阅读说明：本技术 一种干式变压器冷却结构 (Cooling structure of dry-type transformer ) 是由 王晓兵 周奇 包正科 于 2021-06-18 设计创作，主要内容包括：本发明涉及一种干式变压器冷却结构,该冷却结构采用相变材料作为工作介质,该冷却结构包括吸热段、上升段、冷却段和下降段,能够以机械固定的方式构建该冷却结构的稳定的循环流路,使得工作介质在吸热段中吸热后相变为气态下主要从上升段进入冷却段,而在冷却段中被冷却成液态后主要从下降段回流至吸热段,在该循环流路中,气态的工作介质不会与液态的工作介质产生混流干扰,从而既能够大大提高循环流率,同时还能充分利用相变材料的高效冷却,大大地提高了冷却效果。(The invention relates to a cooling structure of a dry-type transformer, which adopts a phase-change material as a working medium, and comprises a heat absorption section, an ascending section, a cooling section and a descending section, wherein a stable circulation flow path of the cooling structure can be constructed in a mechanical fixing mode, so that the working medium is mainly fed into the cooling section from the ascending section after absorbing heat in the heat absorption section and is changed into a gas state after being cooled into a liquid state in the cooling section, and the working medium mainly flows back to the heat absorption section from the descending section.)

1. A dry type transformer cooling structure comprises a primary coil, a secondary coil and an iron core, wherein the primary coil and the secondary coil interact with each other in a magnetic action mode through the iron core, the cooling structure comprises a plurality of cooling units, each cooling unit comprises a heat absorption section, an ascending section, a cooling section and a descending section, the heat absorption section is communicated with the cooling section through the ascending section and the descending section, the heat absorption section is arranged to be capable of exchanging heat with the primary coil, the secondary coil and/or the iron core, the cooling section, the ascending section and the descending section are located in the environment outside the primary coil, the secondary coil and the iron core, working media in the cooling units are made of phase change materials, and the phase change materials can absorb heat in the heat absorption section to be gasified and can release heat in the cooling section to be condensed into liquid.

2. Dry-type transformer cooling structure according to claim 1, characterized in that the phase change material is selected as one of ammonia, n-methanol, ethanol, ethylene glycol, water, acetone, alkanes or a combination of at least two thereof.

3. Dry-type transformer cooling structure according to claim 1, characterized in that the heat absorbing section is arranged in an inclined manner with respect to the horizontal direction, the heat absorbing section is arranged obliquely upwards with respect to the horizontal direction in a direction towards the external environment of the dry-type transformer, the heat absorbing section is ring-shaped, circular or linear.

4. A cooling structure for a dry-type transformer as claimed in claim 1, wherein said cooling section is a fin structure having an inner cavity located inside, said inner cavity being in fluid communication with said heat absorbing section through an ascending section and a descending section, a bottom of said inner cavity being disposed obliquely with respect to a horizontal direction, and a communication port of said descending section and said inner cavity being disposed at a position lower than a communication port of said ascending section and said inner cavity.

5. A dry transformer cooling structure as claimed in claim 1, wherein a fluid one-way structure is provided in the descender for impeding the flow of phase change material from the heat sink section to the cooling section in the descender.

6. A dry transformer cooling structure as claimed in claim 5, wherein the fluid unidirectional structure comprises a broken line segment extending upward in at least a part of the descending segment and a plurality of arc segments distributed on both sides of the broken line segment, a first end of the arc segment is connected to one break point of a broken line, and a second end of the arc segment is connected to the broken line in an upward direction.

7. A dry-type transformer cooling structure as claimed in claim 6, wherein the connection point of the second end of each arc segment to the folding line and the connection point of the first end to the folding line are located on the same straight line segment of the folding line.

8. A dry transformer cooling structure as claimed in claim 6 or 7, wherein each arc segment comprises a straight segment extending from a first end and an arc segment between the straight segment and a second end; the straight line segment and the straight line segment of the broken line at the upstream of the first end are positioned on the same straight line, or an included angle between the straight line segment and the straight line segment of the broken line at the upstream of the first end is an acute angle.

9. A dry type transformer cooling structure as claimed in any one of claims 6 to 8, wherein in the descending section, an angle between a tangent line of the arc-shaped section at the second end and a straight line segment of the folding line at the second end is an obtuse angle in a direction from bottom to top.

10. A dry transformer cooling structure as claimed in any one of claims 6 to 9, wherein the arc segment is in the shape of a circular arc.

Technical Field

The invention relates to the field of transformers, in particular to a cooling structure for a dry-type transformer.

