WO2008043389A1

WO2008043389A1 - Transformer for an ocean current power station

Info

Publication number: WO2008043389A1
Application number: PCT/EP2006/067124
Authority: WO
Inventors: Peter Glasser; Gerhard Wruss
Original assignee: Siemens Transformers Austria Gmbh & Co Kg
Priority date: 2006-10-06
Filing date: 2006-10-06
Publication date: 2008-04-17

Abstract

Electric transformer (1,19) in a transformer tank (2) with electric contacts and an outer shell (3) enclosing the transformer tank (2), filled with a coolant (4). The coolant (4) in the outer shell (3) can be cooled by a cooling system (20) and coupled to further components (21) in the cooling system (20). The transformer (1,19) is particularly suitable for use (10) in ocean current and tidal power stations.

Description

Transformer for ocean current power plant

Transformer, in particular for use under water in a hydro-electric plant, e.g. a sea current power plant.

The invention relates to an electrical transformer in a transformer tank, and with an outer shell surrounding the transformer tank, wherein the space between transformer tank and outer shell is filled with a liquid cooling medium.

The invention further relates to an arrangement for cooling an electrical transformer.

International Patent Application WO 99/63555 discloses an underwater transformer. In this submersible transformer, an electrical transformer is arranged in an oil-filled transformer tank and its electrical connections are led out via provided on the transformer tank contact terminals from the transformer tank. The transformer tank is located inside an outside boiler that is completely filled with transformer oil as the cooling liquid. The contact connections are contacted with connection devices and led through pressure-resistant cable bushings through the outer vessel to the outside, to adjust the pressure in the outer vessel of Unterwassertrans ^¬ formator to the water pressure of the outer vessel surrounding water pressure compensation means are provided. When ^¬ be familiar arrangement of the external boiler is relatively thin walls formed of ^¬, since it only needs to have a ge ^¬ rings pressure load due to the pressure equalizing means. In case of a leak in the Outer vessel collects characterized penetrated water on ^¬ due to its higher compared to the transformer oil specific gravity at the bottom of the outer vessel.

From German Auslegeschrift 1 272 443 a conventional transformer in a transformer tank is also known. The electrical connections of the transformer are routed via contact terminals arranged on the transformer tank to the outside in the air atmosphere. In the transformer boiler oil is provided as cooling and insulating liquid; however, the transformer tank is not completely filled with oil. Above the resulting characterized oil level, a gas space is formed which is ge with gaseous nitrogen ^¬ filled. In order to avoid the penetration of moisture in the known transformer, especially during transport and storage, in the transformer tank, the interior of the transformer tank is kept under slight overpressure against the outer air atmosphere. At the same time, volume changes due to temperature changes in the oil are absorbed within the transformer tank accordingly. For this purpose, a pressure-controlled automatic with storage bottles for nitrogen is provided, is compressed by the Temperaturände ^¬ tion of the oil displaced nitrogen in storage bottles mounted on the transformer when the internal pressure in the transformer exceeds the desired slight overpressure relative to the external atmospheric pressure.

From the German patent application DE 101 27 276 a submersible transformer is also known, which is enclosed with an outdoor boiler. In this known

Underwater transformer, the outer vessel is partially filled with a gas to form a gas space such that the electrical contact terminals completely in the gas space lie. Furthermore, pressure compensation means are provided, which are connected to the gas space. In this submersible transformer, the heat generated during operation by the cooling liquid of the transformer tank via the transformer tank to the cooling liquid of the

Outside boiler and discharged from the external boiler to the surrounding water.

The object of the invention is to provide a transformer which emits as little heat during operation.

The object is achieved in a transformer of the type mentioned according to the invention that means are provided for cooling the liquid cooling medium.

This ensures that the transformer gives little or no heat to its surroundings. The location of the transformer therefore requires no air conditioning to cool the heat emitted by the transformer. By contrast, in the prior art known from German patent application DE 101 27 276, the heat of the transformer is being delivered to the environment.

A first advantageous embodiment of the invention is that the outer shell is designed as a shell, consisting of waterproof and gas impermeable material. This ensures insulation to the outside and to the inside. A jacket as outer shell with waterproof and gas-impermeable material also reduces maintenance and prevents contamination of the

Environment, because eg transformer oil can not get into the environment. Furthermore, the outer shell ensures that no or only minimal waste heat reaches the environment. There the cooling system for the cooling medium between

Transformer boiler and outer shell works under pressure, a waterproof and gas-impermeable outer shell is important for the operation of the cooling system.

