EP3494584A1

EP3494584A1 - Electrical device having a plurality of cooling units

Info

Publication number: EP3494584A1
Application number: EP17772346.7A
Authority: EP
Inventors: Jörg FINDEISEN
Original assignee: Siemens AG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2016-10-06
Filing date: 2017-09-15
Publication date: 2019-06-12
Anticipated expiration: 2037-09-15
Also published as: US11322287B2; EP3494584B1; WO2018065189A1; DE102016219406A1; US20190318862A1

Abstract

The aim of the invention is to create an electrical device (1) for connecting to a high-voltage network, having a vessel (14), which is filled with an insulating fluid (30), an active part, which is arranged in the vessel (14) and which has a magnetizable core (2) and partial windings (3.1, 3.2) for producing a magnetic field in the core (2), and a cooling apparatus (15) for cooling the insulating fluid (30), which electrical device is economical and at the same time can be operated at higher temperatures. This aim is achieved, according to the invention, by means of at least one thermal barrier (4), which delimits cooling spaces, in each of which at least one partial winding (3.1, 3.2) is arranged, the cooling apparatus (15) having at least two cooling units and each cooling unit being designed to cool an associated partial winding (3.1, 3.2).

Description

description

The invention relates to an electrical device for connection to a high-voltage network with a vessel which is filled with an insulating fluid, an active part arranged in the vessel, which has a magnetizable core and partial windings for generating a magnetic field in the core , and a cooling device for cooling the insulating fluid.

Such an electrical device is known in the art. Thus, for example, transformers or reactors, which are connected to a high voltage network, each a vessel, which is usually with a mineral insulating oil as

Insulating fluid is filled. In a transformer, an undervoltage and a high-voltage winding are arranged in the vessel ^¬ , which are inductively coupled together via a magnetizable core. The insulating fluid is used in addition to the insulation of the windings and for cooling the transformer. For this purpose which is in operation heated insulating oil led to ^¬ From result of heat via an externally attached to the vessel cooling device ^¬. The cooling is adjusted so that ei ^¬ ne maximum temperature of the insulating fluid is not exceeded, otherwise the solid insulation of the transformer could be damaged.

Increasingly, alternative insulating fluids, such as ester or silicone oils, are used in transformers that have higher temperature resistance. These alternative insulating fluids ensure greater fire safety and are also biodegradable. Improved environmental compatibility ^¬ friendliness of Isolierfluiden is required in particular for offshore applications. Due to the improved thermal resistance of these alternative insulating fluids, the transformer can be operated at higher temperatures. In this connection reference is made to the standard IEEE 1276 (1997). In addition to the conventional, so currently predominantly ^¬ set, insulation systems and materials so-called high-temperature insulation for electrical equipment are known. These are however expensive. For this reason, so-called hybrid solutions have been proposed, in which both high-temperature materials and conventional materials were used as Isolie ^¬ tion. For example, the barrier ^¬ system of isolation in a conventional insulation materials, while the coil conductor isolated by high-temperature materials. The hybrid solutions, however, have the disadvantage that, despite the use of costly high-temperature insulation materials, the operating temperature of the insulating fluid, due to the still used conventional insulating materials, is significantly below the temperature that would be possible with the exclusive use of high-temperature insulation materials.

The object of the invention is therefore to provide an electrical device of the type mentioned, which is inexpensive and can be operated at the same time at higher temperatures.

The invention achieves this object by at least one ther- mal barrier, the cooling spaces bounded in each of which a part winding is arranged we ^¬ nigstens, wherein the Kühlein ^¬ direction has at least two cooling units each cooling unit is adapted for cooling an associated part of the winding.

According to the invention a thermal barrier in conjunction ^¬ game having at least two cooling units ensures that at least two partial windings may be operated in different temperature portions that are referred to herein as refrigerator temperatures. The thermal barrier provides for the formation of at least two cold rooms, which are connected to one of the cooling units. The cooling units can thus be combined within the scope of the invention in the NEN cooling rooms different cold room temperatures, ie different temperatures of the insulating fluid and / or the windings set. The cooling chamber temperature is expediently set such that a maximum operating temperature predetermined for this cooling chamber is not exceeded. In this way it is possible to use different insulating materials in the cold rooms. In addition, for example, the partial winding, which is arranged in a cold room, which allows higher refrigerator temperatures, be designed lierstoffarm.

In the context of the invention, there are advantages when a partial winding is arranged in the cooling space in which set higher refrigerator temperatures during normal operation, which is designed for lower operating voltages. Here, for example, the use of Netzdrilleiterwicklungen possible.

Furthermore, coated with various insulating lacquer copper wires that can withstand even high temperatures available on the market. This also applies, for example, to a wire with a coating of Pyre-ML-polyimide, which is thermally stable up to 220 ° C. Due to the small thickness of its lacquer layer, good heat dissipation of the wire to the insulating fluid is ensured.

