WO2002023562A1

WO2002023562A1 - Device for recording the operating temperature of a winding

Info

Publication number: WO2002023562A1
Application number: PCT/DE2001/003417
Authority: WO
Inventors: Fritz Sorg; Herbert Ritter
Original assignee: Siemens Aktiengesellschaft
Priority date: 2000-09-15
Filing date: 2001-08-30
Publication date: 2002-03-21
Also published as: DE10046522C1

Abstract

The invention relates to a device for recording the operating temperature of a winding (4A, 35),comprising a temperature sensor (12), arranged outside the winding (4A, 35) and in a flow channel (3, 3a, 3C, 3D) running through the winding (4A, 35) and which is exposed to the operating temperature. According to the invention, in order to record the operating temperature of the winding (4A, 35) with a comparatively higher precision, the flow channel (3, 3a, 3C, 3D) is formed from a closed tube (38), which makes contact with the winding (4A, 35).

Description

description

Device for detecting the operating temperature of a winding

The invention relates to a device for detecting the operating temperature of a winding with a temperature sensor which is arranged outside the winding in a flow channel which is exposed to the operating temperature and runs through the winding.

Such a device is known from the article "Less stressful", electrical engineering 71, S8, 30.11.1989, pages 60 to 65. A transformer is described there, which is arranged with its winding and the core in the interior of a boiler which is sealed off from the outside. The interior is filled with an insulating gas, which also serves to cool the windings, so-called cooling elements are provided on the outside of the boiler, which are designed for the insulating gas to flow through them and via an opening located in their upper area and an opening provided in their lower area During the operation of the transformer, a natural gas circulation of the insulating gas from the interior into the cooling elements and back into the interior occurs. In this way, the insulating gas is heated by the winding of the transformer, thereby rising in the interior of the boiler and passing through the upper one Opening in the cooling element, is cooled in the cooling element, sinks as a result, it descends in the cooling element and, when cooled, enters the interior through the lower opening. In this respect, it can be said that the insulating gas is conducted in a flow channel, which is formed by the interior and a cooling element. In an experimental arrangement with the transformer, temperature sensors are provided in the winding as well as below and above the same to detect the operating temperature of the winding. To support the gas circulation can a blower can also be provided with which the insulating gas is set into a corresponding flow.

In the case of a high-voltage dry transformer from Siemens AG, type AC 20 / LI40, another device for recording the operating temperature is obviously used. It is intended to detect the operating temperature of an undervoltage winding of the dry-type transformer. Said undervoltage winding of the dry-type transformer has two coaxial windings which are spaced apart from one another by an annular channel. The ring channel is designed for the flow of cooling air. The operating temperature is recorded with a temperature sensor. In order not to influence the electrical properties, in particular the partial discharge resistance, of the windings, the temperature sensor must not touch the windings or be arranged in the ring channel. A flow channel designed as a tube is therefore introduced into the ring channel, which emerges from the end of the ring channel and projects beyond the two windings and is open there. The

Temperature sensor in turn is arranged in the flow channel at a point above the windings. In the ring channel, the flow channel lies against the walls of the two windings and is therefore exposed to the respective operating temperature of the windings. During operation, the air in the flow duct heats up and rises to the temperature sensor, at which the temperature of the air is recorded. This recorded temperature enables a statement to be made about the operating temperature of the windings. The flow channel is also open at its lower end lying in the ring channel, so that it can be flowed through. The upper section of the flow channel, which protrudes beyond the windings, is exposed to air movements and in particular drafts, which can enter the flow channel at the upper end.

From the German patent application DE 38 17 280 AI a coil winding is provided with an insulation known electrical conductor, which has a groove along its longitudinal direction, in which an optical waveguide is arranged and thereby runs along the conductor. A coil winding is formed with the electrical conductor; the optical fiber is used for distributed temperature measurement along the winding.

From the German patent DE 42 43 090 Cl a slat-like spacer is known, with which turns of an electrical coil are spaced from each other in such a way that cooling channels are formed between the spacers and the turns for the flow of a coolant. The spacer elements have a cooling surface which is enlarged by appropriate shaping. A sensor, in particular an optical fiber sensor, for detecting the temperature can be provided in such a spacer element.