A further advantageous embodiment of the invention is that the outer shell is designed as a metal outer shell. This ensures both a sealing of the transformer to the outside, as well as a protection of the transformer from external influences (such as shocks). A metal outer shell (for example made of steel or stable aluminum with a thickness of 6mm) as outer shell guarantees the operation of the transformer even at high external pressure. For reasons of weight, the outer shell is advantageously formed single-walled.

A further advantageous embodiment of the invention is that the outer shell is connected to the transformer tank by connecting elements. The connecting elements can be connected to the outer shell and the transformer tank, e.g. be welded and increase the pressure stability of the transformer, in particular by the surface pressure on the transformer is minimized.

A further advantageous embodiment of the invention is that the connecting elements are arranged and / or formed in such a way to achieve a uniform distribution of the liquid cooling medium in the space between the transformer tank and outer shell and to ensure a compressive strength of at least 3 bar external pressure. Since heated cooling water rises, is caused by the arrangement and shape of the connecting elements that the cooling water in the outer shell slowly up to Transformer lid rises, and where it is evenly distributed between the outer shell and transformer tank. This ensures optimal cooling.

A further advantageous embodiment of the invention is that at least a portion of the connecting elements, in particular in the vicinity of the transformer base, are comb-shaped, for a uniform distribution of the liquid cooling medium in the space between transformer tank and outer shell. As a cooling medium in the space between transformer tank and outer shell water can be used, preferably provided with a corrosion protection and / or antifreeze. As heated cooling water rises, the comb-shaped shape of the

Connecting elements ensures that the cooling water in the outer shell is distributed evenly between the outer shell and the transformer tank. This ensures optimal cooling. The comb-shaped connecting elements also cause a certain rigidity of the outer shell and thus also increase the pressure resistance of the outer shell and the transformer tank.

A further advantageous embodiment of the invention is that the connecting elements, in particular in the vicinity of the transformer cover, arranged and / or formed in such a way to ensure a compressive strength of at least 3 bar. The connecting elements, which are arranged in the vicinity of the transformer cover, ie substantially in the upper third of the transformer, serve less the uniform distribution of the cooling water, but mainly have the purpose to produce a high compressive strength. As connecting elements in the upper area of the Transformer tank and the outer shell can therefore be simple metal rods (eg round or square bars) are used, for example, are mounted in parallel rows. The arrangement of the connecting struts in parallel rows of the surface pressure is reduced to the outer shell.

A further advantageous embodiment of the invention is that the means for cooling the cooling medium are coupled to a cooling system of another component. As a result, the cooling effect is amplified for the transformer, also with the coupling of the cooling systems created a redundancy, which increases the reliability for the cooling. As a further component preferably a component is used, which already exists anyway. Other components may e.g. one or more

Frequency converter, one or more generators, or one or more other transformers.

A further advantageous embodiment of the invention is that as means for cooling the cooling medium a

Cooling system of another component is used. Transformers often interact with other electrical components, e.g. Frequency converter. If a cooling system of an already existing component is used as the cooling system for the cooling medium of the outer shell, this results in a space saving, which is particularly advantageous in spatially tight environments, e.g. in the tower of an underwater power plant. Furthermore, there is an efficient use of an existing cooling system.

A further advantageous embodiment of the invention is that the further component is an electrical machine, in particular a frequency converter, a generator or a second transformer is. Electrical machines are often used in interaction with other electrical machines. At a sea current power plant, frequency converters are used to balance the different ocean currents that affect the turbines and generators. In towers of

There is a lack of space in the ocean current power plants, as the towers are relatively small in diameter and therefore relatively narrow. If a cooling system of an already existing component is used as cooling system for the cooling medium of the outer shell (for example frequency converter), the available space in the tower can be used optimally.

A further advantageous embodiment of the invention is that the means for cooling the liquid cooling medium with the cooling system of the further component are arranged in series. This results in a space-saving and compact design, which allows in particular the use in confined spaces.

A further advantageous embodiment of the invention consists in that the means for cooling the liquid cooling medium are arranged in parallel with the cooling system of the further component. Through the parallel arrangement, the amount of water is divided and cooler water is supplied to the transformer. The heat output of the transformer to the environment is thus reduced by this additional cooling effect.

