RU193653U1 - Smoothing reactor - Google Patents

Abstract

The device relates to reactors for smoothing ripples of rectified current in high voltage networks and / or with a significant value of short circuit power. The technical result consists in increasing the stability of the smoothing reactor winding to mechanical stresses during the flow of short circuit currents along the circuit in which the smoothing reactor is installed. The inventive smoothing reactor contains a disk coil winding with external cast insulation mounted on the magnetic circuit. Each coil is made of several layers of thin-sheet conductor, and each of its layers represents one turn of the conductor, thin-sheet insulation is placed between the layers.

Description

The utility model relates to electrical engineering, in particular, to reactors for smoothing rectified current pulsations operating in high voltage networks and / or with a significant value of short circuit power. The device can be used in rectifier or thyristor converter circuits.

It is known that any electric power system, including a combination of various electrical equipment, is designed not only for the nominal parameters and operating modes, but must also take into account various emergency modes, in particular, short circuit mode (short circuit). The short-circuit mode is especially dangerous for electrical equipment in that when short-circuit currents are many times higher than the rated currents, along with significant thermal effects, electrodynamic effects occur in the form of mechanical forces in the electrical conductors, which can lead to destruction of the conductors themselves, damage to their insulation and, as a result equipment failure. Thus, ensuring the stability of electrical equipment to mechanical stress during the flow of short-circuit currents is important for the effective operation of a smoothing reactor.

A known design of a smoothing reactor [Patent RU 2627730, prior. 10/30/2015, publ. 05/11/2017, H01F 38/02, H01F 3/14], containing at least one block including an inductor placed in a non-magnetic medium. The block further comprises a closed radial-cylindrical magnetic system of ferromagnetic material, including at least one rod coaxially mounted in the center of the coil, sectioned by non-magnetic gaps, and a yoke part having a cylindrical shell mounted coaxially around the said coil, and end elements. At the junction of the cylindrical shell and end elements non-magnetic gaps are made.

The disadvantage of this solution is the high material consumption and the complexity of manufacturing a magnetic circuit, due to the presence of yoke parts and the need for sectioning of the rod. The design of the winding in this solution is not disclosed, which does not allow to draw conclusions about its manufacturability and resistance to mechanical stress during the flow of short circuit currents.

Known smoothing reactor RED-4000A, designed for installation in the back of an electric locomotive [Trunk electric locomotives. Electric machines and transformer equipment of electric locomotives. Bocharov V.I. and others, "Engineering". 1968, p. 421], the winding of which has twelve serially connected disk coils wound flat from a copper bus with gaps between the turns. The coils are impregnated with varnish and tightened in the radial direction by six glass bandages. In this case, the magnetic system is closed. In the case of an open-loop magnetic system, the winding is multilayer cylindrical.

In the first case, the winding is performed by a copper bus, that is, from a plate conductor. It is time-consuming to wind the winding with a copper plate busbar due to the significant stiffness of copper. In addition, the magnetic circuit in this case is closed and such a reactor is characterized by low manufacturability. In the second case, the winding is multilayer cylindrical and is characterized by low resistance to mechanical stress. In both cases, there is no external molded insulation of the winding, causing low mechanical resistance during the flow of short circuit currents.

Also known is a smoothing reactor [Reactormash.ru: website of Reactor Machines LLC [Electronic resource]. - Access mode: http://reactormash.ru/products/sglazhivayushhie-i-filtrovyie-reaktoryi/?yclid=13 66713260679904129, free], which is an inductor on a ferromagnetic core. The reactor winding is cast or using a rectangular wire with silicone silicone insulation. When winding, a rectangular multi-wire wire is used, including enameled with silicone insulation. Input and output are located on one side.

The design of the winding in this solution is not disclosed, which does not allow to draw conclusions about its manufacturability and resistance to mechanical stress during the flow of short circuit currents. The photographs presumably show a multilayer cylindrical winding made by wire, which does not have external cast insulation.

Known dry smoothing reactor [Eliz.zp.ua: site LLC "Elise" [Electronic resource]. - Access mode: http://www.eliz.zp.ua/about-company/novosti/181-aprel-2015g.html], the winding of which is cylindrical and the turns are wound with an aluminum bus. With the help of gaskets and rails, the winding is fixed between fiberglass supports and pressed by beams. All metal parts of the reactor have protective anti-corrosion coatings.

The design of the winding of this reactor is characterized by low manufacturability: in addition to the high laboriousness of making turns of coiled aluminum bus, there is a need to perform inter-turn insulation in the axial direction along the winding, which virtually eliminates the possibility of automating the winding process. Insufficient mechanical resistance is ensured in the absence of external cast insulation.

 Known Disk Smoothing Reactor [CN107564711A, prior. 06/30/2016, publ. 01/09/2018, H01F17 / 04; H01F27 / 02; H01F27 / 26] includes a housing with a core and a winding that surrounds the core, the outer wall, an insulating spacer plate between the core and the outer wall of the winding. The device has a disk coil winding wound with a flat copper wire. Another known smoothing reactor [CN206163267 (U), prior. 10/19/2016, publ. 05/10/2017, H01F27 / 06; H01F27 / 24; H01F27 / 30; H01F37 / 00] is made of two-disc and contains a closed magnetic system of two rods and a lower yoke. The winding includes primary and secondary windings, which are wound from one or more wires into a multilayer coil and provided with a gasket between them.