Background

The transformer is basic equipment for power transmission and distribution, and is widely applied to the fields of industry, agriculture, traffic and the like. The transformer is a device for changing alternating voltage by utilizing the far away of electromagnetic induction, main components are a primary coil, a secondary coil and an iron core, and the main functions of the transformer are as follows: voltage transformation, current transformation, impedance transformation, isolation, voltage stabilization, and the like. And according to the capacity and cooling requirements of the transformer, the transformer can be mainly divided into a dry type transformer and an oil immersed type transformer. The dry-type transformer mainly relies on air convection to carry out natural cooling or increase fan cooling, and is mainly used for a small-capacity transformer, and all parts of the dry-type transformer are arranged in the air; the oil-immersed transformer depends on oil as a cooling medium, and comprises an oil-immersed self-cooling type, an oil-immersed air-cooling type, an oil-immersed water-cooling type and a forced oil circulation type.

In the field of electrical equipment, dry-type transformers are widely used in various devices and systems. In order to meet the requirement of long-term safe operation of the dry-type transformer, a fan is usually additionally arranged to accelerate the flow velocity of air flow in the environment where the transformer is located, so that the convection heat dissipation effect is enhanced, and the temperature of the transformer is reduced.

Today's dry-type transformers are typically mounted in an equipment enclosure or cabinet. The cooling fan of the dry-type transformer generally uses a cross-flow cooling fan, and the cross-flow cooling fan is installed at the lower part or the top part of the dry-type transformer, and accordingly, ventilation openings are provided at the lower part and the top part of the equipment housing or the box body, so that the air flow sucked by the cooling fan can flow through the dry-type transformer in the housing or the box body to cool the dry-type transformer.

However, such cooling methods require a targeted design of the transformer structure to meet the requirements of air convection cooling, and when the transformer is in a high load state, the cooling capability provided by such cooling methods is limited; particularly, in summer, the temperature of the transformer is usually high, which not only limits the performance of the dry-type transformer, but also damages the safe operation of the dry-type transformer and affects the service life of the dry-type transformer.

Therefore, providing a cooling method different from the conventional air convection cooling method to improve the cooling capability and safe operation capability of the dry-type transformer is a problem to be solved in the art.

Disclosure of Invention

In order to solve the above technical problems, the present invention provides a cooling structure of a dry-type transformer, the dry-type transformer includes a primary coil, a secondary coil and an iron core, the primary coil and the secondary coil interact with each other in a magnetic action mode through the iron core, the cooling structure comprises a plurality of cooling units, each cooling unit comprises a heat absorption section, an ascending section, a cooling section and a descending section, the heat absorption section is communicated with the cooling section through an ascending section and a descending section, the heat absorption section is arranged to be capable of exchanging heat with the primary coil, the secondary coil and/or the iron core, the cooling section, the ascending section and the descending section are positioned in the environment outside the primary coil, the secondary coil and the iron core, the working medium in the cooling unit adopts a phase-change material, the phase change material is capable of absorbing heat in the heat absorption section to vaporize and capable of releasing heat in the cooling section to condense into a liquid.

Further, the phase change material is selected from one or a combination of at least two of ammonia, normal methanol, ethanol, glycol, water, acetone and alkane.

Further, the heat absorbing section is arranged in an inclined manner with respect to the horizontal direction, the heat absorbing section is arranged obliquely upwards with respect to the horizontal direction in a direction towards the external environment of the dry-type transformer, and the heat absorbing section is annular, circular or linear.

Further, the cooling section is of a fin structure, the cooling section is provided with an inner cavity located inside, the inner cavity is in fluid communication with the heat absorption section through an ascending section and a descending section, the bottom of the inner cavity is arranged obliquely relative to the horizontal direction, and a communication port of the descending section and the inner cavity is arranged at a position lower than a communication port of the ascending section and the inner cavity.

Further, a fluid one-way structure is arranged in the drop leg for impeding the flow of the phase change material in the drop leg from the heat absorption section to the cooling section.

Further, the fluid one-way structure comprises a broken line section and a plurality of arc-shaped sections, the broken line section extends upwards in at least part of the descending section, the arc-shaped sections are distributed on two sides of the broken line section, a first end of each arc-shaped section is connected to a broken point of the broken line, and a second end of each arc-shaped section is connected to the broken line along the upward direction.

Further, the connection point of the second end of each arc-shaped section and the fold line and the connection point of the first end of each arc-shaped section and the fold line are positioned on the same straight line segment of the fold line.