Other partial windings, which are arranged in a cold room in which the insulating fluid has a lower cold room temperature, however, are expediently equipped with the usual conventional, that is not high-temperature resistant Teilwicklungsisolierungen or barrier systems.

In the context of the invention, the material of the insulating material is advantageously selected as a function of the position of the respective insulation with respect to the so-called hot spot of the winding. A hotspot temperature is the hottest temperature of the solid dielectric or insulating fluid in thermally conductive contact during operation of the electrical device standing electrical conductor of the partial winding. Thus, for example, the conductor insulation is selected so that the material is not damaged even when reaching the hot spot temperature. In other words, the conductor insulation can withstand the maximum winding temperature. Solid insulation with a certain distance to the hottest points of the respective partial winding, however, can, if the corresponding temperature gradient permits, be assigned to a lower thermal class.

In the context of the invention, the cooling device has at least two cooling units, wherein each cooling unit is set up for cooling ei ^¬ nes associated cooling space. By the A ^¬ set of two cooling units one of the cooling units can examples game, via supply and discharge lines to a partial winding are connected in such a way that the cooled by a cooling unit isolator fluid is circulated selectively through a ^full-¬ selected part winding and in the refrigerator for the adjustment of the required refrigerator temperature ensures.

Since different vertical distances to the yoke of the ker ^¬ nes are required due to the different voltages of the partial windings, the layered Wick ^¬ ment substructure can be used for targeted delivery of the insulating fluid to the selected sub-winding. The Isolierstoffscheiben the substructure are expediently so out ^¬ leads that a separation of the flow of the insulating fluid is provided to the respective partial windings. Due to the separation of the flow of the Isolierfluides through the cooling space, the cooling circuits can be separated fluidically ^¬ fully continuously, or partially share a common space. This space can each lie upstream or downstream of the cooling chambers in terms of flow.

Advantageously, the thermal barrier forms a ^¬ A passage opening, which is connected to an output of the cooling device. This connection or in other words the connection between the respective cooling unit and the inlet opening can be configured as desired within the scope of the invention. It is essential that the main part of the insulating fluid flow emerging from the respective cooling unit reaches the inlet opening.

Further advantages brings with it when the Eintrittsöff ^¬ voltage is formed by a thermal barrier that ei ^¬ NEN cooling chamber at least partially defined, in which a top is disposed voltage winding. The high-voltage winding is equipped due to the higher voltage with a more complex insulation. To use conventional materials for said isolation there, the upper voltage ^¬ development must be cooled more than the development Unterspannungswick- that is with Hochtemperarturwerkstoffen isolated.

In the context of the invention, the fluid-filled cooling spaces separated from each other by the barrier system are expediently connected hydraulically to one another. This connection can be made via the connection to a common expansion vessel used by both cold rooms, or by a partially open design of winding substructures or winding superstructures. According to a related further development of the thermal barrier encloses a partial winding at least portion as ^¬. The thermal barrier is, for example hohlzylind ^¬ driven constructed and arranged concentrically to at least one part ^¬ development. According to this advantageous further development, the thermal barrier forms a guide or, in other words, cooling channels for the insulating fluid flow, so that the insulating fluid is conducted over the partial winding. The cooling channels can be designed meandering. According to an expedient further development, the thermal barrier is at least partially also an electrical barrier. Conveniently, the first partial winding an underlay ^¬ voltage winding and a second partial winding is a high-voltage winding. The two windings are concentric with one another and, for example, also arranged to a core section extending through the inner low-voltage winding. In other words, the electrical device ge ^¬ Mäss this embodiment of the invention is a transformer with concentric upper and lower voltage windings as part windings. The partial windings are advantageously out as circumferentially closed cylindrical windings out ^¬ .

According to a related variant, a first cooling unit for cooling the low-voltage winding and a second cooling unit for cooling the high-voltage winding are set up. As already stated, it is expedient here for the cooling device to act on the high-voltage winding with colder insulating fluid, so that it can be operated at lower temperatures. The low-voltage winding and the high-voltage winding are then in turn equipped with different insulating materials as partial winding insulation, which can withstand the different Kühlraumtempera ^¬ acids.

In principle, the cooling chambers are hydraulically coupled to one another within the scope of the invention. According to an advantageous variant of this is the cooling chamber, in which the high-voltage winding is arranged, connected with the cooling space in which the low-voltage winding is disposed about an expansion vessel hyd ^¬ raulisch each other.

According to a variant, a cooling unit is designed as a closed circulating cooling system in which a pump to circulate the order ^¬ isolator is provided. A second Kühlein ^¬ integrated is connected to the interior of the vessel, wherein the first cooling unit and the interior of the electrical device are connected to each other only via an expansion vessel. According to this variant, a hydraulic connection of the Cooling rooms exclusively via the expansion tank instead, which is mandatory anyway due to the temperature-dependent volume expansion of the insulating fluid. Advantageously, the gaps between the individual barriers and between the winding and the vessel, which are not required for cooling or for guiding the insulating fluid, can be closed by means of inserts to avoid bypasses.

