Automatic sand removal device for micro pumped storage power stations

Abstract

This invention relates to the field of hydropower station sediment removal equipment technology, and provides an automatic sediment removal device for a micro pumped storage power station, including a reversible turbine generator set, a negative pressure pipeline, a sediment removal pipeline, and a sediment removal pool. The reversible turbine generator set is located between the upper and lower reservoirs. The negative pressure pipeline is connected to the reversible turbine generator set. The sediment removal pipeline includes a sediment suction port and a sediment discharge port. The sediment suction port extends to the bottom of the lower reservoir, and the sediment removal pool is located downstream of the lower reservoir, with the sediment discharge port located below the water surface of the sediment removal pool. The negative pressure pipeline is located on the sediment removal pipeline between the sediment suction port and the sediment discharge port, and is connected to the sediment removal pipeline to provide negative pressure to the sediment removal pipeline. This invention utilizes the negative pressure generated at the tail end of the reversible turbine generator set during shutdown or load shedding conditions, and achieves sediment removal from the lower reservoir through the negative pressure pipeline and the sediment removal pipeline. This method enables sediment removal operations while avoiding water hammer.

Description

Technical Field

[0001] This invention relates to the field of hydropower station sediment removal equipment technology, and in particular to an automatic sediment removal device for a micro pumped storage power station. Background Technology

[0002] A micro pumped storage power station is a small-scale pumped storage power station primarily used to store and regulate electricity, improving the stability and power supply capacity of the power system. Its principle is similar to that of a large pumped storage power station, but on a smaller scale. It is typically used for load regulation and peak-valley regulation of local power grids, and is particularly suitable for use in areas with special needs or limited resources. Furthermore, to ensure stable power generation, a sediment removal system is usually required to remove silt from reservoirs and rivers.

[0003] In some typical embodiments, sediment removal is achieved by setting up a separate sediment removal system, which generates a pressure difference to facilitate sediment removal. Other technical solutions include a surge tank to ensure the normal operation and power generation efficiency of the hydropower station. However, in micro pumped storage power stations, setting up a separate sediment removal system and surge tank is costly, and the complex terrain and small footprint of micro pumped storage power stations limit their construction. Summary of the Invention

[0004] This invention provides an automatic sand removal device for micro pumped storage power stations, which solves the problems of difficult and costly sand removal systems in existing micro pumped storage power stations.

[0005] This invention provides an automatic sand removal device for a micro pumped storage power station, comprising: a reversible hydro-turbine generator set, a negative pressure pipeline, a sand removal pipeline, and a sand removal pool. The negative pressure pipeline is connected to the tail end of the reversible hydro-turbine generator set. The sand removal pipeline includes a sand suction port and a sand discharge port, with the sand suction port extending to the bottom of the lower reservoir. The sand removal pool is located downstream of the lower reservoir, and the sand discharge port is located below the water surface of the sand removal pool. The negative pressure pipeline is located on the sand removal pipeline between the sand suction port and the sand discharge port, and is connected to the sand removal pipeline to provide negative pressure to the sand removal pipeline.

[0006] The automatic sand discharge device for a micro pumped storage power station provided by the present invention further includes an air intake pipe, one end of which is connected to the sand discharge pipe, and the other end of which is located in the lower reservoir. During sand discharge, the port of the other end of the air intake pipe is located below the water surface of the lower reservoir.

[0007] According to the automatic sand removal device for a micro pumped storage power station provided by the present invention, the air intake pipe is located between the sand suction port and the connection position of the negative pressure pipe.

[0008] According to the automatic sand removal device of the micro pumped storage power station provided by the present invention, there is a gap between the port of the air intake pipeline located in the lower reservoir and the sand suction port.

[0009] According to the automatic sand removal device of the micro pumped storage power station provided by the present invention, the tail end of the reversible hydro-turbine generator unit is also connected to a tailwater pipe, and the tailwater pipe is connected to the lower reservoir.

[0010] According to the automatic sand removal device of the micro pumped storage power station provided by the present invention, the connecting port of the tailwater pipe is located in the lower reservoir and between the sand suction port and the inlet of the air intake pipe.

[0011] According to the automatic sand discharge device of the micro pumped storage power station provided by the present invention, a first check valve is provided at one end of the air inlet pipe near the sand discharge pipe, and a second check valve is provided on the sand discharge pipe near the sand discharge port.

[0012] According to the automatic sand removal device for the micro pumped storage power station provided by the present invention, a siphon control valve is provided on the negative pressure pipeline.