A further advantageous embodiment of the invention is that the cooling medium of the transformer in the transformer tank no contact with the transformer cover wherein, as the cooling liquid, mineral oil, ester liquid or silicone oil is usable. This ensures that the transformer emits little or no heat to the environment. This eliminates the need for air conditioning in the vicinity of the transformer. This is particularly advantageous in the confined space of a tower for a sea current or tidal power plant. Furthermore, no energy needs to be supplied to an air conditioner.

A further advantageous embodiment of the invention is that the transformer tank has a sensor, in particular a level indicator. As a result, leaks in the transformer tank can be detected very quickly and the tightness of the transformer cooling system can be checked by the level indicator or other sensors.

A further advantageous embodiment of the invention is that the transformer tank, in particular on

Transformer lid, having an opening to the environment, wherein in the transformer tank penetrating air is passed through a dehumidifier. The oil level (eg mineral oil, ester liquid or silicone oil) in the transformer tank depends on the temperature of the oil used. As the temperature rises, so does the oil level in the transformer tank. When cooled, air is sucked in when the oil level drops. A free oil level is required because no pressure compensation means (eg an expansion tank) is used and the expansion of the corrugated walls of the transformer is not sufficient, especially at 3 bar back pressure. The dehumidifier ensures that air sucked in is dried, otherwise it would be at a Use in damp locations (eg on or in the sea) to damage the transformer's internal insulation system. For example, the dehumidifier can use Silica Gel for its operation.

A further advantageous embodiment of the invention is that the base of the transformer with transformer tank and outer shell does not exceed 1200 mm x 900 mm, the rated power of the transformer is 1250 kVA. This makes it possible to set up the transformer in confined or confined spaces. Furthermore, the transformer can be transported through narrow places. By keeping the transformer tank and outer shell at least at a pressure of 3 bar, it is ensured that the transformer can be used in adverse environments, especially in environments where pressure and stress are present. Such adverse environments can be found e.g. in ocean current or tidal power plants.

A further advantageous embodiment of the invention consists in that the transformer can be used operationally in a plant under water, in particular in a hydroelectric plant. Due to the location and the prevailing environmental conditions electrical equipment and machines that are to be used in hydro-electric systems (eg ocean current or tidal power plants) meet special requirements. For example, a transformer must not be too bulky and its dimensions should not be too large, as there is usually a structural confinement (the resistance of the building in the water should remain low). Also, the heat output of the electrical machines should be kept to a minimum, so no additional air conditioning systems are needed in the facility. By the water jacket (outer shell) of the transformer according to the invention causes no additional air conditioning is needed. Also, the space required for the cooling of the water jacket is kept minimal, if for the cooling system of another anyway existing component (eg frequency converter) is used.

The invention further relates to an arrangement for cooling an electrical transformer, in particular in a hydro-electric system, comprising: a transformer arranged in a transformer tank; an outer shell substantially surrounding the transformer tank, the outer shell including a cooling medium; and means for cooling the cooling medium of the outer shell. The

Arrangement allows locations of the transformer where no air conditioning is needed to cool the heat given off by the transformer. One possible location is e.g. in the tower of a sea current power plant under water.

An embodiment of the invention is illustrated in the drawing and will be explained below.

Showing:

1 shows a schematic representation of the inventive electrical transformer with outer shell and cooling system for the cooling medium in the outer shell.

2 shows a schematic representation of another

Embodiment of the inventive electrical transformer, wherein the outer shell does not surround the underside of the transformer tank, 3 shows a schematic illustration of a further example of the inventive electrical transformer, in which the outer shell does not completely surround the lower region of the transformer tank,

4 shows a simplified representation of a

Series connection of the cooling systems of the inventive transformer and another component,

5 shows a simplified representation of a parallel connection of the cooling systems of the inventive transformer and a further component,

6 shows the tower of a sea current power plant,

7 shows comb-like elements for distributing the cooling water, and

8 shows a schematic representation of an example of an arrangement of the comb-like elements between transformer tank and outer jacket.

Fig.l shows a schematic representation of an electrical transformer 1 in a transformer tank 2. The

Transformer boiler 2 is arranged in an outer shell 3 and enclosed by this. Between the transformer tank 2 and the outer shell 3, a liquid cooling medium 4 is also provided. In the transformer tank 2, a cooling medium 5 is also provided. The transformer tank 2 is connected to the outer shell 3 by connecting elements 14. By the connecting elements 14, the surface pressure on the transformer tank 2 and on the outer shell 3 is reduced. The connecting elements 14 in the upper region of the transformer are used for compressive strength, the connecting elements 14 in lower portion of the transformer used in addition to the compressive strength in particular the uniform distribution of the liquid cooling medium (4) between the transformer tank 2 and outer shell 3. As the cooling medium 4, water can be used. In particular, suitable as the cooling medium 4 water, which is provided with an additive (corrosion protection, antifreeze, coolant), eg glycol.