As already stated, it is advantageous within the scope of the invention that the cooling device has a feed ^¬ circuit which forms a part below the first winding and in particular below the high-voltage winding angeord- designated exit opening. According to this variant, the cooled insulating fluid exits the cooling device via the supply line and is introduced directly into the cooling space of the first part winding, so that the first part winding is cooled more than the other part windings, the first part winding in the flow direction of

Isolating fluids are arranged downstream.

Advantageously, at least one cooling unit is connected to the winding substructure and / or winding superstructure of a sub-winding such that the flows of the insulating fluid guided in each case via the cooling units during normal operation are separated from one another.

Expediently, each cooling unit has at least one cooling register. The term cooling register should also include radiators here. At least one or each cooling unit may be a passive cooling unit or may include a recirculation pump for circulating the insulating fluid over a cooling register. The cooling coil can be equipped with one or more fans or fans.

According to a further variant, the cooling registers are connected to the vessel of the electrical appliance in such a way that these have different vertical distances to a defined by the bottom ^¬ surface of the vessel bottom surface. With ^{¬ on} their words, the cooling coils are mounted at different heights on the vessel. In the case of further development, the cooling units are passive cooling units and have no circulating pump. In the case of passive cooling units, the circulation rate of the insulating fluid via the cooling register, among other influencing variables, is determined by the height offset between the center of the hot fluid column in the cooling passages of the respective part winding and the center of the cold fluid column of the respective cooling register. Since the partial windings are supported on the lower yoke of the core and thus have ei ^¬ NEN fixed distance from the ground, this dependence, the circulation rate of said height difference even with the help of the distance of the respective cooling coil are described to the bottom plane defined by the bottom the vessel is defined.

According to a preferred embodiment, the Teilwicklun- gene different insulation. Thus, beispielswei ^¬ se a first partial winding a high-temperature insulation, while a second partial winding and all other partial windings have customary insulation of materials which are designed for lower temperatures. The term "isolation" here also includes barrier systems and Abstandshal ^¬ ter, which are used in addition to the insulation of the winding conductor.

Further components of the electrical device, for example tap changers, are assigned to one of the two cooling circuits flowing through the cooling chambers in accordance with their respective permissible operating temperature.

Advantageously, the cooling device has a control unit with temperature sensors, wherein the temperature sensors for detecting the temperature of a partial winding and / or for detecting the temperature of the insulating fluid are arranged in a partial winding. The control unit is included For example, for each cooling unit with a threshold from ^¬ equipped, so that the cooling capacity of the respective cooling unit is controllable in dependence of the respective threshold value. The respective threshold is depending on the temperature resistance of the insulating materials of the partial windings be ^¬ true. Detected by the temperature sensors temperature reaches the threshold value, the control unit controls ent ^¬ either a circulation pump or a fan of the respective cooling unit and thus increases the cooling capacity of said cooling unit.

The temperature sensors are set up to detect the temperature of a partial winding and / or to detect the temperature of the insulating fluid. The temperature sensors can therefore also detect the temperature of the winding conductor directly within the scope of the invention.

According to another variant, at least one Teilwick ^¬ ment has a plurality of temperature ranges in which insulating materials of different thermal capacity are arranged. This may be advantageous when insulating materials with lower thermal resistance are arranged in each upstream Temperarturbereich than in downstream temperature ^¬ turbereichen that reciprocates in the direction of flow of the Isolierfluide ter are the upstream temperature range.

In an expedient further development, a temperature sensor for measuring a hot-spot temperature is arranged in at least two temperature ranges, which on the output side provides temperature readings which are compared with a predetermined threshold value depending on the insulators used in the respective temperature range, based on this comparison Control signal is generated. Depending on the design, this can trigger a warning signal, cause the shutdown, trigger a reduction in the load of the electrical device or be used to control the cooling system. According to the invention, the operation at higher temperatures he ^¬ allows, with a costly conversion, for example, the insulating material-rich winding parts of a high-voltage winding ^¬ can be omitted on Hochtemperaturisolierwerkstoffe. In addition, a higher current density in the winding conductors and thus a significant reduction in size are possible. An increase in the temperature of the insulating fluid leads in the context of the invention to a significant increase in the temperature difference to the outer cooling medium such as air or water. Thus, the Effek ^¬ tivity of the cooling increases considerably, so that the electrical device according to the invention can be made more compact.

Arising due to the high viscosity of Isolierfluiden to ester and silicone base further aerodynamic and cooling technical advantages when operating at higher Tem ^¬ tures. It is an optimization of losses for normal load, mög ^¬ Lich at providing a high overload latitude.

For certain applications, the high temperature spread of the insulating fluid enables the effective use of external evaporative coolers and radiators based on heat pipes.

