CN206480466U - A kind of inner side circulating cooling epoxy cast dry transformer - Google Patents

Abstract

The utility model provides a kind of inner side circulating cooling epoxy cast dry transformer, including transformer body, the transformer body includes transformer framework, the iron-core workpiece being located in the transformer framework and located at the external three-phase coil winding of the iron core, the three-phase coil winding is wrapped with housing, wherein, it is provided with by the transformer body between a coolant casing, the three-phase coil winding Inside coil and cooling tube is distributed with, the cooling tube is connected with the coolant casing.A kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, by setting cooling tube inside coil windings, realize that coolant, in coolant casing and cooling tube internal circulation flow, so as to take away the heat in coil windings, improves heat dispersion by elevator pump；In addition, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, is combined by the way of air-cooled and recirculated water cooling, further increases the heat dispersion of transformation.

Description

A kind of inner side circulating cooling epoxy cast dry transformer

Technical field

The utility model is related to transformer technology field, more particularly to a kind of a kind of inner side circulation for improving heat sinking function is cold But epoxy cast dry transformer.

Background technology

Transformer is the device for changing alternating voltage using the principle of electromagnetic induction, and major function has：Voltage transformation, electricity Rheology is changed, impedance is converted, isolate, voltage stabilizing etc..Transformer is the visual plant in generating, power supply and electricity consumption enterprise, and it is in power network In be also at extremely crucial status, be to ensure that power grid security, reliable operation and people's production and household electricity are of crucial importance Equipment.

Dry-type transformer is widely used in local lighting, skyscraper, airport, the place such as harbour CNC plant equipment, simply Say that dry-type transformer just refers to the transformer that iron core and winding are not immersed in insulating oil.The type of cooling is generally divided into natural air Cool down (AN) and force air to cool down (AF).During natural air cooling, transformer can the long-term continuous operation under rated capacity.Force wind When cold, transformer output capacity can improve 50%.Suitable for interrupted running overload, or emergent accident running overload；Due to Load loss and impedance voltage amplification are larger during overload, in non-economy running status, therefore should not be at connecting for a long time Continuous running overload.

As Chinese patent CN105529145A discloses a kind of three-dimensional winding iron core resin insulating dry type transformer, including transformation Device base, the upper clamping piece and lower clamping piece being correspondingly arranged at up and down on transformer base, and it is clamped at upper clamping piece and lower clamping piece Between three-dimensional winding iron core, the three-dimensional winding iron core includes middle part and is formed with three lists that hollow out and profile are round rectangle structure Frame, three single frames are stitched together in equilateral triangle spatial arrangement, and each single frame is respectively by some silicon steel ladders Continuously winding is formed shape material strip successively, and the mosaic of single frame described in each two is wound with coil respectively, and each coil is overall Curing agent and heated curing molding are poured into a mould, and each coil outer is epoxy resin enclosed, the transformer base On be additionally provided with multiple side blown type blower fans, the three-dimensional winding iron core top is connected with HV Terminal and low-voltage terminal, the three-dimensional winding iron Core side is also associated with high-voltage tap termination.Technical scheme disclosed by the invention has three-dimensional winding iron core, saves material saving, and zero load is damaged Consumption, no-load current is low, noise is low, good electric property, shelf depreciation value is low, resistance to lightning impulse ability is strong, anti-short circuit capability is strong, machine The characteristics of tool intensity is high.But the technical scheme that the patent of invention is disclosed still has the following disadvantages：Transformer bottom it is side-blown Formula blower fan is dried to the center position of transformer respectively, therefore, can be in transformation when three transformers open quenching simultaneously The area that prevents wind from passing through is produced at device inner hub location, the area that prevents wind from passing through is not smooth due to being easily caused ventilation by blowing while three directions, because This, can be because cooling radiating is uneven and there is hot unbalanced problem inside and outside serious using such a cooling structure.

