EP4150653A1

EP4150653A1 - Electric device with forced direct cooling

Info

Publication number: EP4150653A1
Application number: EP20754637.5A
Authority: EP
Inventors: Katharina SCHÄFER; David Weber; Viktor WINS; Christer Vogt; Aime Mbuy
Original assignee: Siemens Energy Global GmbH and Co KG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2020-07-23
Filing date: 2020-07-23
Publication date: 2023-03-22
Also published as: US20230268115A1; CN116134560A; WO2022017609A1

Abstract

The invention relates to an electric device (1) for connecting to a high voltage, comprising: - an active part which has a magnetizable core and at least one winding assembly (31), each winding assembly surrounding a core section of the core and having windings (29, 30) which are inductively coupled together, wherein cooling channels (28) (19) are formed in the windings, and - a tank (2) which is filled with an insulating fluid and in which the active part is completely arranged, - said tank (2) having at least one insulating fluid inlet (10) and at least one insulating fluid outlet (11) that are connected together via a circulating system (12) which is arranged outside of the tank (2) and which comprises a cooling unit (14) and a pump (13) for circulating the insulating fluid. The aim of the invention is to provide such an electric device with an improved cooling function. This is achieved in that each insulating fluid inlet (10) is connected to a distributing unit (18), which is arranged on one of the end faces of the winding assembly (31), via an insulating fluid line (19) extending in the tank (2), said distributing unit distributing cooled insulating fluid to the cooling channels (28).

Description

description

Electrical device with forced direct cooling

The invention relates to an electrical device for connection to a high voltage with an active part, which has a magnetizable core and at least one winding arrangement, each of which encloses a core section of the core and has windings that are inductively coupled to one another, with cooling channels being formed in the windings. a tank filled with an insulating fluid, in which the active part is completely arranged, the tank having at least one insulating fluid inlet and at least one insulating fluid outlet, which are connected to one another via a circulating system arranged outside the tank, which has a cooling unit and a pump for circulating the insulating fluid has.

Such an electrical device is already known from WO 2018/184775 A1. There, a traction transformer is shown, which has an active part and a tank in which the active part is completely arranged. The active part comprises a core with two core legs, each of which is enclosed by two windings arranged concentrically to one another. The tank has a central part that surrounds the outer contour of the windings in a form-complementary manner. The insulating fluid placed in the boiler for insulation and cooling is circulated through a cooling system.

WO 2016/038222A1 discloses a traction transformer with an active part and a tank, with the core of the active part being arranged entirely outside the tank. The railway transformer is attached to the rail vehicle via the core, so that no high forces are introduced into the boiler. The boiler can therefore be made of a lightweight material such as plastic. Railway transformers are designed to be mounted on a rail vehicle, such as a locomotive or railcar. They are used to provide a desired traction voltage for driving the locomotive or railcar depending on different input voltages. Previously known railway transformers have a metallic tank which is at ground potential and is filled with an insulating fluid, for example an ester fluid. The so-called active part of the transformer is arranged in the tank and comprises a core consisting of magnetizable flat sheets and at least two windings concentrically enclosing a section of the core. The boiler is equipped with bushings for connecting the transformer to a high voltage. As a rule, the insulating fluid is circulated via a cooling system arranged outside of the boiler.

The previously known electrical device has the disadvantage that due to the shape-complementary structure of the tank, the windings can no longer be adequately cooled, so that the insulating fluid heats up quickly during operation and the electrical device can only be operated at low power levels.

The object of the invention is therefore to provide an electrical device of the type mentioned in which the cooling treatment of the windings is improved.

The invention solves this problem in that the insulating fluid inlet is connected via an insulating fluid line extending in the tank to a distribution unit which is arranged on one of the end faces of the winding arrangement and which distributes cooled insulating fluid to the cooling channels.

