RU210759U1 - SCREW WINDING WITH INSULATION OF CONNECTED WIRE ENDS - Google Patents

Abstract

The utility model relates to the field of electrical engineering, namely to the design of electrical equipment elements, in particular helical windings of electric reactors and/or power transformers, and can be used to strengthen the insulation of the connection of the ends of the cut wires of the helical winding, in relation to which the transposition is performed. The technical result is a simplification of the design of the helical winding, which, in turn, makes it possible to increase its manufacturability. The helical winding contains turns, each of which contains parallel wires forming rows located in the radial direction. Between the rows, a concentrated transposition of parallel wires is made, and the parallel wires, in relation to which the said transposition is performed, are cut, and their ends are connected to each other. The interconnected ends of the cut wires, in relation to which the transposition is performed, are placed inside a tubular element made of an electrically insulating heat-shrinkable material. 6 w.p. f-ly, 3 ill.

Description

The utility model relates to the field of electrical engineering, namely, to the design of electrical equipment elements, in particular, helical windings of electric reactors and/or power transformers, and can be used to reinforce the insulation of the connection of the ends of the cut wires of the helical winding, in relation to which the transposition is performed.

The helical winding consists of turns wound along a helical line. Each turn consists of parallel wires arranged in rows arranged in a radial direction.

In the designs of windings of electrical reactors and power transformers, it is necessary to ensure reliable insulation of wires in order to prevent a short circuit in the circuit, which may result in dynamic loads, a change in the geometry of the winding and a change in the characteristics of the electromagnetic field, which, in turn, can lead to emergency situations. .

In all windings, wire bends are one of the most dangerous places in terms of the possibility of insulation damage [web page address: https://leg.co.ua/transformatory/praktika/tehnologiya-izgotovleniya-obmotok-transformatorov-2.html], therefore, wire bending operations are carried out extremely carefully and accurately, using bending devices, and after bending, the bent sections are isolated. Also, when winding, the ends (outlets, inputs / outputs) of the winding wires are additionally insulated. In addition, when transposition is performed, when the wires to be transposed are cut and the ends of the cut wires are connected, for example, by soldering or welding, the connected ends are also insulated.

Mechanical damage to the insulation of wires can occur, in particular, on bent sections of wires (during bending performed during the winding process) or as a result of external influences by foreign objects on the ends of the wires protruding beyond the winding (for example, these can be coil taps or connected ends cut wires, in relation to which the transposition was performed).

In cases of damage to the insulation, it must be restored to its original thickness. For example, a method of winding a two-way helical coil is known [patent No. CN 109036834 A "A winding method of a double helical elliptical coil", IPC H01F41/063, H01F41/071, H01F41/076, H01F41/12, publ. 12/18/2018], according to which, when the wire is transposed, its S-shaped bend is performed, in case of damage to the insulation on the bend of the wire, a layer of damaged insulation is removed, and then the insulation is restored to its original thickness in this section (for example, wrapped with braided insulating tape). During the formation of the winding taps, the corresponding sections of the wires are bent (if necessary, the insulation is restored), and the output ends of the wires are insulated.

To prevent damage to the insulation (to improve the insulation characteristics), in a number of winding designs, the wire insulation is thickened at the transition points (bends). For example, a technical solution is known according to patent No. CN 102969144 A ["Double-layer cylindrical winding technique for low-voltage coils of transformer", IPC H01F41/071, H01F41/12, publ. 03/13/2013], according to which, when winding the coils of a transformer, the wires are bent to form winding leads, the leads are interconnected by welding, and the wires at the bends are wrapped with a thickened layer of insulating material. However, even a thickened layer of insulating material can be damaged during the further manufacturing of the winding.

