Automatic desilting device of micro pumped storage power station

Abstract

The invention relates to the technical field of hydropower station desilting equipment, and provides an automatic desilting device of a miniature pumped storage power station, which comprises a reversible water-turbine generator set, a negative pressure pipeline, a desilting pipeline and a desilting pool, the reversible water-turbine generator set is arranged between an upper reservoir and a lower reservoir; the negative pressure pipeline is connected with the reversible water-turbine generator set; the desilting pipeline comprises a desilting port and a desilting port, the desilting port extends into the bottom of the lower reservoir, the desilting pool is located at the downstream of the lower reservoir, and the desilting port is arranged below the water surface of the desilting pool; wherein the negative pressure pipeline is arranged on the sand discharge pipeline between the sand suction port and the sand discharge port, and the negative pressure pipeline is communicated with the sand discharge pipeline so as to provide negative pressure for the sand discharge pipeline. Negative pressure can be generated at the tail end of the reversible water-turbine generator set under the shutdown or load shedding working condition, sand discharging of the lower reservoir is achieved through the negative pressure pipeline and the sand discharging pipeline, and in this way, on one hand, sand discharging operation can be achieved, and on the other hand, the water hammer phenomenon can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of sand discharge equipment for hydropower stations, and in particular to an automatic sand discharge device for a micro pumped storage power station. Background Art

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

[0003] In some typical embodiments, sand removal is achieved by setting up a separate sand removal system, that is, a separate sand removal system is set up, and the sand removal system is enabled to generate a pressure difference, thereby performing sand removal operations. In other technical solutions, a surge chamber is provided, and the normal operation and power generation efficiency of the hydropower station are ensured by the setting of the surge chamber. However, in a micro pumped storage power station, it is costly to set up a separate sand removal system and a surge chamber, and since micro pumped storage power stations often have complex terrain and occupy a small area, this limits their construction. Summary of the invention

[0004] The invention provides an automatic sand discharge device for a micro pumped storage power station, which is used to solve the defects of difficulty in setting up a sand discharge system of a micro pumped storage power station and high setting cost in the prior art.

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

[0006] The automatic sand discharge device of the micro pumped storage power station provided according to the present invention also includes an air intake pipeline, one end of which is connected to the sand discharge pipeline, and the other end of the air intake pipeline is located in the lower reservoir, and when discharging sand, the port of the other end of the air intake pipeline is located below the water surface of the lower reservoir.

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

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

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

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

[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 intake pipeline close to the sand discharge pipeline, and a second check valve is provided on the sand discharge pipeline close to the sand discharge port.

[0012] According to the automatic sand discharge device of 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 discharge device of the 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 discharge 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-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.

[0015] The present invention provides an automatic sand discharge device for a micro pumped storage power station. A reversible turbine generator set generates negative pressure at its tail end when it is shut down or in a load shedding condition, and sand is discharged from the lower reservoir through a negative pressure pipeline and a sand discharge pipeline. In this way, on the one hand, sand discharge operations can be achieved, and on the other hand, water hammer phenomena can be avoided, thereby ensuring the stability of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0018] Reference numerals: 1. Upper reservoir; 2. Lower reservoir; 3. Reversible turbine generator set; 31. Tailwater pipeline; 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 intake pipeline; 61. First check valve; 7. Sand discharge pool; 8. Three-way joint. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of explaining the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0021] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0022] In the embodiments of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0023] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms are not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0024] Usually, micro pumped storage reservoirs use micro reversible hydro-turbine generator sets for power generation. When this type of generator is switched from power generation to pumping, shut down, or load shedding, negative pressure will be generated at the valve of the generator, leading to water hammer. Water hammer will cause violent pressure fluctuations in the pipeline. When these fluctuations exceed the design tolerance of the pipeline, they will cause rupture or damage to equipment such as pipelines, valves, and units. The sudden pressure changes caused by water hammer will be accompanied by sharp noise and strong vibration, which will not only damage the equipment and pipelines themselves, but may also affect the surrounding working environment and the stability of the equipment. Severe water hammer events may cause the failure or shutdown of the entire power generation system.

[0025] In the related art, on the one hand, a surge chamber is generally set up in a large pumped storage power station, and the pressure of the water hammer is adjusted through the surge chamber to avoid the impact of water hammer on the pipeline. And the construction of the surge chamber can also effectively solve the problems of unstable water flow and pressure fluctuation, ensuring that the hydro-generator set can work stably and continuously. However, in micro pumped storage power stations, due to geographical location and construction cost considerations, it is difficult to achieve pressure regulation by setting up a surge chamber. Some buffer devices are set up or complex control systems are used for progressive shutdown to reduce the impact of water hammer, but these methods are limited in effect, thus affecting the stability of the entire power generation system.