According to the invention, cooled insulating fluid is no longer single Lich introduced into the boiler. Rather, within the scope of the invention, the cooled insulating fluid is guided directly to the cooling channels of the windings. For direct initiation the cooled insulating fluid into the cooling channels of the windings is used on the one hand by the insulating fluid line. This extends between the insulating fluid inlet and the distribution unit. The cooled insulating fluid is introduced into the tank of the electrical device at the insulating fluid inlet. Because of the insulating fluid line, mixing with the warmer insulating fluid in the boiler no longer occurs directly behind the insulating fluid inlet—as in the prior art. Rather, the entire cooled insulating fluid is routed directly to the distribution unit. Finally, the distribution unit ensures that the cooled insulating fluid is distributed evenly over the cooling channels in the windings. In this way, cooled insulating fluid is introduced directly into the cooling channels of the windings, which improves the cooling of the windings. Due to the improved cooling, the electrical device according to the invention can be operated at higher electrical power levels, for example with higher currents.

The insulating fluid line is advantageously a pipeline. A pipeline is easy to manufacture and is therefore available inexpensively in all variations on the market.

In a preferred variant of the invention, the distribution unit has a receiving unit, the front side of which faces the insulating fluid inlet and which has a through-opening designed to receive the outlet opening of the insulating fluid line, the rear side of the receiving unit being provided with at least one inner groove . According to this embodiment of the invention, the insulating fluid line opens into a through-opening of the receiving unit. The cooled insulating fluid thus flows from the insulating fluid inlet to the through-opening and from there gets into the or each inner groove on the rear side of the receiving unit. The inner groove or the inner grooves are used for the radial distribution of the insulating fluid. In a preferred embodiment, the grooves are ring-shaped and connected to the through-opening. According to the invention, the distribution unit is arranged on the end face of a winding arrangement facing the insulating fluid inlet. Due to the ring-shaped configuration, the distribution of the insulating fluid is adapted to the circular-cylindrical configuration of the windings, since the cooling channels extend through the windings in a uniformly distributed manner in the axial direction parallel to one another.

Advantageously, the distribution unit has a perforated plate lying against the rear of the receiving unit, which has through-holes and is equipped with spacers on its side facing away from the receiving unit. The spacers are radially sighted and point to a common center. They are at a constant distance from one another and are distributed over the entire circumference of the perforated plate. In other words, the spacers define pie-shaped spaces.

According to a further development in this regard, the perforated plate, the spacers and an outer sealing ring delimit partial cavities, which are each connected to at least one cooling channel. The insulating fluid is distributed radially through the grooves of the receiving unit and passes through the through-holes into one of the distribution cavities, which, as already stated above, resemble a piece of cake in their design. Each of these distribution cavities is arranged in the axial direction of the end face of the respective winding and limited the perforated plate. In the radial direction, the spacers delimit each distribution cavity, which is therefore closed off circumferentially on the outside and inside by a ring-shaped sealing ring. The spacers each extend in the radial direction, ie in the form of rays, on the rear side of the perforated plate. The insulating fluid flows from the distribution cavities, which are evenly supplied with cooled insulating fluid, into the cooling channels of the windings. The receiving unit and perforated plate are advantageously designed in the form of a disk. The disk-shaped design enables a compact design of the electrical device.

The distribution unit preferably has a circular outer contour in a plan view. In this way, the distributing unit is adapted to the shape of the winding arrangement on which the distributing unit is arranged within the scope of the invention.

In the context of the invention, windings of a winding arrangement are preferably arranged concentrically with one another. An outer winding of the winding arrangement is designed, for example, as a primary winding for higher voltages than a secondary winding arranged further inside, or vice versa. In addition to a primary and secondary winding, each winding arrangement can also have other windings such as, for example, an auxiliary operation winding, a step winding or the like.

The distribution unit is preferably made of an electrically non-conductive material. In this way, the electromagnetic properties of the electrical device according to the invention are not, or at least only slightly, influenced by the distribution unit.

The boiler preferably has two metallic end caps between which a central part made of an electrically non-conductive material extends. The central part is designed, for example, to complement the outer contour of the windings and is made from a lightweight material.

A lightweight material within the meaning of the present invention is any material with a lower intrinsic weight by a factor of 2 than steel. Steel has a density of 7.85-7.87 g/cm ³ . Materials with a density of less than 3.9 g/cm3 are lightweight materials within the meaning of the invention. Examples of such lightweight materials are aluminum, plastics and fiber reinforced plastics. Preferably, the middle mainly made of glass fiber reinforced plastic with a density of 2.5 g/cm3.