And for example Chinese patent CN204242762U discloses a kind of water circulation type triangle volume iron transformer, including fuel tank, It is characterized in that：The fuel tank is connected with water circulation mechanism, and the water circulation mechanism includes water tank, and the inside of the water tank is provided with water Pump, the water tank is connected with outlet pipe and return pipe, and the outlet pipe is connected to water pump, and the outlet pipe connects respectively with return pipe Logical fuel tank, the inside of the fuel tank is provided with the helical pipe that the vertical direction for being used for taking away oil temperature is set, the helical pipe point Lian Jie not outlet pipe and return pipe, the water tank, outlet pipe, return pipe and the logical circulating path of helical pipe composition current.On The technical scheme of content disclosure is stated, is passed through the helical pipe that cooling water flows into bottom-up setting by outlet pipe again using water pump Oil temperature in fuel tank is taken away acceleration radiating by return pipe reflow tank, cooling water, and the higher oil meeting elevating screw pipeline of temperature is certainly Upward setting can largely take away oil temperature down, and the control of water pump can be controlled to start with closing on switch board, and increase is used Security.But, it is suitable only for oil-filled transformer in the technical scheme, it is impossible to applied to dry-type transformer.

Utility model content

The problems such as to overcome present in above-mentioned prior art, the utility model provides a kind of raising heat sinking function, and A kind of inner side circulating cooling epoxy cast dry transformer simple in construction, safe and reliable.

A kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, including transformer body, institute State transformer body including transformer framework, the iron-core workpiece that is located in the transformer framework and external located at the iron core Three-phase coil winding, the three-phase coil winding is wrapped with housing, wherein, a tank for coolant is provided with by the transformer body Cooling tube is distributed between body, the three-phase coil winding Inside coil, the cooling tube is connected with the coolant casing.

In some embodiments, the coolant casing is below the transformer body, the coolant casing It is fixedly connected with the skeleton.

In some embodiments, it is described to dissipate provided with some circular radiating air channels for being used to radiate in the coil windings Hot-flow flue is axially arranged along the coil windings, through the coil windings.

In some embodiments, the cooling tube is uniformly surrounded on one of them described annular in the coil windings and dissipated In hot-flow flue.

In some embodiments, the cooling tube in coil windings described in two adjacent groups joins end to end, and is connected, positioned at two Cooling tube in the coil windings of side is connected with the coolant casing respectively.

In some embodiments, the cooling tube curl described in every group in coil windings is uniformly surrounded on described In heat dissipation wind channel.

In some embodiments, the cooling tube described in every group in coil windings is surrounded on the radiating into roundabout shape In air channel.

In some embodiments, the cooling tube in the vertical direction present down back and forth roundabout mode be surrounded on it is described In heat dissipation wind channel, the cooling tube is totally located on vertical direction.

In some embodiments, one of them is located at the cooling in the coil windings on the outside of the transformer body Pipe is connected by riser with the coolant casing, and described riser one end is connected with the cooling tube, and the other end is passed through institute State in tank for coolant body, one end end that the riser is located at the coolant box house sets elevator pump.

In some embodiments, cooling blower, the air outlet of the cooling blower are set below the transformer body Towards the coil windings.

Compared with prior art, a kind of inner side circulating cooling epoxy cast dry transformer of the utility model offer has Beneficial effect is：

First, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, by coil windings Inside sets cooling tube, meanwhile, cooling tube is connected with coolant casing, and installing coolant, passes through elevator pump in tank for coolant body Realize that coolant, in coolant casing and cooling tube internal circulation flow, so as to take away the heat in coil windings, improves radiating Performance.

2nd, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, by coil windings Interior uniform ring, while forming the coolant circulated in cooling tube, constantly takes away the heat in coil windings around cooling tube, So as to improve the rate of heat dispation of coil windings, heat dispersion is improved, is carried out with the air-cooled of prior art and in coil windings bottom Water cooling is compared, and improves its radiating effect.

3rd, a kind of inner side circulating cooling epoxy cast dry transformer that utility model is provided, by coil windings Some heat dissipation channels are formed, the cooling wind for being easy to cooling blower to blow out is blown over out of heat dissipation channel, so as to take away in coil windings Radiating fin and radiating branch piece in the heat in portion, heat dissipation channel, further improve air-cooled rate of heat dispation.

4th, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, using air-cooled and circulation The mode of water cooling is combined, and further increases the heat dispersion of transformation.