Further, each of the arcuate segments includes a linear segment extending from a first end and an arcuate segment between the linear segment and a second end; the straight line segment and the straight line segment of the broken line at the upstream of the first end are positioned on the same straight line, or an included angle between the straight line segment and the straight line segment of the broken line at the upstream of the first end is an acute angle.

Further, in the descending section, an included angle between a tangent line of the arc-shaped section at the second end and a straight line segment of the broken line at the second end is an obtuse angle in a direction from bottom to top.

Further, the arc-shaped segment is in the shape of a circular arc.

The implementation of the invention has the following beneficial effects: a cooling structure adopting a phase-change material as a working medium is arranged in the dry-type transformer, and the cooling structure has a simple structure and occupies a small space; the cooling structure comprises a heat absorption section, an ascending section, a cooling section and a descending section, and a stable circulation flow path of the cooling structure can be constructed in a mechanical fixing mode, so that a working medium is subjected to heat absorption in the heat absorption section and then changes phase into a gas state, the working medium mainly enters the cooling section from the ascending section, and the working medium mainly flows back to the heat absorption section from the descending section after being cooled into a liquid state in the cooling section.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic view of a cooling structure of a dry type transformer of the present invention.

Fig. 2 is a schematic view of the cooling section of the cooling structure of the present invention.

Fig. 3 is a schematic view of the fluid one-way structure in the drop leg of the present invention.

Reference numerals: 1. a dry-type transformer winding; 2. winding; 3. a heat absorption section; 4. a cooling section; 5. a rising section; 6. a descending section; 7. a fin; 8. a fluid one-way structure; 9. folding lines; 10. an arc-shaped section; 11. straight line segmentation; 12. and (4) arc-shaped segmentation.

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 of the present invention without any inventive step, are within the scope of the present invention.

In order to improve the cooling capacity and cooling effect of the dry type transformer and improve the working margin and service life of the dry type transformer, the dry type transformer comprises a primary coil, a secondary coil and an iron core, wherein the primary coil and the secondary coil interact in a magnetic action mode through the iron core and are used for outputting power supplies with corresponding voltages according to a certain transformation ratio. Dry-type transformers are generally used in indoor environments and are often placed in a transformer cabinet equipped with a cooling or suction fan for blowing or sucking air into the cabinet, so that a cooling air flow is formed in the cabinet to cool the windings and the core of the dry-type transformer.

As shown in fig. 1, the present invention proposes a cooling structure particularly suitable for a general box-type dry transformer, which includes a plurality of independent cooling units respectively provided at different positions of each phase winding, of course, the positions being arranged according to the heat generation distribution of the dry transformer in practice. In the present embodiment, only one cooling unit disposed in the winding is exemplified.

As shown in fig. 1, each cooling unit comprises a heat absorbing section 3, an ascending section 5, a cooling section 4 and a descending section 6, the heat absorbing section 3 is communicated with the cooling section 4 through the ascending section 5 and the descending section 6, and the heat absorbing section 3 is arranged to be capable of exchanging heat with the primary coil, the secondary coil and/or the iron core so as to extract generated heat from the primary coil, the secondary coil and/or the iron core to keep the temperature of the primary coil, the secondary coil and/or the iron core within a permissible working range without overtemperature.

In particular, the heat absorbing section 3, as shown in fig. 1, is arranged in the middle of the winding, which is adjacent to two layers of windings, so that it is possible to sufficiently absorb heat from the winding to cool down the area. The heat absorbing section 3 may be in the shape of a ring or a C, and thus may be arranged to have a maximum area corresponding to the ring shape of the winding 2, so that the heat absorbing section 3 and the winding 2 have a maximum contact area or heat absorbing area, and the heat exchange capacity of the heat absorbing section 3 is improved. Alternatively, the heat absorbing section 3 may also be circular or rod-shaped, which is inserted in a smaller area to exchange heat with the winding or core, instead of a full turn.

In order to dissipate the heat absorbed by the heat absorbing section 3 from the winding or core, the cooling section 4, the rising section 5 and the falling section 6 are located in an environment outside the primary coil, the secondary coil and the core.

Preferably, in order to improve the cooling capacity, the invention proposes to use a phase change material as the working medium in the cooling unit, wherein the phase change material can absorb heat in the heat absorption section 3 to change from a liquid state to a gas state and can release heat in the cooling section 4 to condense from the gas state to the liquid state, so that the working medium can be switched between two phase states according to the heat absorption and cooling working states in different thermal environments, and the change between the phase states implies a huge heat change, that is, a large amount of heat is absorbed from the dry-type transformer through the change of the working medium between the two phase states, thus embodying the advantage of the phase change material as the working medium.

