Method for manufacturing a hydropower plant

Abstract

Method for manufacturing a hydroelectric power plant (1) comprising a powerhouse, an electric machine (2) and a hydraulic machine (3), wherein the hydraulic machine comprises a first assembly and a module, and wherein a crossbeam ring (5) comprises a base body and an inner partial ring, and wherein the method comprises the following steps: S1: providing the first assembly, wherein providing the first assembly includes encasing the spiral casing (4) in concrete and connecting the base body to the spiral casing; S2: providing the module; S3: positioning the module below or above the first assembly; S4: moving the module to bring at least a first contact surface into contact with a second contact surface; S5: connecting the module to the first assembly;and wherein steps S1 and S2 are performed at least partially in parallel and the inner partial ring is used in step S2 to ensure a precise fit between the module and the crossbeam ring.

Description

The invention relates to a method for manufacturing a hydropower device, wherein the device comprises a hydraulic machine with a vertical or horizontal axis of rotation. This machine can be a turbine, pump, or pump-turbine. The hydraulic machine includes an impeller designed for radial or axial flow. Impellers with radial flow are, for example, of the Francis type. Hydraulic machines with an impeller for axial flow can, for example, be a so-called propeller machine. The hydraulic machine can be single-stage or multi-stage, i.e., it can have one or more such impellers. The rapidly increasing demands on the manufacturing accuracy of hydraulic machines, driven by growing efficiency, are making trial assembly at the manufacturer's plant increasingly necessary. This entails a complete additional disassembly and assembly cycle. Therefore, reducing assembly time is highly desirable, provided it does not negatively impact manufacturing accuracy. EP 3 942 173 B1 discloses a method for assembling a hydropower plant with a vertical axis of rotation, 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 time-efficient. Document JP 2019-27314 A discloses a method for assembling a hydropower plant in which the crossbeam ring is designed in two parts. An outer portion of the crosshead ring is connected to the spiral casing. An inner portion of the crosshead ring can be separated from the outer portion. During assembly, the inner portion of the crosshead ring can be installed together with other parts of the hydraulic machine, thus reducing assembly time. The largest assembly disclosed in this document, which can be installed together with the inner portion of the crosshead ring, additionally includes the guide vane assembly, the upper turbine cover, the lower turbine cover, and the guide vane assembly opening-closing mechanism (see Fig. 2 of JP 2019-27314 A). Installation and removal are performed from above. The object of the invention is to improve the methods known from the prior art for manufacturing a water power plant with a hydraulic machine in such a way that both the precision of the workmanship and the manufacturing time of such a water power plant can be improved. The problem is solved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention are found in the dependent claims. The inventors were guided by the idea of ​​not only making the actual assembly in the powerhouse of the hydroelectric plant as efficient as possible, but also including the manufacturing of certain components of the hydroelectric plant. The production of these components takes place in a manufacturing facility, usually the manufacturer's plant, and includes a trial assembly. The inventors recognized that the modular assembly disclosed in EP 3 942 173 B1 represents a good starting point, as it already saves considerable time. Furthermore, the inventors recognized that the use of a two-part crossbar ring, as disclosed in JP 2019-27314 A, can facilitate and further accelerate assembly. However, the inventors also recognized that simply combining these two concepts does not fully exploit their potential with regard to the manufacturing process, as will be explained in more detail below. In both documents EP 3 942 173 B1 and JP 2019-27314 A, the module or the relevant assembly is mounted from above. In the method described in this document, the module can be mounted from both above and below, whereby the terms "above" and "below" are used in a broader sense than usual, as will be explained in more detail below. The inventors have recognized that mounting the module from below offers several advantages (su), which is why mounting from below is preferred. Therefore, the inventive method will be described in more detail below mainly for this preferred case. However, mounting the module from above is not thereby excluded. The invention is explained below with reference to the figures. The figures show in detail: Fig. 1: Water power plant with one module during assembly; Fig. 2: Detail from Fig. 1; Fig. 3: Water power plant from Fig. 2 in the assembled state; Fig. 4: Detail from Fig. 3; Fig. 5: Crossbeam ring of a water power plant in the method according to the invention; Fig. 6: Detail of the method according to the invention. Fig. 1 shows a water power plant. The water power plant is designated 1 and is depicted in a state relating to the assembly of the water power plant 1. In the depicted state, certain parts are not yet assembled. These parts are therefore only indicated by dashed lines in Fig. 1. These parts include at least parts of the suction pipe and usually also the electric motor. Further special features relating to the assembly are discussed in more detail below in connection with the method according to the invention. 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. 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. The electric machine 2 includes a generator shaft, which is labelled 2.1. 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 can be configured such that it can be directly connected to the generator shaft 2.1. That is, the water power unit 1 then does not include an intermediate shaft. 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. The hydraulic machine 3 shown in Fig. 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. 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. The hydraulic machine 3 shown in Fig. 1 comprises three assemblies that are not connected in the illustrated state. A first assembly is formed from the spiral casing 4 and the crosshead ring 5. This first assembly is already in its final position, i.e., in the installed position. A second assembly is arranged "freely suspended" below the first assembly in Fig. 1; that is, the lifting means required to hold this second assembly 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, wherein 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 one in Fig.The second assembly shown in Figure 1 also includes the stationary waterways 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 can be the case, for example, with simple pumps. In this case, the module naturally does not include a guide vane assembly. Instead, the module then includes other stationary elements, such as a turbine cover and a lower deck for the impeller. To bring the second assembly into its final position (see Fig. 3), it must be moved in a vertical direction in Fig. 1. 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 Fig. 1, and possibly rotary unions for it. The third assembly must not yet be fully assembled in order for the second assembly or module to be in the position shown in Fig. 1. It should be noted 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. For hydraulic machines with a vertical axis of rotation, the terminology used in this document corresponds to common usage, since in such machines the electric machine 2 is located at the very top and the suction pipe 10 at the very bottom.In the case of hydraulic machines with a horizontal axis of rotation, the terminology used in this document differs from ordinary usage, as the terms "above" and "below" no longer refer to the direction of gravity, but solely to the position of the components electrical machine 2 and suction pipe 10, which, in a hydraulic machine with a horizontal axis of rotation, are arranged laterally to the side of the hydraulic machine in the axial direction. In any case, the hydraulic machine is positioned between these two components. If a hydroelectric power plant includes several elements with the same name, such as two turbine covers, then in every case the "upper turbine cover" is located closer to the electric machine than the "lower turbine cover". Fig. 2 shows an enlarged detail from Fig. 