Brief description of the drawings

A kind of inner side circulating cooling epoxy cast dry that Fig. 1 provides for first and second kind of embodiment of the utility model The structural representation of transformer；

Fig. 2 be Fig. 1 shown in a kind of inner side circulating cooling epoxy cast dry transformer in the circulatory system structural representation Figure；

A kind of inner side circulating cooling epoxy cast dry transformer that Fig. 3 provides for the utility model the first embodiment The structural representation of middle cooling tube and coil windings；

A kind of inner side circulating cooling epoxy cast dry transformer that Fig. 4 provides for second of embodiment of the utility model The structural representation of middle cooling tube and coil windings.

Embodiment

Below in conjunction with the drawings and specific embodiments, the utility model is further elaborated.It should be appreciated that herein Described specific embodiment only to explain the utility model, is not used to limit the utility model.

It is cold that Fig. 1 to Fig. 4 schematically shows that a kind of inner side provided according to two kinds of embodiments of the utility model is circulated But epoxy cast dry transformer.

Embodiment 1：

Fig. 1 to Fig. 3 schematically shows cold according to a kind of inner side circulation of the utility model the first embodiment offer But epoxy cast dry transformer.

As shown in figure 1, the utility model discloses circulating cooling epoxy cast dry transformer on the inside of one kind, including transformation Device body 20, transformer body 20 includes transformer framework 1, the iron-core workpiece 2 being located in transformer framework 1 and is set around iron core Coil windings 3 outside body 2.

As shown in figure 1, transformer framework 1 includes upper clamping piece 101 and lower clamping piece 102, upper clamping piece 101 and the table of lower clamping piece 102 Face is coated with corrosion protection layer, and corrosion-mitigation scale-inhibition processing is carried out to upper clamping piece 101 and lower clamping piece 102.

As shown in figure 1, iron-core workpiece 2 includes the stem 201 being vertically arranged and the connection that three high magnetic conduction silicon-steel sheet coiled is coiled into Upper yoke, the lower yoke of three upper and lower ends of stem 201, three stems 201, upper yoke and the yoke of lower iron 203 constitute a lying " day " font.Transformer framework 1 upper clamping piece 101 clamping upper yoke, lower clamping piece 102 clamping lower yoke, upper clamping piece 101 and under Folder 102 is bolted clamping respectively, and upper clamping piece 101 and lower clamping piece 102 are used to fasten iron-core workpiece 2 and coil windings 3.

As shown in figure 1, as preferred, some cushion blocks 15 are provided between the upper surface of upper clamping piece 101 and coil windings 3, Rubber packing 16 is lined between lower clamping piece 102 and iron-core workpiece 2 respectively, to mitigate the noise of transformer operationally, passes through upper folder Part 101, lower clamping piece 102 are tightened up, and some cushion blocks 15 securely fix three-phase coil winding 3, prevent coil windings 3 upper Under, left and right directions movement so that iron-core workpiece and coil windings 3 are not influenceed by external mechanical stress as far as possible.

As shown in figure 3, each coil windings 3 include high pressure winding 302 and low pressure winding 301.The low pressure winding 301 For the copper cash winding or copper foil winding being wound on outside the stem 201 of iron-core workpiece 2, as preferred, in this reality of the present utility model Apply in mode, low pressure winding 301 is copper foil winding；High pressure winding 301 be wound on enamel-cover flat type copper wire outside low pressure winding 301 around Group or high pressure copper foil winding.In the utility model this embodiment, a kind of inner side circulating cooling ring that the utility model is provided Coil windings 3 in oxygen casting dry type transformer can be divided into band filler cast-type coil windings and without material filling type coil windings, Wherein, with poured with epoxy resin of the filler cast-type coil windings using addition quartz powder filler, to promote transformer to radiate, together When, the high-tension coil with filler cast-type coil windings carries out reinforcement using fiberglass gridding；And poured without filler Note formula coil windings use not filled poured with epoxy resin, meanwhile, coil is strengthened using glass fabric.Either band is filled out Expect cast-type coil windings or without material filling type coil windings, make one firm entirety of every phase winding formation, so that transformation Utensil has mechanical strength, electrical strength height, the characteristic that overload capacity is strong, shelf depreciation is small, good reliability.In said structure, twine Fiberglass gridding or glass fabric in coiling winding have self extinguishment characteristics, and electric arc, therefore tool will not be produced because of short circuit There is fire-retardant, explosion-proof characteristic and coil is nonhygroscopic.