Further, the phase change material is selected from one or a combination of at least two of ammonia, normal methanol, ethanol, glycol, acetone, alkane and water. The inside of the cooling unit, namely the environment of the working medium, is set to be negative pressure, namely lower than the normal atmospheric pressure of the outside, so that the working medium selected as the phase-change material has a lower phase-change temperature point, namely can absorb heat at a lower temperature to become gaseous, and the cooling unit can exert a larger cooling capacity at a lower temperature, so that the temperature of the dry-type transformer is controlled at a lower temperature. Of course, the specific negative pressure value needs to be determined according to the required temperature of the dry-type transformer, the cooling capacity of the cooling unit and the working medium selection, but the invention provides an idea that the phase change temperature point of the working medium can be adjusted to match the working temperature of the dry-type transformer.

Further, in order to enable a relatively stable distribution of the working fluid in the heat absorbing section 3, said heat absorbing section 3 is arranged in an inclined manner with respect to the horizontal direction, as shown in fig. 1, said heat absorbing section 3 being arranged obliquely upwards with respect to the horizontal direction in a direction towards the external environment of the dry-type transformer. Therefore, due to the influence of density and gravity, the working medium in the liquid state in the heat absorption section 3 is positioned at the lower part of the heat absorption section 3 or at the end part of the heat absorption section 3 positioned at the winding; the working medium which has been gasified into a gaseous state after heat absorption is located at the upper part of the heat absorption section 3 or at the end part of the heat absorption section 3 leading to the external environment due to the lower density and under the action of natural pressure difference. Therefore, due to the inclined arrangement of the heat absorption section 3, the working medium can be different in phase state in the heat absorption section 3 according to the heat absorption condition, the gaseous working medium and the liquid working medium are naturally separated from each other, and the gaseous working medium can be favorably advanced towards the cooling section 4.

Because the cooling section 4 is in the external environment, especially in the air environment of box transformer room, the cooling section 4 has received the cooling of box transformer room's cooling air flow to can distribute the heat of the gaseous working medium of the higher temperature in the cooling section 4 to the environment in, reduce the temperature of working medium in the cooling section 4, thereby make working medium cooled down and change from gaseous state into liquid state in the cooling section 4. In order to increase the cooling capacity of the cooling section 4, as shown in fig. 2, a plurality of fins 7 are provided outside the housing of the cooling section 4, and the plurality of fins 7 can be heat-exchanged in a convective manner with the cooling air flow to dissipate the heat of the working medium in the cooling section 4 into the air, which greatly increases the heat dissipation capacity of the cooling section 4.

Furthermore, as shown in fig. 1, the cooling section 4 has an internal interior which is in fluid communication with the heat absorption section 3 via a rising section 5 and a falling section 6, preferably with the bottom of the interior being arranged at an angle to the horizontal, such that, when the working medium is condensed from the gaseous state to the liquid state in the cooling section 4, the liquid working medium can collect at the lower end and the gaseous working medium continues to dissipate heat to the outside at the higher end. Further, the communication opening of the descending section 6 and the inner cavity is arranged at a position lower than the communication opening of the ascending section 5 and the inner cavity, so that the gaseous working medium in the ascending section 5 can directly enter the gaseous environment of the inner cavity of the cooling section 4, and the liquid working medium in the cooling section 4 can intensively flow back from the descending section 6 to the heat absorption section 3. Therefore, the gaseous working medium can not impact the condensed liquid working medium when flowing into the cooling section 4, so that the phenomenon of water hammer in the cooling section 4 is prevented, and severe vibration and noise can be caused by the phenomenon of water hammer, so that the structure of the cooling unit is damaged. In addition, the arrangement can enable the working medium to circulate more smoothly.

In order to ensure that most of gaseous working media rise from the heat absorption section 3 to the cooling section 4 through the rising section 5, and most of liquid working media flow back to the heat absorption section 3 from the cooling section 4 through the falling section 6, and particularly to prevent the gaseous working media from entering the cooling section 4 through the falling section 6 to cause the gaseous working media and the liquid working media to be mixed in the falling section 6, so as to cause unsmooth backflow of the liquid working media and vibration and noise caused by gas-liquid mixed flow, as shown in fig. 1, the invention provides that a fluid one-way structure 8 is arranged in the falling section 6, and the fluid one-way structure 8 is used for preventing gaseous phase-change materials from flowing from the heat absorption section 3 to the cooling section 4 in the falling section 6.

