Technical installation for generating electricity

Abstract

The invention relates to a technical installation (1) for generating electricity, having, for a power mode, a shafting (2), comprising at least one turbine (3) and a first generator (4) which can be driven by the at least one turbine (3), and a transformer (7) which is electrically connected to the first generator (4) and can be selectively connected to or disconnected from an electrical network (9) via an electrical switching device (8). The technical installation is characterized in that the transformer (7) is in the form of a three-winding transformer; a second generator (10) is provided on a separate shafting (11) for a phase-shifting mode; both generators (4, 10) are connected to the transformer (7); and a second electrical switching device (12) is provided which is designed and mounted in such a way that an electrical connection between the two generators (4, 10) can be selectively closed or interrupted by means of the electrical switching device.

Description

[0001] 2024PF00792 Foreign version

[0002] 1

[0003] Description

[0004] Technical plant for electricity generation

[0005] The invention relates to a technical plant for generating electricity, in particular in the form of a power plant, which for power operation has a shaft train with at least one turbine and a first generator which can be driven by the at least one turbine and a transformer electrically connected to the first generator, which can be selectively connected to or disconnected from an electrical network via an electrical switching device.

[0006] Such systems are generally known in the state of the art. In principle, it would be desirable to enable, in addition to power operation where active power is fed into an electrical grid, a so-called phase-shifting operation for generating controlled reactive power without active power feed-in, in accordance with DIN EN IEC 60034-3 (VDE 0530, 3): 2021-07. It would also be desirable to be able to supplement such systems with a flywheel device, for example, to provide instantaneous reserve within the framework of market-based procurement of instantaneous reserve. Corresponding requirements are addressed in the current draft of the German Power Plant Security Act.

[0007] During operation, at least one turbine and the generator must be mechanically coupled to each other via the shaft train in order to convert the mechanical power of the turbine into electrical power in the generator.

[0008] In pure phase shifter operation or in phase shifter and flywheel operation, it is technically necessary to use the 2024PF00792 foreign version.

[0009] 2. To decouple at least one turbine from the rotating operation of the generator in order to avoid losses caused by the turbine being dragged along and the associated risk of damage.

[0010] A current decoupling solution involves a mechanical coupling in the form of a self-synchronizing coupling between at least one turbine and the generator. Since the shaft train on which the at least one turbine and the generator are mounted is intended to have only one fixed bearing, and this bearing is located on the side of the turbine facing away from the generator, the coupling must transmit shaft train expansions and thrust forces. This places high technical demands on the coupling and currently limits its applicability to small and medium-sized steam turbines.

[0011] Starting from this state of the art, it is an object of the present invention to create a technical plant for generating electricity of the type mentioned above with an alternative structure.

[0012] To solve this problem, the present invention provides a technical system for generating electricity, in particular in the form of a power plant, which for power operation comprises a shaft train with at least one turbine and a first generator which can be driven by the at least one turbine, and a transformer electrically connected to the first generator, which can be selectively connected to or disconnected from an electrical network via a first electrical switching device, characterized in that the transformer is designed as a three-winding transformer, and that for phase-shifting operation a second generator is connected to a

[0013] 3. A separate shaft train is provided for both generators to be connected to the transformer, and a second electrical switching device is provided, which is designed and arranged such that an electrical connection between the two generators can be selectively closed or broken. To start up and synchronize both generators with the electrical grid, both generators are electrically connected to each other by appropriately switching the second electrical switching device, while the transformer is still disconnected from the electrical grid via the first electrical switching device. Thus, the first generator, which is responsible for power operation, pulls the second generator along via the electrical connection.Once the two generators are running synchronously with the electrical grid, the transformer is connected to the grid by appropriately switching the first electrical switching device. The coupling of the generators provided by the second electrical switching device allows the tasks of power generation in mains operation and grid service in phase-shifting operation to be distributed between two geographically independent shaft trains, without requiring a second feed-in point to the electrical grid. This reduces the overall length of the two shaft trains compared to a single shaft train, resulting in the advantage of reduced twisting during torsional vibrations. Furthermore, each shaft train can be implemented with a fixed bearing, so there are no longer any limitations on the application of the solution according to the invention with regard to turbine size.By dividing the turbine into two shaft trains, the phase shifter operation can be maintained even when service and repair work is being carried out on the turbine. (See the initial foreign version 2024PF00792.)