From German utility model auxiliary application 1 980 288, a winding combination with two coaxially spaced, radially spaced windings is known, which are cast with casting resin. A pipe running in the axial direction is provided between the two windings and is also cast into the winding in such a way that a cooling medium can flow through it.

From the German translation of the European patent DE 689 20 530 T2 a device for temperature detection in a microwave oven is known; there steam is released into a circuit by heating a food in a heating chamber via a flow channel. A temperature sensor for detecting the steam temperature is provided in the flow channel and a blower motor is also provided for forcing a steam flow through the flow channel. The object of the invention is to provide a device of the first-mentioned type, in which the operating temperature can be determined with comparatively high accuracy.

The object is achieved according to the invention in a device of the type mentioned at the outset in that the flow channel is formed by a self-contained hose which bears against the winding.

Characterized in that the flow channel is formed with a hose which is self-contained and lies against the winding, the heat transport medium present in the hose is brought to the temperature of the winding and is guided separately from the cooling air used for cooling and is therefore largely unaffected by this. The temperature of the heat transport medium is therefore determined almost exclusively by the temperature of the winding and is little influenced by the temperature outside the hose. Therefore, with the temperature sensor arranged in the hose, the operating temperature can be detected much more precisely than in the prior art, because the temperature sensor there is directly exposed to the cooling gas. In addition, the hose forms a simple and inexpensive means of forming the flow channel.

The invention also relates to a device for detecting the operating temperature of a winding, which has a coil and a further one which has a coil which leaves an annular channel, by means of a temperature sensor which is arranged outside the winding in a flow channel exposed to the operating temperature. which is guided between the coils and is self-contained.

Such a device is also known from the article already mentioned at the beginning. The winding of the transformer already described above has two coils, which are one inside the other and leave an annular channel are arranged. The ring channel is designed to flow through with the insulating gas; to this extent the flow channel described above is also guided between the two coils.

The object of the invention is also to provide a device of the type described, in which the operating temperature can be determined with comparatively high accuracy.

The object is achieved according to the invention in a device of the aforementioned type in that the flow channel is formed with a partial channel separated from the annular channel and with an outer channel piece which is guided outside the winding and is connected in each case to the end exits of the partial channel.

In this embodiment, the flow channel likewise forms a flow path for the heat transport medium, which is separated from the actual cooling channel lying outside the partial channel through the remaining ring channel. The

The temperature sensor does not come into contact with the cooling medium in the cooling channel, but only detects the temperature of the heat transport medium that corresponds to the winding temperature. The temperature measurement is therefore almost unaffected by the cooling medium, so that it is comparatively more accurate.

The winding is preferably part of a cast resin or dry-type transformer.

The temperature sensor can be assigned at various points outside the winding in the closed flow channel, for example it can be located below the winding. The temperature sensor is preferably arranged above the winding. This is a particularly short path for the heat transport medium present in the flow channel, such as. B. Air, from the winding to the temperature sensor, since the heated heat transfer medium naturally rises. The device according to the invention works flawlessly solely using convection. In a preferred embodiment of the invention, means for forcing a flow are provided in the flow channel. This ensures the flow within the flow channel and the flow channel can be guided in any way.

According to a further preferred embodiment, the flow channel is thermally insulated outside the winding. This further reduces thermal influence on the temperature sensor by environmental factors. An even lower thermal influence can be achieved in that the flow channel is also thermally insulated inside the ring channel where it comes into contact with cooling air present in the ring channel.

To further explain the invention, exemplary embodiments of the device according to the invention are shown in the figures. Corresponding parts are provided with the same reference numerals.

1 shows a vertical section through a winding arrangement with a winding with a flow channel,

FIG. 2 shows a cross section along the line II-II according to FIG. 1,

FIG. 3 shows a cross section through a further winding arrangement with a modified flow channel,

Figure 4 is a vertical section through a three-phase

Another version of a transformer with a winding with a flow channel

5 shows a vertical section through a winding arrangement with a flow channel in a fourth embodiment and 6 shows a vertical section through a winding with a flow channel passed through it.