Advantageously, a plurality of fluidly connected temperature ranges in the cooling chamber with sensors to measure the hot spot temperature of the winding element are fitted in the respective temperature range, wherein the signals of each of these temperature sensors each have their own thresholds for triggering control functions are assigned to which the thermi ^¬ specific class of each in the Temperature ranges of the partial winding used insulating materials are matched. Further expedient refinements and advantages of the inven ^¬ tion are the subject of the following description of embodiments of the invention with reference to the figures the drawing, wherein like reference numerals refer to like-acting components and wherein

Figures 1 to 7 show different Ausführungsbeispie- le of the electrical device according to the invention in a partially ge ^¬ cut side view schema ^¬ table. Figure 1 shows a first embodiment of the fiction, ^¬ contemporary electrical device 1 in a sectional side view, wherein the electrical device is performed as a transformer 1 ^¬ . The transformer 1 has a vessel 14 in which a magnetizable core 2, a low-voltage winding 3.1 and a high-voltage winding 3.2 are each arranged as a partial winding in the context of the invention concentric with each other. The said windings 3.1, 3.2 are designed hollow cylinder ^¬ . The high-voltage winding 3.2 can be connected to a high-voltage network via a connection, which is not shown in the FIGURE, wherein the low-voltage winding 3.1 can be connected to a distribution network or a load via a connection line, likewise not shown. The upper and lower voltage winding 3.1, 3.2 are inductively coupled to each other via the magnetizable core 2, so that the high-voltage winding 3.2 in the low-voltage winding 3.1 induces a voltage or vice versa.

The vessel 14 is provided with an isolator 30 and filled in the vorlie ^¬ constricting case a commercially available ester. A thermal barrier 4 is arranged between the high-voltage winding 3.2 and the low-voltage winding 3.1. The thermal barrier 4 is circumferentially closed and also formed as a hollow cylinder. They also encloses the zy ^{¬-cylindrical} low-voltage winding 3.1 completely. Above the vessel 14, an expansion vessel 18 is arranged, which serves to accommodate the temperature-induced volume fluctuations of the insulating fluid 30. For cooling the partial windings 3.1 and 3.2, a cooling device is provided which has two cooling units, wherein a first cooling unit has a cooling register 15.1, a Umpälzpum ^¬ PE 16.1 and a temperature sensor 22.1, a supply line 37.1 and a return line 38.1. The second cooling unit has a cooling register 15.2, a circulation pump 16.2, a temperature sensor 22.2, a supply line 37.2 and a return line 38.2. The supply line 37.1 has an outlet opening 32, which is arranged below the radially inwardly located lower voltage winding 3.1. An inlet opening of the return line 38.1 is connected directly to a winding superstructure 9.1 of the winding 3.1. The winding superstructure 9.1 is fluidically sealed, this means that the flow of the insulating fluid 30 is guided by the winding ^{superstructure} . The return line 38.1 is connected via a connecting line with the expansion vessel 18, which in turn ^{¬ is} connected via a second connecting line to the interior of the vessel 14 of the transformer 1. The supply line 37.2 of the second cooling unit opens with its

Outlet opening directly in the side wall of the vessel 14. The return line 38.2 is connected near the top of the vessel. By the inner wall of the thermal barrier 4 thus a first cooling space is limited, in which the lower voltage winding 3.1 is arranged. The outer wall of the thermal barrier ^¬ 4 limits together with the vessel 14 a second cooling space in which the high-voltage winding is 3.2. According to the exemplary embodiment illustrated in FIG. 1, the insulating fluid 30 cooled by the first cooling unit 15.1, 16.1, 37.1, 38.1 is led directly to the low-voltage winding 3.1 via the sealed winding substructure 8.1 and from there directly to the cooling register 15.1. In this exemplary embodiment, the hydraulic coupling of the cooling chambers takes place only via the expansion vessel 18. Different cooling chamber temperatures are set in the cooling chambers. The

Insulations are adapted to these refrigerator temperatures. The temperature sensors 22.1 and 22.2 are each connected to a control unit not shown figuratively via a signal line. Detected by the temperature sensors 22.1 and 22.2 temperature of the isolator fluid 30 exceeds a previously set for the respective partial winding 3.1 or 3.2 threshold, the control unit increases the output of the circulating pump and thus the performance of the jeweili ^¬ gen cooling unit. The threshold values were determined as a function of the thermal class of the insulating materials of the respective partial windings.

FIG. 2 shows an exemplary embodiment of the electrical device 1 according to the invention, in which the hydraulic coupling of the cooling circuits takes place via the upwardly open winding superstructures 9.1, 9.2 of the partial windings 3.1, 3.2. It comes above the partial windings 3.1 and 3.2 to a mixture of the insulating fluid 30. In each of a partial winding 3.1, 3.2 associated cooling units, the insulating fluid 30 is cooled differently. Thus, in the cooling circuit for the part winding 3.2 whose winding conductors are equipped with a complex high-voltage insulation, a higher cooling costs be ^¬ driven. In other words, the insulating fluid 30 is cooled to a lower temperature. The cooling space of the partial winding 3.1, and the core 2 are included in the cooling circuit formed over the radiator 15.2.