[0026] On the other hand, the sediment in the lower reservoir will affect the stable operation of the entire power generation system, so it is necessary to regularly discharge the sediment. In the related art, a separate sediment discharge system is often required to discharge the sediment in the lower reservoir. The sediment discharge system generates a pressure difference to achieve the sediment discharge operation. This method requires a layout site, and this method will increase the layout cost and the complexity of the entire system.

[0027] Regarding the problems in related technologies, such as Figure 1As shown, this example provides an automatic sand discharge device for a micro pumped storage power station, including a reversible hydro-generator set 3, a negative pressure pipeline 4, a sand discharge pipeline 5 and a sand discharge pool 7, wherein the reversible hydro-generator set 3 is arranged between the upper reservoir 1 and the lower reservoir 2, and the upper reservoir 1 is located upstream of the lower reservoir 2; the negative pressure pipeline 4 is connected to the tail end of the reversible hydro-generator set 3; the sand discharge pipeline 5 includes a sand suction port and a sand discharge port, and the sand suction port extends to the bottom of the lower reservoir 2; the sand discharge pool 7 is located downstream of the lower reservoir 2, and the sand discharge port is located below the water surface of the sand discharge pool 7; wherein the negative pressure pipeline 4 is arranged on the sand discharge pipeline 5 between the sand suction port and the sand discharge port, and the negative pressure pipeline 4 is connected to the sand discharge pipeline 5 to provide negative pressure for the sand discharge pipeline 5. For the sand discharge of the lower reservoir 2, it is usually necessary to set up a sand discharge pipeline 5 system, and the discharge of silt is achieved by the negative pressure generated in the sand discharge pipeline 5 system. In this embodiment, the negative pressure pipeline 4 is connected to the tail end of the reversible hydro-turbine generator set 3, and can be connected to the sand discharge pipeline 5 through the negative pressure pipeline 4 when the reversible hydro-turbine generator set 3 generates negative pressure, so that the sand discharge pipeline 5 can form a siphon to realize sand discharge operation, and utilize the negative pressure generated by the reversible hydro-turbine generator set 3 to solve the water hammer problem at the same time, reduce the complexity of the overall system, and reduce the overall layout cost.

[0028] Specifically, the reversible hydro-turbine generator set 3 is connected to the upper reservoir 1 through a pipeline so that power generation can be achieved by utilizing the water level difference. The water in the upper reservoir 1 can drive the reversible hydro-turbine generator set 3 to work under the action of the pressure difference to achieve continuous power generation. A tailwater pipe is provided at the tail end of the reversible hydro-turbine generator set 3. The water in the upper reservoir 1 will impact the impeller in the reversible hydro-turbine generator set 3 to rotate, thereby driving the generator to rotate and generate electricity. The tailwater pipe is used to discharge the tailwater passing through the reversible hydro-turbine generator set 3. The negative pressure pipeline 4 is connected to the tailwater pipe. When the reversible hydro-turbine generator set 3 is shut down or in load rejection condition, the water flow stops or slows down, so that the inertia and pressure fluctuation of the waterway will cause negative pressure to be generated. At this time, the generated negative pressure is utilized through the negative pressure pipeline 4 to enable sand discharge.

[0029] It can be understood that in this embodiment, the coordinated arrangement of the negative pressure pipeline 4 and the sand discharge pipeline 5 forms a siphon pipeline system, which can realize the sand discharge operation by utilizing the negative pressure generated during shutdown or load shedding conditions. The overall pipeline is simple and can realize the discharge of mud and sand in time. At the same time, it avoids the occurrence of water hammer phenomenon, improves the stability of the entire system, and no additional energy is consumed during the sand discharge process, thereby reducing its working cost.

[0030] During the specific setting, there is a certain water level in the sand discharge pool, and the sand discharge port is located below the water surface in the sand discharge pool, 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 tube structure is formed. After negative pressure is introduced into the sand discharge pipeline 5, the sand suction port can extract the sediment, so that the sediment can be discharged from the sand discharge port.

[0031] Continue as Figure 1 As shown, the sand discharge pool 7 is arranged downstream of the lower reservoir 2, which makes a certain height difference between the sand discharge pool 7 and the lower reservoir 2, and by immersing the sand discharge port into the sand discharge pool, the sand discharge port is in a sealed state, which can realize the absorption of mud and sand when the negative pressure pipe generates negative pressure. Through this arrangement, the operating cost can be further reduced.

