the system’s integrity.

In addition, the high voltage elements are designed to keep both the staff and the facilities safe. These are:

  • High voltage towers: the large structure transmits the current from one point to another safely.
  • High voltage cables: they have insulation that is resistant and specific for high voltage, located in underground networks.
  • Transformers: devices that transform the voltage with electrical insulation and powerful control mechanisms to prevent safety failures.

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