Electricity is a form of energy. Electricity is the effect of moving charged particles within a “conductor” under the effect of a potential difference at the ends of that conductor. It is the circulation of electrons that causes electricity to appear.

Matter is made up of atoms. Each atom is composed of :

• of a nucleus made up of protons and neutrons. The protons are positively charged. Neutrons, as their name suggests, are not charged and are therefore neutral;
• of electrons orbiting this nucleus. The electrons are negatively charged.
  In general, an atom contains as many electrons as protons, so the atom is electrically neutral. But it is enough that the equilibrium is broken by the addition of an additional electron (by friction with another atom for example) and that the atom becomes negative. Similarly, it is enough that an electron is torn from this atom for the atom to become positive. That is why electricity is the result of the movement of these electrons.

Electricity manifests itself in nature in many phenomena such as :

• lightning, which corresponds to an electrical discharge between a cloud and the Earth, or between two clouds
• nerve impulses from certain living organisms that emit electric shocks (such as eels);
• static electricity created by rubbing or contacting different materials, for example between hair and wool by removing a sweater;

Electricity can be artificially generated in power plants by transformation :

• fossil energy sources such as coal, oil or natural gas ;
• fissile energy sources such as uranium, whose atoms can be broken to release heat and energy (nuclear electricity);
• renewable energy sources such as water, wind, sun, geothermal energy or biomass.

Electricity a very old story

Electricity or electrical phenomena have existed since the existence of the universe. Electricity is everywhere, discreet but sometimes manifesting itself in a very spectacular and brutal way like lightning.

The effects of electricity (and magnetism) were discovered early in human history. Proof of this is that the root of the word “electricity” originates from the Greek word “êlektron”, which refers to yellow amber, a fossil resin with electrostatic properties.

Archaeological discoveries have shown that Mesopotamians in the 3rd century BC used curious objects, now known as the “Baghdad electric battery”. These potteries have been so named since some 20th century archaeologists hypothesized that they would have been used as electric batteries.

Scientific developments: electricity and power cables

The 17th and 18th centuries are considered as decisive in the birth of modern theory around electrical and magnetic phenomena. Several great names such as Isaac Newton, Wilhelm Leibniz, Alembert, Benjamin Franklin, Alessandro Volta, inventor of the Voltaic battery, Charles Coulomb, etc. have associated their research with this theme considered central to the research..

In the 18th century Stephen Gray’s experiments marked the discovery of electrical conduction and distinguished insulating and conductive materials.

Electricity is a new technical medium that has enabled remote communication since the middle of the 19th century, replacing the optical telegraph. It is the subject of an international telegraph convention with its widespread use after the first Baltimore-Washington link in the United States (1844). Telephony is developing, it allows instant telecommunications installed in areas of dense housing. 
The electricity as a “vector of communication” or “vector of information” was born. There is an application importance before the “energy vector”.

At the end of the 19th century, electricity can become an energy producing mechanical movements from remote sources, and thus the practical conversion into kinetic energy and vice versa. This possible use is in addition to its potential uses already observed from the calorific, luminous and chemical effects.

This is the result of the preliminary technical progress made in the conductive materials industries and leads to the development of workshops and plants for drawing and drawing non-magnetic copper alloys and resistant steels (electrical wires, “electrical resistance”).

At the same time, the electrical insulation industry is growing with the development of the glass, porcelain-ceramic, rubber and wood industries. To these materials already in place for other uses, bakelite and varnishes were added at the beginning of the 20th century, followed by oils for winding science.

Around 1876, electricity was used intensively in the streets of the three “capitals of light”: London, New York and Paris. Lighting is provided by electric arc lamps. The electrical energy supply to the lamps is provided by overhead cables between buildings where electromagnetic generators are scattered.

In 1879, Thomas Edison introduced the first incandescent electric lamp (with carbon filaments) developed with the English Joseph Swan and which remained on for 45 hours. It is of possible use in interiors, while the electric light with arc lamps was too powerful.

In 1878, a 7 kW hydroelectric power plant was built in St. Moritz, Switzerland.

At the end of August 1883, Marcel Deprez carried out an experiment to transport electricity between Vizille and Grenoble over a distance of 14 km by direct current, to illuminate the hall in downtown Grenoble with 108 Edison lamps. The same year, Lucien Gaulard and the Englishman John Dixon Gibbs put into service a demonstration loop powered by 133 Hz alternating current at 2,000 volts and making the round trip from Turin to Lanzo (80 km).

We then end up acknowledging the interest of the transformer, which makes it possible to raise the voltage delivered by an alternator and thus facilitates the transmission of electrical energy through high-voltage lines.