[0032] 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 interfaces of a three-way joint 8, and the remaining interface of the three-way joint 8 is connected to the negative pressure pipeline 4, wherein the diameter of the sand discharge pipe section 52 is smaller than the diameter of the sand suction pipe section 51, so that a suction effect is formed in the pipeline during the sand discharge process, and rapid sand discharge is achieved. 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, and the same diameter can facilitate processing, and those skilled in the art can make corresponding adjustments according to needs.

[0033] It can be understood 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 tube structure, and the sand discharge pool 7 has a height difference with the lower reservoir 2, thereby forming a siphon structure, which can continuously realize sand discharge operations.

[0034] In some embodiments, the negative pressure pipeline 4 includes a first pipe section 41 connected to the reversible turbine generator set 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 discharge the air in the sand discharge pipeline 5 at the beginning, so as to absorb the silt and realize the sand discharge operation. In this embodiment, by arranging the second pipe section 42 above the sand discharge pipeline 5, the absorbed silt can be prevented from entering the negative pressure pipeline 4, thereby improving the stability of the device.

[0035] Specifically, the second pipe section 42 is connected to the sand discharge pipeline 5 through a reducing tee joint 8, and the connection between the second pipe section 42 and the sand discharge pipeline 5 is vertically arranged to prevent the sucked sand from clogging the negative pressure pipeline 4. The second pipe section 42 is located directly above the sand discharge pipe section 52, further preventing the sand from entering the negative pressure pipeline 4, so that it can achieve stable sand discharge.

[0036] It can be understood that there is a transition section (that is, the reducing tee joint 8 section) between the sand suction pipe section 51 and the sand discharge pipe section 52. The transition section can achieve a change in flow direction, that is, a transition from a suction flow direction to a vertical downward flow direction. The negative pressure pipeline 4 is connected to the transition section position, thereby avoiding the backflow of the sucked sand.

[0037] According to the embodiment provided by the present invention, the automatic sand discharge device further includes an air intake pipeline 6, one end of which is connected to the sand discharge pipeline 5, and the other end of which is located in the lower reservoir 2. During the sand discharge process of the sand discharge pipeline 5, the sand discharge needs to be stopped after a certain amount of sand is extracted. In this embodiment, through the setting of the air intake pipeline 6, after a certain amount of sand is extracted, the water level drops to the point where one end of the air intake pipeline 6 located in the lower reservoir 2 is exposed, and at this time, air can enter the negative pressure pipeline 4 from the air intake pipeline 6 to realize the automatic stop of sand discharge.

[0038] Specifically, the pipe opening of the air intake pipe 6 in the lower reservoir 2 is submerged below the water surface of the lower reservoir 2. Initially, the water surface forms a seal for the air intake pipe 6, which enables a siphon to be generated smoothly. After the siphon is formed, mud discharge can be achieved. During the mud discharge process, the water level of the lower reservoir continues to drop, and eventually the air intake pipe 6 is connected to the outside air, at which time the siphon is destroyed to automatically stop the sand discharge.

[0039] Specifically, the air intake pipeline 6 is arranged on the sand suction pipe section 51, and the pipe mouth of the air intake pipeline 6 located in the lower reservoir 2 is provided with a funnel-shaped pipe mouth structure. Initially, the pipe mouth of the air intake pipeline 6 is located below the water surface to prevent air from entering and destroying the siphon formation. In this way, the stability of the sand discharge process is improved.

[0040] According to some embodiments provided by the present invention, a spacing is provided between the port of the air intake pipeline 6 located in the lower reservoir 2 and the sand suction port. The setting of the spacing can realize the automatic stop of sand discharge when the water level in the lower reservoir 2 reaches a certain position. That is, the amount of sand discharge can be controlled by setting the height of the position of the air intake pipeline 6 located in the lower reservoir. For example, when a large amount of sand discharge is required, the length of the part of the air intake pipeline 6 submerged in the water surface can be increased. On the contrary, when a small amount of sand discharge is required, the length of the part of the air intake pipeline 6 submerged in the water surface can be shortened.

[0041] According to some embodiments provided by the present invention, the tail end of the reversible hydro-generator set 3 is also connected to a tailwater pipe 31, and the tailwater pipe 31 is connected to the lower reservoir 2. The tailwater pipe 31 is used to discharge the water discharged from the tailwater pipe of the reversible hydro-generator set 3, and the tailwater is discharged into the lower reservoir 2 through the tailwater pipe 31, so that the tailwater can be stored and utilized.

[0042] Specifically, a tailwater pipe 31 is provided between the reversible hydro-turbine generator set 3 and the lower reservoir 2, and the tailwater pipe 31 is connected to the tail end of the reversible hydro-turbine generator set 3, so that the tailwater can be discharged into the lower reservoir 2, and when necessary, the water in the lower reservoir 2 can be pumped back to the upper reservoir 1 for reuse.