[0013] According to the automatic sand removal device for a micro pumped storage power station provided by the present invention, the siphon control valve is an electrically controlled valve.

[0014] According to the automatic sand removal device of the micro pumped storage power station provided by the present invention, the negative pressure pipeline includes a first pipe section connected to the reversible hydro-turbine generator set and a second pipe section connected to the sand removal pipeline; the first pipe section is connected to the second pipe section, and the second pipe section is located above the sand removal pipeline.

[0015] The present invention provides an automatic sand removal device for a micro pumped storage power station. When the reversible turbine generator unit is shut down or under load shedding conditions, it generates negative pressure at its tail end. Sand is removed from the lower reservoir through negative pressure pipeline and sand removal pipeline. In this way, sand removal can be achieved on the one hand, and water hammer phenomenon can be avoided on the other hand, ensuring the stability of the pipeline. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the automatic sand removal device for the micro pumped storage power station provided by the present invention.

[0018] Figure label:

[0019] 1. Upper reservoir; 2. Lower reservoir; 3. Reversible hydro-turbine generator set; 31. Tailrace pipe; 4. Negative pressure pipeline; 41. First pipe section; 42. Second pipe section; 5. Sand discharge pipeline; 51. Sand suction pipe section; 52. Sand discharge pipe section; 521. Second check valve; 6. Air inlet pipeline; 61. First check valve; 7. Sand discharge pool; 8. T-joint. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of clarifying the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0023] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0025] Miniature pumped-storage reservoirs typically use miniature reversible hydro-turbine generator sets for power generation. When these generators switch from power generation to pumping, or are shut down or shedding load, negative pressure can occur at the generator valves, leading to water hammer. Water hammer causes severe pressure fluctuations within the pipelines. When these fluctuations exceed the pipeline's design capacity, they can cause ruptures or damage to pipelines, valves, generator sets, and other equipment. The sudden pressure changes caused by water hammer are accompanied by sharp noises and intense vibrations, which not only damage the equipment and pipelines themselves but can also affect the surrounding working environment and the stability of the equipment. Severe water hammer events can lead to the failure or shutdown of the entire power generation system.

[0026] In related technologies, on the one hand, large pumped storage power stations typically include surge tanks to regulate water hammer and prevent it from impacting the pipelines. The construction of surge tanks can also effectively address issues such as unstable water flow and pressure fluctuations, ensuring the stable and continuous operation of the turbine generator units. However, in micro pumped storage power stations, due to geographical location and construction cost considerations, it is difficult to achieve pressure regulation through surge tanks. Some systems mitigate the impact of water hammer by installing buffer devices or employing complex control systems for gradual shutdown, but these methods have limited effectiveness, thus affecting the stability of the entire power generation system.

[0027] On the other hand, the sediment deposited in the lower reservoir can affect the stable operation of the entire power generation system, so regular sediment removal is necessary. In related technologies, a separate sediment removal system is often required to remove sediment from the lower reservoir. The sediment removal operation is achieved by generating a pressure difference through the system. This method requires a suitable site and increases the deployment cost and complexity of the entire system.

[0028] Regarding the problems in related technologies, such as Figure 1As shown, this example provides an automatic sediment removal device for a micro pumped storage power station, including a reversible turbine generator set 3, a negative pressure pipeline 4, a sediment removal pipeline 5, and a sediment removal pool 7. The reversible turbine generator set 3 is located between the upper reservoir 1 and the lower reservoir 2, with the upper reservoir 1 upstream of the lower reservoir 2. The negative pressure pipeline 4 is connected to the tail end of the reversible turbine generator set 3. The sediment removal pipeline 5 includes a sediment suction port and a sediment discharge port, with the sediment suction port extending to the bottom of the lower reservoir 2. The sediment removal pool 7 is located downstream of the lower reservoir 2, and the sediment discharge port is located below the water surface of the sediment removal pool 7. The negative pressure pipeline 4 is located on the sediment removal pipeline 5 between the sediment suction port and the sediment discharge port, and the negative pressure pipeline 4 is connected to the sediment removal pipeline 5 to provide negative pressure to the sediment removal pipeline 5. Sediment removal from the lower reservoir 2 typically requires the installation of a sediment removal pipeline 5 system, where the negative pressure generated in the sediment removal pipeline 5 system facilitates sediment discharge. In this embodiment, the negative pressure pipeline 4 is connected to the tail end of the reversible hydro-generator unit 3. When the reversible hydro-generator unit 3 generates negative pressure, it can connect with the sand discharge pipeline 5 through the negative pressure pipeline 4, so that the sand discharge pipeline 5 can form a siphon to realize sand discharge operation. Moreover, by utilizing the negative pressure generated by the reversible hydro-generator unit 3, the problem of water hammer is solved at the same time, the complexity of the overall system is reduced, and the overall layout cost is reduced.