Via openings 6, the liquid cooling medium 4 is connected to a cooling system 11,12,13. In the upper region of the transformer in the vicinity of the transformer cover 15, the heated cooling liquid 4 is discharged from the opening 6 in the conduit 11 and fed to a heat exchanger 13. The cooled heat transfer medium 4 is supplied through the opening 6 ', which is preferably located near the bottom of the transformer, in the space between the transformer tank 2 and outer shell 3 again. Preferably, the line 11 is provided with a pump 12 (hydraulic pump) to ensure optimum cooling. When used in a sea current power plant, the seawater can be used in the heat exchanger 13 for cooling the cooling medium 4. The heat exchanger 13 is to be attached because of the pressure conditions, preferably near the sea level. When used in a marine current plant, the heat exchanger 13 may be e.g. made of titanium, because of the high corrosion resistance.

The cooling system for the cooling water between the outer shell 3 and the transformer tank 2 can operate in stand-alone mode, ie independently, without connection to other components. However, the cooling system for the cooling water between the outer shell 3 and the transformer tank 2 may also be coupled to the cooling system of another component or other components. The operative interaction with the cooling system of another Component, eg an electrical machine (frequency converter, further transformer, generator, etc.) enhances the cooling effect. If the other component is present anyway also results in a space savings. This is particularly useful in confined environments (eg in the tower of a sea current power plant). As a connecting line 11, a pipe or a hose can be used. The connecting line 11 may be fastened and connected to the connection openings 6, 6 ', for example, by a screw, plug-in or coupling mechanism with the outer shell.

The outer shell 3 is formed as a jacket (so-called water jacket) with a waterproof and gas-impermeable material. When using the transformer under water, e.g. in the tower of a tidal or ocean current power plant, must

Outer shell to ensure adequate pressure resistance. The material for the outer shell will thus be substantially rigid when used underwater. In environments that require high compressive strength, the outer shell is preferably formed as a metal shell. As metals is e.g. Steel suitable, but also solid aluminum (6 mm thickness) is conceivable.

For the operation of the transformer 1 in the transformer tank 2, a so-called. Open cooling system is used, i. the space between the transformer 1 and the transformer tank 2 is connected through an opening 9 with the environment. For operation as an open system, no pressure compensation means such as expansion tanks are required. As the cooling liquid 5 in the transformer tank 2, e.g. Mineral oil, ester liquid or silicone oil usable. The fluid level of the

Coolant 5 in the transformer tank 2 is dependent on the temperature of the coolant. When the temperature rises, the liquid level rises 8. When cooled the liquid level 8 drops and air is sucked in. A free liquid level 8 is necessary because in metal corrugated walls as good as no expansion is possible and the operation of the transformer should be ensured even at high back pressure (eg use in the tower of a sea current or tidal power plant). The transformer according to the invention also works properly even at 3 bar back pressure. The dehumidifier 10 ensures that the air sucked in on cooling is dried before it enters the transformer tank 2. Because of the risk of corrosion, it makes sense only to let dry air into the transformer tank. Especially when used in or at sea, the ambient air is very humid. The dehumidifier 10 is preferably mounted on or in the vicinity of the transformer cover 15.

Due to the design and construction of the transformer 1 and the transformer tank 2 ensures that the cooling liquid 5 in the transformer tank 2 has no contact with the transformer cover 15. This is done by the

Transformer cover 15 no heat dissipated to the environment. By means of a sensor system 7 (for example level gauge), the level 8 of the cooling liquid is detected permanently or at intervals. When filling the transformer tank 2 with the cooling medium 5 for the

Transformer boiler is e.g. Detected via the sensor 7 when too much cooling liquid 5 is supplied or was supplied and the cooling liquid 5 could come into contact with the transformer cover 15. During operation of the transformer, the sensor 7 detects when the liquid level 8 of the

Transformer oil 5 approaches the transformer cover 15. Since the transformer emits little or no heat to the environment, the environment does not require air conditioning for cooling. This saves energy and space.

