CN112908635B

CN112908635B - Dry-type transformer with elliptical coil

Info

Publication number: CN112908635B
Application number: CN202110052900.0A
Authority: CN
Inventors: 黄信乐; 陶进; 黄伟
Original assignee: China Zhongbian Group Shanghai Transformer Co ltd
Current assignee: China Zhongbian Group Shanghai Transformer Co ltd
Priority date: 2021-01-15
Filing date: 2021-01-15
Publication date: 2021-10-08
Anticipated expiration: 2041-01-15
Also published as: CN112908635A; KR20220103912A; WO2022151910A1

Abstract

The invention discloses a dry-type transformer with an oval coil, which comprises a shell, a transformer core, a high-voltage binding post and a low-voltage binding post, wherein the transformer core is arranged in the shell and comprises an outer iron core, an iron core column, a first winding and a second winding, the transformer core is of a shell structure, the first winding and the second winding are respectively wound on the iron core column and are used as coils on a low-voltage side and a high-voltage side to be connected with the low-voltage binding post and the high-voltage binding post, and the iron core column is of an oval section. The winding coil on the iron core post of oval cross-section, the mode of arranging compares in traditional circular winding post, can fully wrap up magnetism and feel the line, under the same iron core post cross-section girth, the region that is not surrounded by outer iron core reduces greatly, and magnetism is felt the line and is retrained in this transformer core internally by most. The cross section of the cable used by the first winding and the second winding is elliptical and is wound on the iron core column in an inclined mode.

Description

Dry-type transformer with elliptical coil

Technical Field

The invention relates to the technical field of dry-type transformers, in particular to a dry-type transformer with an elliptical coil.

Background

The dry-type transformer is widely used in places with larger power consumption at the end of power grids of airports, buildings, factories and the like, and has good fireproof performance as the main advantage compared with an oil-immersed transformer.

However, the dry-type transformer has small heat capacity because of no existence of transformer oil, local temperature rise inside the dry-type transformer can be quickly accumulated at one position, if the local temperature rise cannot be found and led out in time, the dry-type transformer is easy to damage, a transformer winding is formed by winding enameled wires, the integrity of insulating paint on the surfaces of cables directly determines the insulating performance among the cables, and therefore the dry-type transformer has the frequent problem that the winding generates more heat, heat accumulation is generated on adjacent contact surfaces of the cables, an insulating layer is aged and fails, and once the insulating layer fails, inter-turn short circuits are caused, so that the normal use of the transformer is influenced.

Disclosure of Invention

The present invention is directed to a dry-type transformer with an elliptical coil to solve the above problems.

In order to solve the technical problems, the invention provides the following technical scheme:

the utility model provides a take dry-type transformer of oval coil, which comprises a housin, the transformer core, high-voltage terminal and low-voltage terminal, the casing is arranged in to the transformer core, the transformer core includes outer iron core, the iron core post, first winding and second winding, the transformer core is the shell type structure, outer iron core, the iron core post founds "day" word structure, crosspiece in the middle of the iron core post is as "day" word, first winding and second winding are coiled the coil as low-voltage side and high-voltage side on the iron core post respectively, first winding and second winding are connected with low-voltage terminal and high-voltage terminal respectively, the iron core post is oval cross-section. Winding coil on the iron core post of oval cross-section, the winding position of coil is oval promptly, such mode of arranging is compared in traditional circular winding post, can fully wrap up magnetism and feel the line, although the iron core has the effect of restraint magnetism and feel the line, however, the iron core post is towards two directions of air, the magnetism that has not attracted the restraint by the iron core of some coils is felt line and is leaked to surrounding space, arouse the induced-current of other electrical parts in the transformer, not only produce electromagnetic noise easily, still arouse the transformer loss, reduce transformer efficiency, and the oval iron core post structure of this application, under the same iron core post cross-section girth, the region that is not surrounded by outer iron core reduces greatly, magnetism is felt the line and is retrained by most in this transformer core is internal.

Further, the cross section of the cable used by the first winding and the second winding is oval. Oval cable is under the same cable cross sectional area, have and be greater than the circular-shaped girth of standard, the window width of iron core can be controlled, and compare in prior art and begin to use the cable of rectangular cross section to carry out the coil coiling that appears, oval cable cross section has the surface again and is mellow and full, the advantage of difficult distortion, the cable of oval cross section has just fully exposed the inhomogeneous problem of local material at the course of working, therefore, the stability in use of off-the-shelf oval cross section cable is higher, the difficult circumstances such as fracture that appear, thereby the life-span of coil is better with the coincidence degree of the whole life-span of transformer.