[0029] Specifically, the reversible hydro-turbine generator unit 3 is connected to the upper reservoir 1 via a pipeline to generate electricity using the water level difference. The water in the upper reservoir 1, under the influence of the pressure difference, drives the reversible hydro-turbine generator unit 3 to operate, achieving continuous power generation. A tailrace pipe is installed at the tail end of the reversible hydro-turbine generator unit 3. The water in the upper reservoir 1 impacts the impeller inside the reversible hydro-turbine generator unit 3, causing it to rotate and thus drive the generator to generate electricity. The tailrace pipe is used to discharge the tailwater passing through the reversible hydro-turbine generator unit 3. A negative pressure pipeline 4 is connected to the tailrace pipe. When the reversible hydro-turbine generator unit 3 is shut down or under load shedding conditions, the water flow stops or slows down, causing inertia and pressure fluctuations in the waterway to generate negative pressure. This negative pressure is utilized through the negative pressure pipeline 4 for sand removal.

[0030] It is understandable that in this embodiment, the combination of negative pressure pipeline 4 and sand discharge pipeline 5 forms a siphon pipeline system. By utilizing the negative pressure generated during shutdown or load shedding, sand discharge can be achieved. The overall pipeline is simple, and sand can be discharged in a timely manner. At the same time, water hammer phenomenon is avoided, the stability of the entire system is improved, and no additional energy is consumed during the sand discharge process, thus reducing its operating cost.

[0031] In the specific setup, the sand discharge tank has a certain water level, and the sand discharge port is located below the water surface in the sand discharge tank, which makes the sand discharge port in a sealed state. Due to the height difference between the sand suction port and the sand discharge port, a U-shaped pipe structure is formed. After negative pressure is introduced into the sand discharge pipe 5, the sand suction port can extract the mud and sand, so that the mud and sand can be discharged from the sand discharge port.

[0032] Continue as Figure 1 As shown, the sand discharge pool 7 is located downstream of the lower reservoir 2, which creates a certain height difference between the sand discharge pool 7 and the lower reservoir 2. By immersing the sand discharge port in the sand discharge pool, the sand discharge port is sealed, enabling the absorption of sediment when negative pressure is generated in the negative pressure pipe. This method of setting can further reduce operating costs.

[0033] Specifically, the sand discharge pipeline 5 includes a sand suction pipe section 51 directly connected to the lower reservoir 2 and a sand discharge pipe section 52 directly connected to the sand discharge pool 7. The sand suction pipe section 51 and the sand discharge pipe section 52 are connected through two ports of a tee connector 8. The remaining port of the tee connector 8 is connected to the negative pressure pipeline 4. The diameter of the sand discharge pipe section 52 is smaller than that of the sand suction pipe section 51, thereby creating a suction effect in the pipeline during the sand discharge process, achieving rapid sand discharge. Of course, in other embodiments, the diameters of the sand suction pipe section 51 and the sand discharge pipe section 52 can also be set to the same diameter. The same diameter facilitates processing, and those skilled in the art can make corresponding adjustments according to requirements.

[0034] It is understandable that by submerging the sand discharge port below the water surface and the sand suction port into the lower reservoir 2, the sand discharge pipeline 5 forms a U-shaped pipe structure, and the sand discharge pool 7 and the lower reservoir 2 have a height difference, thus forming a siphon structure, which can continuously realize sand discharge operation.

[0035] In some embodiments, the negative pressure pipeline 4 includes a first pipe section 41 connected to the reversible hydro-generator unit 3 and a second pipe section 42 connected to the sand discharge pipeline 5; the first pipe section 41 is connected to the second pipe section 42, and the second pipe section 42 is located above the sand discharge pipeline 5. The negative pressure pipeline 4 is used to initially expel air from the sand discharge pipeline 5, thereby achieving the suction of sediment and realizing the sand discharge operation. In this embodiment, by placing the second pipe section 42 above the sand discharge pipeline 5, the suctioned sediment can be prevented from entering the negative pressure pipeline 4, improving the stability of the device.