[0014] In the known solution described in section 4, which uses a single shaft and a self-synchronizing coupling, this is not possible, as part of the shaft would still be rotating during work, thus posing a hazard to service personnel. Regarding costs, it is expected that the additional construction costs resulting from the extra generator can be recouped, since the turbine housing no longer needs to be extended to accommodate the space required for the mechanical coupling, bearings, and, if applicable, the flywheel. With regard to operating costs, the solution according to the invention has the advantage that the optimal generator technology can be selected for both power generation and grid service.For example, the first generator can be designed as a high-efficiency, hydrogen-cooled power generator, while the second generator used for grid service can be an air-cooled generator operating with variable casing pressure, minimizing power losses during grid service provision. The solution according to the invention can also be retrofitted to existing installations, as the new functionality is no longer tied to the power generation location. Instead, only the transformer needs to be replaced and a cable connection installed between the second generator and the transformer.

[0015] According to one embodiment of the present invention, a starting converter or starting motor connected to the second generator is provided, and a third electrical switching device is designed and arranged such that the electrical connection between the second generator and the transformer can be selectively closed or opened. 2024PF00792 Foreign version

[0016] Thanks to the starting inverter or starting motor, the second generator can be synchronized even if at least one turbine is unavailable. This increases the availability of grid services compared to a solution without a starting device on the second generator.

[0017] Preferably, the technical system is configured to be operated optionally in a passive phase-shifting operating mode, in which the first electrical switching device is switched in such a way that the transformer is connected to the electrical network, and in which the second electrical switching device is switched in such a way that the electrical connection between the two generators is interrupted, and in which the third electrical switching device, if present, is switched in such a way that the transformer is electrically connected to the second generator.

[0018] Advantageously, the technical system is configured to operate in two modes: first, in which the second electrical switching device and, if present, the third electrical switching device are switched such that the generators are electrically connected, and second, in which the first electrical switching device is switched such that the transformer is disconnected from the electrical grid. Accordingly, in starting mode, the second generator is driven by the first generator via the electrical coupling between the two generators provided by the second electrical switching device until both generators are synchronized with the electrical grid. The first electrical switching device can then be switched to connect both generators to the electrical grid. 2024PF00792 Foreign version

[0019] 6

[0020] Advantageously, the technical system is configured to operate in a second starting mode, in which the second electrical switching device is configured such that the first generator is electrically disconnected from the transformer, in which, if present, the third electrical switching device is configured such that the second generator is electrically connected to the transformer, and in which the first electrical switching device is configured such that the transformer is electrically connected to the electrical grid. Accordingly, in the second starting mode, the first generator can be started up until it is synchronized with the electrical grid, while the second generator, already synchronized with and connected to the electrical grid, provides grid services.Once the first generator is synchronized with the electrical grid, it can also be electrically connected to the electrical grid and the second generator by appropriately switching the second switching device.

[0021] Preferably, the technical system is configured to be operated optionally in an active power mode in which the first electrical switching device and the second electrical switching device are connected in such a way that the generator is electrically connected to the transformer, and that the transformer is connected to the electrical network.

[0022] Preferably, the first electrical switching device is arranged between the transformer and the electrical network. 2024PF00792 Foreign version

[0023] 7

[0024] The second electrical switching device is preferably arranged between the first generator and the transformer.

[0025] At least one of the turbines could be a gas turbine, a steam turbine, or a water turbine.

[0026] Advantageously, no mechanical coupling device is provided between at least one turbine and the first generator.

[0027] Several turbines can also drive the first generator together. For example, the plant can be designed as a combined cycle gas turbine (CCGT) single-shaft plant. In this case, at least one turbine can preferably be connected to or disconnected from the first generator via a mechanical coupling. Preferably, no mechanical coupling device is provided between the first turbine and the first generator, although a mechanical coupling can be provided between the second turbine and the first generator.

[0028] Each shaft preferably has only a single fixed bearing.

[0029] The second generator is advantageously designed to be connected to a flywheel device via the separate shaft train.

