Hydropower device, and method for installing a hydropower device

Abstract

The invention relates to a hydropower device (1) comprising an electric machine (2) and a hydraulic machine (3) with a vertical rotational axis, wherein the hydraulic machine comprises a first and second assembly and a suction tube (10), the first assembly comprising a spiral housing (4) encased in concrete, at least one part of a traverse ring (5), and at least one first contact surface (5.1), and the second assembly comprising at least one impeller (7) against which water can flow radially and at least one second contact surface (9.1); the at least one first contact surface and the at least one second contact surface contact one another and are connected by connecting means (11); and the first contact surface is oriented towards the suction tube and the second contact surface is oriented towards the electric machine such that the connecting means is relieved by the water pressure acting during the operation of the hydropower device.

Description

[0001] File: 28848 DE / HZT - 1 -

[0002] Hydropower plant and method for assembling a hydropower plant

[0003] The invention relates to a hydropower plant and a method for assembling a hydropower plant, wherein the plant comprises a hydraulic machine with a vertical axis of rotation. This machine can be a turbine, pump, or pump-turbine. The hydraulic machine comprises at least one impeller designed for radial flow. Impellers with radial flow are, for example, of the Francis type. The hydraulic machine can be single-stage or multi-stage, i.e., it can have one or more such impellers.

[0004] Methods for assembling a hydropower plant with a hydraulic machine with a vertical axis of rotation are known from the prior art. For most hydraulic machines with a vertical axis of rotation, assembly is predominantly carried out from above, with component-by-component installation and removal. During disassembly for maintenance, it is then necessary to remove the electric motor. DE 69303085 T3 discloses a method in which the impeller and part of the guide vanes are removed downwards. This requires a working space located below.

[0005] From the publication JP 2019-27314 A, a method for assembling a hydroelectric power plant is known in which the traverse ring is designed in two parts. An outer part of the traverse ring is connected to the spiral casing. An inner part of the traverse ring can be separated from the outer part. During assembly, the inner part of the traverse ring can be assembled together with other parts of the hydraulic machine, thus reducing assembly time. The largest assembly disclosed in this publication, which can be assembled together with the inner part of the traverse ring, additionally includes the guide vane assembly, the upper turbine cover, the lower turbine cover, and the guide vane opening-closing mechanism (see Fig. 2 of JP 2019-27314 A). Installation and removal are carried out from above. File: 28848 DE / HZT - 2 -

[0006] Another method for assembling a hydropower plant with a vertical axis of rotation is disclosed in EP 3942 173 B1, in which the components to be assembled are removed and installed from above and laterally. This requires an assembly space that is arranged vertically between the spiral casing and the electric machine and extends horizontally beyond the edge of the electric machine, being open upwards at least in part of the area projecting beyond the edge of the electric machine. Furthermore, the components to be assembled are not installed and removed individually, but rather as a module, which is removed and installed as a whole. This modular installation and removal makes assembly more time-efficient.

[0007] For this process to be implemented, the hydropower plant must include an intermediate shaft long enough to allow for the module to be removed and installed. This has the disadvantage of lengthening the rotating parts, which makes the shaft dynamics more challenging. Potentially critical natural frequencies for bending tend to decrease, bringing them closer to the machine's rotational speeds and their multiples. Additionally, the deflection of the shaft train increases, necessitating larger sealing gaps between rotating and stationary parts, which can increase losses and reduce efficiency.

[0008] Multi-stage hydraulic machines represent another special case. Due to the large axial extent of the rotating parts, these are mounted above a central assembly shaft. Since this shaft is not aligned with the final installation position, the assembled hydraulic machine must then be moved horizontally into its installation position. For this reason, the spiral casings of such multi-stage hydraulic machines are not embedded in concrete, but fixed to a rail system. The large recess in the ceiling required for this rail system poses certain challenges to the overall structural design of the powerhouse. The force system of the hydraulic machine also requires more careful consideration, as the thrust forces at the spiral casing inlet cannot be transferred into the concrete relatively easily via the embedded spiral, as is usually the case. (Further details: File: 28848 DE / HZT - 3 -)

[0009] This design requires a special pressure-compensated expansion sleeve at the inlet of the spiral casing. Furthermore, the freestanding spiral has lower stiffness than a conventionally embedded spiral. This results, for example, in lower stiffness of the upper guide bearing of the hydraulic machine. Generally, the freestanding spiral also tends to produce higher vibrations and thus more noise than conventionally embedded spirals.