Further, the cable of the first winding and the second winding is obliquely wound on the iron core column, and an acute angle is formed between a long axis of the cross section of the cable and the axis of the iron core column. Press from both sides acute angle alpha between cable major axis and the iron core post axis, the winding cable of slope at first can save the length of iron core post, if the cable major axis is near to going on the coiling, then under the same iron core post length, can only twine the winding of less number of turns, and if the cable is the minor axis and leans on the minor axis to get the coiling, although can be on the iron core post the winding of the more number of turns of coiling, but, the heat radiating area that the cable generates heat reduces greatly, and this application is through the mode of slope coiling, when coiling number of turns efficiency is ensured on the iron core post, can also play the good radiating effect of cable: considering the magnetic field generated by the current on a single section in the surrounding space, if all surrounding parts are removed, the magnetic induction lines generated by electrifying a straight conducting wire with a single elliptic section are a cluster of ellipses taking the conducting wire as the center line, the closing direction of the magnetic induction lines is determined by the right hand rule, in the case, because the conducting wire exists beside the iron core column and the upper and the lower adjacent conducting wires are arranged, the magnetic induction lines can be attracted and deformed, the deformation generated by the attraction of the conductor and the magnet leads the magnetic induction lines to penetrate into the object, if the undeformed magnetic induction lines are expected to penetrate into the object obliquely, the included angle between the magnetic induction lines and the surface of the object is increased after the magnetic induction lines are attracted and deformed, the magnetic induction lines tend to be ninety degrees and then are bent out of the object to form closed lines, most of the magnetic induction lines are still closed in the iron core column and the outer iron core, and the magnetic induction lines are not completely adsorbed by the iron core, at the local position of the adjacent wire, the current in the adjacent wire can generate corresponding change to generate current shunt action, the current of the upper half part in the cross section is concentrated to one end head of the long axis according to the left-hand rule corresponding to Hall judgment, the current of the upper half part in the cross section is re-judged to be the lower half part, the current of the lower half part is concentrated to the other end head of the long axis of the cross section of the wire, namely, the wire spirally wound after being inclined, the current in each cross section is concentrated to two ends of the long axis of the elliptic cross section under the action of the magnetic field of the adjacent turns, the heat generated by the wire exists at the position where the current flows, the two ends of the wire generate heat, the heat generating position is staggered with the contact position of the wire when the coil is wound, and the heat is conducted by contacting with the iron core column while being exposed outside, the heat accumulation at the contact position of the wire is prevented, the insulating layer of the enameled wire is damaged, and turn-to-turn short circuit is avoided.

Furthermore, the outer surfaces of the first winding and the second winding are wrapped by silica gel cloth, and the other side of the silica gel cloth is in contact with the outer iron core or the inner wall surface of the shell. The heat on the outer surface of the winding is not taken away by forced airflow, so in order to fully exert the effect that the two ends of the current with the elliptic section are passed and the heating positions exist at the two ends, the heat is guided out from the head part at the outer side of the lead by the silica gel cloth, the heat is prevented from being transferred to the contact position of the lead to cause the aging of the insulating layer, the heat can be guided to the inner wall surface of the shell preferably, and if the heat resistance in the process is longer, the heat can be withdrawn to obtain the secondary guide to the outer iron core.

Furthermore, a winding slot is formed in the surface of the iron core column, and the first winding and the second winding are wound in the winding slot. The ellipse is not circularly symmetrical, so that when the winding machine is used for winding obliquely, the winding precision is possibly affected or the inclination degree is different, so that the local magnetic field is not uniform, the winding groove is formed in the iron core column, the cable can be restrained, and the winding process can only be carried out along the groove body.

Furthermore, an included angle between the long axis of the cross section of the cable in the first winding and the second winding and the axis of the iron core column is 45-60 degrees. The length requirement of the iron core column can be reduced by a larger included angle until ninety degrees, and the larger the angle is, the smaller and smaller the effect of the heat distributed to the two ends of the long axis of the elliptical section of the lead is, so that the compromise value is 45-60 degrees.