FIG. 1 shows a winding arrangement 1 which extends along a winding axis 2. For the sake of clarity, the winding arrangement 1 is only shown on the right side of the winding axis 2. The winding arrangement 1 is formed by an high-voltage winding 4 and a winding 4A with coils 5 to 8, which represents an undervoltage winding. The high-voltage winding 4 and the coils 5 to 8 are each arranged upright. The coils 5 and 7 are arranged one above the other and surrounded by the coils 6 and 8 arranged one above the other while leaving an annular channel 9 (see FIG. 2). During operation, the high-voltage winding 4 and the winding 4A heat up and assume a respective operating temperature depending on the electrical load. The operating temperature of the winding 4A is exposed to the section 10 of a flow channel 3 which is carried out between the coils 5 and 6 or 7 and 8 and which is closed in itself. In section 10, the flow channel 3 lies against the coils 5 to 8 in order to achieve good heat transfer from the coils 5 to 8 into the fluid in the flow channel 3. The fluid located in the flow channel 3 is heated in the section 10 of the flow channel 3 and thereby starts to move, as indicated by the arrows 11. To record the temperature of the fluid, a temperature sensor 12 is arranged above the winding arrangement 1 in the flow channel 3, the connections of which are led through the wall 13 of the flow channel 3. On the basis of the temperature of the fluid detected by the temperature sensor 12, the

Operating temperature of the winding 4A or the coils 5 to 8 are closed. Characterized in that the flow channel 3 is self-contained, the detection of the respective operating temperature by external influences, such as. B. draft, which is indicated by arrows 14, unaffected. As a result, the operating temperature of the winding 4A can be determined with high accuracy from the temperature detected by the temperature sensor 12. be determined. For example, air or oil is suitable as the fluid. Of course, further temperature sensors for detecting the temperature of the fluid can be provided in addition to the one temperature sensor 12.

In order to reduce an impairment of the measurement by thermal influences from outside the flow channel 3 on the temperature sensor 12 or the fluid, the flow channel 3 is outside the coils 5 and 6 or 7 and 8, in particular above the winding arrangement 1, with a thermal Insulation 15 provided so that the fluid experiences almost no change in temperature, at least on the way from the coils 5 and 6 to the temperature sensor 12. The flow channel 3 can also be thermally insulated within the ring channel 9 where it is in contact with cooling air flowing in the ring channel 9 (see also FIG. 2). Thermal insulation of the flow channel can also be achieved in that the flow channel is double-walled. At the points where good heat transfer is to be given, the two walls of such a double-walled flow channel lie directly against one another, whereas at the points where high thermal insulation is desired, a space is provided between the two walls, which can be filled with air, for example. Such a double-walled flow channel can be realized, for example, with two hoses running into one another - also referred to as a "hose in hose" solution.

It can be clearly seen in FIG. 2 that the flow channel 3 has an almost circular cross section and runs in the annular channel 9 lying between the coils 5 and 6 or 7 and 8. The area remaining in the flow channel 3 outside the flow channel 3 can be flowed through, for example, for cooling the windings 5 and 6.

In the exemplary embodiment according to FIG. 3, the flow channel 3A differs from the flow channel 3 according to the FIG. guren 1 and 2 in that it is formed between the coils 5 and 6, or 7 and 8 as a sub-channel 16 of the ring channel 9. The subchannel 16 is divided between the coils 5 and 6 or the delimiting elements 17 and 18 arranged not visible coils 7 and 8. The sub-channel 16 is connected to an outer channel piece 16A to form the closed flow channel 3A at its end-side outlets from the winding arrangement 1, which are not shown in detail.

In Figure 4, three winding arrangements 1, 19 and 20 are shown schematically. Each of the winding arrangements 1, 19 and 20 is assigned to a phase of a three-phase transformer. The winding arrangements 1, 19 and 20 each extend along an assigned axis 2, 21 and 22 and are only shown on the left-hand side of their respective axes 2, 21 and 22, respectively. Each of the winding arrangements 1, 19 and 20 has a structure corresponding to the winding arrangement 1 according to FIG. 1 with the high-voltage windings 4, 23 and 24 and the windings 4A, 23A and 24A formed from the coils 5 to 8 or 25 to 28 or 29 up to 32. A flow channel 3C is here guided through all three windings 4A, 23A and 24A, the flow channel 3C being guided through the windings 23A and 24A in the ring channel 9 of the winding 4A and the ring channels corresponding to the ring channel 9. As a result, it is exposed to the operating temperatures of the windings 4A, 23A and 24A of all three winding arrangements 1, 19 and 20. The flow channel 3C is likewise closed here, with part of the flow channel 3C being indicated by a dashed center line 33. The temperature sensor 12 is arranged above the central winding arrangement 1 to the flow channel 3C.

