EP3057112A1

EP3057112A1 - Oil transformer

Info

Publication number: EP3057112A1
Application number: EP15155155.3A
Authority: EP
Inventors: Thomas Schmidt; Ulrich DÜLLBERG
Original assignee: ABB Technology AG
Current assignee: Hitachi Energy Switzerland AG
Priority date: 2015-02-16
Filing date: 2015-02-16
Publication date: 2016-08-17
Anticipated expiration: 2035-02-16
Also published as: EP3057112B1

Abstract

The invention is related to an oil transformer, comprising a high voltage transformer (32 + 34) arranged in an oil filled vessel (36), an expansion vessel (42), a fluidic connection (52 + 54 + 56) in between the expansion vessel (42) and the oil filled vessel (36) and at least one cooling means (58). At least the expansion vessel (42) is fixedly integrated in a mechanical supporting structure (10, 22, 24, 46, 48, 50) having four upper (12, 26) and four lower (14, 28) corner points arranged in the form of a square, wherein the corner points (12, 14, 26, 28) each are in the form of load transfer points and are arranged according to the dimensions of a CSC container.

Description

The invention is related to an oil transformer, comprising a high voltage transformer arranged in an oil filled vessel, an expansion vessel, a fluidic connection in between the expansion vessel and the oil filled vessel and at least one cooling means.
It is known, that transformers, reactors and other electrical devices used in HV transmission networks of for example 380kV are typically arranged within an oil filled vessel. The oil is on one hand insulation medium and on the other hand cooling medium. An expansion vessel is fluidic connected with the oil filled vessel in order to handle the thermal expansion of the oil which arises during operation of the respective HV component, for example an oil transformer. In the frame of this invention the wording "transformer" has also to be seen as synonym for a reactor and the wording "oil" covers also comparable insulation fluids such as Ester. Typically cooling means are foreseen for cooling the oil transformer, mainly heat exchangers, in particular an oil air heat exchanger or an oil water heat exchanger, or radiators which might be arranged as a radiator battery.
An HV oil transformer might have a rated power of several 100MVA, a weight of several 100t, a height of for example 6m and above and a length of 12m and above. Thus the transportation of such an oil transformer from the factory to site is a challenging task. In order to facilitate transportation, the attached components such as cooling means and expansion vessel are transported separately and assembled together with the main part of the oil transformer on site.
Disadvantageously within the state of the art is that the attached components are normally individually designed with respect to individual requirements for the respective oil transformer. Thus the attached components typically differ in size and shape so that as well their transport as their assembly on site is rather individual and time consuming therewith. Also seismic requirements, for example with respect to groundwork and a stable arrangement, have to be fulfilled when assembling the components to be attached on site.
The objective of the invention is to provide an oil transformer with attached components, which are easier to transport and to easier assemble on site.
The problem is solved by an oil transformer of the aforementioned kind. This is characterized in that at least the expansion vessel is fixedly integrated in a mechanical supporting structure having four upper and four lower corner points arranged in the form of a square, wherein the corner points each are in the form of load transfer points and are arranged according to the dimensions of a CSC container. CSC means Container Safety Convention wherein the standards related thereto are described for example in ISO 668.
Basic idea of the invention is to modularize the components to be attached to an oil transformer, for example an expansion vessel or the like. All modules have in common, that they are designed in that way, that they can be transported exactly like a CSC container. A module comprises a mechanical supporting structure with outer dimensions like a CSC container and a component of an oil transformer fixedly integrated therein.
CSC containers are a widely known and standardized transportation medium. A CSC container complies with standardized dimensions, for example a standardized length of 6,058m or 12,192m, wherein the height amounts 2,591 m and the width 2,438m. A transport by ships, trucks or train to any location in the world is possible without any problem. Thus the transportation of the components to be attached to an oil transformer is facilitated therewith compared to the transportation in bulky cases as it is common now.
According to the invention a respective component to be attached to an oil transformer is fixedly integrated in the mechanical supporting structure, which is not only of advantage for an easier transportation, moreover an easier installation on site is enabled therewith. The mechanical supporting structure enables an easy placing on site on the four lower corner points. Any complex groundwork is as less required as a direct assembly with the vessel of the oil transformer. It is also possible to stack the mechanical supporting structures of several modules easily each on each other. Only respective fluidic connections in between the oil filled transformer vessel and the respective mechanical supporting structure have to be mounted on site.
Typically the mechanical supporting structure is designed in that way, that it has a comparable life cycle than the oil transformer itself, so that the components fixedly integrated in the mechanical supporting structure can permanently remain therein.
According to a further embodiment of the invention the mechanical supporting structure of the expansion vessel comprises coupling means at its outer surface which are foreseen as a part of the fluidic connection in between the expansion vessel and the oil filled vessel. The first part of the fluidic connection in between the expansion vessel and the coupling means is integrated in the mechanical supporting structure. So the second part from the coupling means to the oil filled vessel can easily be carried out comparable to a plug and play connection.
According to another embodiment of the oil transformer the at least one cooling means are fixedly integrated in a further respective mechanical supporting structure having four upper and four lower corner points arranged in the form of a square, wherein the corner points each are in the form of load transfer points and are arranged according to the dimensions of a CSC container. Integrating also the cooling means into a mechanical supporting structure of same dimensions increases the flexibility of the modular system. If required two or more modules with mechanical supporting structure and fixedly integrated cooling means can be attached to one oil transformer. Due to the identic dimensions the respective mechanical supporting structures respectively modules can be placed side by side or stacked each on each other.
According to a further embodiment of the invention the at least one cooling means are a heat exchanger, in particular an oil air heat exchanger or an oil water heat exchanger. In this case a fluidic connection in between the heat exchanger and the oil filled vessel is required. A heat exchanger has not necessarily to be placed side by side to the oil filled vessel, but in order to keep the respective fluidic connection as short as possible it would be at least of advantage to place it in close proximity. Optionally pumps or other components which are required to operate the heat exchanger are integrated in the respective module.
According to a further embodiment of the invention the mechanical supporting structure of the heat exchanger comprises coupling means at its outer face which are foreseen as a part of a fluidic connection in between the heat exchanger and the oil filled vessel. The first part of the fluidic connection in between the cooling means and the coupling means is integrated in the mechanical supporting structure. So the second part from the coupling means to the oil filled vessel can easily be carried out comparable to a plug and play connection.
According to another embodiment of the invention the at least one cooling means are one or more radiators. Radiators should be placed at least in close proximity to the oil filled vessel in order to increase the cooling effect of the air flow caused by the radiators. Radiators can be arranged as well with horizontal as with vertical alignment.
According to another variant of the invention the radiators are divided into two groups, which are foreseen to be operated independently each from each other. This enables an easy adaptation of the cooling power to the actual need for cooling.
According to another embodiment of the invention a respective mechanical supporting structure comprises at least one hollow bar, which is as well load bearing as foreseen as a part of the fluidic connection in between the expansion vessel respectively the cooling means and the oil filled vessel. Thus it is possible to reduce the effort for the fluidic connection by integrating the functionality of a pipe into the load bearing hollow bar of the mechanical support structure.
According to another embodiment of the oil transformer further means - in particular control equipment - are fixedly integrated in a further respective mechanical supporting structure having four upper and four lower corner points arranged in the form of a square, wherein the corner points each are in the form of load transfer points and are arranged according to the dimensions of a CSC container. This increases once again the flexibility of the modular system. Even an empty mechanical supporting structure could be used to lift one or more modules stacked thereon in a suitable height.
A suitable height for an expansion vessel is above the top of the oil filled vessel. Considering that the height of a transformer might amount 5m and above the mechanical support structure with the expansion vessel could be placed on a stack with two other mechanical supporting structures so that it is in a suitable height. Preferably the supporting structures below could have cooling means integrated therein, but in case that there is only need for one mechanical supporting structure with cooling means the other mechanical supporting structure could be even empty with the only purpose to lift the stack up.
Thus according to another embodiment of the invention at least two respective mechanical supporting structures are stacked each on each other. According to a further embodiment of the invention a respective mechanical supporting structure with an expansion vessel is stacked over a respective mechanical supporting structure with cooling means.
According to another embodiment of the invention at least one supporting structure is arranged side by side to the oil filled vessel. This reduces the length of the fluidic connections to the oil filled vessel and in case of the use of radiators as cooling means the cooling efficiency is increased therewith.
Further advantageous embodiments of the invention are mentioned in the dependent claims.
The invention will now be further explained by means of an exemplary embodiment and with reference to the accompanying drawings, in which:

Figure 1 shows an exemplary mechanical support structure,
Figure 2 shows a stack of two mechanical support structures and
Figure 3 shows an exemplary oil transformer.

Figure 1 shows an exemplary mechanical support structure 10, which is carried out as a truss structure, for example by use of beams respectively hollow beams. The mechanical support structure has the outer shape of a cuboid which is defined by four upper 12 and four lower 14 corner points. The mechanical support structure comprises a base frame 16 which is designed in that way that an integrated component such as an oil filled expansion vessel can be worn. Traverses 18 increase the mechanical stability.
Figure 2 shows a stack of two mechanical support structures in a sketch 20. A first 22 and a second 24 truss like mechanical support structure are stacked each on each other. The support structures 22, 24 comprise each four upper 26 and four lower 28 corner points.
Figure 3 shows an exemplary oil transformer 30. A transformer with a transformer core 32 and transformer coils 34 is arranged in a vessel 36 which is filled with oil 38. An HV bushing 40 is foreseen at the top of the vessel 36. A stack of mechanical support structures 46, 48, 50 is foreseen left of the vessel 36. An expansion vessel 42, which is partly filled with oil 44, is integrated in the first mechanical support structure 46. A fluidic connection in between the expansion vessel 42 and the vessel 36 is realized by a first part 52 leading from the expansion vessel 42 to coupling means 54 and by a second part 56 leading from the coupling means 54 to the vessel 36.
The second mechanical support structure 48 has cooling means 58 integrated therein, in this case a heat exchanger. The heat exchanger comprises several disk like cooling modules which are arranged side by side along the axial length of the mechanical support structure 48. Each cooling module is supplied by a main feed line 64 with oil to be cooled and which is returned after cooling over a main return line 66. Each cooling module has an own feed 60 and return 62 line which are connected to the respective main line 64 respectively 66.
The third mechanical support structure 50 comprises a fan 68 and control equipment 70, in particular a computer for logging and analyzing measured data of the oil transformer 30. Additionally the stack of the first 46 and second 48 mechanical support structures is lifted up therewith, so that the expansion vessel 42 of the first mechanical support structure is above the top of the vessel 36 therewith. The whole arrangement is placed on a ground floor 72.

