Cascaded water diversion power station using Pelton turbines

Abstract

The present invention discloses a cascade-connected water diversion power station using Pelton turbines, belonging to the technical field of design and construction of water conservancy and hydropower engineering structures. A cascade-connected water diversion power station using Pelton turbines is provided, which can effectively utilize the height difference between the normal operating water level and the upper limit water level of the accident condition, reduce the excavation height, and lower the energy dissipation requirements. The cascade-connected water diversion power station includes at least an upper-level water diversion and power generation system and an adjacent lower-level water storage and regulation reservoir. The tailwater output end of the upper-level water diversion and power generation system is connected to the adjacent lower-level water storage and regulation reservoir. The cascade-connected water diversion power station also includes an emergency water level regulation system. Each level of water storage and regulation reservoir is independently connected to the emergency water level regulation system. The installation elevation of the Pelton turbine of the upper-level water diversion and power generation system is not lower than the highest water level of the adjacent lower-level water storage and regulation reservoir when the corresponding part of the emergency water level regulation system is at the maximum water level.

Description

Technical Field

[0001] The present invention relates to a cascade-connected water diversion type power station, in particular to a cascade-connected water diversion type power station using a Pelton turbine, and belongs to the technical field of design and construction of water conservancy and hydropower engineering structures. Background Art

[0002] For diversion-type power plants, if the water drop is too large, and the turbine and penstock design and manufacturing constraints are limited, a multi-stage series connection must be used, and the turbines must be Pelton turbines. To minimize the impact of the operation of the upper and lower power plants and to allow sufficient response time in the event of an emergency, a regulating tank is typically installed between the upper and lower diversion power plants, connecting the tailwater outlet of the upper power plant with the water inlet of the lower power plant, thereby improving the operational stability and safety of the entire system.

[0003] In conventional designs, during stable operation, the flow rate of tailwater from the upstream power station entering the regulating pond equals the inlet flow rate of the downstream power station, and the water level in the regulating pond remains unchanged. If the upstream power station suddenly shuts down due to an accident, the downstream power station will continue to operate for a period of time, causing the regulating pond to enter water supply mode and the water level to drop. If the downstream power station suddenly shuts down due to an accident, the upstream power station will continue to operate, and tailwater will continue to enter the regulating pond, causing the regulating pond to enter water storage mode and the water level to rise. The regulating pond must be designed to meet the water level and storage capacity requirements of both accident conditions.

[0004] When the water head in a diversion power station is too high, a Pelton turbine is required. This type of turbine must be installed above the free water surface and at a safe distance. However, under normal operation, the downstream tailwater level is at the normal level, which is a certain distance from the upper limit of the emergency condition. Therefore, the turbine must be installed above the upper limit of the emergency condition, and the height difference between the lower and normal tailwater levels cannot be utilized. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a cascade-connected water diversion power station using Pelton turbines that can effectively utilize the height difference between the normal operating water level and the upper limit water level of the accident condition, reduce the excavation height, and lower the energy dissipation requirements.

[0006] The technical solution adopted to solve the above technical problems is: a cascade-connected water diversion power station using Pelton turbines, which includes at least an upper-level water diversion and power generation system and an adjacent lower-level water storage and regulation reservoir. The tail water output end of the upper-level water diversion and power generation system is connected to the adjacent lower-level water storage and regulation reservoir. The cascade-connected water diversion power station also includes an emergency water level regulation system. The water storage and regulation reservoirs at each level are independently connected to the emergency water level regulation system. The installation elevation of the Pelton turbine of the upper-level water diversion and power generation system is not lower than the highest water level of the adjacent lower-level water storage and regulation reservoir when the corresponding part of the emergency water level regulation system is at the maximum water level.

[0007] Furthermore, each level of water storage and regulating reservoir is respectively composed of the riverbed or the excavated regulating water supply pool between two adjacent levels of water diversion and power generation systems.

[0008] A preferred embodiment of the above scheme is that the emergency water level regulating system includes a plurality of regulating water reservoirs whose number is equal to the number of water storage regulating reservoirs, and one regulating water reservoir corresponds to a blockable connection with the first-level water storage regulating reservoir.

[0009] Furthermore, the cascaded water diversion power station also includes a plurality of overflow weirs whose number is equal to the number of water storage and regulating reservoirs. The water storage and regulating reservoirs at each level are separated from the regulating water tanks at the corresponding positions by overflow weirs and are connected with the cooperation of the overflow weir tops.

[0010] The preferred embodiment of the above scheme is that the water storage and regulating reservoir and the regulating water storage tank of the same level are arranged in upstream and downstream positions along the direction of water flow.

[0011] Furthermore, the water storage and regulating reservoir is arranged in parallel with the regulating water storage tank of the same level along the direction of water flow.

