According to modern scientific ideas, energy is a general quantitative measure of the movement and interaction of all kinds of matter, which does not arise from anything and does not disappear. For human life, the most important is the consumption of electrical energy, which can be extracted from natural sources.
Energy resources are primary sources of energy in the surrounding nature.
Electromagnetic energy is known and used by people since ancient times. There are silver-plated and gold-plated ancient Egyptian products, the coating of which is made by the electrochemical method. It is likely the use of the ancient peoples of the analog of the voltaic pile the first electrochemical cell, in which electric current is obtained through the chemical reaction in the column of rings of copper, zinc, and cloth soaked in acid. Also widely known since ancient times the effect of accumulation of electric charge when rubbing amber on wool.
Electric Power Industry
At the district (i.e., close to the sources of energy resources) power plant, electricity is most often produced by electric machine generators of alternating current. To reduce losses during its transmission and distribution, the voltage removed at the output of the generator is increased by the transformer substation. Electricity is then transmitted over high-voltage transmission lines (transmission lines) over long distances, which can be measured in hundreds of kilometers.
A number of distribution substations are connected to the power line, diverting electricity to local power consumption centers. Since the electricity is then transmitted through the streets and populated areas, the voltage at the substations for safety is once again reduced by transformers.
Electrical Energy Transmission
The electrical energy generated by the generator is diverted to the step-up transformer via massive hard copper or aluminum conductors called bus bars. Bus each of the three phases is isolated in a separate metal sheath, which is sometimes filled with insulating gas (sulfur hexafluoride).
Transformers increase the voltage to the values required for efficient transmission of electricity over long distances.
Generators, transformers, and buses are connected to each other through disconnecting high-voltage devices manual and automatic switches that allow you to isolate the equipment for repair or replacement and protect it from short-circuit currents.