In the section of the flow duct 3C lying between the winding arrangements 19 and 1, a blower 34 is provided to force a flow of the fluid present in the flow duct 3. Depending on the choice of the fluid, a pump can also be provided instead of a blower 34. By means of the blower In the flow channel 3, as indicated by the arrows 11, a circular flow is forced, so that heat given off by the coils 5 to 8 and 25 to 32 is transported to the temperature sensor 12. On the basis of the temperature recorded with it, the thermal load on the windings 4A, 23A and 24A can be concluded. The temperature sensor 12 is arranged above the middle winding arrangement 1, since the coils 4 to 8 of this winding arrangement 1 heat up more because of their middle position between the two outer winding arrangements 19 and 20. Outside the coils 5 to 8 and 25 to 32, the flow channel 3 is provided with the thermal insulation 15 at least in sections. The flow channel 3 can also be thermally insulated in the ring channels of the windings 4A, 23A and 24A at those points where it comes into contact with cooling air flowing in each of these ring channels.

In FIG. 5, in contrast to the flow channel 3 according to FIG. 1, the flow channel 3D shown in FIG. 5 is guided through the ring channel 9 with two sections 10 and 35. The flow channel 3D is thus exposed to the operating temperature of the coils 5 to 8 over a greater length than the flow channel 3 according to FIG. 1. This guidance of the flow channel 3D results in smaller external dimensions than in the winding arrangement 1 with the flow channel 3D according to the figure 1. A fan 34 is provided below the coils 7 and 8 in the flow channel 3D in order to force a flow of the fluid (direction of the arrows 11) in the flow channel 3D. Here, too, the flow channel 3D is provided with thermal insulation 15 outside the coils 5 to 8.

FIG. 6 shows a winding 35 which extends along a winding axis 36. A channel 37 leads through the winding 35, which either itself forms part of the self-contained flow channel 3 or through which the flow channel 3 is passed. The temperature sensor 12 can be seen in the flow channel 3 above the winding 35. Version of the operating temperature of the winding 35 is provided. The flow channel 3 is designed here as a hose 38.

The winding arrangements 1, 19 and 20 shown in the figures can in particular be provided as winding arrangements for a cast resin transformer or dry type transformer. For this purpose, the individual windings are insulated with cast resin.

Claims

claims

1. Device for detecting the operating temperature of a winding (4A, 35) with a temperature sensor (12) which is outside the winding (4A, 35) and in a flow channel (3, 35) which is exposed to the operating temperature and runs through the winding (4A, 35). 3a, 3C, 3D), characterized in that the flow channel (3,3a, 3C, 3D) is formed by a self-contained hose (38) which bears against the winding (4A, 35).

2. Device for detecting the operating temperature of a winding (4A, 35), which has a coil (6) and another, which has a coil (5) surrounding it while leaving an annular channel (9), by means of a temperature sensor (12) which is outside the winding (4A, 35) and in a flow channel (3,3A, 3C, 3D) exposed to the operating temperature, which is guided between the coils (5,6) and is self-contained, characterized in that the flow channel (3rd , 3A, 3B, 3C) is formed with a partial channel (16) separated from the ring channel (9) and with an outer channel piece (16A) which is guided outside the winding (4A) and is each connected to the end exits of the partial channel (16).

3. Apparatus according to claim 2, d a d u r c h g e k e n n z e i c h n e t that the winding (4A, 35) is part of a cast resin or dry type transformer.

4. Device according to one of the preceding claims 1 to 3, characterized in that the temperature sensor (12) above the winding (4A, 35) is arranged.

5. Device according to one of the preceding claims, that means that means (34) for forcing a flow are provided in the flow channel (3,3A, 3C, 3D).

6. Device 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 the flow channel (3,3A, 3C, 3D) outside the winding (4A, 35) is thermally insulated.