[0010] The object of the invention is to provide a hydropower device and a method for assembling a hydropower device in which the assembly can be carried out in a time-efficient manner, and in which the disadvantages described above in connection with an intermediate shaft and a multi-stage hydraulic machine can be avoided.

[0011] The problem is solved according to the invention by an embodiment according to the independent claims. Further advantageous embodiments of the present invention are found in the dependent claims.

[0012] The invention will be explained below with the aid of figures. The figures show, in detail:

[0013] Fig. 1: Hydropower device according to the invention during assembly

[0014] Fig. 2: Detail from Figure 1

[0015] Fig. 3: Water power plant from Figure 2 in assembled state

[0016] Fig. 4: Detail from Figure 3

[0017] Fig. 5: Crossbeam ring of a water power device according to the invention

[0018] Fig. 6: Detail of the method according to the invention

[0019] Figure 1 shows a water power plant according to the invention. The water power plant is designated by 1 and is shown in a state relating to the assembly of the water power plant 1. In the illustrated state, certain parts are not yet assembled. These parts are therefore not shown in Figure 1. File: 28848 DE / HZT - 4 -

[0020] These parts are only indicated by dashed lines. They include at least parts of the intake manifold and usually also the electric motor. Further details relating to the assembly will be discussed below in connection with the method according to the invention.

[0021] The hydropower plant 1 comprises an electric machine, designated 2, and a hydraulic machine, designated 3. The hydraulic machine 3 can be a turbine, pump, or pump-turbine. Similarly, the electric machine 2 can be a generator, motor, or motor-generator. The hydropower plant 1 includes a powerhouse in which the other components of the hydropower plant 1 are arranged.

[0022] To avoid unnecessarily complicating the description and claims, the term "turbine" will be used for "hydraulic machine" and the term "generator" for "electric machine" in the following text. This means that the terms mentioned do not restrict their literal meaning but always refer to the broader terms unless a literal meaning is explicitly indicated. The same applies in particular to adjectives such as "generator-side" or to compound nouns such as "generator shaft," "turbine shaft," or "turbine cover," as using the corresponding broader terms "hydraulic machine" or "electric machine" would result in very cumbersome formulations.

[0023] The electric machine 2 includes a generator shaft, which is labelled 2.1.

[0024] The hydraulic machine 3 comprises a spiral casing, designated 4, a crosshead ring, designated 5, a turbine shaft, designated 6, at least one impeller, at least one guide vane assembly with a plurality of guide vanes, and a suction pipe, designated 10. The at least one impeller is designed for radial flow. In a particularly advantageous embodiment, the turbine shaft 6 is designed such that it directly [File: 28848 DE / HZT - 5 -]

[0025] can be connected to the generator shaft 2.1. This means that the hydropower unit 1 does not include an intermediate shaft.

[0026] The spiral casing 4 is connected to the crossbeam ring 5. The spiral casing 4 is encased in concrete, so that shear forces acting on the spiral casing 4 during operation are reliably transferred into the foundations and vibrations and noise are minimized.

[0027] The hydraulic machine 3 shown in Figure 1 is an example of a two-stage pump turbine. Such a pump turbine comprises two impellers with reversible rotation, only one of which is indicated by the dashed line labeled 7. The pump includes a guide vane assembly with a plurality of guide vanes for each impeller 7. For the impeller 7 indicated by a dashed line, one of the guide vanes is also indicated by a dashed line and labeled 8. The dashed representation for guide vane 8 and impeller 7 was chosen because these elements are located inside the illustrated assembly and are not visible from the outside. The same applies to parts of the turbine shaft 6.