[0030] Furthermore, the present invention provides a method for operating a technical plant according to one of the preceding claims, in which an active power mode is provided, in which the first electrical switching device and the second electrical switching device 2024PF00792 Foreign version

[0031] 8 are connected in such a way that the generator is electrically connected to the transformer, and that the transformer is connected to the electrical network, and / or in which a passive phase-shifting mode is provided, in which the first electrical switching device is connected in such a way that the transformer is connected to the electrical network, and in which the second electrical switching device is connected in such a way that the electrical connection between the two generators is interrupted, and in which the third electrical switching device, if present, is connected in such a way that the transformer is electrically connected to the second generator, and / or in which a first starting mode is provided, in which the second electrical switching device and, if present, the third electrical switching device are connected in such a way that the generators are electrically connected to each other,and in which the first electrical switching device is connected in such a way that the transformer is disconnected from the electrical network, and / or in which a second starting mode is provided in which the second electrical switching device is connected in such a way that the first generator is electrically disconnected from the transformer, in which, if present, the third electrical switching device is connected in such a way that the second generator is electrically connected to the transformer, and in which the first electrical switching device is connected in such a way that the transformer is electrically connected to the electrical network.

[0032] Further features and advantages of the present invention will become clear from the following description with reference to the accompanying drawing. This is the foreign version 2024PF00792.

[0033] Figure 1 shows a schematic view of a known technical plant for generating electricity;

[0034] Figure 2 shows a schematic view of a technical plant for generating electricity according to a first embodiment of the present invention;

[0035] Figure 3 shows a schematic view of a technical plant for generating electricity according to a second embodiment of the present invention and

[0036] Figure 4 shows a schematic view of a technical plant for generating electricity according to a third embodiment of the present invention.

[0037] The following reference references refer to identical or similar components or component areas.

[0038] Figure 1 shows a known technical plant 101 for generating electricity, which for power and phase shift operation includes a single shaft train 102 with a turbine designed here as a steam turbine.

[0039] 103 and a generator driven by turbine 103

[0040] 104. Furthermore, the system 101 includes a transformer 106 electrically connected to the generator 104, which can be selectively connected to or disconnected from an electrical network 108 via an electrical switching device 107. The shaft train 102 includes a single fixed bearing 109, which is positioned on the side of the turbine 103 facing away from the generator 104. A mechanical coupling 110 is provided between the turbine 103 and the generator 104, which in this case is a self-synchronizing coupling. The system 101 is designed to drive a flywheel assembly 111, shown in dashed lines in Figure 1. 2024PF00792 Foreign version

[0041] 10 to be retrofitted, which would also be connected to the generator 104 via the shaft train 102 .

[0042] In power operation, the turbine 103 and the generator 104 are mechanically connected via the coupling 110 to convert the mechanical power of the turbine 103 into electrical power in the generator 104. In pure phase-shifting operation, or in phase-shifting and flywheel operation, the coupling 110 is open to prevent losses caused by the turbine 103 being dragged along, as well as the associated risk of damage to the turbine 103. One problem with this design is that the shaft assembly 102 is intended to have only the single fixed bearing 109 at the position shown. This means that the coupling 110 must absorb expansions of the shaft assembly 102 as well as thrust forces, which current coupling designs can only accommodate to a limited extent. Accordingly, the applicability of this design is currently limited to small and medium-sized steam turbines.If a flywheel assembly 111 is retrofitted, the design of the shaft train 102 also presents a challenge in terms of shaft dynamics and structural engineering. In plants designed as combined cycle single-shaft plants, the generator is positioned between the gas and steam turbines, which is why neither phase shifter operation nor the addition of a flywheel assembly is possible.

[0043] Figure 2 shows a technical system 1 for generating electricity according to a first embodiment of the present invention, in this case in the form of a power plant. For power operation, the system 1 comprises a first shaft 2 with a turbine 3 and a first generator 4 driven by the turbine 3. The turbine 3 can be designed as a gas, water, or steam turbine. The first shaft 2 has a single fixed bearing 6. No mechanical coupling device is provided between the turbine 3 and the first generator 4. Furthermore, the system 1 has a transformer 7 electrically connected to the first generator 4, which is designed as a three-winding transformer and can be selectively connected to or disconnected from the electrical network 9 via a first electrical switching device 8, which is arranged between the transformer 7 and an electrical network 9.For phase-shifting operation, a second generator 10, electrically connected to the transformer 7, is provided on a second shaft 11, which is also equipped with only one fixed bearing 6. A second electrical switching device 12, designed and arranged such that an electrical connection between the two generators 4, 10 can be selectively closed or opened, is arranged between the first generator 4 and the transformer 7. The second generator 10 can be designed to be connected via the second shaft 11 to a flywheel assembly 13, shown in dashed lines in Figure 2.