[0036] Specifically, the second pipe section 42 is connected to the sand discharge pipe 5 via a reducing tee connector 8, and the connection between the second pipe section 42 and the sand discharge pipe 5 is vertically arranged to prevent the sucked-in silt from clogging the negative pressure pipe 4. Furthermore, the second pipe section 42 is located directly above the sand discharge pipe section 52, further preventing silt from entering the negative pressure pipe 4 and enabling stable sand discharge.

[0037] It is understandable that there is a transition section (i.e., reducing tee joint 8) between the sand suction pipe section 51 and the sand discharge pipe section 52. The transition section can realize the change of flow direction, that is, the transition from the suction flow direction to the vertical downward flow direction. The negative pressure pipe 4 is connected to the transition section, thereby preventing the backflow of the suctioned mud and sand.

[0038] According to the embodiments provided by the present invention, the automatic sand discharge device further includes an air inlet pipe 6, one end of which is connected to the sand discharge pipe 5, and the other end of which is located in the lower reservoir 2. During the sand discharge process in the sand discharge pipe 5, it is necessary to stop the sand discharge after a certain amount of silt has been extracted. In this embodiment, by setting up the air inlet pipe 6, after a certain amount of silt has been extracted, the water level drops until the end of the air inlet pipe 6 located in the lower reservoir 2 is exposed. At this time, air can enter the negative pressure pipe 4 through the air inlet pipe 6 to realize the automatic stop of sand discharge.

[0039] Specifically, the air intake pipe 6 is located inside the lower reservoir 2, with its opening submerged below the water surface. Initially, the water surface creates a seal on the air intake pipe 6, allowing it to generate a siphon. Once the siphon is formed, sludge removal can be achieved. During the sludge removal process, the water level in the lower reservoir continuously decreases, eventually connecting the air intake pipe 6 with the outside air. At this point, the siphon is broken, and the sludge removal process automatically stops.

[0040] Specifically, the air intake pipe 6 is located on the sand suction pipe section 51. The opening of the air intake pipe 6 in the lower reservoir 2 has a funnel-shaped opening structure. Initially, the opening of the air intake pipe 6 is located below the water surface to prevent air from entering and disrupting the siphon formation. This method improves the stability of the sand discharge process.

[0041] In some embodiments of the present invention, a gap is provided between the port of the air intake pipe 6 located in the lower reservoir 2 and the sand suction port. This gap allows for automatic cessation of sand discharge when the water level in the lower reservoir 2 reaches a certain level. In other words, the amount of sand discharged can be controlled by adjusting the height of the air intake pipe 6 within the lower reservoir. For example, when a larger amount of sand needs to be discharged, the length of the portion of the air intake pipe 6 submerged in the water can be increased; conversely, when a smaller amount of sand needs to be discharged, the length of the portion of the air intake pipe 6 submerged in the water can be shortened.

[0042] In some embodiments of the present invention, the tail end of the reversible hydro-turbine generator set 3 is also connected to a tailrace pipe 31, which is connected to the lower reservoir 2. The tailrace pipe 31 is used to discharge water flowing through the tailrace pipe of the reversible hydro-turbine generator set 3. The tailrace water is discharged into the lower reservoir 2 through the tailrace pipe 31, so as to realize the storage and utilization of the tailrace water.

[0043] Specifically, a tailrace pipe 31 is provided between the reversible hydro-turbine generator set 3 and the lower reservoir 2. The tailrace pipe 31 is connected to the tail end of the reversible hydro-turbine generator set 3, so that the tailrace can be discharged into the lower reservoir 2 and the water in the lower reservoir 2 can be pumped back into the upper reservoir 1 when needed, so as to achieve reuse.

[0044] According to the embodiment provided by the present invention, the connection port of the tailwater pipe 31 is located inside the lower reservoir 2, and is situated between the sand suction port and the inlet of the air inlet pipe 6. The tailwater pipe 31 is used to discharge tailwater into the lower reservoir 2, thereby achieving water storage.

[0045] In an embodiment provided by the present invention, a siphon control valve is provided on the negative pressure pipeline 4. The control valve is configured in a way that enables the active stopping of sand discharge.

[0046] Specifically, the control valve is connected to an external connection. When it is necessary to stop the sand discharge operation, opening the control valve allows air to enter the negative pressure pipe, thereby disrupting the siphon and actively stopping the sand discharge. The valve itself can be a manual valve, allowing for manual control of its opening and closing.

[0047] In the embodiments provided by the present invention, the siphon control valve is an electrically controlled valve. The electrically controlled valve enables remote control, thereby allowing remote control of the sand discharge process.