[0028] The second impeller, not shown, is located above the impeller 7, shown with dashed lines. A guide vane assembly is also part of this second impeller assembly. An upper deck belonging to this second guide vane assembly is designated 9. Such an upper deck can also be part of an upper turbine cover. The guide vanes 8 are often rotatable and thus adjustable. They could also be non-rotatable.

[0029] The hydraulic machine 3 shown in Figure 1 comprises three assemblies that are not connected in the illustrated state. A first assembly consists of a spiral casing 4 and a crosshead ring 5. This first assembly is already in its final position, i.e., in the installed position.

[0030] A second assembly is arranged "freely suspended" below the first assembly in Figure 1; that is, the lifting means required to lift this second assembly are shown in Figure 1. File: 28848 DE / HZT - 6 -

[0031] The components that hold the turbine shaft in this position are not shown for clarity. The second assembly comprises a turbine shaft 6, at least one impeller 7, and at least one guide vane assembly with a plurality of rotatably mounted guide vanes 8. The guide vane assembly may also include the associated opening-closing mechanism, e.g., a control ring and a plurality of levers and links. Such a second assembly is also referred to as a module. The term "module" also expresses the fact that this second assembly can be installed and removed as an integral unit. The second assembly or module may also comprise more than the elements mentioned. For example, the second assembly shown in Figure 1 also includes the stationary water channels that hydraulically connect the two impellers and the lower deck of the lower impeller. There are also hydraulic machines that do not include a guide vane assembly, which is the case, for example, with...This can be the case with pure pumps. In this case, the module naturally does not include a guide vane. Instead, the module includes other stationary elements, such as a turbine cover and a lower deck for the impeller.

[0032] To bring the second assembly into its final position (see Figure 3), it must be moved vertically in Figure 1.

[0033] The third assembly comprises at least the intake manifold 10. It may also include further elements, such as a bearing for supporting the lower part of the turbine shaft 6 shown in Figure 1, and possibly rotary unions for the same. The third assembly must not yet be fully assembled in order for the second assembly or module to be in the position shown in Figure 1.

[0034] It should be mentioned here that the terms "above" and "below" and their corresponding grammatical forms are used in this document to mean that "above" refers to the electric machine 2 and that "below" refers to the suction pipe 10, since these elements are arranged in relation to gravity in a water power device according to the invention, i.e., at the very top and the very bottom. Therefore, if an invention file: 28848 DE / HZT - 7 -

[0035] If a hydroelectric power plant comprises several elements with the same name, such as two turbine covers, then accordingly the "upper turbine cover" is located closer to the electric machine than the "lower turbine cover".

[0036] Figure 2 shows an enlarged detail from Figure 1 relating to the connection between the first and second assemblies. A water power device 1 according to the invention comprises a first contact surface, designated 5.1, and a second contact surface, designated 9.1. The first contact surface 5.1 is located on the first assembly, specifically on the crossbeam ring 5. The second contact surface 9.1 is located on the second assembly, and in the illustrated example, on the upper deck 9 of the guide vane. The first contact surface 5.1 is oriented towards the suction pipe 10, while the second contact surface 9.1 is oriented towards the electric motor 2.

[0037] In the embodiment shown in the figures, the contact surfaces each have the shape of circular rings, and the surface normals of contact surfaces 5.1 and 9.1 point precisely in the directions mentioned. The surface normals could also run obliquely to the vertical, so that the contact surfaces take the shape of the hulls of nested truncated cones.

[0038] Conventional hydropower plants also have such contact surfaces, but these are arranged in reverse, i.e., in conventional hydropower plants the first contact surface 5.1 is oriented towards the electric machine 2, while the second contact surface 9.1 is oriented towards the suction pipe 10.

