Pumped storage unit

Abstract

The invention discloses a pumped storage unit, and relates to the technical field of pumped storage. The pumped storage unit comprises an impeller, a guide vane and a rectifying plate, and the guide vane is arranged on the outer side of the impeller, is configured to be rotatable and is used for controlling the flow of water flow entering the impeller. The rectifying plate is arranged on the upstream face of the guide vane and used for guiding the flow direction of water flow at an outlet of the guide vane. Through the arrangement of the rectifying plate, water flow can be restrained by the rectifying plate to adjust the flowing direction in a self-adaptive mode, the rectifying plate plays a rectifying role, vortex formation and pressure pulsation are relieved, and the operation stability of the pumped storage unit is improved. Particularly, under the working condition of small flow, the rectifying plate can relieve pressure pulsation caused by the phenomena of flow separation, vortex and the like due to unbalanced distribution of the water flow velocity at the outlet of the guide vane, so that the problem that the operation stability of the pumped storage unit is reduced due to the phenomena is relieved.

Description

Technical Field

[0001] This application relates to the field of pumped storage technology, and in particular to a pumped storage unit. Background Technology

[0002] Pumped storage units are crucial for building new power systems, ensuring their stable operation, and enabling the large-scale development of new energy sources. The pump-turbine, the core component of a pumped storage power station, experiences severe pressure pulsations in the bladeless region between its guide vanes and impeller, significantly impacting the stable operation of the pumped storage unit. Summary of the Invention

[0003] This application provides a pumped storage unit to at least partially solve the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, a pumped storage unit is provided, comprising an impeller, guide vanes, and a rectifier plate. The guide vanes are disposed on the outer side of the impeller and are configured to be rotatable for controlling the flow rate of water entering the impeller. The rectifier plate is disposed on the upstream side of the guide vanes and is used to guide the flow direction of the water outlet from the guide vanes.

[0005] In one possible implementation, the rectifier plate is positioned on the side of the guide vane's rotation center line close to the impeller.

[0006] In one possible implementation, the rectifier plate has a first end near the guide vane outlet and a second end away from the impeller inlet, and the width of the rectifier plate gradually narrows from the second end to the first end.

[0007] In one possible implementation, the rectifier plate has a first side facing away from the guide vane, and the first side has a first included angle α with the water-facing surface of the guide vane, satisfying 12°≤α≤16°.

[0008] In one possible implementation, the rectifier plate has a first side, a second side, and a third side, the second side and the third side being spaced apart along the length of the rectifier plate; one end of the first side is connected to the second side, and the other end is connected to the third side; the first side smoothly transitions to the upstream surface of the guide vane via the second side; and / or, the first side smoothly transitions to the upstream surface of the guide vane via the third side.

[0009] In one possible implementation, the rectifier plate has a first end near the guide vane outlet and a second end away from the guide vane outlet;

[0010] From the second end to the first end, the distance between the first side surface and the upstream surface of the guide vane gradually decreases; and / or,

[0011] From the second end to the first end, the distance between the third side and the water-facing surface of the guide vane gradually increases.

[0012] In one possible implementation, multiple rectifier plates are provided, and the multiple rectifier plates are spaced apart along the height direction of the guide vane.

[0013] In one possible implementation, the height of the guide vane is H1, and the thickness of the rectifier plate is H2, satisfying 0.02H1≤H2≤0.03H1; and / or,

[0014] The guide vane has a length of L1 and the rectifier plate has a length of L2, satisfying 0.65L1≤L2≤0.75L1.

[0015] In one possible implementation, 2mm ≤ H2 ≤ 30mm.

[0016] In one possible implementation, multiple guide vanes are provided, and the multiple guide vanes are circumferentially spaced around the impeller. An inlet channel for supplying water flow into the impeller is defined between two adjacent guide vanes. The rectifier plate is located in the inlet channel. The distance between the rotation center lines of two adjacent guide vanes is W, and the width of the rectifier plate is L, satisfying 0.3W≤L≤0.5W.