As shown in figure 1, each coil windings 3 are encapsulated with housing 31, the housing 31 and are equipped with for drawing lead Outlet terminal 311, the both sides of upper clamping piece 101 are respectively equipped with high-tension insulator 1011 and low tension insulator, (low-voltage insulation terminal figure Not shown in), the outlet of coil windings 3 is drawn after connection set Dyn11 connections from outlet terminal 311, is drawn from outlet terminal 311 The high-voltage connection of the high pressure winding gone out is connected with high-tension insulator 1011, low-voltage lead and low-voltage insulation that low pressure winding is drawn Son connection, facilitates terminal block, high-voltage connection and low-voltage lead are wrapped up by insulation tube.In high-pressure side, point of high pressure winding Joint 312 is exchanged by copper lug 313, facilitates pressure regulation.

As utility model point of the present utility model, as shown in Figure 1 to Figure 3, in one kind that the utility model is provided Side circulating cooling epoxy cast dry transformer also includes a coolant casing 4, and coolant casing 4 is fixed on transformer body 20 Side, as preferred, in the utility model this embodiment, in order to reduce the area occupied of transformer, coolant casing 4 is consolidated Due to the bottom of transformer body 20, i.e., as shown in figure 1, in the utility model this embodiment, the section of lower clamping piece 102 into " L " shape, including one be located at connecting portion 1021 on horizontal plane, coolant casing 4 is fixed under lower clamping piece 102 by bolt 1022 Side, is fixedly connected with the connecting portion 1021 of lower clamping piece 102.

As it is further preferred that as shown in Figure 1 to Figure 3, in the utility model this embodiment, in coil windings 3 Provided with cooling tube 402, the cooling tube 402 between two neighboring coil windings 3 is connected, cold in the coil windings 3 of both sides But pipe 402 is connected with the coolant casing 4 of the lower section of transformer body 20.I.e. as shown in Fig. 2 in this embodiment of the utility model In, one of them cooling tube 402 being located in the coil windings 3 in outside is connected by riser 401 with coolant casing 4, separately One cooling tube 402 being located in the coil windings 3 in outside is connected by pipeline 403 with coolant casing 4, wherein, riser 401 one end being passed through in coolant casing 4 are communicated with elevator pump 404.

As shown in figure 3, as preferred, in the utility model this embodiment, some use are also set up in coil windings 3 In the loop coil heat dissipation wind channel 32 of radiating, as shown in figure 3, heat dissipation wind channel 32 is axially arranged along coil windings 3, positioned at coil Between, it is encapsulated in coil windings 3.As shown in figure 3, cooling tube 402 is located at the wherein ring heat dissipation wind channel 32 in coil windings 3 It is interior, in the utility model this embodiment, it is located at cooling tube 402 in coil windings 3 in outermost heat dissipation wind channel 32 and is Example is illustrated.As preferred, in the utility model this embodiment, the curl of cooling tube 402 be wrapped in coil around In 3 outermost heat dissipation wind channels 32 of group, so as to extend cooling path, to improve cooling effect.Due in this reality of the utility model Apply in mode, the curl of cooling tube 402 is wrapped in coil windings 3, therefore, as shown in Fig. 2 riser 401 and wherein one The link position of cooling tube 402 in the individual coil windings 3 positioned at outside is located at the top of transformer body 20, i.e., positioned at the outside Coil windings 3 top, cooling tube 402 in this coil windings 3 centrally located coil windings 3 adjacent thereto The link position of middle cooling tube 402 is located at the lower section of transformer body 20, the i.e. bottom positioned at this two coil windings 3, equally, Cooling tube 402 is located at the cooling tube 402 in the coil windings 3 in outside with another in centrally located coil windings 3 Link position is located at the top of transformer body 20, the i.e. top positioned at this two coil windings 3, and cold in this coil windings 3 But the link position of pipe 402 and pipeline 403 is located at the lower section of transformer body 20, the i.e. bottom positioned at the coil windings 3, pipeline 403 connect with coolant casing 4.