The partial winding 3.1 with lower requirements for their dielectric strength, which thus has a small proportion of insulating materials compared to the other partial winding, is equipped with an insulation of a higher thermal class and can thus be operated at a higher temperature. The equipment of this part winding with high temperature insulation materials requires little cost. In the context of the invention, it is expedient to operate partial windings with a comparatively low dielectric strength at a higher temperature than the partial windings with a high dielectric strength. The design of the core 2 to higher temperatures requires only a very small effort, since no moldings are required and an electric field stress must not be taken into account. Accordingly, the core 2 is just ^¬ if exposed to higher operating temperatures.

The supply of cooled in separate cooling units insulating fluid 30 to the partial windings 3.1 and 3.2 via the winding substructure 8.1, 8.2 of the respective partial winding 3.1 or. 3.2.

The respective layered winding substructure 8.1, 8.2 is used for separate supply of the insulating fluid 30 to the separated by the thermal barrier part windings

3.1, 3.2 used. The not shown here in detail Iso ^¬ lierstoffScheiben of the respective winding substructure 8.1, 8.2 are designed such that a separation of the flow of the isolator 30 is provided to the respective partial windings 3.1 and 3.2.

To decouple the fluid flows, the winding substructures 8.1 and 8.2 are sealed against each other. Furthermore, at least one connecting line 37.1 is provided, which extends between the cooling unit 15.1, 16.1 and the winding substructure 8.2, so that the flow of the cooled insulating fluid is sealed relative to the interior of the vessel 14. In the exemplary embodiment, the cooling coil 15.1 is connected via a pipe 37.1 directly to the winding substructure 8.2.

In the exemplary embodiment, the spaces 40 not required for cooling or for guiding the insulating fluid 30 between the partial windings 3.2 and the vessel 14 are closed by means of supplements 11.2 in order to avoid bypasses.

FIG. 3 shows a further exemplary embodiment of the invention with two cooling chambers separated by the thermal barrier 4. men. The thermal barrier 4 comprises cylindrical Abschnit ^¬ te 4.1 and 4.2 and a partition 4.5. In the illustrated exporting ^¬ approximately example, the thermal barrier 4 made of a thermally insulating material causes thermal and fluidic decoupling of lie radially outside ^¬ part winding 3.2 of the inner part winding 3.1, and the core 2 of the transformer 1. The decoupling is in other words by the separation of Isolierfluidströme both cooling circuits by means of the thermal barrier 4 achieved.

In the illustrated embodiment, an electric Barrie ^¬ re 7 is integrated as a section in the barrier 4. For thermi ^¬ isolation of the Isolierfluidströmung the winding base 8.2 of the partial winding 3.2 is fluidically connected to the feed line 37.2 which of the outside

Vessel arranged radiator register 15.2 of the second cooling unit leads. The radially inner part of the winding 3.1 and the cooling channels of the core 2 are open to the fluid space of the vessel 14. Furthermore, the supply conduit 37.1 of the first cooling register 15.1 is connected at a level below the lower edge of the partial winding ^¬ 3.1 with the vessel fourteenth The inner part-winding 3.1, and the core 2 are thus fed by "free" so not guided flow with chilled iso ^¬ lierfluid 30th Each sub-winding not only has a winding base 8.1 or 8.2 over a Wick ^¬ lung superstructure 9.1, 9.2. Each winding superstructure 9.1 and 9.2 is open to the fluid space of the vessel 14. Through the openings of their winding superstructure 9.1, 9.2 in the embodiment, both cooling chambers on the inside of the vessel so the fluid space of the vessel 14 are hydraulically connected to each other.

To accommodate the thermally induced volume fluctuations of the insulating fluid 30, the interior of the vessel 14 and thus both cooling chambers are connected to the expansion vessel 18. Within the said fluid spaces of the transformer 1 there is a thermal stratification of the insulating fluid 30 due to the temperature dependence of the density of the insulating fluid 30. This thermal stratification is characterized by a high viscosity. reinforced insulating fluid used 30 and the very low flow rates in the large cross-section. In the specific embodiment, this effect is used for thermal separation of the two cooling circuits. For this purpose, the arrangement of the terminal according to the invention

Return line 38.2 to the cooling coil 15.2 below the connection of the return line 38.1 to the cooling coil 15.1. In order to avoid a thorough mixing of the different degrees heated iso-lierfluids 30, a further section 4.5 of the thermal barrier 4 is provided in the usually open area above the windings. This section 4.5 projects beyond the electrical barrier 7. In the ^exemplary embodiment, the vertical distance H5 from the upper edge of the section 4.5 of the thermal barrier 4 to the return line 38.2 is a multiple of the flow limiting

Diameter of the return line 38.2. This prevents that significantly higher tempered insulating fluid 30, wel ^¬ Ches has passed through the low-voltage winding 3.1, enters the return line 38.2.