[0012] The preferred embodiment of the above scheme is that the cascaded water diversion power station also includes a tailwater tunnel and a diversion tunnel, the upper-level water diversion power generation system is connected to the adjacent lower-level water storage and regulating reservoir through the tailwater tunnel, and the adjacent upper-level water storage and regulating reservoir transmits water to the turbine generator of the lower-level diversion power generation system through the diversion tunnel.

[0013] Furthermore, each regulating water reservoir is provided with a connecting hole, and the regulating water in each regulating water reservoir is output through the connecting hole.

[0014] A preferred embodiment of the above scheme is that the emergency water level regulating system further includes a secondary regulating water reservoir, and the regulating water in each regulating water reservoir is input into the corresponding secondary regulating water reservoir through a connecting hole.

[0015] Furthermore, the water storage and regulating reservoirs at each level are underground compartment regulating water supply tanks respectively arranged at the tailwater end of the adjacent upper-level power station, and the emergency water level regulation system is a surface regulating water tank at the input end of the adjacent lower-level power station connected through a water diversion tunnel.

[0016] The beneficial effects of the present invention are as follows: the technical solution provided by the present application is based on an existing cascade power station comprising at least an upper-level water diversion and power generation system and an adjacent lower-level water storage and regulation reservoir, wherein the tailwater output end of the upper-level water diversion and power generation system is connected to the adjacent lower-level water storage and regulation reservoir. By adding an emergency water level regulation system, the cascade series-connected water diversion and power generation station of the present application is formed, and each level of water storage and regulation reservoir is independently connected to the emergency water level regulation system. Then, the installation elevation of the pelton turbine of the upper-level water diversion and power generation system is not lower than the highest water level of the adjacent lower-level water storage and regulation reservoir when the corresponding part of the emergency water level regulation system is at the maximum water level. In this way, by limiting the upper limit water level of the accident condition to the normal operating water level, the height difference between the normal operating water level and the upper limit water level of the accident condition is fully utilized, and the excavation height and energy dissipation requirements are significantly reduced, thereby achieving the purpose of effectively reducing the scale of energy dissipation. Specifically, by dividing the total storage capacity of the regulating tank into a regulating water supply tank and a regulating water storage tank according to their functions and establishing a hydraulic connection between the two through an overflow weir, the following are achieved: 1) the scale of a single tank is significantly reduced, which can significantly reduce the difficulty of engineering excavation and support treatment; 2) the spatial position relationship between the regulating water supply tank and the regulating water storage tank can be flexibly combined to better adapt to the terrain and geological conditions; 3) the highest water level under accident conditions is equal to the water level under normal operating conditions, the installation elevation of the impact unit does not consider the problem of high accident water level, and the head utilization rate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a conceptual diagram of a cascade-connected water diversion power station using Pelton turbines according to the present invention;

[0018] Figure 2 This is a conceptual structural diagram of an embodiment of a cascade-connected water diversion power station using Pelton turbines according to the present invention;

[0019] Figure 3 、 Figure 4 as well as Figure 5 The present invention adopts three simplified structural schematic diagrams of a cascade-connected water diversion power station with Pelton turbines;

[0020] Figure 6 This is a conceptual structural diagram of another embodiment of a cascade-connected water diversion power station using Pelton turbines according to the present invention.

[0021] The following are marked in the figure: water diversion and power generation system 1, water storage and regulation reservoir 2, emergency water level regulation system 3, hydro-generator 4, overflow weir 5, tailwater tunnel 6, diversion tunnel 7, connecting tunnel 8, river channel 9, underground compartment regulation water supply tank 10, water transfer tunnel 11, and surface regulation water storage tank 12. DETAILED DESCRIPTION

[0022] like Figures 1 to 6The present invention provides a cascaded water diversion power station using Pelton turbines, which can effectively utilize the height difference between the normal operating water level and the upper limit water level of the emergency condition, reduce excavation height, and lower energy dissipation requirements. The cascaded water diversion power station includes at least an upper-level water diversion and power generation system 1 and an adjacent lower-level water storage and regulation reservoir 2, wherein the tailwater output end of the upper-level water diversion and power generation system 1 is connected to the adjacent lower-level water storage and regulation reservoir 2. The cascaded water diversion power station also includes an emergency water level regulation system 3, and each level of the water storage and regulation reservoir 2 is independently connected to the emergency water level regulation system 3. The Pelton turbine 4 of the upper-level water diversion and power generation system 1 is installed at an elevation not lower than the highest water level of the adjacent lower-level water storage and regulation reservoir 2 when the corresponding portion of the emergency water level regulation system 3 is at the maximum water level. The technical solution provided by the present application is based on an existing cascade power station that includes at least an upper-level water diversion and power generation system and an adjacent lower-level water storage and regulation reservoir, wherein the tailwater output end of the upper-level water diversion and power generation system is connected to the adjacent lower-level water storage and regulation reservoir. By adding an emergency water level regulation system, the cascade series-connected water diversion and power generation station of the present application is formed, and each level of water storage and regulation reservoir is independently connected to the emergency water level regulation system. Then, the installation elevation of the bucket turbine of the upper-level water diversion and power generation system is not lower than the highest water level of the adjacent lower-level water storage and regulation reservoir when the corresponding part of the emergency water level regulation system is at the maximum water level. In this way, by limiting the upper limit water level of the accident condition to the normal operating water level, the height difference between the normal operating water level and the upper limit water level of the accident condition is fully utilized, and the excavation height and energy dissipation requirements are significantly reduced, thereby achieving the purpose of effectively reducing the scale of energy dissipation.

