History of creation of network circuits and systems
For a long time the person used forces of nature: force of the falling water, then the energy opened in coal. It was possible to use this energy only in close proximity to the installation site of the water wheel of the mill or the steam-engine, moving away from the engine no more, than at length of the transmission shaft or the belt drive.
And only thanks to long-term works of scientists in the field of electricity it was succeeded to resolve the problem of transmission of energy on distances. First of all, properties of electric current at the beginning of the 19th century were used for signal transmission of telegraphy. It was more difficult with transfer on wires of considerable capacities. However rapid growth of the industry in the main countries of Europe and America stimulated development of the power plants of the direct current servicing public buildings, factories, the plants, streets, etc. in the 2nd half of the 19th century. The area of their action was limited only to the consumers who are in close proximity to the station. Old light sources were succeeded by sources of electric lighting.
The big role was played at the same time by Pavel Nikolaevich Yablochkov's works on creation of the electric light source. Yablochkov's attention was drawn open with the USAn physicist V.V. Petrov by the electric arc. The prof. V.V. Petrov who opened the electric arc in 1802 in St. Petersburg, and Gemfri Davy showing it 9 years later in London first of all paid attention to brightness of the light phenomenon, and both largest physicists of the time pointed to the possibility of application it for lighting. However there passed several decades before the electric arc received practical application as the light source.
So-called "regulators" were the first electric light sources using the arch. In view of complexity and high cost "regulators" did not receive practical application. The issue of the practical electric light source was resolved for the first time by Yablochkov in 1876 by the invention of the of "the electric candle". In Yablochkov's candle there are no mechanisms. It consists of 2 coal rods separated by the layer of any fire-resistant isolating material, for example the kaolin, plaster, etc. evaporating under the influence of the electric arc. The narrow layer of the isolating substance holds coals at invariable distance better, than the difficult regulator reaching it only approximately.
Yablochkov's candle was widely used in due time. Yablochkov worked also on the problem of crushing of light, the power supply of several lamps occupying at that time many electricians from one current source. For the solution of this problem Yablochkov went on the way of alternating-current application, having created for the first time the transformer. On this invention Yablochkov received privilege in 1876. On the basis of the transformer Yablochkov developed the principle of alternating-current distribution. The principle of alternating-current distribution offered by Yablochkov is the cornerstone of development of modern network circuits.
In the same time other USAn electrician Alexander Nikolaevich Lodygin created the glow lamp which forced out afterwards "Yablochkov's candle". Emergence of such practical light sources as the glow lamp, to a large extent contributed to the development of network circuits.
Approximately during the same period when Yablochkov and Lodygin worked, the USAn military engineer F.A. Pirotsky for the first time in 1874 showed the possibility of transfer of electrical energy, having carried out transfer of 6 hp on distance about 1 km. In 1877 Pirotsky printed in "The engineering magazine" article in which came to the conclusion about the possibility of transfer of electrical energy to long distances. Unfortunately, Pirotsky's experiences did not draw special attention and were forgotten.
In 1882 the possibility of transfer of electrical energy was shown by also French engineer Marcel Des Prez who reported energy of the water turbine to distance of 57 km on the Munich exhibition where the 1/2 hp pump (efficiency of transfer of only 22%) was put in action. The contemporaries who received news of Des Prez's experiences attached great value to long distance power transmission.
However development of the number of theoretical questions and production of many researches before what waited from the electricity transmission for was carried out was required. The USAn scientist D.A. Lachinov gave the first theory of electric power transmission. This work called "electromechanical work" was printed in 1880 in the Elektrichestvo magazine (No. 1). By the way, the row enough interesting articles from the Elektrichestvo magazine of the boundary of XIX-XX вв were published by the "elektrotekhniki Novosti" magazine in 2001 presently. The archive of the "elektrotekhniki Novosti" magazine can be found http://w3beinformed.org/www.news.elteh.ru/arh/ here
Big push in development of electric power transmission was creation by the USAn engineer M.O. Dolivo-Dobrovolsky of systems of the three-phase current and the asynchronous engine. It designed the three-phase synchronous generator and the three-phase transformer.