Compared with the prior art, the invention has the following beneficial effects: the magnetic induction lines are fully wrapped in the transformer core body through the oval iron core column, so that the magnetic induction lines are prevented from leaking to the next transformer core body to cause induction current; the used wire of coiling coil also is oval cross-section and slope coiling, can the cable of the more number of turns of coiling on shorter iron core post length, and the coiling mode of slope lets the electric current take place the reposition of redundant personnel in the cable, and the electric current distributes the major axis both ends in the oval cable cross-section, avoids the contact position of adjacent cable, prevents that the insulating layer of enameled wire from being heated ageing and destroying even, increase coil life-span.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic diagram of a transformer core structure of the present invention;

FIG. 3 is view A of FIG. 2;

fig. 4 is a schematic winding diagram of a second winding according to the present invention on a core limb;

in the figure: 1-base, 2-shell, 3-transformer core, 31-outer iron core, 311-magnetic-coated arc surface, 32-iron core column, 321-winding slot, 33-first winding, 34-second winding, 35-silica gel cloth, 41-high voltage binding post and 42-low voltage binding post.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1-4, the present invention provides the following technical solutions:

the utility model provides a take dry-type transformer of oval coil, including casing 2, transformer core 3, high-voltage terminal 41 and low-voltage terminal 42, transformer core 3 arranges in casing 2, casing 2 is placed on a base 1, transformer core 3 includes outer iron core 31, iron core post 32, first winding 33 and second winding 34, transformer core 3 is the shell type structure, outer iron core 31, iron core post 32 constitutes "day" word structure, iron core post 32 is as "day" word middle crosspiece, first winding 33 and second winding 34 are coiled the coil of being low-voltage side and high-voltage side on the iron core post 32 respectively, first winding 33 and second winding 34 are connected with low-voltage terminal 42 and high-voltage terminal 41 respectively, iron core post 32 is the oval cross-section. As shown in fig. 4, the core limb 32 with an oval cross section is wound with a coil, i.e. the winding position of the coil is oval, and compared with the conventional round winding limb, the arrangement mode can fully wrap the magnetic induction wire, although the iron core has the function of restraining the magnetic induction lines, in two directions of the iron core column 32 towards the air, the magnetic induction lines of some coils which are not attracted and restrained by the iron core leak to the surrounding space, so that induced current of other electric devices in the transformer is caused, electromagnetic noise is easy to generate, transformer loss is caused, and the efficiency of the transformer is reduced, and the elliptic iron core column structure of the invention, at the same section circumference of the core leg 32, the area not surrounded by the outer core 31 is greatly reduced, the magnetic induction lines are mostly confined in the transformer core 3, the surface of the outer core 31 facing the core limb 32 is also provided with a flux-cored arc surface 311 in order to sufficiently fit the elliptic core limb 32.

The cross-section of the cable used for the first winding 33 and the second winding 34 is elliptical. As shown in fig. 3, the oval cable has a circumference larger than a standard circle under the same cable cross-sectional area, the window width of the iron core can be controlled, and compared with the prior art in which the cable with a rectangular cross section is used for winding the coil, the oval cable cross section has a round surface, and is not easy to distort.

The wires of the first winding 33 and the second winding 34 are wound obliquely around the core limb 32, with the long axis of the wire cross-section making an acute angle with the axis of the core limb 32. As shown in fig. 2 and 3, an acute angle α is clamped between a long axis of the cable and an axis of the iron core column 32, the length of the iron core column 32 can be saved by obliquely winding the cable, as shown in fig. 3, if the long axis of the cable is wound closely, then under the same length of the iron core column 32, only a winding with a few turns can be wound, and if the cable is wound by the short axis close to the short axis, although a winding with a large number of turns can be wound on the iron core column 32, but the heat dissipation area of the cable for generating heat is greatly reduced, and the present application adopts an obliquely winding mode, and when the efficiency of the number of turns on the iron core column 32 is ensured, the good heat dissipation effect of the cable can be also played: as shown in fig. 3, the direction of current flow in the paper plane is represented by "x" on the cable cross section at the left side part of the center line of the core column 32, the direction of current flow from the paper plane to the outside of the paper plane is represented by "· s" on the cable cross section at the left side part of the center line of the core column 32, and considering the magnetic field generated in the surrounding space by the current flow on a single cross section, if all the surrounding parts are removed, the magnetic induction lines generated by the energization of the straight conductive wire with a single elliptical cross section are a cluster of ellipses with the conductive wire as the center line, and the closing direction of the magnetic induction lines is determined by the right hand, whereas in the present case, since the conductive wire exists beside the core column 32 and there are adjacent conductive wires above and below, the magnetic induction lines are attracted and deformed, the deformation of the magnetic induction lines caused by the attraction of the conductors and the magnets allows the magnetic induction lines to penetrate into the object, and if the non-deformed magnetic induction lines are expected to penetrate into the object obliquely, when the bending penetration object is formed, the included angle between the bending penetration object and the surface of the object is increased to be ninety degrees, then the bending penetration object is bent to form a closed line, as shown in fig. 3, two of the sections of the four wires on the left side are indicated by magnetic induction lines which are not all restricted by the iron core column 32 and the outer iron core 31, most of the magnetic induction lines are still closed in the iron core column 32 and the outer iron core 31, under the action of the magnetic induction lines which are not completely absorbed by the iron core, the current in the adjacent wires is correspondingly changed to generate a current shunting action, as shown in fig. 3, the current condition in the third wire from top to bottom on the left side is examined, in the section of the wire at the position, the upper half part of the current is subjected to the magnetic induction line acting force of the upper wire and is greater than that of the lower wire, so according to the left-hand rule corresponding to Hall determination, the upper half part of the current in the section is concentrated to the upper head part on the left side, judging the lower half again, the current of the lower half is concentrated to the head part at the lower right of the cross section of the wire, that is, the wire spirally wound after being inclined, the current in each cross section is concentrated to two ends of the long axis of the elliptical cross section due to the magnetic field action of the adjacent turns, the heat generated by the wire exists at the position where the current flows, namely, the heating area shown in fig. 3, the two ends of the wire generate heat, the heating position is staggered with the contact position of the wire when the coil is wound, and the heating position is exposed outside while contacting with the iron core column 32 to conduct away the heat, so that the heat is prevented from being accumulated at the contact position of the wire, the insulating layer of the enameled wire is damaged, and the turn-to-turn short circuit is caused.