In some cases, to prevent emergencies, it is proposed to use automated control of the parameters of the winding wires, and in case of an emergency, turn off the system. For example, a technical solution is known related to the design of a transposed wire for winding a transformer coil [patent No. CN 101707073 A "Transposed conductor with sensing function", IPC G01B7/16, G01K11/32, H01B7/32, H01F27/40, publ. 05/12/2010], according to which the wire contains elements for controlling deformation (pressure sensor) and temperature increase (thermal sensitive element), which ensure constant monitoring of the parameters of the wire. The control elements are located in the wire between two lines of conductors, the narrow edges of which are in contact with each other. With an increase in temperature (at short-circuit currents) or pressure (at wire deformation), information is transmitted to the parameter control unit, and if the permissible values are exceeded, the transformer is turned off. This technical solution makes it possible to monitor the condition of the winding wires in order to receive a signal about damage to the wire insulation (melting of the insulating material and / or mechanical damage to the insulation) and turn off the transformer in a timely manner, however, it is characterized by a very high design complexity, and also requires the inclusion of additional functional blocks that control the state of the corresponding sensors (control elements). These factors greatly increase the complexity of the product as a whole, while reducing its operational reliability.

As a technical solution (prototype) closest to the claimed utility model in terms of design, a transformer winding is proposed according to patent No. US8154374B2 [“Transformer winding and a method of reinforcing a transformer winding”, IPC H01F27 / 28, date publ. 04/10/2012]. The well-known technical solution can be used in the construction of various types of windings, including screw windings that are part of electrical reactors or power transformers. The winding contains many turns. Each turn is usually formed by rows of parallel wires located in the radial plane of the winding. As a rule, windings, including screw windings, are carried out with the transposition of wires necessary to equalize electrical and inductive resistances. In places of winding transitions (by which we mean places where the path of the conductor deviates from the usual winding path, i.e. in places where the wires are bent; the term "transitions" is also used), reinforcing parts (elements) are located that cover the wire by more than 180 degrees . Reinforcing elements can be tubular and, as indicated in the description of the known technical solution, are made in the form of a whole pipe covering 360 degrees of the circumference of the conductor (i.e. have a closed surface), or in the form of a partial pipe (i.e. have an open surface ) covering less than 360 degrees of the circumference of the conductor.

The preferred locations of the reinforcing elements, according to the known technical solution, are layer transitions between layers of the winding, transitions between disks, transitions and end sections of the input/output of the conductor in the winding.

The use of reinforcing elements in the well-known design of the winding provides an increase in mechanical strength (namely, the bending strength of the wire at the installation sites of these elements) and the dielectric strength of the winding under the action of, for example, bending stresses arising from the Lorentz magnetic forces in the places of winding transitions in the event of a short circuit .

According to the known technical solution, the reinforcing parts (elements) are made of fibre-reinforced thermosetting polymers with insulating properties, for example, epoxy resin, vinyl ester, polyester, etc. Fiberglass, carbon fiber, para-aramid fibers, etc. can be used as reinforcing fibers.

It should be noted that the use of a tubular reinforcing element with a closed surface provides higher strength and reliability compared to a reinforcing element having an open surface. In addition, when using a partial tube (i.e., open face) reinforcing element, it must be positioned so that the minimum bending stress occurs along that part of the conductor circumference that is not covered by the reinforcing element.

The reinforcing element is formed by applying a fibrous tape or mat pre-impregnated with a thermosetting material to the wire, or by sequentially applying first a reinforcing fiber (for example, in the form of a roving, unidirectional fiber thread, woven material), and then (after applying the fiber) - a thermosetting polymer . The thermoset polymer is usually applied by brush, roller, injection, etc. The polymer is then cured. Curing can be carried out simultaneously with hot drying of the winding. Thus, the implementation of a reinforcing element from a thermosetting fiber-reinforced polymer containing two components, each of which is prepared separately, causes the complexity of the design and its low technology.