In order to avoid the formation of bypasses, potential unwanted flow channels 10.5, for example, between ^sections 7.5 of the barrier system 4 and the electrical barrier 7 are completely or partially closed at one of their ends by inserts made of insulating material.

In the illustrated embodiment, the partial windings form 3.1 and 3.2 vertically superposed inside refrigerators temperature ranges 5.1, 5.2, 5.3 or 6.1, 6.2, which are equipped with electrical insulation from insulating materials having a different of Temperaturbe ^¬ rich to temperature range thermal Be ^¬ bearing capacity exhibit. Thus, the thermal load capacity of the insulating materials in the temperature range 5.1, which is first flowed through by the insulating fluid 30, is lower than the insulating materials of the downstream temperature ranges. In addition, at least partially insulating materials can also be rather thermal classes are used. Thus, the thermal capacity of an insulating material may be lower, if it adheres to the hottest point of the temperature range so ^¬ example, to a certain winding position the necessary distance. Thus, for example within a temperature range 5.1 a gradation of thermal class take place, depending on whether the insulating material is used as a conductor Isola ^¬ tion, spacers, or potential control ring barrier.

This arrangement is applicable to a variety of insulating materials and there ^¬ with different temperature ranges. An exemplary assignment of the thermal classes to the temperature ranges shown in the exemplary embodiment is given below. In the embodiment, an insulating fluid based on an ester is used.

Design example for a winding arrangement according to FIG. 3 (thermal classes of insulating materials according to EN 60085: 2008)

The term "spacer" is intended here to encompass radial and axial spacers, such as, for example, strips, riders, intermediate layers or the like The term "barrier system" is intended to include barriers, angle rings, caps, disks, insulating cylinders or the like.

The staggering of the thermal performance of insulating materials can also be carried out within the thermal classes according to EN 60085, there are a variety of possibilities, for example, a staggering in differences smaller than 10K is possible. Furthermore, the hot points of the Tem ^¬ ranges shown are equipped with thermal sensors 25.1, 25.2, 25.3, 26.1, 26.2, which are each connected to a not illustrated figuratively control unit in the embodiment. In the exemplary embodiment, a sensor 27, 28 for measuring the maximum temperature of the insulating liquid 30 is further arranged in the region of the respective outlet opening in the winding superstructure 9.1 or 9.2.

Thus, in FIG. 3, five temperature ranges 5.1, 5.2, 5.3, 6.1, 6.2 are provided, each of which is equipped with isolating materials of 3 different thermal classes. This results in different permissible maximum temperatures for each temperature range. The insulating liquid 30 may not reach the permissible for the isolator maximum temperature ^¬ structure in the front is arranged in the flow path of temperature ranges ^¬ chen, otherwise the temperature gradient of the winding to the isolator 30 is too low in the perfused subsequently winding portions for adequate cooling.

Since, as described, the permissible temperatures are different in the different temperature ranges, it makes sense to separately monitor the temperatures in the temperature ranges. Therefore, in the embodiment, the hot points of all temperature ranges with thermal sensors equipped kitchens ^¬ tet and signals a control unit are supplied. Each of ^these signals is assigned a threshold value adapted to the thermal class of the insulating materials of the corresponding winding area. Exceeds one of the temperature signals ^¬ its associated threshold value is generated Steuersig ^¬ nal. Depending on the design, this can trigger a warning signal, cause the shutdown, trigger a reduction in the load of the electrical device or be used to control the cooling system. Preferably, the signal of each temperature sensor 25.1, 25.2, 25.3, 26.1, 26.2, various threshold values for Kühlan ^¬ attitude control, alarm and tripping be assigned. 4 shows a further exemplary embodiment in which a cooling unit is designed as an active cooling unit and has a circulating pump 16.2, while the other cooling unit is a passive cooling unit 15.1, in which the insulating fluid 30 circulates over the cooling register 15.1 due to a temperature difference that occurs becomes.

In the exemplary embodiment shown, the winding 3.2 with the higher high-voltage requirements, that is to say the winding with a high proportion of insulating materials and insulating parts to be produced in a complex manner, is forcedly cooled by the active cooling unit 15.2, 16.2. The partial winding 3.2 is again enclosed by cylindrical sections 4.1 of the thermal barrier 4. The supply of the cooled insulating fluid 30 takes place via the fluidically sealed winding substructure 8.2 which is connected via the supply line 37.2 to the cooling unit 15.2 and the pump 16.2.