[0039] Figure 3 shows the second assembly or module in its final or installed position. In this position, the two contact surfaces 5.1 and 9.1 are in contact with each other. Furthermore, the turbine shaft flange is arranged in this position so that it can be bolted to the generator shaft flange, since the illustrated particularly preferred embodiment does not have an intermediate shaft. File: 28848 DE / HZT - 8 -

[0040] Figure 4 shows further details relating to the connection of the first and second assemblies. The hydropower device includes connecting elements designed to connect the first and second contact surfaces. Advantageously, these connecting elements can consist of a plurality of screws that penetrate the crossbeam ring 5 and engage with the second assembly, as shown in Figure 4 and designated 11.

[0041] The inventors have recognized that the arrangement according to the invention leads to the connecting elements 11 being relieved of stress by the water pressure acting in the hydraulic machine during operation. This results from the fact that the first and second contact surfaces form a positive fit which counteracts the water pressure acting in the hydraulic machine during operation, since the contact surfaces are pressed together by the water pressure.

[0042] In order for the described positive locking and thus the relief of the connecting elements 11 by the water pressure to occur, the second contact surface 9.1 must be located on an element of the module that is pressed by the water pressure towards the electric machine and thus against the first contact surface 5.1. Such elements are the aforementioned upper deck 9 or the upper turbine cover. These two elements can also form an integral unit.

[0043] In conventional hydropower plants, the opposite is true, i.e., the water pressure during operation leads to a permanent load on the connecting means 11, since the water pressure causes the two contact surfaces to be pushed away from each other.

[0044] A water power device according to the invention can comprise more than one first and more than one second contact surface. Figure 4 shows in particular that the embodiment described so far comprises a further first and a further second contact surface which are in contact with each other in the final or installed position of the module. The further contact surfaces are arranged below the contact surfaces described above. The further contact surfaces can be used for [File: 28848 DE / HZT - 9 -]

[0045] to arrange guiding elements at this point. In addition to the guiding elements, connecting elements can also be provided at this point, which provide axial fixation of the module or parts of the module. The other contact surfaces are not pressed together by the water pressure, so there is no relief of the axial connecting elements at this point.

[0046] Figure 4 shows such guide elements in the form of a plurality of guide pins, one of which is labelled 12. These guide elements serve to center and guide the module during installation, making it easier to bring it into its final position. Guide elements can be arranged on any contact surface. The previously mentioned design of the contact surfaces themselves as truncated cone shells also constitutes such a guide element, as it facilitates the centering of the module. Guide elements in the form of guide pins stiffen the hydropower device against torsional forces, thus relieving the screws of such forces.

[0047] The inventive method for assembling a hydropower plant in a first embodiment comprises the following steps:

[0048] S1: Provision of a first assembly, wherein the provision of the first assembly includes the encasing of the spiral casing in concrete;

[0049] S2: Provisioning a module;

[0050] S3: Positioning of the module below the first assembly;

[0051] S4: Lifting the module to bring at least one first contact surface into contact with a second contact surface;

[0052] S5: Connecting the module to the first assembly;

[0053] where steps S1 and S2 are executed at least partially in parallel.

[0054] For steps S3 and S4, suitable lifting equipment for the vertical movement and suitable equipment for the horizontal movement of the module must be available. A rail system is suitable for the horizontal movement. A ceiling crane or a floor-mounted lifting system can be used as the lifting equipment. A floor-mounted hydraulic gantry crane can be used for the vertical movement. (File: 28848 DE / HZT - 10 -)

[0055] and horizontal movement can be achieved in combination. Furthermore, the linear servomotors of a gantry crane enable particularly controlled lifting of the module, which is very advantageous for carrying out step S4.

[0056] The inventive design of a hydropower plant and the inventive assembly method offer a number of related advantages over the prior art: The installation of a large assembly in the form of the module described above reduces assembly time. This is made possible by the fact that bottom installation provides sufficient space for the installation of even large modules, such as those found in multi-stage pumps or pump-turbines. Furthermore, in these latter cases, encasing the volute casing in concrete allows for its associated advantages. No intermediate shaft is required, thus avoiding the disadvantages associated with such a shaft. Alternatively, a short intermediate shaft can be used if free access from above is required for other reasons. The arrangement of the contact surfaces ensures that the connecting elements are relieved of stress during operation.A further time advantage is achieved by the at least partially parallel execution of steps S1 and S2.