It should be noted that it is possible to prefabricate the reinforcing element, including its formation from the components of a thermosetting fibre-reinforced polymer and subsequent curing of the composition, after which, for example, the end section of the winding in/out conductor can be passed through the tubular element. However, in this case, it should be noted that the inner hole of the prefabricated and cured reinforcing element must be made of such a size as to allow the wire to pass freely through the tubular element, as a result of which the "tubular element - wire" connection will have a guaranteed gap and additional fixing of the tubular element will be required. element on the wire (to exclude spontaneous displacement of the tubular element on the wire), which will lead to an increase in the design complexity of the winding and a deterioration in manufacturability. The above circumstances make it inexpedient to use a prefabricated tubular element to reinforce individual sections of the winding wires. In addition, taking into account these factors, it also seems inappropriate to use a prefabricated tubular element in the case when the wire has a variable cross section, or, for example, in the case of connecting the ends of the wires (soldering, welding, twisting, etc.), when the thickness of the connection along the length of the conductor is uneven.

Thus, the above factors indicate that the disadvantage of the known technical solution is its structural complexity and the resulting non-technological design.

The technical result, the achievement of which is provided by the claimed utility model, is the simplification of the design of the helical winding, which, in turn, makes it possible to increase its manufacturability.

To achieve the above technical result, a helical winding is proposed, which contains turns, each of which contains parallel wires forming rows located in the radial direction. Between the rows, a concentrated transposition of parallel wires is made, and the parallel wires, in relation to which the said transposition is performed, are cut, and their ends are connected to each other. The interconnected ends of the cut wires, in relation to which the transposition is performed, are placed inside a tubular element made of an electrically insulating heat-shrinkable material.

In the claimed technical solution, the execution of interconnected ends of the cut wires placed inside a tubular element made of electrically insulating heat-shrinkable material (heat-shrinkable tube widely used in electrical engineering) is a simpler design compared to the prototype, in which the reinforcing tubular element is made of reinforced thermosetting polymer fiber, which requires separate preliminary preparation of each component of the composition and separate application of the components to the wire. In addition, the design of the tubular element, made of heat-shrinkable material, provides, compared with the prototype, a significant simplification of the installation of the tubular element on the section of the wire that requires reinforcement, i.e. provides an increase in the manufacturability of the design, while when heating a tubular element made of a heat-shrinkable material, the tubular element, shrinking under the influence of temperature, will tightly wrap around the reinforced section (connected ends of the wires), even in the case of an uneven thickness of the section, along its entire length.

The ends of the cut wires, in relation to which the transposition is performed, can be interconnected by welding or soldering, since these types of wire connections are the most technologically advanced and reliable.

In order to simplify the design of the helical winding and improve its manufacturability, sections of wires in the places of winding transitions can be made placed inside tubular elements made of electrically insulating heat-shrinkable material. It should be noted that the heat-shrinkable tube, before it is subjected to temperature exposure, is a flexible element and can be stretched along the conductor and installed in the section of the winding transition (in the section of the bend of the wire), and after thermal exposure, it will shrink and it will tightly wrap around the section the wire on which it is located.

In order to ensure higher strength, the interconnected ends of the cut wires of the helical winding can be insulated and placed inside a tubular element made of electrically insulating heat-shrinkable material.

In order to improve the manufacturability of the design, the interconnected ends of the cut wires of the helical winding, in relation to which the transposition is performed, can be located behind the outer diameter of the helical winding, while these wires pass through a horizontal channel made between adjacent turns of the helical winding.

It is also possible to make a helical winding, in which the interconnected ends of the cut wires, in relation to which the transposition is performed, are located in the above-mentioned horizontal channel and do not protrude beyond the outer diameter of the helical winding.

The operation of the helical winding, made according to the claimed technical solution, is carried out as part of electrical equipment, namely, electrical reactors or power transformers.

Graphic materials contain an example of the inventive helical winding with concentrated transposition.

In FIG. 1 is a schematic representation of a helical winding that is part of an electric reactor.