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. In a water power device where the module is mounted from below, the first contact surface 5.1 is oriented towards the draft tube 10, while the second contact surface 9.1 is oriented towards the electric motor 2. In hydropower installations where the module is mounted from above, the contact surfaces are oriented in reverse, i.e. 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. 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. Fig. 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 positioned so that it can be bolted to the generator shaft flange, since the illustrated particularly preferred embodiment (i.e., when the module is mounted from below) does not have an intermediate shaft. This keeps the axial length of the rotating parts short, resulting in improved shaft dynamics compared to hydropower plants with an intermediate shaft. Fig. 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 Fig. 4 and designated by 11. The inventors recognized that the arrangement shown in the figures causes the connecting elements 11 to be relieved of stress by the water pressure acting on 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 on the hydraulic machine during operation, since the contact surfaces are pressed together by the water pressure. 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. In hydropower installations where the module is mounted from above, the opposite is true, i.e., the water pressure during operation leads to a permanent load on the connecting means 11, as the water pressure causes the two contact surfaces to be pushed away from each other. A water power device relating 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 to arrange guide elements at this location. In addition to the guide elements, connecting elements can also be provided at this location, which effect axial fixation of the module or parts of the module. The further contact surfaces are not pressed together by the water pressure, so that there is no relief of the axial connecting elements at this location. Fig. 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 system against torsional forces, thus reducing the load on the screws from such forces. The manufacturing process according to the invention provides for the use of a two-part traverse ring, which, however, is not used only during transport to the powerhouse and during assembly in the powerhouse, as in JP 2019-27314 A. This is explained in more detail below. Fig. 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 Fig. 5, one of the trusses is labeled 5.4. The trusses 5.4 fulfill two functions. Firstly, they act as tie rods, preventing the truss decks from being moved apart by water pressure. Secondly, 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. According to the invention, the truss ring 5 is provided in two parts. 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 designated as the "base body" and the other as the "inner partial ring." In Fig. 5, the base body is designated 5.2 and the inner partial ring 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 partial ring 5.3 represents, so to speak, the interface to the module. The base body 5.2 and the inner partial ring 5.3 are designed such that they can be detachably connected to one another. The base body 5.2 surrounds the inner partial ring 5.3. The inventive method for manufacturing a hydropower plant in a first embodiment comprises the following steps: S1: Providing a first assembly with a two-part crossbeam ring, wherein the provision of the first assembly includes encasing the spiral casing in concrete and connecting the base body to the spiral casing; S2: Providing a module; S3: Positioning the module below or above the first assembly; S4: Moving the module to bring at least a first contact surface into contact with a second contact surface; S5: Connecting the module to the first assembly; wherein steps S1 and S2 are carried out at least partially in parallel and the inner partial ring of the crossbeam ring is used in step S2 to ensure a precise fit between the module and the crossbeam ring. According to the invention, in step S1, the base body is embedded in concrete together with the spiral casing, or connected to the embedded spiral casing. Simultaneously, in step S2, the inner partial ring is used during the module's preparation. This inner ring serves to ensure the precise fit between the module and the crossbeam ring. This precise fit includes, for example, the stepless guidance of the water path from the crossbeam ring to the guide vane assembly, i.e., the relative positioning of the stationary parts of the module located above and below the impeller. In other words, the inner partial ring transfers the relevant geometric information from the construction site (i.e., the powerhouse) to the production facility and thus to the module, enabling the processes at these two separate locations to be carried out as parallel as possible. The method according to the invention is particularly advantageous when the customer requires a trial assembly at the manufacturer's plant, since the inner partial ring can also be used to demonstrate the accuracy of fit during the trial assembly. The module can always be transported to the powerhouse in one piece, saving further time. If no trial assembly is required at the manufacturer's plant, the module can also be assembled in or near the powerhouse. A trial assembly can also include a functional test of the module's rotating parts (i.e., the impellers) and the moving parts of the guide vanes. By ensuring the precise fit between the module and the traverse ring and by performing the functional test, rework in the powerhouse can be reliably avoided. The movement of the module in step S4 always occurs predominantly in the axial direction. With a hydraulic machine with a vertical axis of rotation, the module is therefore raised or lowered. With a hydraulic machine with a horizontal axis of rotation, however, the module is moved predominantly horizontally. Fig. 6 shows the inner partial ring 5.3 with parts of the module that adjoin the inner partial ring 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. 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. It is advantageous if the inner partial ring 5.3 is designed so that it can be connected to an adjacent part of the module. The inner partial ring 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 partial ring 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 partial ring 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 portion of the crosshead ring 5. It is particularly advantageous if the inner ring can be connected to the module in such a way that it can establish a force flow from the stationary elements located above the rotating parts to the stationary elements of the module located below the rotating parts. The stationary elements then form a unit fixed by the inner ring, against which the rotating parts can also be braced. This allows the module to be transported safely with a horizontal axis of rotation, which significantly reduces the transport height, especially in the case of multi-stage hydraulic machines. The rotating parts include all impellers and the turbine shaft. The stationary elements include all parts of the module that do not rotate together with the rotating parts during operation of the hydropower plant. Reference symbol list 1 Hydroelectric power plant 2 Electric machine or generator 2.1 Shaft of the electric machine or generator shaft 3 Hydraulic machine or turbine 4 Spiral casing 5 Crosshead ring 5.1 First contact surface 5.2 Base body 5.3 Inner partial ring 5.4 Crosshead 6 Shaft of the hydraulic machine or turbine shaft 7 Impeller 8 Guide vane 9 Upper deck of the guide vane assembly or upper turbine cover 9.1 Second contact surface 10 Intake pipe 11 Connecting element 12 Guide pin 13 Lower deck of the guide vane assembly or lower turbine cover