[0057] The latter advantage can be further enhanced by assembling the module in a production facility during step S2, and then transporting the entire module from there to the powerhouse of the hydroelectric plant. A further time saving arises if the customer requests a trial assembly of the hydraulic machine, as this can then be carried out as a sub-step of step S2 in the production facility, eliminating the need to disassemble and reassemble the module at the powerhouse. For the trial assembly, it may be necessary to use an additional, manufactured crossbeam ring as a placeholder for the crossbeam ring that will be embedded in the powerhouse, connected to the spiral casing.

[0058] This disadvantage can be avoided by the measures described in connection with Figures 5 and 6. File: 28848 DE / HZT - 11 -

[0059] Figure 5 shows a truss ring, labeled 5. A truss ring typically comprises an upper and a lower deck. The two decks are connected by a multitude of trusses. In Figure 5, one of the trusses is labeled 5.4. The trusses 5.4 fulfill two functions. First, they act as tie rods, preventing the truss decks from being moved apart by water pressure. Second, they serve to channel water. To minimize hydraulic losses during water flow through the trusses, the cross-sectional profile of the trusses is hydraulically optimized.

[0060] According to the invention, it is advantageous if the truss ring 5 is provided in two parts in step S1. Each of the two separate parts comprises a portion of both truss decks and of all trusses. To distinguish between the two parts, one is referred to as the "base body" and the other as the "inner division." In Figure 5, the base body is designated 5.2 and the inner division 5.3. The base body 5.2 comprises the parts of the truss ring that are connected to the spiral housing 4, while the inner division 5.3 represents, so to speak, the interface to the module. The base body 5.2 and the inner division 5.3 are designed such that they can be detachably connected to one another. The base body 5.2 surrounds the inner division 5.3.

[0061] According to the invention, it is further advantageous if, in step S1, the final machining of the crossbeams 5.4 takes place when the base body 5.2 and the inner partial ring 5.3 are joined together. This ensures the best possible fit between the base body 5.2 and the inner partial ring 5.3 in the area of ​​the crossbeams 5.4.

[0062] The base body 5.2 can now be embedded in concrete together with the spiral housing 4 in step S1, while in parallel the inner partial ring 5.3 is used in step S2 when preparing the module. A trial assembly can then be performed to ensure the correct fit between the module and the crossbeam ring 5. (File: 28848 DE / HZT - 12 -)

[0063] This can be verified. In this way, rework in the powerhouse can be avoided.

[0064] Figure 6 shows the inner division 5.3 with parts of the module that adjoin the inner division 5.3, i.e., in an arrangement that could result during assembly of the module to ensure a precise fit. These are the upper deck of the guide vane assembly, designated 9, and the lower deck of the guide vane assembly, designated 13. In differently designed hydraulic machines, these could also be other parts, e.g., the upper and lower turbine covers.

[0065] It is advantageous if the inner division 5.3 is designed so that it can be connected to an adjacent part of the module. The inner division 5.3 can then be transported and moved together with the module in steps S3, S4, and S5. The connection can be detachable or permanent. In the latter case, the inner division 5.3 forms an integral part of the relevant part of the module, for example, the upper or lower guide vane deck or the upper or lower turbine cover. In this case, the inner division 5.3 belongs to the module, and the first assembly comprises only the base body 5.2 and the spiral casing 4. The first assembly thus comprises only a part of the crosshead ring 5. File: 28848 DE / HZT

[0066] - 13 -

[0067] Reference symbol list

[0068] 1 hydroelectric power plant

[0069] 2. Electric machine or generator

[0070] 2.1 Shaft of the electric machine or generator shaft

[0071] 3 Hydraulic machine or turbine

[0072] 4 spiral casings

[0073] 5 traverse ring

[0074] 5.1 First contact surface

[0075] 5.2 Basic body

[0076] 5.3 Inner partial ring

[0077] 5.4 Traverse

[0078] 6 Shaft of the hydraulic machine or turbine shaft 7 Impeller

[0079] 8 guide vanes

[0080] 9 Upper deck of the guide vane assembly or upper turbine cover 9.1 Second contact surface