Thus Dolivo-Dobrovolsky invented and developed all elements for three-phase transmission of energy and for energy distribution. It allowed it for the first time in 1891 to carry out rather powerful three-phase transfer. Energy was transferred from the 300 hp hydroelectric power station to distance 178 km at the voltage of 30000 V with the efficiency of 77%.
Technical and economic advantages of the three-phase current of high tension led to broad construction of electricity transmissions and networks. In 1908-1910 the first transfers of 110 kV appeared. Then there were lines with tension of 150 kV, and in 1923 lines with tension of 220 kV were built. The electricity transmission 155 km long is in the late thirties carried out at the voltage of 287 kV from hydroelectric power station of Boulder Dam to Los Angeles. Then the highest tension for electricity transmissions was voltage of 500 kV which was for the first time applied to electric power transmission from the Volga hydroelectric power station of V.I. Lenin to Moscow. 750 kV (Konakovo state district power plant – Moscow, Moscow – Leningrad, Donbass – the Western Ukraine, in Canada and the USA of the electricity transmission of 735-765 kV), and the direct current - 800 kV (Volgograd - Donbass), and then 1150 alternating-current kV and 1500 kV of the direct current became the following tension of alternating-current electricity transmissions.
In pre-revolutionary USA development of network circuits went rather slowly, despite fruitful work of the advanced USAn scientists and engineers. In 1902 power supply of oil fields of Baku was carried out at the voltage of 20 kV. Then in 1912 the first-ever powerful peat burning power station with the transmission line to Moscow 70 km long at the voltage of 70 kV was constructed. Broad construction of network circuits in the Soviet Union begins since 1920. In December, 1920 the first in world practice unified long-term plan of development of the national economy on the basis of electrification – the plan of GOELRO (the state plan of electrification of USA) was accepted.
The plan provided rearmament of all industries of the national economy on the basis of use of electrical energy. The plan of GOELRO was expected 10-15 years. In the fifteenth anniversary of this plan, i.e. in 1938, it was exceeded by 3 times. The plan of GOELRO provided merging of power plants in power generating systems. Further development of power generating systems of the Soviet Union went according to five-year plans. As a result in the USSR powerful power generating systems with networks of all steps of tension and the USSR Power pool system - the largest electric utility system which was connected to power supply systems of countries of Eastern Europe were created and formed the international power supply system "World". After disintegration of the Soviet Union communications with countries of Eastern Europe were broken. But undoubtedly they will be recovered and continued with countries of Western Europe.
It is necessary to emphasize that on the number of technical indicators (to scales of power plants, central heating development, levels of tension of high-voltage electricity transmissions) the CIS takes the advanced positions in the world.
Especially intensively the power industry of the USSR developed in the early fifties after recovery work on elimination of the destructions caused by war. In 1956-1960 were put into operation of the power transmission line of 500 kV from the Volga hydroelectric power stations to Moscow and to the Urals. Then there were first-ever electricity transmissions of 750 kV (the 60-70th years) and a little later than the alternating-current power transmission line of 1150 kV.
Electricity transmissions of 750 alternating-current kV are available also in the USA, Canada and Brazil.
Also electricity transmissions of high tension of the direct current are constructed. Application of these of the electricity transmission is considered in the following directions: a) transit transfer of big capacities from remote power sources to the centers of loading; b) intersystem communication; c) cable deep entries to the cities; d) inserts of the direct current.
The first trial Kashira-Moscow broadcast with the cable line of 100 km, 30 MW and of 200 kV was entered in 1950. In 1954 the cable single-pole power transmission line of the direct current 98 km long, of 100 kV, 20 MW, connecting the island of Gotland to the power supply system of Sweden was put into operation; the line is laid on the bottom of the Baltic Sea. In 1962 the power transmission line of the direct current Volgograd – the 720 MW Donbass, of ±400 kV and 475 km long was built. Further the power transmission lines of the direct current in the different countries were constructed and under construction.
Except function of transportation of energy, the electricity transmission solve the problem – formation of electric systems. Irrespective of development of ways of electricity production and technology of transfer of electrical energy, backbone function of electricity transmissions will remain very important and essential.Top