The history of the development of the main high-voltage equipment. Part 1

One of the most important elements of an electrical installation is the transformer. The development of this device depend on the capacity growth and power lines voltage. As already mentioned, the construction of the first transformer pin and shell type were developed in the 70s of XIX century.

The first design of transformers have been perfect, we had a large magnetic scattering as their primary and secondary windings located on different cores of the magnetic circuit. Further searches of rational structures of transformers were aimed at reducing the magnetic scattering (especially by a concentric arrangement of the windings), improving mezhduvitkovoy isolation, the development of cooling systems, and so on. D.

At the turn of the 80's - 90's, attempts were made to use for cooling and winding insulation mineral oil. During the first two decades of this century preferential distribution in the US plants have received three-phase groups of single-phase transformers, and in Europe - three-phase oil transformers rod and shell type cooling circulating water.

The history of the development of the main high-voltage equipment. Part 1

Rod and armor types of transformers have survived to the present time, the first received preferential distribution. As a material used almost exclusively windings bandpass rectangular copper. Sometimes, as was the case in Germany during the First World War, was built power transformers up to 60 th. KVA with aluminum coil. In general, the improvement of the windings of transformers is to improve their mechanical and electrical strength, heat resistance, efficiency and improvement of technological methods of production.

It has undergone significant changes, one of the most important structural parts of transformers - High-voltage bushings. For relatively low voltages, of the order of 35 kV, various firms such as «Westinghouse» and some other commonly used porcelain designs. For higher voltages ranging from 50-60 kW, were the most common two types: hollow and condenser bushings with oil filling. Condenser bushings have been proposed in Germany in 1906

The transformer building plays an important role reducing the size and weight of vehicles. In this regard, is characterized by such indicators: if in 1900 the oil transformer capacity of 1200 kVA weighed 18,100 kg, then in 1920 the same type of vehicle of the same capacity weighed 7550 kg, ie, its weight was only 41.. 7% with respect to sample 1900 g.

With the growth of the electric power stations more complicated task off operating currents, especially short-circuit currents. Be used to suppress the special high-voltage devices - switches have passed a long way of development. Simple switching devices have appeared about 20 years of XIX century. It had metal cores, admitted into the vessels with mercury. These switches used by D. Henry and AM Ampere ( "rocker Ampere") to change the direction of the current in electrical circuits.

The principle of mercury in switches contacts remained until the early 90-ies already in connection with the energy use of electricity. These devices operate, for example, a power plant in Rome, worked for 2 kV transmission line at a current of 200 A. The Budapest firm "Ganz and K 0 'built switches with mercury contacts for voltages up to 10 kV. But mercury contacts were uncomfortable: the device gets cumbersome, non-transportable, does not provide a reliable shutdown.

In the 90s there were design with movable contact elements, such as a circuit breaker MO Dolivo-Dobrovolsky (1893) features original plate springy contacts. As long as the voltage does not exceed the electrical systems of 15 kV and current of 300 A, the use of such devices has been permitted without special means for extinguishing the arc. However, increasing the voltage to 22 kV, as it were, for example, on the Niagara hydroelectric power in 1901, led to the urgent need for switches, in which would ensure reliable arc gap with the arc additional funds. One of the first arc of devices that have received wide recognition, horn-shaped steel pins, applied originally in the surge arrester. Massive horns contributed to the rapid deionization of the arc gap. Switch contacts with hornlike, patented by «Brown, Boveri & C0" in 1897 for a long time used in electrical engineering. To accelerate the arc interruption began to be used as a "magnetic blow" artificially generated magnetic field. This principle arc suppression was also borrowed from the practice of lightning protection - arresters with magnetic quenching were proposed I. Thomson, and is widely used in the 90s to protect DC applications.

As power plants growth, a new difficulty: the arc, free climbs the horn electrodes extend to very great distances and threaten the security is located near the equipment. Safety means suggested MO Dolivo-Dobrovolsky: Towards an arc established cross dividers made of insulating material. Doug, curving around the lower edges of the plates, lengthened, the resistance of the arc gap increased, the arc will deionized.

In 1912 Dolivo-Dobrovolsky introduced another promising proposal: to establish an arc path of a lattice of metal plates - the so-called blow-out grille. This invention hitherto widely used in many types of switchgear: contactors, circuit breakers, disconnectors.

However, the switch to an open arc in the air can not completely solve the problem of reliable off large short-circuit currents. Therefore, in parallel with the development of this kind of vehicles ranging from the 50s did not stop attempts to create fuses and circuit breakers with high insulating properties of mineral oils. The first construction of oil circuit breakers and fuses, by J. Thomson in S. America and Ferranti in the UK, is a device in which the contacts were broken off in the air, followed by withdrawal of the movable contact by a layer of oil.

The next step in the development of oil circuit breakers was the division of the functions of the workers and the arcing contacts. In 1898, Charles Brown has developed a structure in which each phase is accounted for by two workers and four arcing contact. The process of extinguishing the arc in such an apparatus has accelerated, and the permissible switching capacity has increased significantly due to a number of significant features: arcing contacts, breaking arc in a few short arcs were deep under the layer of oil and quickly divorced strong springs.

In 1898, this type of circuit breakers have been built in the United States engineer EM Hewlett. They came to modern forms of oil circuit breakers, although the first design had special interrupters. Quenching was carried out by increasing the distance between the radiating terminals. But this increase could not be unlimited, and while the electrical voltage and power plants continued to increase, the dimensions of the switches and unacceptably increased oil volume. There was a need for new dugogasya-ing means, the first of which was gazomaslyanoe blast generated by arcing in special chambers. In 1908, American engineers J. Hilliard and Charles Parsons built the oil switch interrupters longitudinal blast. In the future, the principle gazomaslyanogo blast firmly established vyklyuchatelestroenii.

In the 90 years of XIX century. and beginning to XX. there was still some fundamentally new devices to break the arc, such as water, tubular, Autogas and finally, air circuit breakers, but they did not get in the first two decades of the XX century. any recognition and practical application.

In the initial period of the development of high-current equipment is more convenient transfer of electric current through the wires using cable underground lines. It was believed that the underground wiring will protect electrical networks from mechanical damage and atmospheric interference and will not spoil the appearance of the city.

Shukhardin S. "Technology in its historical development"