The vessel 14 is further connected to the cooling register 15.1. The more cooled part winding 3.2 is provided with insulating materials of a low thermal class. Since the operation of a shown Transformtors 1 large differences in the temperatures of the insulating fluid 30 set inside and outside the thermal barrier 4, are additional

Barrier sections 4.6 provided that avoid fluid flow directly to the wall of the barrier 4.2 and thus reduce the thermal influence of the partial winding 3.2. In the exemplary embodiment, the barrier ^{sections 4, 4 are} provided with electrical inserts and angle rings directly following the barriers, which prevent fluid flow within the channel between the barriers.

In this embodiment, only the partial winding 3.1 two temperature ranges 5.1 and 5.2. With regard to the Temperature ranges, the statements apply to Figure 6 here accordingly.

Figure 5 illustrates an embodiment of a transformer 1 with natural cooling (ONAN cooling). Here, the movement of the insulating liquid is caused by thermal buoyancy. The windings of the part 3.1, 3.2 iso- heated lierfluid 30 rises due to its lower density compared ^¬ over the insulating liquid 30 of the wider area of the winding and will be replaced by incoming cold Angle Iso ^¬ lierflüssigkeit 30th The difference in weight between the warm liquid column in the winding channels and the colder liquid column in the cooling register 15.1 or 15.2 creates a pressure difference which serves as a driving force for the fluid circuit. In addition, a higher geometric arrangement of the cold insulating fluid column of the cooling ^¬ registers leads to an increase in the coolant flow driving pressure difference. This effect is used in the embodiment to supply a winding 3.1 with an increased pressure and thus a higher volume flow of the insulating liquid. For this purpose, the cooling coil 15.1, wel ^¬ ches the winding 3.1 supplied with cooled insulating fluid, arranged at a greater distance from the center of the winding 3.1, as the cooling coil 15.2, which is provided to supply the part winding 3.2 and the core 2.

This height offset is described here - on the basis of the fixed distance of the partial winding to a bottom plane defined by the bottom of the vessel - by the distance between the respective cooling register and said bottom plane. These different altitudes are therefore considered here as a vertical distance Hl, H2 of the respective cooling register 15.1, 15.2 to the ground plane, which is defined by the bottom of the vessel 14.

Hl is greater than H2. Since both partial windings 3.1 and 3.2 are supported on the lower yoke of the core 4, their centers are approximately the same height. As a result, the distance between the center of the first radiator 15.1 and the center of the first winding 3.1 is greater than the distance between the center of the second radiator 15.2 and the middle of the second winding 3.2. If this driving force is too high, then due to the flow resistance in the winding, there is a strong secondary flow of the insulating fluid 30 between the partial winding and the vessel wall of the transformer 1, which lowers the effectiveness of the cooling. In order to avoid this, in the exemplary embodiment, the supply of the cooled insulating fluid 30 to the winding 3.1 connected to the higher-level cooling unit 15.1 is effected via the winding substructure 8.1 fluidically sealed for this purpose. Thus, the Isolierfluidströmung is adapted to the different operating temperatures of the two partial windings and their different flow resistance.

The cooling registers 15.1 and / or 15.2 can be equipped with fans in the context of the invention.

Figure 6 shows a further embodiment of the OF INVENTION ^¬ to the invention the electric appliance 1, which then differs from that shown in Figure 5 embodiment in that the cooling coils are equipped with fans or blowers 17 15.1 and 15.2. In this case, the cooling register 15. 1 and the cooling register 15. 2 have a different number of fans 17. In addition, the cooling coils are 15.1 and 15.2 at the same height. The supply line 37.1 of the first cooling unit is located just below the first partial winding 3.1, that is, the low-voltage winding. The thermal barrier 4 extends in contrast to the embodiments shown in Figures 1 to 5 to the upper wall of the vessel 14, wherein the return line 38.1 the cooling space inside the thermal barrier 4 with the cooling coil

15.1 connects. Therefore, the first cooling unit forms again ei ^¬ NEN closed circulating cooling circuit, wherein the hyd ^¬ raulische coupling between the first cooling chamber and the two th refrigerator, which is defined by the outer wall of the thermal barrier 4 and the inner wall of the vessel 14, via the expansion vessel 18 takes place. For this purpose, the corresponding connecting lines are provided.

Since in the exemplary embodiment, the thermal and flow ^¬ technical separation of the windings also continues above the windings, both cold rooms are each equipped with its own Buchholz relay 20 to monitor gas accumulation in both cold rooms.

As the load on the transformer 1 increases, the temperatures in both partial windings 3.1, 3.2 increase differently and are initially cooled without fan assistance (ONAN cooling). The fans 17 are switched on or controlled differently for each cooling circuit at different temperatures for both subsystems.

In the exemplary embodiment, the cooling unit for the cooling chamber with the partial winding which is equipped with insulating materials of a lower thermal class, already switched at ei ^¬ ner lower temperature fan operation, as the cooler for the partial winding with insulating materials of a higher thermal class. To operate both partial windings at full load, the cooling register has

15.2 compared to the cooling register 15.2 over a larger number of fans 17th

Figure 7 shows a further embodiment of the invention of the electrical device 1 according to the invention, which substantially corresponds to the embodiment of Figure 1, but wherein the cooling units 15.1 and 15.2 are each designed as passive cooling units, so that the cooling units depending Weil ^¬ no circulating pump.