In FIG. 2 shows a schematic representation of a fragment of a helical winding in a cross section (a top view of a horizontal channel), containing the ends of the cut wires connected to each other (located behind the outer diameter of the helical winding) and the places of the bends of the wires.

In FIG. 3 shows a schematic representation (on an enlarged scale) of one of the pairs of interconnected ends of the cut wires of the helical winding, in relation to which a concentrated transposition is performed, and placed inside the tubular element and the places of the bends of the wires, where the sections of the wires in the places of their bends are also placed inside the tubular elements .

One of the main components of an electrical reactor of any type or a power transformer is a winding, in particular, a screw winding. Each turn 1 contains parallel wires 2 forming rows 3 (Fig. 2, 3). Rows 3 are located in the radial direction (in the radial plane of the winding). A concentrated transposition of parallel wires is made between the rows. The wires 2.1, 2.2, in relation to which the transposition is performed, are cut, and their ends 4.1, 4.2 (Fig. 2, 3) are interconnected, for example, by welding (soldering, etc. is also possible). In the above example of the screw winding, a horizontal channel 5 is formed (for example, by installing rails 6 in the radial plane of the winding, Fig. 1), through which wires 2 pass, the ends 4 of which are interconnected according to a given transposition scheme. The ends of the cut wires, interconnected, are placed inside the tubular element 7 (Fig. 3) - an electrically insulating heat-shrinkable tube (for example, Heat-shrinkable tube VT-220). In the presented example of the implementation of the helical winding in the places of the winding transitions 8 (places of wire bends), the wire sections are also placed inside the tubular elements 9 - heat-shrinkable tubes.

In the manufacture of a helical winding, wires are wound and concentrated transposition of parallel wires is performed. Transposition is performed in order to equalize the lengths of the wires, their electrical and inductive resistances, ensure a uniform current density, and reduce additional losses in the windings. The layout of the cut wires, in relation to which the transposition is performed, is carried out according to a predetermined scheme, while the ends of the wires (even before they are connected to each other) are led out through the horizontal channel 5 and located outside the outer diameter of the winding. The ends 4 of the cut wires 2 are connected (for example, by welding or soldering) to each other according to a predetermined pattern. Connection by welding or soldering is preferred in terms of manufacturability and reliability. At the same time, it is technologically preferable to connect the ends of the wires by welding or soldering, when these ends are brought out beyond the outer diameter of the winding (Fig. 2). The interconnection of the ends of the cut wires during transposition provides a reduction in the axial dimension of the winding. A heat-shrinkable tube 7 is put on the interconnected ends 4.1 and 4.2 of the cut wires 2.1 and 2.2 (Fig. 2, 3). It should be noted that in places of winding transitions 8, heat-shrinkable tubes 9 are placed in the process of winding the conductor, since the heat-shrinkable tube (before the temperature effect on it) is a flexible element and, when winding the conductor, can be stretched along the conductor and placed on the bent section 8 of the wire. The diameter of the heat-shrinkable tube is chosen in such a way as to be able to freely place in the tubular element the interconnected ends of the wires, in relation to which the transposition is performed, or to install the tube on the bend section of an individual wire. After connecting the ends of the wires and placing them in a heat-shrinkable tube, the connected ends can be left located outside the outer diameter of the winding (Fig. 2) or bent inside the horizontal channel (i.e. located inside the channel, Fig. 1) to prevent accidental mechanical damage external items. It should also be noted that after connecting the ends of the cut wires, they can first be insulated, and the already insulated connected ends can be placed inside the tubular element, which will increase both the mechanical and dielectric strength of the connection. Heat shrinking of the tube can be carried out at the final stage of winding manufacturing, for example, during the winding hot drying technological operation or as a separate technological operation. When heated, the tube shrinks, and it tightly wraps around the section of the wire on which it is located.