[0017] In the pumped storage unit of this application embodiment, by setting a rectifier plate, the water flow can be constrained and its flow direction can be adaptively adjusted, allowing the rectifier plate to perform a rectification function, thereby alleviating eddy formation and pressure pulsation, and improving the operational stability of the pumped storage unit. Especially under operating conditions with low flow rates, the rectifier plate can alleviate pressure pulsation caused by phenomena such as flow separation and eddies caused by unbalanced water flow velocity distribution at the guide vane outlet, thereby mitigating the problem of reduced operational stability of the pumped storage unit caused by such phenomena.

[0018] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0021] Figure 1 Schematic diagrams of pumped storage units provided for some embodiments of this application;

[0022] Figure 2 A schematic diagram of the assembly of the guide vane and the rectifier plate provided for some embodiments of this application;

[0023] Figure 3 A schematic diagram of the structure of a rectifier board provided for some embodiments of this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 100-Pumped storage unit;

[0026] 20-Impeller;

[0027] 30-guide vane;

[0028] 10-Rectifier plate; 14-First end; 15-Second end; 11-First side surface; 12-Second side surface; 13-Third side surface;

[0029] 40 - Liquid inlet channel;

[0030] 50-lower ring; Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0032] The ideal operating conditions for pumped storage units are set during the design phase. Ideal operating conditions refer to specific working conditions that maximize the unit's operating efficiency (energy conversion efficiency reaches its peak, such as around 95% for mixed-flow units), optimize performance (lowest vibration and noise, and minimal mechanical wear), and ensure the best stability.

[0033] Currently, guide vanes are designed to match the ideal operating conditions of pumped storage units, only enabling boundary regulation and control of the inlet or outlet of the bladeless zone, without directly interfering with the bladeless zone itself. This results in insufficient suppression of pressure pulsations in the bladeless zone when operating conditions deviate from the ideal. In particular, when the water flow forms a rotating vortex at the guide vane outlet due to flow separation and uneven velocity distribution, the vortex disturbance in the water body will cause pressure fluctuations. Furthermore, when operating conditions deviate from the ideal (such as low-load operation), the turbulence of the water flow at the guide vane outlet intensifies, and the intensity of the vortex and the amplitude of pressure pulsations further increase, leading to instability in the operation of the pumped storage unit.

[0034] In view of this, this application provides a pumped storage unit 100.

[0035] Figure 1 Schematic diagram of the structure of a pumped storage unit 100 provided for some embodiments of this application; Figure 2 A schematic diagram of the assembly of the guide vane 30 and the rectifier plate 10 provided for some embodiments of this application; Figure 3 A schematic diagram of the structure of the rectifier board 10 provided for some embodiments of this application.

[0036] Reference Figures 1 to 3 The pumped storage unit 100 includes an impeller 20, guide vanes 30, and a rectifier plate 10. The guide vanes 30 are located on the outer side of the impeller 20 and are configured to be rotatable to control the flow rate of water entering the impeller 20. The rectifier plate 10 is located on the water-facing side of the guide vanes 30 and is used to guide the flow direction of the water at the outlet of the guide vanes 30.

[0037] It can be understood that the blades of the impeller 20 rotate under the impact or drive of the water flow, thereby realizing the mutual conversion of water energy and mechanical energy. The impeller 20 can be installed in the flow channel between the top cover and the bottom ring of the pumped storage unit 100 through its mounting shaft, and the upper end of the mounting shaft of the impeller 20 is connected to the generator rotor.

[0038] It is understood that the guide vanes 30 are mainly used to control the flow rate of water entering the impeller 20, and can also cut off the water flow to stop the pumped storage unit 100. Specifically, multiple guide vanes 30 are provided, which are spaced around the impeller 20. The guide vanes 30 rotate synchronously around their own axis, which can change the area of ​​the liquid inlet channel 40 between two adjacent guide vanes 30, thereby controlling the flow rate and direction of water entering the impeller 20, and thus adjusting the power and speed of the pumped storage unit 100 to adapt to different usage scenarios such as power generation.