[0044] To start up and synchronize both generators 4 and 10 with the electrical grid 9, both generators 4 and 10 are electrically connected to each other by appropriately switching the second electrical switching device 12, while the transformer 7 is still disconnected from the electrical grid 9 via the first electrical switching device 8. Thus, the first generator 4, which is responsible for power operation, pulls the second generator 10 along via the electrical connection. As soon as the two generators 4 and 10 are synchronized with the electrical grid 9, the transformer 7 is disconnected from the electrical grid 9 via the first electrical switching device 8.

[0045] 12

[0046] When the transformer 7 is connected to the electrical network 9, it is connected to the network by appropriate switching of the first electrical switching device 8. The coupling of the generators 4, 10 provided by the second electrical switching device 12 allows the tasks of power generation in power operation and grid service in phase-shifting and, if applicable, flywheel operation to be distributed between the two shaft trains 2, 11, which can be located separately from each other, without requiring a second feed point into the electrical network 9. This results in a very short overall length for both shaft trains 2, 11, which is why twisting of the shaft trains 2, 11 during torsional vibrations is not a problem. In addition, each shaft train 2, 11 can be implemented with a single fixed bearing, so that there are no longer any restrictions on the application of the solution according to the invention with regard to the turbine 3.By dividing the system into two shaft trains 2, 11, passive phase-shifting operation can be maintained even when service and repair work is being carried out on turbine 3. Turbine 3 and generator 4 can then be started up in a further start-up mode, with the second switching device 12 switched accordingly, electrically isolated from transformer 7 and thus from the electrical grid 9 and the second generator 10, while the second generator 10 continues to provide grid services. Once the first generator 4 is synchronized with the electrical grid 9 and the second generator 10, it can be reconnected to transformer 7 and, consequently, to the electrical grid 9 and the second generator 10 by switching the second switching device 12.With regard to operating costs, the previously described structure of the inventive plant 1 has the advantage that for the 2024PF00792 foreign version.

[0047] 13

[0048] The optimal generator technology can be selected for power generation and grid service, respectively. For example, the first generator 4 can be designed as a high-efficiency, hydrogen-cooled generator, while the second generator 10 used for grid service can be an air-cooled generator operating with variable casing pressure, minimizing power losses during grid service provision. The solution according to the invention can also be retrofitted to existing installations, since the second shaft 11 is not tied to the power generation location.

[0049] Figure 3 shows a technical system for generating electricity according to a second embodiment of the present invention. This differs from the system shown in Figure 2 and described above only in that a starting converter 14 connected to the second generator 10 and a third electrical switching device 15 are provided, wherein the third electrical switching device 15 is designed and arranged between the second generator 10 and the transformer 7 such that the electrical connection between the second generator 10 and the transformer 7 can be selectively closed or opened.

[0050] Figure 4 shows a plant 1 according to a third embodiment of the present invention. This differs from the plant shown in Figure 2 and described above in that the first shaft train 2 accommodates two turbines 3a and 3b, which together drive the first generator 4 and which are positioned between them. Thus, plant 1 can, for example, be a combined cycle single-shaft plant with a gas turbine 3a. 2024PF00792 Foreign version

[0051] 14 and a steam turbine 3b, to name just one example. In the illustrated embodiment, the turbine 3b can be selectively connected to or disconnected from the generator via a mechanical coupling 5.

[0052] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived from them by a person skilled in the art without leaving the scope of protection of the invention.

[0053] Regardless of the grammatical gender of a particular term, persons with male, female, or other gender identities are included.

Claims

2024PF00792 Foreign version Patent claims 1. Technical installation (1) for power generation, comprising for power operation a shaft train (2) with at least one turbine (3) and a first generator (4) which can be driven by the at least one turbine (3) and a transformer (7) electrically connected to the first generator (4), which can be selectively connected to or disconnected from an electrical network (9) via a first electrical switching device (8), characterized in that the transformer (7) is designed as a three-winding transformer, that for phase-shifting operation a second generator (10) is provided on a separate shaft train (11), that both generators (4, 10) are connected to the transformer (7), and that a second electrical switching device (12) is provided which is designed and arranged in such a way that an electrical connection between the two generators (4, 10) can be selectively closed or interrupted.

2. Plant (1) according to claim 1, characterized in that a starting converter (14) connected to the second generator (10) is provided, and that a third electrical switching device (15) is provided which is designed and arranged in such a way that the electrical connection between the second generator (10) and the transformer (7) can be selectively closed or interrupted.