[0081] 10 Intake pipe

[0082] 11 Fasteners

[0083] 12 guide pins

[0084] 13 Lower deck of the guide vane assembly or lower turbine cover

Claims

File: 28848 DE / HZT - 14 - Patent claims 1. Hydropower device (1) comprising an electric machine (2) and a hydraulic machine (3) with a vertical axis of rotation, wherein the electric machine (2) comprises a generator shaft (2.1), and wherein the hydraulic machine (3) comprises a first and a second assembly and a suction pipe (10), and wherein the first assembly comprises a encased spiral casing (4), at least a part of a crossbeam ring (5) and at least one first contact surface (5.1), and wherein the second assembly comprises a turbine shaft (6), at least one radially flowable impeller (7) and at least one second contact surface (9.1), and wherein the at least one first contact surface (5.1) and the at least one second contact surface (9.1) are in contact with each other and are connected by connecting means (11), characterized in that the at least one first contact surface (5.1) is oriented towards the suction pipe (10), and the at least one second contact surface (9.1) is oriented towards the suction pipe (10).1) is oriented towards the electric machine (2) so that a first contact surface (5.1) forms a positive connection with a second contact surface (9.1) which can counteract a pressure load generated by the water pressure acting during the operation of the water power device (1).

2. Hydropower device (1) according to claim 1, wherein the traverse ring (5) comprises an upper deck, a lower deck and a plurality of traverses (5.4) connecting the upper to the lower deck, and wherein the traverse ring (5) is formed in two parts, and wherein a first part forms a base body (5.2) and a second part forms an inner partial ring (5.3), wherein the base body (5.2) and inner partial ring (5.3) each comprise a part of the two decks and a part of each traverse (5.4) and are designed such that they can be detachably connected to one another, and wherein the base body (5.3) comprises the parts of the traverse ring (5) which are connected to the spiral casing (4). File: 28848 DE / HZT - 15 - 3. Hydropower device (1) according to claim 2, wherein the inner division (5.3) can be detachably connected to the second assembly.

4. Hydropower device (1 ) according to claim 2, wherein the inner division (5.3) is permanently connected to a part of the second assembly.

5. Hydropower device (1) according to one of the preceding claims, wherein the hydraulic machine (3) is designed in multiple stages.

6. Hydroelectric power plant (1) according to one of the preceding claims, wherein the turbine shaft (6) is directly connected to the generator shaft (2.1).

7. Hydropower plant (1) according to one of the preceding claims, wherein the second assembly comprises at least one guide apparatus with a plurality of rotatably mounted guide vanes (8).

8. Method for assembling a hydropower plant (1) according to one of the preceding claims, wherein the second assembly forms a module, and wherein the method comprises the following steps: S1: Provision of the first assembly including the encasing of the spiral casing in concrete (4); S2: Provisioning of the module; S3: Positioning of the module below the first assembly; S4: Lifting the module to bring at least one first contact surface (5.1) into contact with a second contact surface (9.1); S5: Connecting the module to the first assembly; and wherein steps S1 and S2 are performed at least partially in parallel.

9. Method according to claim 8 for assembling a hydropower plant (1) according to any one of claims 2 to 7, wherein the finishing of the crossbeams (5.4) is carried out while the base body (5.2) is connected to the inner division (5.3). File: 28848 DE / HZT - 16 - 10. Method according to claim 8 or 9 for assembling a hydropower device (1) according to any one of claims 2 to 7, wherein the inner division (5.3) is used in step S2.

11. Method according to claim 10 for assembling a hydropower device (1) according to any one of claims 2 to 7, wherein step S2 comprises a trial assembly of the module in which the inner division (5.3) is used to demonstrate a fit between the module and the crossbeam ring (5).

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