[0023] Accordingly, based on the layout of existing cascade hydropower stations, each level of the water storage and regulating reservoirs 2 in this application is formed by the riverbed or excavated regulating water supply tanks between two adjacent levels of water diversion and power generation systems. In this way, the emergency water level regulation system 3 of this application can be configured to include a number of regulating reservoirs equivalent to the number of water storage and regulating reservoirs, thereby enabling a corresponding blockable connection between a regulating reservoir and a first-level water storage and regulating reservoir 2. Furthermore, to reduce the amount of excavation work and ease the difficulty of excavation, the cascade hydropower station described in this application also includes a number of overflow weirs 5 equivalent to the number of water storage and regulating reservoirs 2. Each level of the water storage and regulating reservoirs 2 is separated from the corresponding regulating reservoirs by overflow weirs 5 and connected to each other through the top of the overflow weirs 5. In this case, the water storage and regulating reservoirs 2 and the regulating reservoirs of the same level can be arranged upstream and downstream along the direction of water flow, or they can be arranged in parallel along the direction of water flow. Combined with the structural characteristics of the cascade water diversion power station, which also includes a tailwater tunnel 6 and a diversion tunnel 7, the upper-level water diversion power generation system 1 of the present application is connected to the adjacent lower-level water storage and regulating reservoir 2 through the tailwater tunnel 6, and the adjacent upper-level water storage and regulating reservoir 2 transmits water to the hydro-turbine generator of the lower-level diversion power generation system through the diversion tunnel 7.

[0024] At the same time, in order to facilitate the emptying of the regulating water reservoir, the present application further provides a connecting hole 8 on each regulating water reservoir, and the regulating water in each regulating water reservoir is output through the connecting hole 8. Furthermore, the emergency water level regulating system 3 of the present application also includes a secondary regulating water reservoir, and the regulating water in each regulating water reservoir is input into the corresponding secondary regulating water reservoir through the connecting hole 8.

[0025] like Figure 6 As shown, the water storage and regulating reservoirs 2 at each level of the present application are underground compartment regulating water supply tanks 10 respectively arranged on the tail water end of the adjacent upper power station, and the corresponding emergency water level regulation system 3 is a surface regulating water storage tank 12 at the input end of the adjacent lower power station connected through a water diversion tunnel 11.

[0026] To sum up, this application addresses the problems raised in the previous technology and proposes a regulating tank with an overflow-type auxiliary tank. By limiting the upper limit water level of the accident condition to the normal operating water level, it solves a series of problems such as head waste, excessive excavation height difference, and large energy dissipation scale.

[0027] The technical solution of this application is further described below through specific embodiments:

[0028] Example 1

[0029] 1. Implementation conditions

[0030] like Figure 1 As shown in FIG, in order to build a bank-side ground regulating pond in a narrow river valley, the site is constrained by high slopes, longitudinal river channels 9, and transverse tributaries in the narrow river valleys of high mountains. If a conventional regulating pond is used, due to the limited area, a higher dam (or retaining wall) has to be built to meet the reservoir capacity requirements, which increases the technical difficulty.

[0031] 2. Shore "front and back" layout plan

[0032] In this embodiment, due to the narrow river valley, the basic layout pattern can only be arranged longitudinally along the river channel 9, but there are multiple branch ditches in the valley, which further divide the terrain. According to the different functions and operating conditions of the regulating water supply tank and the regulating water storage tank, the regulating water supply tank is arranged in a relatively complete terrain area surrounded by the river channel, hillside, and branch ditches to ensure the normal operation of the power station. On the other hand, since the regulating water storage tank is only put into use under the accident conditions of the lower power station, which is a special case with a low probability, its requirements for terrain and geological regulation can be reduced. It can be arranged at the mouth of the branch ditch, and the water in the branch ditch can enter the river channel through the culvert below. When a large flood or mudslide occurs in the branch ditch, the regulating water storage tank is allowed to be damaged, which will not affect the safe operation of the regulating water supply tank and the main water diversion line.