The transformer 1 is equipped with electrical contact terminals 16. These are in the upper area of the

Transformer boiler 2, in particular on the transformer cover 15. For the sake of clarity, only three electrical contact terminals 16 are shown in FIG. The actual necessary number of electrical contact terminals 16 results from the number of phases for which the

Transformer 1 is formed; usually two or more ports are required per phase. With electrical terminals 18, the transformer 1 is connected to the electrical contact terminals 16. About the electrical contact terminals 16 of the transformer with electrical connection lines 17 is connected to its operation. The electrical connections and electrical connections for the transformer can be designed differently (for example, detachable plug or screw connections are conceivable). The advantages of the transformer are that it gives little or no heat and its compact design. The base area of the transformer with transformer tank and outer shell does not exceed 1200 mm x 900 mm, whereby the nominal power of the transformer amounts to 1250 kVA. As a result, it can be used in confined spaces, where these

Environments need no additional air conditioning for cooling. Possible locations are residential areas, shopping centers, as well as ocean current and tidal power plants. The transformer 1 can be operated in stand-alone mode, ie the cooling system (12,13) for the cooling medium 4 between the transformer tank 2 and outer shell 3 operates independently and independently of other cooling systems. The cooling system (12,13) but also with other external Cooling systems operatively coupled. As a result, the cooling capacity is increased and also provides the coupling with other cooling systems for a redundancy in the cooling components, resulting in a higher reliability and reliability. It is also possible as a cooling system (12,13) for the cooling medium 4 between transformer tank 2 and outer shell 3 to take the cooling system of another component, such as another electric machine (generator, frequency converter, transformer, etc.). This waiver of a separate cooling system (12,13) results in a space savings, which in particular allows the use in tight environments.

Instead of the heat exchanger 13, other cooling mechanisms (e.g., radiator, heat sink) may be used to cool the coolant 4.

The outer shell 3 may completely or partially surround the transformer 1 and the boiler 2. Depending on the configuration, the cooling medium 4 comes into contact with it on all outer sides of the transformer tank 2, or only on certain outer walls of the transformer tank 2. If the cooling medium 4 comes in contact with it, for example, only on the lateral outer walls of the transformer tank 2, this makes it possible simpler construction and manufacturing. The larger the area, with which the cooling medium 4 comes into contact with the outer sides of the transformer tank 2, the better the cooling of the boiler 2 and the transformer 1, with particularly good cooling effects are achieved when the cooling medium 4 in the lower part of the transformer tank 2 comes into contact with this. Preferably, the cooling medium 4 is supplied in the lower region of the outer shell 3 and discharged (after consumption of the cooling) in the upper region. Supply and removal of the cooling medium takes place at the connection openings 6 and 6 '. Since the inventive transformer 1 with boiler 2 and outer shell 3 is particularly designed to withstand at least 3 bar ambient pressure, the shaft walls of the boiler 2 are robust and therefore designed to be less flexible. On the lateral outer walls of the boiler 2 are the

Fasteners 14 attached to the tips (ends) of the shaft walls and connected to the outer shell 3. The connecting elements 14 may be welded, screwed or attached by a plug connection. The connecting elements 14 may be round bars or edged bars. But it is also a form of T-beam conceivable. Round rods are easy to produce, fasteners 14 in the form of a T-beam provide greater stability and pressure resistance. The connecting elements 14 in the lower region of the gap between the boiler 2 and outer shell 3 have in addition to the stabilization and pressure resistance the task to distribute the cooling medium 4 evenly in this space, so that optimal cooling of the heat loss is ensured. The connecting elements 14 in the lower region of the gap between the boiler 2 and the outer shell 3 are therefore structurally designed to ensure optimum distribution of the cooling medium 4 in the intermediate space. For example, allow comb-like configured connecting elements 14 a very good distribution of the cooling medium 4 in the space.

Through the corrugation walls of the boiler 2, the heat loss of the transformer 1 to the cooling medium 4, which is located between the boiler 2 and outer shell 3, dissipated. The outer shell 3 is preferably not formed as a corrugated wall, since it does not have the function, the heat loss to the

Environment. Cooled by the cooling medium 4, no or only little heat loss of the transformer 1 is released to the environment. 2 shows in a schematic representation of a further embodiment of the inventive electrical transformer, wherein the outer shell does not surround the underside of the transformer tank. In this embodiment, the bottom, ie the bottom of the transformer 1 and the boiler 2 is not surrounded by the cooling medium 4. The transformer tank 2 sits either directly on the outer shell 3, or the transformer tank 2 and the outer shell 3 have a common bottom, which is formed for example by a steel plate. This embodiment allows a simple and material-saving design and manufacture of the transformer.