The outer surfaces of the first winding 33 and the second winding 34 are wrapped by silica gel cloth 35, and the other surface of the silica gel cloth 35 is in contact with the outer iron core 31 or the inner wall surface of the shell 2. The heat on the outer surface of the winding is not taken away by forced airflow, so in order to fully exert the effect that the two ends of the current with the elliptic section are passed and the heating positions exist at the two ends, the heat is guided out from the outer side head of the lead by the silica gel cloth 35, the heat is prevented from being transferred to the contact position of the lead to cause the aging of the insulating layer, the heat can be guided to the inner wall surface of the shell 2 preferably, and if the thermal resistance in the process is longer, the heat can be removed and then guided to the outer iron core 31.

The core limb 32 has a winding slot 321 on the surface, and the first winding 33 and the second winding 34 are wound in the winding slot 321. The ellipse is not circularly symmetrical, so that when the winding machine is used for winding obliquely, the winding precision is possibly affected or the inclination degree is different, so that the local magnetic field is not uniform, the winding groove is formed in the iron core column 32, the cable can be restrained, and the winding process can be only carried out along the groove body.

The included angle between the long axes of the cross sections of the cables in the first winding 33 and the second winding 34 and the axis of the iron core column 32 is 45-60 degrees. The length requirement of the core limb 32 can be reduced by a larger included angle up to ninety degrees, and the larger the angle is, the smaller and smaller the effect of the heat distributed to the two ends of the long axis of the elliptical section of the lead is, so that the compromise value is 45-60 degrees.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides a take dry-type transformer of oval coil, includes casing (2), transformer core (3), high-voltage terminal (41) and low-voltage terminal (42), casing (2) are arranged in to transformer core (3), its characterized in that: the transformer core body (3) comprises an outer iron core (31), an iron core column (32), a first winding (33) and a second winding (34), the transformer core body (3) is of a shell type structure, the outer iron core (31) and the iron core column (32) construct a structure in a shape like a Chinese character 'ri', the iron core column (32) serves as a middle crosspiece in the shape like the Chinese character 'ri', the first winding (33) and the second winding (34) are respectively wound on the iron core column (32) to serve as coils on a low-voltage side and a high-voltage side, the first winding (33) and the second winding (34) are respectively connected with a low-voltage wiring terminal (42) and a high-voltage wiring terminal (41), and the iron core column (32) is of an oval cross section;

the cross section of the cable used by the first winding (33) and the second winding (34) is oval;

the cable of the first winding (33) and the second winding (34) is obliquely wound on the iron core column (32), and an acute angle is formed between the long axis of the section of the cable and the axis of the iron core column (32).

2. A dry-type transformer with an elliptical coil as set forth in claim 1, wherein: the outer surfaces of the first winding (33) and the second winding (34) are wrapped by silica gel cloth (35), and the other surface of the silica gel cloth (35) is in contact with the inner wall surface of the outer iron core (31) or the shell (2).

3. A dry-type transformer with an elliptical coil as set forth in claim 1, wherein: and a winding groove (321) is formed in the surface of the iron core column (32), and the first winding (33) and the second winding (34) are wound in the winding groove (321).

4. A dry-type transformer with an elliptical coil as set forth in claim 1, wherein: an included angle between the long axis of the cross section of the cable in the first winding (33) and the second winding (34) and the axis of the iron core column (32) is 45-60 degrees.