Claims

Method for manufacturing a hydroelectric power plant (1) comprising a powerhouse, an electric machine (2) and a hydraulic machine (3), wherein the hydraulic machine (3) comprises a first and a second assembly, and wherein the first assembly comprises a spiral casing (4), at least a part of a crosshead ring (5) and at least a 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 a second contact surface (9.1), and wherein the crosshead ring (5) comprises a base body (5.2) and an inner partial ring (5.3), and wherein the second assembly forms a module, and wherein the method comprises the following steps: S1: Providing the first assembly, wherein providing the first assembly involves encasing the spiral casing (4) in concrete and connecting the base body (5.2) with the spiral housing (4); S2: Provision of the module; S3: Positioning of the module below or above the first assembly; S4: Moving the module to bring at least a 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 and the inner partial ring (5.3) is used in step S2 to ensure a fit between the module and the crossbar ring (5). Method according to claim 1, wherein step S2 includes a trial assembly of the module in a production facility separate from the powerhouse, and the inner partial ring (5.3) is used to demonstrate a fit between the module and the crossbeam ring (5). Method according to claim 2, wherein the module is transported as a whole from the production site to the powerhouse. Method according to claim 3, wherein the module comprises stationary elements (9, 13) and an axis of rotation, and wherein the stationary elements (9, 13) form a unit fixed by the inner partial ring (5.3) during transport, and wherein the module is transported with a horizontally extending axis of rotation. Method according to one of claims 2 to 4, wherein the module comprises rotatable parts (6, 7) and the guide apparatus comprises movable parts (8), and wherein the trial assembly includes a functional test of rotatable parts (6, 7) of the module and of movable parts (8) of the guide apparatus. Method according to one of the preceding claims, wherein in step S1 a final machining of the crossbeams (5.4) takes place when the base body (5.2) and the inner partial ring (5.3) are connected to each other. Method according to one of the preceding claims, wherein the inner partial ring (5.3) can be detachably connected to the module. Method according to any one of claims 1 to 6, wherein the inner partial ring (5.3) is permanently connected to a part (9) of the module. Method according to one of the preceding claims, wherein the first assembly comprises at least one guide apparatus with a plurality of rotatably mounted guide vanes (8).

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