Other not shown here components of the electrical device 1, for example, tap changer, are accordingly their respective permissible operating temperature assigned to one of the two refrigerated rooms.

Claims

claims

1. Electrical device (1) for connection to a high voltage ^¬ network with

a vessel (14) filled with an insulating fluid (30),

an active part arranged in the vessel (14), comprising a magnetizable core (2) and partial windings (3.1, 3.2) for generating a magnetic field in the core (2), and cooling means (15) for cooling the insulating fluid (30 )

marked by

be ^¬ adjacent at least a thermal barrier (4), the cooling spaces, is disposed in each of which at least one partial winding (3.1, 3.2), wherein the cooling means (15) Wenig ^¬ least has two cooling units and (each cooling unit for cooling an associated component winding 3.1 , 3.2) is set up.

2. Electrical device (1) according to claim 1,

d a d u r c h e c e n c i n e s that

the thermal barrier (4) forms at least one inlet opening, which is connected to an outlet of the cooling device (15).

3. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the thermal barrier (4) encloses a partial winding at least in sections.

4. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the thermal barrier (4) is at least partially an electrical barrier.

5. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the first part winding is a low voltage winding (3.1) and a second part winding is a high voltage winding (3.2), the windings (3.1, 3.2) being concentric with each other and to a core portion (2) extending through the inner low voltage winding.

6. Electrical device (1) according to claim 5,

d a d u r c h e c e n c i n e s that

a first cooling unit (15.1, 16.1) for cooling the underlay ^¬ voltage winding (3.1) and a second cooling unit (15.2, 16.2) for cooling the high-voltage winding (3.2) are arranged.

7. Electrical device (1) according to claim 6,

d a d u r c h e c e n c i n e s that

the cooling space, in which the high-voltage winding is arranged, is hydraulically coupled via an expansion vessel to the cooling space in which the low-voltage winding is arranged.

8. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

at least one cooling unit (15.1, 16.1) with the Wicklungsun ^¬ window construction (8.1, 8.2) and / or winding superstructure (9.1, 9.2) ei ^¬ ner part winding (3.1, 3.2) such that each have in normal operation the cooling units (15.1, 16.1) guided flows of the insulating fluid (30) are separated from each other.

9. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

each cooling unit (15) has a cooling register (15.1, 15.2).

10. Electrical device (1) according to claim 9, characterized in that

the cooling registers (15.1, 15.2) have different perpendicular ^{ab ¬} stände (Hl, H2) to a through a bottom surface of the vessel (14) defined bottom plane (35).

11. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the partial windings (3.1, 3.2) have different partial winding insulation.

12. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the cooling device has a control unit with Temperatursen ^¬ sensors, wherein the temperature sensors for detecting the temperature of a partial winding and / or for detecting the temperature of the insulating fluid are arranged in a partial winding.

13. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

at least one partial winding temperature ranges (5.1, 5.2, 5.3), in which insulating materials of different thermal capacity are arranged.

14. Electrical device (1) according to claim 13,

d a d u r c h e c e n c i n e s that

in at least two temperature ranges (5.1, 5.2, 5.3) are each a temperature sensor for measuring a hot punk temperature is disposed, which provides the output side temperature readings ready ^¬, which are compared with a predetermined function of the insulating materials used in the respective temperature range threshold value, on the basis of the ^¬ ses comparison, a control signal is generated.

15. Electrical device (1) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

several fluidically connected temperature ranges (5.1, 5.2, 5.3) in the refrigerator with sensors (25.1, 25.2, 25.3) for measuring the hot spot temperature of the partial winding (3.1, 3.2) in the respective temperature range (5.1, 5.2, 5.3) are equipped and the signals of each of these Temperature sensors are each assigned their own threshold values for triggering control functions which are matched to the thermal class of the insulating materials used in the respective temperature ranges (5.1, 5.2, 5.3) of the part winding (3.1, 3.2).

16. Electrical device according to one of the preceding Ansprü ^¬ che,

d a d u r c h e c e n c i n e s that

each of the fluidically and thermally separated part windings (3.1, 3.2) via its own sensors for temperature monitoring of the winding temperature (25.3, 26.2) and / or

Sensors (27, 28) for measuring the maximum Isolierfluidtem- temperature in the thermally separated cooling chambers of the windings (3.1, 3.2) has and the sensors are connected to a control unit, which with means for monitoring the compliance of the different for each cooling chamber permissible Temperatures of the windings (3.1, 3.2) and / or the insulating fluid 30 and for independent control of the respective cooling chamber associated cooling units (15.1, 15.2) is provided.