FIG. 3 shows in a simplified schematic representation a further example of the inventive electrical system

Transformer in which the outer shell does not completely surround the lower part of the transformer tank. In the example of FIG. 3, the outer shell 3 surrounds the transformer tank 2 only in a region of the lateral outer walls of the transformer tank 2

Transformer lid 15, the bottom of the transformer tank 2 and a lower portion on the lateral outer walls of the transformer tank 2 is not included in the outer shell 3. If the lower portion of the transformer tank 2 not covered by the outer shell 3 is too large, it will have a negative effect on the cooling effect. Depending on the size and performance of the transformer 1, the distance a from the bottom of the transformer tank 2 to the lower beginning of the outer shell 3 can be in the range of 1 to 20 cm. This embodiment of the transformer allows for a simple design and manufacture, and on the other hand, this embodiment is particularly for heavy transformers. 1 and heavy boilers 2 advantageous because the weight pressure on the underside of the outer shell 3 is omitted.

4 shows a highly simplified representation of a series connection of the cooling systems of the inventive

Transformer 19 and a further component 21. In FIG 4, the transformer 19 is a transformer with transformer tank and outer shell according to the invention. In this embodiment of the invention, the cooling system 20 of a further component 21 for cooling the cooling medium 4 between the transformer tank 2 and outer shell 3 is used. The cooling system 20 of the further component 21 can act instead of the means for cooling (12, 13) of the cooling medium 4. In this mode of operation, the transformer 19 does not have its own cooling means (e.g.

Heat exchanger) of the cooling medium 4 between transformer tank 2 and outer shell 3. In this operation, only the cooling system 20 of a further component 21 is used for cooling the cooling medium 4. Via the line 11, the cooling medium 20 is supplied to the transformer 19 via the connection opening 6 'from the cooling system 20 of the component 21 and discharged again via the connection opening 6 after cooling.

However, the cooling system 20 of the further component 21 can also act together with the means for cooling (12, 13) the cooling medium 4. The cooler 13 (eg heat exchanger) and the pump of the transformer 19 operate together in this operating condition and increase the cooling effect for the transformer 19. In the environment of the transformer 19 can thus be dispensed with an air conditioner. Such an air conditioner would take up extra space, would require additional power, and also cause corresponding maintenance efforts. If component 21 is present anyway Thus, the use of their cooling system 20 results in considerable advantages in terms of cooling capacity and space utilization. The series-connected cooling systems thus continue to result in a space-saving and compact design, which allows in particular the use in confined spaces.

As component 21, electrical machines, e.g. Generators, dynamos, frequency converters or other transformers. It is also the cooling systems 20 of several other components 21 to the coolant (12,13) of the transformer 19 are connected in series, or the cooling systems 20 of several other components 21 can replace the means for cooling (12,13) of the transformer 19. If in addition to the cooling means (12,13) of the transformer 19, the cooling systems 20 of other components 21 are used, a redundancy of cooling systems is present, whereby the reliability for the cooling of the cooling medium 4 between the boiler 2 and outer shell 3 is increased. The cooling systems 20 of the further components 21 may all be connected in series with the cooling system (12, 13) of the transformer 19. But it is also possible that some or all of the cooling systems 20 of the other components 21 are connected in parallel to each other. In this embodiment, the cooling systems 20 of the other components 21 can be flexibly added or removed by valves. By disconnecting or connecting cooling systems 20, a scaled cooling for the transformer 19 can be achieved. The cooling for the transformer 19 is thus adaptable to different requirements.

FIG. 5 shows, in a greatly simplified illustration, a parallel connection of the cooling systems of the inventive transformer 19 with the cooling system 20 of another Component 21. In FIG. 5, the transformer 19 represents a transformer according to the invention with a transformer tank and outer shell.

By the parallel-connected arrangement, the amount of water is divided and cooler water is supplied to the transformer 19. The heat output of the transformer 19 to the environment is thus reduced by this additional cooling effect again. If the component 21 is present anyway resulting from the use of their cooling system 20 thus considerable advantages in terms of cooling capacity and the

Use of space. As component 21, electrical machines, e.g. Generators, dynamos, frequency converters or other transformers. It is also possible to connect the cooling systems 20 of several components 21 in parallel with the transformer 19. For example, Several frequency inverters can act as components connected in parallel. The components 21 may be e.g. be switched on or off by valves. By disconnecting or connecting cooling systems 20, a scaled cooling for the transformer 19 can be achieved. The cooling for the transformer 19 is thus adaptable to different requirements. Furthermore, a redundancy of cooling systems is present, whereby the reliability for the cooling of the transformer 19 is increased.