Thus, the use in the claimed technical solution of a tubular element made of an electrically insulating heat-shrinkable material (heat-shrinkable tube) provides, in comparison with the prototype, a simplification of the design, since the prototype uses a tubular element made of a fiber-reinforced thermosetting polymer containing two components, as well as provides an increase in the manufacturability of the design, since in the manufacture of the winding according to the claimed utility model, the heat-shrinkable tube is put on the conductor section (on the interconnected ends of the wires and / or on the section of the winding transition), while in the manufacture of the winding according to the prototype, it is necessary to separately prepare each of two components of the fiber-reinforced thermosetting polymer from which the reinforcing tubular element is made, and applying each component to the surface of the conductor section to be reinforced.

During the operation of electrical equipment, which includes a helical winding, for example, an electric current-limiting reactor, when a short-circuit current passes, the conductor in the places of winding transitions is subjected to bending stresses as a result of the action of Lorentz magnetic forces, which can lead to deformation of the conductor up to its mechanical damage. The use of tubular elements (heat-shrinkable tubes) located in separate sections of the conductor makes it possible to provide the necessary mechanical and dielectric strength of the conductor under severe operating conditions of the device (at high voltage, short circuit, etc.).

In addition, it should be noted that during the manufacture of the winding, in particular, during transposition, the conductors are subjected to mechanical stress, for example, bending, as a result of which the insulation covering the wire can receive both obvious mechanical damage (insulation tear) and visually imperceptible damage, but which can subsequently lead to breakdown and melting of the insulation. In this case, the presence of a tubular element (heat-shrinkable tube) in the section of the wire with damaged insulation will provide the necessary dielectric characteristics of the wire during the operation of the electrical equipment.

The implementation of the insulated interconnected ends of the wires, in relation to which the transposition is performed, located in a heat-shrinkable electrical insulating tube provides high mechanical and dielectric strength of these connected ends of the wires and thereby protects against possible external mechanical influences (scratches, damage), as well as from breakdown and melting insulation (for example, when foreign metal objects get on the conductor, which, when in a magnetic field, can heat up and heat the wire insulation).

Sometimes foreign metal objects can also get into the transposition channel (a horizontal channel formed between the turns of the winding), and therefore (to ensure high dielectric strength) after laying out the transposition wires and preparing them for welding (stripping the ends of the wires), each conductor is put on a heat-shrinkable tube from the exit point of the conductor from the layer to the beginning of the section prepared for welding.

Thus, as follows from the above information, the proposed implementation of the helical winding provides, compared with the prototype, a simpler design and the resulting increase in the manufacturability of the design while ensuring the mechanical and dielectric strength of the insulation of the wires.

Claims (7)

1. A helical winding, characterized in that it contains turns, each of which contains parallel wires forming rows located in the radial direction; between the rows, a concentrated transposition of parallel wires is made, and the parallel wires, in respect of which said transposition is performed, are cut, and their ends are interconnected; at the same time, the interconnected ends of the cut wires are placed inside a tubular element made of an electrically insulating heat-shrinkable material. 2. Screw winding according to claim 1, characterized in that the ends of the cut wires, in respect of which the transposition is performed, are interconnected by welding. 3. Screw winding according to claim 1, characterized in that the ends of the cut wires, in respect of which the transposition is performed, are interconnected by soldering. 4. Helical winding according to claim 1, characterized in that the sections of wires in the places of winding transitions are made placed inside tubular elements made of electrically insulating heat-shrinkable material. 5. Screw winding according to claim 1, characterized in that the interconnected ends of the cut wires are insulated and placed inside a tubular element made of electrically insulating heat-shrinkable material. 6. A screw winding according to claim 1, characterized in that between its adjacent turns a horizontal channel is made through which the wires pass, in relation to which the transposition is performed, while the interconnected ends of the cut wires are located behind the outer diameter of the screw winding. 7. Screw winding according to claim 1, characterized in that at least one horizontal channel is made between its turns, in which the interconnected ends of the cut wires are located, in relation to which the transposition is performed, while the interconnected ends of the cut wires do not protrude for the outer diameter of the screw winding.

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