As for the specific structure of the fluid one-way structure 8, as shown in fig. 3, the fluid one-way structure 8 includes a folding line 9 and a plurality of arc-shaped segments 10, the folding line 9 extends from bottom to top in at least a part of the descending segment 6, and the plurality of arc-shaped segments 10 are distributed on both sides of the folding line 9. In particular, the fluid unidirectional structure 8 has at least one arc-shaped segment 10.

Wherein a first end of said arcuate segment 10 is fluidly connected to a break point on the fold line 9 and a second end of said arcuate segment 10 is fluidly connected to the fold line 9 in an upward direction. In particular, the connection point of the second end of said arc-shaped segment 10 to the fold line 9 and the connection point of the first end to the fold line 9 are located on the same straight line segment of the fold line 9. Thus, both ends of each arcuate segment 10 are in fluid communication with the same straight segment of the fold line 9.

For the purpose of hindering the flow of gaseous phase change material in said descending section 6 from said heat absorption section 3 to said cooling section 4, said each arcuate section 10 comprises a linear section 11 extending from a first end and an arcuate section 12 located between the linear section 11 and a second end; the straight line segment 11 and the straight line segment of the fold line 9 at the upstream of the first end are located on the same straight line, or an included angle between the straight line segment 11 and the straight line segment of the fold line 9 at the upstream of the first end is an acute angle. In fig. 3, the straight line segment 11 is substantially collinear with the straight line segment of the fold line 9. For the arc-shaped segment 12, along the direction from bottom to top, the included angle between the tangent line of the arc-shaped segment 12 at the second end and the straight line segment of the broken line at the second end is an obtuse angle; further, the arc-shaped segment is in the shape of a circular arc. The arrangement is that the gaseous working medium flows from the heat absorption section 3 to the cooling section 4 along the descending section 6, and the gaseous working medium can smoothly flow into the straight section 11 of the arc-shaped section 10 in the folding line 9 and further flow into the arc-shaped section 12 of the arc-shaped section 10; and the exit of the second end of arc-shaped section 12 is obtuse with the contained angle of broken line 9, then gaseous state working medium when flowing out arc-shaped section 12, then can flow towards heat absorption section 3's direction, like this, make gaseous state working medium flow resistance greatly increased in this fluid one-way structure 8 on the one hand, on the other hand make get into in the fluid one-way structure 8 and from the gaseous state working medium that flows out in arc-shaped section 12 can flow back to heat absorption section 3 in, thereby make fluid one-way structure 8 reach the one-way hindrance effect to gaseous state working medium from heat absorption section 3 flow direction cooling section 4.

Correspondingly, in the descending section 6, when the liquid working medium condensed in the cooling section 4 flows back from the cooling section 4 to the heat absorbing section 3, the liquid working medium flows smoothly in the fold line 9, while the liquid working medium is substantially impossible to flow into the curved section 10 and only flows along the fold line 9 to return to the heat absorbing section 3 because the outlet of the curved section 12 of the curved section 10 is substantially directed towards the heat absorbing section 3. Therefore, the fluid one-way structure 8 in the descending section 6 can well prevent the gaseous working medium from flowing to the cooling section 4 from the heat absorption section 3, and the liquid working medium cannot be prevented from flowing back to the heat absorption section 3 from the cooling section 4.

By constructing the cooling structure of the present invention, the fluid one-way structure 8 is arranged in the descending section 6, so that the gaseous working medium generated in the heat absorbing section 3 can basically flow only from the ascending section 5 to the cooling section 4, but can not flow from the descending section 6 to the cooling section 4; due to the inclined arrangement of the cooling section 4, the liquid working medium condensed in the cooling section 4 also flows back into the heat absorption section 3 substantially only from the descending section 6. Therefore, a working medium loop with basically one-way circulation is constructed, so that the cooling structure provided by the invention has high circulation multiplying power and good cooling capacity.

The implementation of the invention has the following beneficial effects: a cooling structure adopting a phase-change material as a working medium is arranged in the dry-type transformer, and the cooling structure has a simple structure and occupies a small space; the cooling structure comprises a heat absorption section, an ascending section, a cooling section and a descending section, and a stable circulation flow path of the cooling structure can be constructed in a mechanical fixing mode, so that a working medium is subjected to heat absorption in the heat absorption section and then changes phase into a gas state, the working medium mainly enters the cooling section from the ascending section, and the working medium mainly flows back to the heat absorption section from the descending section after being cooled into a liquid state in the cooling section.

While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.