In a preferred variant of the invention, the core has two core limbs running parallel to one another, which are each surrounded by a winding arrangement, the core limbs being connected to one another by a lower and an upper yoke. In this way, a closed circuit is formed. In this variant of the invention, two winding arrangements are therefore provided with, for example, a total of four windings, with two windings being arranged concentrically to one another and enclosing a common leg of the core as the core section. This is, for example, an inner low-voltage winding and a high-voltage winding enclosing the low-voltage winding. The core also has a further leg, which is also enclosed by a low-voltage or high-voltage winding. The two low-voltage and high-voltage windings are connected in series, for example. The core limbs, which each extend through one of the two winding arrangements, are therefore aligned in parallel with one another. The inner wall of the central part of the boiler follows the outer contour of the outer windings of the respective winding arrangement in its entirety.

Of course, three or more legs can also be provided within the scope of the invention, each leg being equipped with a winding arrangement which consists of two or more windings.

Advantageously, the end caps are also adapted to the active part sections that are arranged in their inner volume. According to this further development of the invention, the tank also nestles outside of its central part, at least in its inner configuration, not only to the outer contour of the outer windings. Rather, the boiler is also complementary in shape to other sections of the active part designed, which also define the outer contour of the active part.

The upper and lower yoke, together with the respective press frame, define the outer contour of the active part, which is not defined by the windings. While the windings generally define a cylindrical outer contour, the remaining outer contour of the active part deviates considerably from this. The shape-complementary adaptation of the shell to this somewhat more complex outer contour is therefore limited to forming a box-shaped envelope. By this is meant that the shell does not replicate every screw or bolt in its design, but replicates the entire section with a box-shaped and partially rounded contour. This box-shaped contour then delimits an interior space that allows the said active part sections to be accommodated in a stress-resistant manner, but at the same time limits the interior volume of the boiler to a minimum.

The end caps are advantageously made of a metal or a metal alloy. It is particularly preferred that the end caps are made of steel. Steel has high mechanical strength.

The end caps are expediently designed in each case in the form of a box. A box-shaped design can be done as standard. An adaptation to the respective individually manufactured active part is not required in this variant of the inventions. In this way, further costs can be saved.

Advantageously, at least one end hood has a viewing window and/or a hand opening. According to this further development of the invention, the electrical device can be easily manufactured and maintained.

The electrical device is preferably a railway transformer. A magnetizable material is understood here to be a ferromagnetic material such as iron. Within the scope of the invention, the core preferably forms a closed iron circuit.

Further advantageous refinements and advantages of the inventions are the subject of the following description of exemplary embodiments of the invention with reference to the figures of the drawing, where the same reference symbols refer to components that have the same effect and where the

Figure 1 shows an embodiment of the electrical device according to the invention in a perspective view,

FIG. 2 shows the electrical device according to FIG. 1 without the circulation system and support frame,

FIG. 3 shows the electrical device according to FIG. 2 with an indicated insulating fluid line,

Figure 4 and 5 front and back of a receiving unit of a distribution unit in a perspective view,

FIG. 6 shows the rear side of a perforated plate in a perspective view,

FIG. 7 shows the end face of a winding arrangement in a plan view and

FIG. 8 illustrates an exemplary embodiment of a distribution unit in a side view.

Figure 1 shows an embodiment of the electrical device 1 in a perspective view, the electrical device shown there is designed as a railway transformer 1. The traction transformer 1 has a boiler 2, which consists of a central part 3 and two end caps 4 and 5. The end caps 4 and 5 are made of steel, while the central part 3 is made of a glass fiber reinforced plastic. An active part, not shown in the figure, is arranged in the boiler 2, the boiler being filled with an insulating fluid. The active part includes a Magnetizable iron core, which has two core legs that are connected to one another via an upper and lower yoke. Each core leg is surrounded by a winding arrangement, each winding arrangement consisting of an inner low-voltage winding and an outer high-voltage winding. The winding arrangement also includes an auxiliary winding. The upper, lower and auxiliary windings are arranged as an axial extension of the low-voltage winding concentrically to one another and to the core limb, which protrudes through these windings on the inside.