[0048] In some embodiments, a first check valve 61 is provided at the end of the air intake pipe 6 near the sand discharge pipe 5, and a second check valve 521 is provided on the sand discharge pipe 5 near the sand discharge port. The first check valve 61 prevents silt in the sand discharge pipe 5 from entering the air intake pipe 6, and the second check valve 521 prevents water in the sand discharge pool 7 from being drawn into the sand discharge pipe due to excessive negative pressure.

[0049] It is understandable that, due to the height difference between the sand discharge pool 7 and the lower reservoir 2, the negative pressure generated will not usually draw back the water in the drainage pool. In this embodiment, the setting of the second check valve 521 can further improve the stability of the overall system and prevent backflow.

[0050] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment utilizes the reversible unit to generate negative pressure when the operating conditions change, which can automatically start and stop the siphon sand discharge system formed by the downstream negative pressure pipeline 4 and the sand discharge pipeline 5, making full use of the negative pressure that could damage the pipeline, achieving sand discharge, and solving the water hammer problem. Furthermore, by utilizing the negative pressure at the tail end of the reversible hydro-turbine generator unit 3, and with the negative pressure being conducted from the negative pressure pipeline 4 to the sand discharge pipeline 5, as the negative pressure accumulates and increases, the sand discharge pipeline 5 starts the siphon. When the sand dredging operation in the lower reservoir 2 reaches a certain level, the water level in the lower reservoir 2 drops, and air enters the negative pressure pipeline 4 through the air intake pipeline 6, automatically breaking the siphon and stopping the sand discharge operation. The entire process can be automatically shut down and automatically started, simplifying the control system and reducing the cost of sand discharge operations.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic sediment removal device for a micro pumped storage power station, comprising an upper reservoir, a lower reservoir, and a reversible turbine generator set, wherein the upper reservoir is located upstream of the lower reservoir, and the reversible turbine generator set is located between the upper reservoir and the lower reservoir, characterized in that, Also includes: A negative pressure pipeline is connected to the tail end of the reversible hydro-generator unit; A sand discharge pipeline, comprising a sand suction port and a sand discharge port, wherein the sand suction port extends to the bottom of the lower reservoir; A sediment flushing pond is located downstream of the lower reservoir, and the sediment flushing port is located below the water surface of the sediment flushing pond. The negative pressure pipeline is located on the sand discharge pipeline between the sand suction port and the sand discharge port, and the negative pressure pipeline is connected to the sand discharge pipeline so as to provide negative pressure to the sand discharge pipeline.

2. The automatic sand removal device for a micro pumped storage power station according to claim 1, characterized in that, It also includes an air intake pipe, one end of which is connected to the sand discharge pipe, and the other end of which is located in the lower reservoir. During sand discharge, the port of the other end of the air intake pipe is below the water surface of the lower reservoir.

3. The automatic sand removal device for a micro pumped storage power station according to claim 2, characterized in that, The air intake pipe is located between the sand suction port and the connection point of the negative pressure pipe.

4. The automatic sand removal device for a micro pumped storage power station according to claim 2, characterized in that, There is a gap between the port of the air intake pipe located in the lower reservoir and the sand suction port.

5. The automatic sand removal device for a micro pumped storage power station according to claim 4, characterized in that, The tail end of the reversible hydro-turbine generator set is also connected to a tailrace pipe, which is connected to the lower reservoir.

6. The automatic sand removal device for a micro pumped storage power station according to claim 5, characterized in that, The outlet of the tailwater pipe is located inside the lower reservoir, between the sand suction port and the inlet of the air intake pipe.

7. The automatic sand removal device for a micro pumped storage power station according to claim 2, characterized in that, A first check valve is provided at one end of the air intake pipe near the sand discharge pipe, and a second check valve is provided on the sand discharge pipe near the sand discharge port.

8. The automatic sand removal device for a micro pumped storage power station according to claim 1, characterized in that, A siphon control valve is installed on the negative pressure pipeline.

9. The automatic sand removal device for a micro pumped storage power station according to claim 8, characterized in that, The siphon control valve is an electrically controlled valve.

10. The automatic sand removal device for a micro pumped storage power station according to claim 1, characterized in that, The negative pressure pipeline includes a first pipe section connected to the reversible hydro-turbine generator set and a second pipe section connected to the sand discharge pipeline; the first pipe section is connected to the second pipe section, and the second pipe section is located above the sand discharge pipeline.

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