3. System (1) according to claim 1 or 2, characterized in that it is configured to be operated selectively in a passive phase-shifting operating mode, in which the first electrical switching device (8) is connected such that the transformer (7) with 2024PF00792 Foreign version 16 is connected to the electrical network (9), and in which the second electrical switching device (12) is switched in such a way that the electrical connection between the two generators (4, 10) is interrupted, and in which the third electrical switching device (15), if present, is switched in such a way that the transformer (7) is electrically connected to the second generator (10).

4. System according to one of the preceding claims, characterized in that it is configured to be operated optionally in a first start-up mode in which the second electrical switching device (12) and, if present, the third electrical switching device (15) is / are switched such that the generators (4, 10) are electrically connected to each other, and in which the first electrical switching device (8) is switched such that the transformer (7) is disconnected from the electrical network (9).

5. System according to one of the preceding claims, characterized in that it is configured to be operated optionally in a second start-up mode, in which the second electrical switching device (12) is switched such that the first generator (4) is electrically disconnected from the transformer (7), in which, if present, the third electrical switching device (15) is switched such that the second generator (10) is electrically connected to the transformer (7), and in which the first electrical switching device (8) is switched such that the transformer (7) is electrically connected to the electrical network (9). 2024PF00792 Foreign version 17 6. System according to one of the preceding claims, characterized in that it is configured to be operated selectively in an active power mode in which the first electrical switching device (8) and the second electrical switching device (12) are connected such that the generator (4) is electrically connected to the transformer (7), and that the transformer (7) is connected to the electrical network (9).

7. System (1) according to one of the preceding claims, characterized in that the first electrical switching device (8) is arranged between the transformer (7) and the electrical network (9).

8. System (1) according to one of the preceding claims, characterized in that the second electrical switching device (12) is arranged between the first generator (4) and the transformer (7).

9. Plant (1) according to one of the preceding claims, characterized in that the at least one turbine (3) is a gas turbine, a steam turbine or a water turbine.

10. Plant (1) according to one of the preceding claims, characterized in that no mechanical coupling device is provided between the at least one turbine (3) and the first generator (4).

11. Plant (1) according to one of the preceding claims, characterized in that several turbines (3a, 3b) jointly drive the first generator (4), wherein between a first turbine (3a) and the first generator 2024PF00792 Foreign version 18 (4) preferably no mechanical coupling device is provided, and wherein a mechanical coupling (5) is preferably provided between the second turbine (3b) and the first generator (4).

12. Plant (1) according to one of the preceding claims, characterized in that a starting converter (14) connected to the second generator (10) is provided, and that a third electrical switching device (15) is provided which is designed and arranged in such a way that the electrical connection between the second generator (10) and the transformer (7) can be selectively closed or interrupted with it.

13. Plant (1) according to one of the preceding claims, characterized in that each shaft section (2, 11) has only one fixed bearing (6).

14. Plant (1) according to one of the preceding claims, characterized in that the second generator (10) is designed to be connected to a flywheel assembly (13) via the separate shaft train (11).

15. Method for operating a technical installation (1) according to one of the preceding claims, wherein an active power mode is provided, wherein the first electrical switching device (8) and the second electrical switching device (12) are connected such that the generator (4) is electrically connected to the transformer (7), and that the transformer (7) is connected to the electrical network (9), and / or wherein a passive phase-shifting mode is provided, wherein the first electrical switching device (8) is connected such that 2024PF00792 Foreign version 19 is that the transformer (7) is connected to the electrical network (9), and in which the second electrical switching device (12) is switched such that the electrical connection between the two generators (4, 10) is interrupted, and in which the third electrical switching device (15), if present, is switched such that the transformer (7) is electrically connected to the second generator (10), and / or in which a first starting mode is provided in which the second electrical switching device (12) and, if present, the third electrical switching device (15) are switched such that the generators (4, 10) are electrically connected to each other, and in which the first electrical switching device (8) is switched such that the transformer (7) is disconnected from the electrical network (9), and / or in which a second starting mode is provided in which the second electrical switching device (12) is switched such thatthat the first generator (4) is electrically isolated from the transformer (7), in which, if present, the third electrical switching device (15) is connected such that the second generator (10) is electrically connected to the transformer (7), and in which the first electrical switching device (8) is connected such that the transformer (7) is electrically connected to the electrical network (9).

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