The central part 3 forms two housing tubes 6 and 7, each of which encloses one of the winding arrangements. The lower and upper yokes are located in the upper 4 and lower end hood 5, respectively. An input bushing 8 serves to connect the high-voltage windings, which are connected in parallel to one another, to the high-voltage contact wire. The low-voltage winding is connected to cable connection sockets 9 on the output side. The desired traction voltage can be tapped off by inserting suitable cable plugs into the respective cable connection socket 9 .

The end hood 4 has two insulating fluid inlets 10 , whereas the end hood 5 is equipped with an insulating fluid outlet 11 . Finally, a circulation system 12 can be seen that, in addition to a pump 13, includes a cooling unit 14 that is equipped with a heat exchanger for cooling the circulated insulating fluid. The circulation system 12 also has pipelines 15. With the aid of the circulation system 12, heated insulating fluid is sucked out of the insulating fluid outlet 11 and fed to the heat exchanger of the cooling unit 14 via the pipelines 15. From there, the cooled insulating fluid reaches the insulating fluid inlets 10 in order to be reintroduced into the boiler 2 there. The railway transformer 1 also has a support frame 16 for mounting on a rail vehicle, which does not need to be discussed in more detail at this point.

FIG. 2 shows the boiler 2 of the electrical device according to FIG. 1 in a perspective representation, the circulation system and the support frame having been omitted for the sake of a better overview. The end hood 4 with the insulating fluid inlet 10 can be seen in the foreground, while the end hood 5 with the insulating fluid outlet 11 is shown in the background. It can be seen that the end caps 5 are equipped with hand holes 17, which facilitate the assembly and maintenance of the traction transformer 1.

Since the central part 3 is made of a light-weight material and two tubes 6 and 7 fit closely to the winding assemblies, less insulating fluid is required to completely fill the tank. Due to the reduced volume of insulating fluid, this reaches critical temperature ranges more quickly during operation and constant cooling.

For this reason, the cooling of the windings has been improved within the scope of the invention.

FIG. 3 shows the boiler according to FIG. 2, but with the means for the improved cooling being indicated. An insulating fluid line 19 thus extends between each insulating fluid inlet 10 and a distribution unit 18. With the aid of the insulating fluid line 19, which is tubular, the cooled insulating fluid introduced into the insulating fluid inlet 10 is guided directly to the distribution unit 18, so that it no longer comes into contact with the mixed in the inner end hood 4 arranged warm insulating fluid. The distribution unit 18 is arranged on the end face of the winding arrangement, which faces the insulating fluid inlet 10 in each case. In this case, the distribution unit is ring-shaped when viewed from above, so that it covers the entire end face of the winding arrangement. The distribution unit 18 has a receiving unit 20, which is shown in FIG. 4 from the front and in FIG. 5 from the rear. It can be seen that the front side is flat, with a through hole 21 being visible, which is used to accommodate the outlet orifice of the connecting line 19 . In this way, the inflowing cooled insulating fluid passes through the through hole 21 to the back of the receiving unit 20, which is equipped with an inner 23 and outer 22 annular groove. Both grooves 22 and 23 open into the receiving opening 21 so that the insulating fluid flowing in is guided through the grooves 22 and 23 .

The rear side of the receiving unit 20 shown in FIG. 5 bears against the front side of a perforated disk 24, which is shown from the rear in FIG. The perforated disk 24 is equipped with through holes 25, which allow the passage of insulating fluid from the grooves 22, 23 of the receiving unit 20 into distribution cavities 26, which is delimited in the axial direction by the perforated disk 24 and by the end face of the winding arrangement, not shown. The distribution cavities 26 are laterally delimited by spacers 27 which are aligned radially or radially and form distribution cavities 26 similar to a piece of pie. An outer boundary ring, not shown in the figures, and an inner boundary ring, also not shown in the figures, ensure that insulating fluid is prevented from escaping in the radial direction inwards or outwards from the distribution cavities 26 .