In summary, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, by online Enclose and cooling tube 402 is set in winding 3, meanwhile, cooling tube 402 is connected with coolant casing 4, installing cooling in coolant casing 4 Liquid, coolant is realized in coolant casing 4 and the internal circulation flow of cooling tube 402 by elevator pump 404, thus take away coil around Heat in group, improves heat dispersion.In the utility model this embodiment, installing coolant is in coolant casing 4 Water or high-temperature insulation oil.

In addition, as shown in figure 3, in the utility model this embodiment, other are not provided with above-mentioned cooling in coil winding Supported in the heat dissipation wind channel 32 of pipe 402 by multi-disc radiating fin 321, radiating fin 321 is axially arranged along coil windings 3, Even distribution, and both sides are connected with the inwall of heat dissipation wind channel 32 respectively, the setting of heat dissipation wind channel 32 can improve the thermal diffusivity of transformer Can, while the setting of radiating fin 321 can further improve the heat dispersion of transformer, as it is further preferred that adjacent two Radiating fin 321 in ring heat dissipation wind channel 32 is staggered, not in the same plane, thus, heat dissipation channel is staggered, It is easy to heat diffusion, improves heat dispersion.As still more preferably, as shown in Figure 3 and Figure 4, each radiating fin 321 Upper some radiating branch pieces 3211 of connection, radiating branch piece 3211 is axially arranged along coil windings 3 and vertical with radiating fin 321, In this structure, radiating branch piece 3211 is further set to be easy to heat to be passed from the radiating transmission of branch piece 3211 on radiating fin 321 Pass, improve heat dispersion.Again cooling blower is additionally provided with as shown in figure 1, being located on transformer body 20 at the side of lower clamping piece 102 5, the air outlet of cooling blower 5 is towards coil windings 3, and cooling blower 5 is fixed on the top of coolant casing 4.Therefore, this practicality is new A kind of inner side circulating cooling epoxy cast dry transformer that type is provided, is combined by the way of air-cooled and recirculated water cooling, entered One step improves the heat dispersion of transformation.

Embodiment 2：

Fig. 1, Fig. 2 and Fig. 4 schematically show that providing a kind of inner side according to second of embodiment of the utility model follows Ring cools down epoxy cast dry transformer.

As depicted in figs. 1 and 2, the utility model provides a kind of inner side circulating cooling epoxy casting of this embodiment offer The structure of dry-type transformer with it is essentially identical in embodiment 1, its difference is, the structure of cooling tube 402.

As shown in figure 4, as preferred, in the utility model this embodiment, some use are also set up in coil windings 3 In the loop coil heat dissipation wind channel 32 of radiating, as shown in figure 3, heat dissipation wind channel 32 is axially arranged along coil windings 3, positioned at coil Between, it is encapsulated in coil windings 3.As shown in figure 3, cooling tube 402 is located at the wherein ring heat dissipation wind channel 32 in coil windings 3 It is interior, in the utility model this embodiment, it is located at cooling tube 402 in coil windings 3 in outermost heat dissipation wind channel 32 and is Example is illustrated.As preferred, in the utility model this embodiment, cooling tube 402 into roundabout shape be wrapped in coil around In 3 outermost heat dissipation wind channels 32 of group, i.e., as shown in figure 4, the in the vertical direction of cooling tube 402 is in downward roundabout mode back and forth It is surrounded in the outermost heat dissipation wind channel 32 of coil windings 3, so that further extension cooling path, to improve cooling effect.By In in the utility model this embodiment, the curl of cooling tube 402 is wrapped in coil windings 3, therefore, as shown in Fig. 2 The link position that riser 401 is located at the cooling tube 402 in the coil windings 3 in outside with one of them is located at transformer body 20 Cooling tube 402 in top, i.e., the top of the coil windings 3 on the outside of this, this coil windings 3 it is adjacent thereto be located at centre The link position of cooling tube 402 is located at the lower section of transformer body 20 in the coil windings 3 of position, i.e., positioned at this two coil windings 3 bottom, equally, cooling tube 402 is located at another in coil windings 3 in outside in centrally located coil windings 3 The link position of cooling tube 402 be located at the top of transformer body 20, the i.e. top positioned at this two coil windings 3, and this line The link position of the cooling tube 402 enclosed in winding 3 and pipeline 403 is located at the lower section of transformer body 20, i.e., positioned at the coil windings 3 bottom, pipeline 403 is connected with coolant casing 4.