6 shows the tower 22 of a sea current power plant. Such a tower is a possible place of use of the transformer 1,19 according to the invention. With hydro-electric systems such as ocean current or tidal power plants, the flow of water is used to generate energy. Usually, several towers 22 with one or more under the water surface 24 rotors 23 such hydro- Electrical system. 6 shows a tower 22 with 2 rotors 23. The rotors 23 work like turbines in a power plant and generate electricity which is forwarded via lines to the mainland. Since there are different flow conditions during the operation of such a system, frequency converters are required in particular. Furthermore, the spatial conditions in the tower 22 are narrow and limited. Now, if the transformer is used 1.19 in a tower 22 of a sea current power plant, for the dimensions (volume) of the transformer corresponding

Requires requirements and continue to heat dissipation of the transformer 1.19 may be low to the environment. If the heat dissipation is too high, the tower will require air conditioning, which will add extra cost and space. The direct cooling of the transformer 1 is carried out by the cooling medium 5 in the transformer tank 2 (for example, mineral oil, ester liquid or silicone oil). If the cooling medium 5 in the transformer tank 2 has no contact with the transformer cover, little heat is released to the outside. In order to further reduce the heat output of the transformer according to the invention was surrounded with an outer shell 3, which contains water as a cooling medium 4, possibly water with cooling additive. If now, for the cooling of the outer shell 3 as a substituting cooling system or as a supplementary cooling system, the cooling system of a component which is present anyway in the tower 22, e.g. a frequency converter is used, one obtains an improved cooling effect for the transformer 1,19 without the need for additional space. The footprint of the overall transformer (with transformer tank and outer shell) can thus be advantageously dimensioned, and does not exceed 1200 mm x 900 mm.

The transformer according to the invention 1,19 with transformer tank 2 and the outer shell 3 must due to the harsh environmental conditions (eg pressure under water) can withstand at least a pressure of 3 bar. As means for cooling 13 of the cooling medium 4 between transformer tank 2 and outer shell 3 is particularly suitable when used in a tidal power plant

Heat exchanger 13, which is supplied through the line 11 by the waste heat of the transformer 1 heated cooling water 4 and brings the heated cooling water 4 in contact with the relatively cold sea water and thereby cools again. The heat exchanger 13 in the tidal power plant can be located just below sea level. Just below sea level moderate pressure conditions prevail. The transformer 1, 19 itself with boiler 2 and outer shell 3 can be used much deeper (more than 30 meters below sea level), since it can withstand at least 3 bar pressure.

7 shows comb-like elements which can be arranged between the transformer tank 2 and the surrounding outer shell 3 in order to ensure as uniform a distribution of the cooling medium (for example cooling water) 4 as possible. Since usually the cooling medium 4 is supplied to the transformer bottom and discharged to the transformer cover 15, the comb-like elements are to be attached in particular to the transformer base for a uniform cooling effect. The

Connecting elements 14, which are mounted between transformer tank 2 and outer wall 3, may be formed as comb-like elements. As a result, in addition to a stability of the transformer, the connecting elements 14 also effect the distribution of the cooling medium 4. However, the comb-like elements can also be attached in addition to the connecting elements 14. Advantageously, the comb-like elements engage between the cooling fins of the Transformer tank, so that the transformer tank 2 can deliver its waste heat effectively to the cooling medium 4.

8 shows a schematic representation of an example of an arrangement of the comb-like elements between

Transformer tank 2 and outer shell 3. The comb-like elements engage in the ribs of the corrugated walls of the transformer tank 2 and ensure a uniform distribution of the cooling water. The connecting elements 14 serve in addition to their stability function for uniform

Distribution of the cooling medium 4 between transformer tank 2 and outer shell 3. In the illustration of Figure 8, the connecting elements 14 are part of the comb-like elements.

The embodiment of the invention makes it possible, in particular, to use the transformer according to the invention in environments in which only little heat may be emitted, such as shopping centers, residential areas, underwater power plants. The outer shell 3 also provides a seal. As a result, the transformer is also suitable for critical sites with regard to environmental compatibility (for example, water protection, environmental protection), since oil leakage (cooling medium 5 in the boiler 2) is avoided in the event of a malfunction (for example leak in the boiler 2). The outer shell 3 also ensures that the noise output of the transformer 1.19 is low.