List of reference signs

10: exemplary mechanical support structure
12: upper corner points
14: lower corner points
16: base frame
18: traverse
20: stack of two mechanical support structures
22: upper mechanical support structure
24: lower mechanical support structure
26: upper corner points of upper mechanical support structure
28: lower corner points of lower mechanical support structure
30: exemplary oil transformer
32: transformer core
34: transformer coil
36: vessel
38: oil
40: HV-bushing
42: expansion vessel
44: oil
46: first mechanical support structure
48: second mechanical support structure
50: third mechanical support structure
52: first part of fluidic connection
54: coupling means
56: second part of fluidic connection
58: cooling means
60: feed line of cooling module
62: return line of cooling module
64: main feed line
66: main return line
68: fan
70: control equipment
72: ground floor

Claims

Oil transformer (30), comprising
• a high voltage transformer (32 + 34) arranged in an oil filled vessel (36),

• an expansion vessel (42),

• a fluidic connection (52 + 54 + 56) in between the expansion vessel (42) and the oil filled vessel (36),

• at least one cooling means (58),
characterized in that
the expansion vessel (42) is fixedly integrated in a mechanical supporting structure (10, 22, 24, 46, 48, 50) having four upper (12, 26) and four lower (14, 28) corner points arranged in the form of a square, wherein the corner points (12, 14, 26, 28) each are in the form of load transfer points and are arranged according to the dimensions of a CSC container.
Oil transformer according to claim 1, characterized in that the mechanical supporting structure (10, 22, 24, 46, 48, 50) of the expansion vessel (42) comprises coupling means (54) at its outer surface which are foreseen as a part of the fluidic connection (52 + 54 + 56) in between the expansion vessel (42) and the oil filled vessel (36).
Oil transformer according to claim 1 or 2, characterized in that the at least one cooling means (58) are fixedly integrated in a further respective mechanical supporting structure (10, 22, 24, 46, 48, 50) having four upper (12, 26) and four lower (14, 28) corner points arranged in the form of a square, wherein the corner points (12, 14, 26, 28) each are in the form of load transfer points and are arranged according to the dimensions of a CSC container.
Oil transformer according to claim 3, characterized in that the at least one cooling means (58) are a heat exchanger, in particular an oil air heat exchanger or an oil water heat exchanger.
Oil transformer according to claim 4, characterized in that the mechanical supporting structure (10, 22, 24, 46, 48, 50) of the heat exchanger (58) comprises coupling means at its outer face which are foreseen as a part of a fluidic connection in between the heat exchanger (58) and the oil filled vessel (36).
Oil transformer according to claim 3, characterized in that the at least one cooling means (58) are one or more radiators.
Oil transformer according to claim 6, characterized in that the radiators are divided into two groups, which are foreseen to be operated independently each from each other.
Oil transformer according to any of the previous claims, characterized in that a respective mechanical supporting structure (10, 22, 24, 46, 48, 50) comprises at least one hollow bar, which is as well load bearing as foreseen as a part of the fluidic connection (52 + 54 + 56) in between the expansion vessel (42) respectively the cooling means (58) and the oil filled vessel (36).
Oil transformer according to any of the previous claims, characterized in that further means - in particular control equipment - are fixedly integrated in a further respective mechanical supporting structure (10, 22, 24, 46, 48, 50) having four upper (12, 26) and four lower (14, 28) corner points arranged in the form of a square, wherein the corner points (12, 14, 26, 28) each are in the form of load transfer points and are arranged according to the dimensions of a CSC container.
Oil transformer according to any of the previous claims, characterized in that at least two respective mechanical supporting structures (10, 22, 24, 46, 48, 50) are stacked each on each other.
Oil transformer according to claim 10, characterized in that a respective mechanical supporting structure (10, 22, 24, 46, 48, 50) with an expansion vessel (42) is stacked over a respective mechanical supporting structure (10, 22, 24, 46, 48, 50) with cooling means (58).
Oil transformer according to any of the previous claims, characterized in that at least one supporting structure (10, 22, 24, 46, 48, 50) is arranged side by side to the oil filled vessel (36).