In summary, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, by online Enclose and cooling tube 402 is set in winding 3, meanwhile, cooling tube 402 is connected with coolant casing 4, installing cooling in coolant casing 4 Liquid, coolant is realized in coolant casing 4 and the internal circulation flow of cooling tube 402 by elevator pump 404, thus take away coil around Heat in group, improves heat dispersion.In the utility model this embodiment, installing coolant is in coolant casing 4 Water or high-temperature insulation oil.In addition, a kind of inner side circulating cooling epoxy cast dry transformer that the utility model is provided, is used Air-cooled and recirculated water cooling mode is combined, and further increases the heat dispersion of transformation.

Preferred embodiment of the present utility model has shown and described in described above, as previously described, it should be understood that this practicality is new Type is not limited to form disclosed herein, is not to be taken as the exclusion to other embodiment, and available for various other groups Close, change and environment, and above-mentioned teaching or the technology of association area can be passed through in utility model contemplated scope described herein Or knowledge is modified.And the change and change that those skilled in the art are carried out do not depart from spirit and scope of the present utility model, then All should be in the protection domain of the utility model appended claims.

Claims (10)

1. a kind of inner side circulating cooling epoxy cast dry transformer, including transformer body (20), the transformer body (20) transformer framework (1), the iron-core workpiece (2) being located in the transformer framework (1) are included and located at the iron-core workpiece (2) Outer three-phase coil winding (3), the three-phase coil winding (3) is wrapped with housing (31), it is characterised in that the transformer It is provided with by body (20) between a coolant casing (4), three-phase coil winding (3) Inside coil and cooling tube is distributed with (402), the cooling tube (402) connects with the coolant casing (4).

2. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 1, it is characterised in that described cold But liquid case body (4) is below the transformer body (20), and the coolant casing (4) is fixedly connected with the skeleton (1).

3. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 1, it is characterised in that the line Enclose in winding (3) provided with some circular radiating air channels (32) for being used to radiate, the heat dissipation wind channel (32) is along the coil windings (3) it is axially arranged, through the coil windings (3).

4. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 3, it is characterised in that described cold But pipe (402) is uniformly surrounded in the coil windings (3) in one of them described circular radiating air channel (32).

5. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 4, it is characterised in that adjacent two Cooling tube (402) in the group coil windings (3) joins end to end, and is connected, the cooling in the coil windings (3) of both sides Pipe (402) is connected with the coolant casing (4) respectively.

6. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 5, it is characterised in that every group of institute The cooling tube (402) curl in coil windings (3) is stated uniformly to be surrounded in the heat dissipation wind channel (32).

7. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 5, it is characterised in that every group of institute The cooling tube (402) stated in coil windings (3) is surrounded in the heat dissipation wind channel (32) into roundabout shape.

8. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 7, it is characterised in that described cold But pipe (402) in the vertical direction is presented down back and forth roundabout mode and is surrounded in the heat dissipation wind channel (32), the cooling tube (402) it is overall to be located on vertical direction.

9. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 6 or 7, it is characterised in that its In one be located at the transformer body (20) on the outside of the coil windings (3) in cooling tube (402) pass through riser (401) connected with the coolant casing (4), described riser (401) one end is connected with the cooling tube (402), the other end It is passed through in the coolant casing (4), the riser (401) is located at the internal one end end of the coolant casing (4) and set Put elevator pump (404).

10. a kind of inner side circulating cooling epoxy cast dry transformer according to claim 9, it is characterised in that described Cooling blower (5) is set below transformer body (20), and the air outlet of the cooling blower (5) is towards the coil windings (3).