FIG. 7 shows the end face of a winding arrangement 31 in a top view, the end face shown facing away from the distribution unit 18 . The winding arrangement 31 has an inner low-voltage winding 29, which is extended in the axial direction by an auxiliary operating winding, and an outer high-voltage winding 30 arranged concentrically with the low-voltage winding. It can be seen that the layers of the respective winding 29 and 30 are not wound directly on top of each other, but are spaced from each other. This is done by wrapping so-called winding bars, which are not shown in the figure.

The strips ensure the radial spacing of the winding layers that is necessary there, so that cooling channels 28 are formed between the winding layers and the strips. Because of the cooling channels 28, the rear side of the perforated disk 24, which is arranged on the other end face of the winding arrangement 31, including its spacers 27 and its through hole 25, can be seen. It can thus be understood that cooled insulating fluid penetrating into the distribution cavities 26 flows through the cooling channels 28 of the windings and thus ensures improved cooling of the windings 29 and 30 .

FIG. 8 shows the end of the winding arrangement 31 facing the distribution unit 18 and the distribution unit 18 itself. The distribution unit 18 is shown partially in section. First of all, the receiving unit 20 can be seen, which has an inner groove 23 and an outer groove 22 on its rear side, which—as already explained—are both connected to the receiving opening, which is not shown in FIG. The perforated disk 24 which delimits the grooves 22 and 23 can also be seen. The perforated disk 24 is equipped with through openings, not shown in the figure, which allow the insulating fluid to pass from the grooves 22, 23 into the distributor cavity 26, which are delimited on the one hand by the perforated disk 24 and on the other hand by the end face of the winding arrangement. In order to prevent insulating fluid from escaping from the distributor cavities 26, an outer sealing ring 32 and an inner sealing ring 33 can be seen, which ensure that the cooled insulating fluid from the distributor cavities 26 reaches the cooling channels 28 of the windings.

Claims

patent claims

1. Electrical device (1) for connection to a high voltage with an active part, which has a magnetizable core and at least one winding arrangement (31), which in each case encloses a core section of the core and has windings (29, 30) inductively coupled to one another, wherein cooling channels (28) (19) are formed in the windings, a tank (2) filled with an insulating fluid, in which the active part is completely arranged, the tank (2) having at least one insulating liquid inlet (10) and at least one insulating liquid outlet (11 ) which are connected to each other via a circulation system (12) arranged outside the boiler (2) and comprising a cooling unit (14) and a pump (13) for circulating the insulating fluid, characterized in that each insulating liquid inlet (10) has a in the boiler (2) extending insulating fluid line (19) arranged on one of the end faces of the winding arrangement (31). Distribution unit (18) is connected, which distributes the cooled insulating fluid to the cooling channels (28).

2. Electrical device (1) according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the insulating fluid line is a pipeline (19).

3. Electrical device (1) according to claim 1 or 2, characterized in that the distribution unit (18) has a receiving unit (20), the front side of which faces the or one of the insulating fluid inlets (10) and which has a through-opening (21) which is set up to receive the outlet orifice of the insulating fluid line (19), the rear side of the receiving unit (20) being provided with internal grooves (22, 23). 4. Electrical device (1) according to claim 3, characterized in that the grooves (22, 23) are annular and are connected to the through-opening (21).

5. Electrical device (1) according to claim 3 or 4, characterized in that the distribution unit (18) has a rear side of the receiving unit (20) abutting perforated plate (24), which has through holes (25) and on its from the Recording unit (20) side facing away with spacers

(27) is equipped.

6. Electrical device (1) according to claim 5, d a d u r c h g e k e n n z e i c h n e t that the perforated plate (24), the spacers (27) and an outer sealing ring (33) delimit distribution cavities (26), which are each connected to at least one cooling channel (28).

7. Electrical device (1) according to claim 6, d a d u r c h g e k e n n z e i c h n e t that the receiving unit (20) and perforated plate (24) are designed disc-shaped.

8. Electrical device (1) according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that

Distribution unit (18) has a circular outer contour in a plan view.

9. Electrical device (1) according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that

Distribution unit (18) is made of an electrically non-conductive material.

10. Electrical device (1) according to one of the preceding claims, characterized in that the boiler (2) and two metallic end hoods (4, 5), between which a central part (3) extends from an electrically non-conductive material.