Electric transformer 1.19 in a transformer tank 2 with electrical contact terminals, and with a transformer tank 2 enclosing, filled with a cooling medium 4, outer shell 3. The cooling medium 4 of the outer shell 3 can be cooled by a cooling system, which is connected to the cooling system 20 of other components 21st can be coupled. Of the Transformer 1.19 is particularly suitable for operation in ocean current and tidal power plants.

reference numeral

1 Electric transformer 2 transformer tank

3 outer shell

4 Cooling medium between transformer tank and outer shell

5 cooling medium in the transformer tank 6, 6 'connection opening

7 sensor

8 fluid level

9 air opening

10 dehumidifier 11 pipe

12 pump

13 heat exchangers

14 connecting element

15 Transformer cover 16 Electrical contact connection

17 Electrical connection line

18 Electrical connection

19 Transformer with transformer tank and outer shell 20 Cooling system

21 component

22 Tower of a sea current power plant

23 rotor

24 sea levels

Claims

claims

1. Electric transformer (1) in a transformer tank (2), and with a transformer tank (2) surrounding the outer shell (3), wherein the space between the transformer tank (2) and outer shell (3) with a liquid cooling medium (4) is filled , characterized in that means (11,12,13) are provided for cooling the liquid cooling medium (4).

2. Transformer (1) according to claim 1, characterized in that the outer shell (3) is designed as a jacket, consisting of waterproof and gas-impermeable material.

3. Transformer (1) according to claim 1, characterized in that the outer shell (3) is designed as a metal outer shell.

4. Transformer (1) according to claim 1, characterized in that the outer shell (3) is connected to the transformer tank (2) by connecting elements (14).

5. Transformer (1) according to claim 4, characterized in that the connecting elements (14) are arranged and / or formed in such a way to achieve a uniform distribution of the liquid cooling medium (4) in the space between the transformer tank (2) and outer shell (3) and to ensure a compressive strength of at least 3 bar external pressure.

6. Transformer (1) according to claim 4, characterized in that at least part of the connecting elements (14), in particular in the vicinity of the transformer base, are comb-shaped, for a uniform distribution of the liquid cooling medium (4) in the space between the transformer tank (2). and outer shell (3).

7. Transformer (1) according to claim 4, characterized in that the connecting elements (14), in particular in the vicinity of the transformer cover (15), arranged and / or formed in such a way to ensure a compressive strength of at least 3 bar.

8. Transformer (1) according to claim 1, characterized in that the means (11, 12, 13) for cooling the cooling medium (4) are coupled to a cooling system (20) of a further component (21).

9. Transformer (1) according to claim 1, characterized in that a cooling means (11, 12, 13) for cooling the cooling medium (4)

Cooling system (20) of another component (21) is used.

10. Transformer (1) according to claim 8 or 9, characterized in that the further component (21) is an electrical machine, in particular a frequency converter, a generator or a second transformer.

11. Transformer (1) according to claim 8, characterized in that the means (11, 12, 13) for cooling the liquid cooling medium (4) with the cooling system (20) of the further component (21) are arranged in series.

12. Transformer (1) according to claim 8, characterized in that the means (11, 12, 13) for cooling the liquid cooling medium (4) with the cooling system (20) of the further component (21) are arranged in parallel.

13. Transformer (1) according to claim 1, characterized in that the cooling medium (5) of the transformer (1) in the transformer tank (2) is not in contact with the

Transformer cover (15), wherein as a cooling liquid mineral oil, ester liquid or silicone oil is used.

14. Transformer (1) according to claim 13, characterized in that the transformer tank (2) has a sensor (7), in particular a fill level indicator.

15. Transformer (1) according to claim 13, characterized in that the transformer tank (2), in particular on the transformer cover (15), an opening (9) to the environment having, in the transformer tank (2) penetrating air through a dehumidifier (10) is passed.

16. Transformer (1) according to claim 1, characterized in that the base area of the transformer (1) with

Transformer tank (2) and outer shell (3) does not exceed 1200 mm x 900 mm, whereby the nominal power of the transformer is 1250 kVA.

17. Transformer (1) according to claim 1, characterized in that the transformer (1) can be used operationally in a plant under water, in particular in a hydro-electric plant (22, 23).

18. An arrangement for cooling an electrical transformer (1), in particular in a hydro-electric system (22,23), comprising: a transformer (1) arranged in a transformer tank (2); an outer shell (3) substantially surrounding the transformer tank (2), the outer shell (3) including a cooling medium (4); and means (11, 12, 13) for cooling the cooling medium (4) of the outer shell (3).