[0033] 3. Project benefits

[0034] This embodiment has four aspects of engineering benefits:

[0035] 1) Reduce the storage capacity of a single regulating pond and reduce the difficulty of design and construction;

[0036] 2) Partially break through terrain restrictions and make layout more flexible;

[0037] 3) The regulating reservoir can adopt a lower design standard, saving some project investment while ensuring operational safety;

[0038] 4) Lower the installation height of the upper power station units to improve power generation efficiency.

[0039] Example 2

[0040] 1. Implementation conditions

[0041] like Figure 6 As shown, due to various restrictions, underground regulating pools must be used. However, due to adverse geological conditions such as faults, large-scale underground caverns are difficult to form and support.

[0042] Underground "separate" layout plan

[0043] In this embodiment, a separate regulating water supply tank and regulating water storage tank are used. Because it is underground, the regulating water supply tank is divided into multiple compartments connected by connecting tunnels. The regulating water supply tank is connected to the surface regulating water storage tank via a water transfer tunnel. The surface regulating water storage tank can be located in a suitable location based on topographical conditions, geological conditions, and economic feasibility.

[0044] 3. Project benefits

[0045] This embodiment has three aspects of engineering benefits:

[0046] 1) Reduce the scale of underground cavern excavation and reduce the difficulty of excavation and support design for large-scale underground cavern groups.

[0047] 2) The regulating reservoir can adopt a lower design standard, saving some project investment while ensuring operational safety;

[0048] 3) Lower the installation height of the upper power station units and improve power generation efficiency.

Claims

1. A cascaded water diversion power station using Pelton turbines, comprising at least an upper-stage water diversion power generation system (1) and an adjacent lower-stage water storage and regulation reservoir (2), wherein the tailwater output end of the upper-stage water diversion power generation system (1) is connected to the adjacent lower-stage water storage and regulation reservoir (2), and characterized in that: The cascaded water diversion power station further comprises an emergency water level regulating system (3), each level of water storage regulating reservoir (2) is independently connected to the emergency water level regulating system (3), and the installation elevation of the peal turbine (4) of the upper level water diversion power generation system (1) is not lower than the highest water level of the adjacent lower level water storage regulating reservoir (2) when the corresponding part of the emergency water level regulating system (3) is at the maximum water level. Each level of water storage and regulation reservoir (2) is composed of the riverbed or excavated regulating water supply pool between two adjacent levels of water diversion and power generation systems. The emergency water level regulating system (3) includes a plurality of regulating water reservoirs whose number is equal to the number of water storage regulating reservoirs, and one regulating water reservoir corresponds to a blockable connection with the first-level water storage regulating reservoir (2). The cascade-connected water diversion power station further comprises a plurality of overflow weirs (5) whose number is equal to the number of the water storage and regulating reservoirs (2). The water storage and regulating reservoirs (2) at each level are separated from the regulating water reservoirs at corresponding positions by the overflow weirs (5) and are connected with the help of the tops of the overflow weirs (5). The cascaded water diversion power station further comprises a tailwater tunnel (6) and a diversion tunnel (7), wherein the upper-level water diversion power generation system (1) is connected to the adjacent lower-level water storage and regulation reservoir (2) through the tailwater tunnel (6), and the adjacent upper-level water storage and regulation reservoir (2) transmits water to the turbine generator of the lower-level diversion power generation system through the diversion tunnel (7). Each regulating water reservoir is also provided with a connecting hole (8), and the regulating water in each regulating water reservoir is output through the connecting hole (8). Each level of water storage and regulation reservoir (2) is an underground compartment regulating water supply tank (10) respectively arranged on the tailwater end of the adjacent upper power station, and the emergency water level regulation system (3) is a surface regulating water storage tank (12) at the input end of the adjacent lower power station connected through a water transfer tunnel (11).

2. The cascade-connected water diversion power station using Pelton turbines according to claim 1, characterized in that: The water storage and regulating reservoir (2) and the regulating water storage tank of the same level are arranged in upstream and downstream positions along the direction of water flow.

3. The cascade-connected water diversion power station using Pelton turbines according to claim 1, characterized in that: The water storage and regulating reservoir (2) is arranged in parallel with the regulating water storage tank of the same level along the direction of water flow.

4. The cascade-connected water diversion power station using Pelton turbines according to claim 1, 2 or 3, characterized in that: The emergency water level regulating system (3) also includes secondary regulating water reservoirs, and the regulating water in each regulating water reservoir is input into the corresponding secondary regulating water reservoir through the connecting hole (8).

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