[0043] According to the embodiment provided by the present invention, the connecting port of the tailwater pipe 31 is located in the lower reservoir 2 and between the sand suction port and the pipe opening of the air intake pipe 6. The tailwater pipe 31 is used to discharge the tailwater into the lower reservoir 2 to achieve water storage.

[0044] According to the embodiment provided by the present invention, a siphon control valve is provided on the negative pressure pipeline 4. The arrangement of the control valve can realize active stopping of sand discharge.

[0045] Specifically, the control valve is connected to the outside, and when the sand discharge operation needs to be stopped, the control valve is opened to allow air to enter the negative pressure pipe, thereby destroying the siphon and actively stopping the sand discharge. The specific type of the valve may be a manual valve, which is manually controlled to open and close.

[0046] According to the embodiment provided by the present invention, the siphon control valve is an electric control valve. The setting of the electric control valve can realize remote control, so that the stopping of sand discharge can be remotely controlled.

[0047] In some embodiments, a first check valve 61 is provided at one end of the air intake pipeline 6 close to the sand discharge pipeline 5, and a second check valve 521 is provided on the sand discharge pipeline 5 close to the sand discharge port. The first check valve 61 can prevent the silt in the sand discharge pipeline 5 from entering the air intake pipeline 6, and the second check valve 521 can prevent the water in the sand discharge pool 7 from being sucked into the sand discharge pipe due to excessive negative pressure.

[0048] It is understandable that, due to the height difference between the sand drainage pool 7 and the lower reservoir 2, the negative pressure generated generally will not suck back the water in the drainage pool. In this embodiment, the provision of the second check valve 521 can further improve the stability of the overall system and avoid back suction.

[0049] Through the description of the above embodiments, the technicians in this field can clearly understand that each embodiment can generate negative pressure when the working condition changes by using the reversible unit, and can automatically start and close the siphon sand discharge system formed by the downstream negative pressure pipeline 4 and the sand discharge pipeline 5, so as to make full use of the negative pressure that damages the pipeline, realize sand discharge, and solve the water hammer problem. Further, by utilizing the negative pressure at the tail end of the reversible turbine generator set 3, and the negative pressure is transmitted 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 siphoning, and when the sand pumping operation of the lower reservoir 2 reaches a certain level, the water level of the lower reservoir 2 drops, and air enters the negative pressure pipeline 4 from the air intake pipeline 6, automatically destroying the siphon and stopping the sand discharge operation. The whole process can be automatically closed and automatically opened, which simplifies the control system and reduces the cost of sand discharge operation.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automatic sand discharge device for a micro pumped storage power station, comprising an upper reservoir, a lower reservoir and a reversible hydro-generator set, wherein the upper reservoir is located upstream of the lower reservoir, and the reversible hydro-generator set is arranged between the upper reservoir and the lower reservoir, characterized in that: Also includes: A negative pressure pipeline, the negative pressure pipeline is connected to the tail end of the reversible hydro-generator set; A sand discharge pipeline, the sand discharge pipeline comprising a sand suction port and a sand discharge port, the sand suction port extending into the bottom of the lower reservoir; A sand discharge pool, wherein the sand discharge pool is located downstream of the lower reservoir, and the sand discharge port is located below the water surface of the sand discharge pool; Wherein, the negative pressure pipeline is arranged on the sand discharge pipeline between the sand suction port and the sand discharge port, and the negative pressure pipeline is communicated with the sand discharge pipeline so as to provide negative pressure for the sand discharge pipeline.

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

3. The automatic sand discharge device of the micro pumped storage power station according to claim 2 is characterized in that: The air intake pipeline is arranged between the sand suction port and the negative pressure pipeline connection position.

4. The automatic sand discharge device of the micro pumped storage power station according to claim 2 is characterized in that: A distance is provided between the port of the air intake pipeline located in the lower reservoir and the sand suction port.

5. The automatic sand discharge device of the micro pumped storage power station according to claim 4 is characterized in that: The tail end of the reversible hydro-generator set is also connected to a tailwater pipeline, and the tailwater pipeline is connected to the lower reservoir.

6. The automatic sand discharge device of the micro pumped storage power station according to claim 5, characterized in that: The connecting port of the tailwater pipeline is located in the lower reservoir and between the sand suction port and the pipe opening of the air intake pipeline.

7. The automatic sand discharge device of the 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 pipeline close to the sand discharge pipeline, and a second check valve is provided on the sand discharge pipeline close to the sand discharge port.

8. The automatic sand discharge device of the micro pumped storage power station according to claim 1, characterized in that: A siphon control valve is arranged on the negative pressure pipeline.

9. The automatic sand discharge device of the 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 discharge device of the 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-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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