These smoothing reactors have disk coil windings without external cast insulation. One of the main disadvantages of such windings is their telescoping, that is, the possibility of axial displacement of the turns relative to each other. This leads to low mechanical resistance of the winding during the flow of short circuit currents.

Thus, the known solutions are characterized by insufficient resistance to mechanical stress during the flow of short circuit currents along the circuit in which the reactor is installed. This is due to the choice of the type of winding, the method of performing external insulation, the use of additional elements that reduce the density and rigidity of the winding design. At the same time, most analogues are not technologically advanced in production, have high material consumption, and therefore have a higher cost.

The technical result, which is aimed at achieving a utility model, is to increase the stability of the winding of the smoothing reactor to mechanical stress during the flow of short circuit currents along the circuit in which the smoothing reactor is installed. At the same time, the necessary level of manufacturability of the structure is maintained by reducing the complexity of manufacturing.

The inventive smoothing reactor contains a disk coil winding with external cast insulation mounted on the magnetic circuit. Each coil is made of several layers of thin-sheet conductor and each of its layers represents one turn of the conductor, thin-sheet insulation is placed between the layers. Improving the structural stability to mechanical stress is achieved by reducing the specific axial and radial forces from the action of short-circuit currents. In addition, the design of a smoothing reactor allows you to automate most production operations, thereby reducing the complexity and increasing the manufacturability of the device.

As indicated above, the smoothing reactor is designed to smooth the ripples of the rectified current, that is, to work at almost constant current, which contains higher harmonics of the alternating current, usually not exceeding 10% of the nominal direct current. This feature of a smoothing reactor (operating at almost constant current) allows the use of tape conductive materials (for example, aluminum or copper foil) in its design without fear of significant effects such as eddy currents in the conductor (Foucault currents) and current displacement to the ends of the conductor ( uneven distribution of current density over the cross section of the conductor) and, as a result, large additional losses in the conductor and heating. Also this feature allows you to perform coil winding of the reactor, without the need to align the current distribution between the coils.

The essence of the claimed utility model is illustrated by drawings, which depict:

 - in FIG. 1 - active part of the reactor, General view,

 - in FIG. 2 is a top view of the reactor,

 - in FIG. 3 - winding with parallel connection of coils, sectional view.

To confirm the feasibility of realizing its purpose with a useful model and achieving the claimed technical result, we consider an embodiment of the reactor.

The inventive smoothing reactor has an aluminum or copper disk coil winding 1 of the coils 4 in an amount of N ≥ 2, connected in parallel or in parallel-series. The winding 1 is installed on the core magnetic core 2, consisting of sheets of electrical steel.

Each coil 4 in the winding 1 is made of a sheet conductor, for example, tape or foil. Each layer represents one turn of foil. Between the turns, thin-sheet insulation is laid, for example, a polyethylene, polyester or polyester film, which is necessary for the normal functioning of the reactor winding, as it prevents inter-turn short circuit during current flow (rated and short-circuit current). The coil winding itself 1 has an external cast insulation 3 in the form of an electrical insulating compound.

This design provides the best filling of the cross section, high winding density and, as a result, the necessary rigidity of the design of each coil. The flat lateral surfaces of the sheet material allow transmitting radial forces in the coil from coil to coil as evenly as possible (with a uniform distribution of force along the side surface of the coil), significantly reducing the specific radial force (N / mm) on the interturn insulation. By reducing the specific radial force provides high resistance to the radial component of the forces during the flow of short-circuit currents. In this case, the coils do not have contact between themselves in the axial direction, respectively, the axial forces from the action of short-circuit currents are not transmitted from coil to coil, in contrast to, for example, a multilayer cylindrical winding. Thus, the specific axial force between the coils is zero. This provides high resistance to the axial component of the forces during the flow of short-circuit currents.

The implementation of the coils by a disk and thin-sheet conductor with compound (cast) pouring also makes it possible to reduce the complexity of manufacturing a smoothing reactor by automating the winding of the winding and eliminating some technological operations (for example, shifting, transposition). So, for example, a wire coil winding is wound manually, and there is often a laborious operation of transferring the coils during the winding process. When using a thin-sheet conductor with thin-sheet insulation, joint continuous winding of each individual disk coil can be carried out on an automated machine, since in the case of a disk winding circuit, the conductors simply overlap without axial displacement. The operations of shifting, transposing, installing rails, gaskets, and other channel-forming elements are excluded. The use of a coil winding also provides a sufficient heat dissipation area without the use of additional cooling elements. Soldering or welding operations are also excluded if the coils are connected together in parallel.

Cast insulation, tightly covering each coil of the winding, fixes all the turns, preventing the possibility of axial displacement of the turns inside the coil, that is, eliminating telescopicity. As a result, all degrees of freedom of the coils are blocked. In addition, the winding in the compound is monolithic and has sufficient rigidity in itself, therefore, when installed on the magnetic circuit, pressing is not required. In this case, cast insulation provides high electrical strength, so the thin-sheet conductor does not have its own insulation, insulation is laid only between the layers. Filling and baking of the compound of the external insulation of the winding can be carried out in an autoclave, the process is automated, accordingly, along with ensuring high quality filling, the need for manual labor is eliminated, that is, the laboriousness of operations is reduced.

Claims (1)

A smoothing reactor containing a disk coil winding with external cast insulation mounted on a magnetic circuit, each coil made of several layers of thin-sheet conductor and each layer of it is one turn of the conductor, and thin-sheet insulation is placed between the layers.

Images