[0039] In one example, the guide vanes 30 are arranged in a circle around the impeller 20.

[0040] The guide vane 30 has a first surface facing the impeller 20 and a second surface facing away from the impeller 20. The first surface is the water-facing surface of the guide vane 30.

[0041] The guide vane 30 is located at the end closest to the impeller 20, which is the outlet of the guide vane 30. Correspondingly, the guide vane 30 is located at the end furthest from the impeller 20, which is the inlet of the guide vane 30. Along the direction of water flow, the water first passes through the inlet of the guide vane 30 and is constrained by the guide vane 30, and then leaves the guide vane 30 at the outlet and enters the impeller 20.

[0042] In the pumped storage unit 100, the guide vane 30, as a key component for water flow regulation, has its structural parameters and angles designed and matched according to ideal operating conditions. Under these conditions, the water flow path between the guide vane 30 and the impeller 20 is smooth, the energy conversion efficiency is ideal, and the unit operates stably. However, when the actual operating flow rate is less than the design flow rate, the guide vane 30 needs to close its opening to accommodate the smaller flow. This causes an imbalance in the velocity distribution of the water flow at the guide vane 30 outlet, leading to undesirable flow patterns such as flow separation and eddies. The turbulent water flow impacts the blades of the impeller 20, generating periodic pressure changes, i.e., pressure pulsations. If the frequency of these pressure pulsations is close to the unit's natural frequency, resonance may occur, significantly reducing the unit's operational stability.

[0043] In this embodiment, by setting a rectifier plate 10, the water flow can be constrained and its flow direction can be adaptively adjusted, allowing the rectifier plate 10 to perform a rectification function, thereby alleviating eddy formation and pressure pulsation, and improving the operational stability of the pumped storage unit 100. Especially under conditions of low flow rate, the rectifier plate 10 can alleviate pressure pulsation caused by phenomena such as flow separation and eddies caused by the imbalance of water flow velocity distribution at the outlet of the guide vane 30, thereby mitigating the problem of reduced operational stability of the pumped storage unit 100 caused by such phenomena.

[0044] In some embodiments, in the pumped storage unit 100, the impeller 20 includes an upper crown, blades, and a lower ring 50. The upper end of the blade is connected to the upper crown, and the lower end is connected to the lower ring 50. The lower ring 50 is an annular structure disposed at the bottom of the blades of the impeller 20, which is used to connect the lower end of the blades and enhance the structural strength.

[0045] In some embodiments, the mounting shaft of the guide vane 30 is connected to the control loop of the pumped storage unit 100.

[0046] In some embodiments, the guide vane 30 has a mounting groove, and the rectifier plate 10 is embedded in the mounting groove. Exemplarily, the mounting groove is a rectangular groove, and the width of the mounting groove is adapted to the thickness of the rectifier plate 10.

[0047] In some embodiments, the rectifier plate 10 is fixedly connected to the guide vane 30 by welding, bonding or other means.

[0048] In some embodiments, the rectifier plate 10 is positioned on the side of the guide vane 30 closest to the impeller 20 along the rotation center line.

[0049] It is understandable that the rectifier 10 is closer to the outlet of the guide vane 30 than the rotation center line of the rectifier 10. In other words, the rectifier 10 is located between the rotation center line of the guide vane 30 and the impeller 20.

[0050] In an embodiment where the guide vane 30 is provided with a rotating shaft, the rectifier plate 10 is located between the rotating shaft of the guide vane 30 and the impeller 20.

[0051] Typically, a flow-through component, such as a volute, is also provided on the outer side of the guide vane 30. This volute, together with the guide vane 30, serves to guide the water flow and optimize energy conversion. The volute, spiraling around the guide vane 30, is the first flow-through channel for water entering the unit. As the water flows from the inlet of the volute along the spiral path towards the center, the volute converts the pressure energy of the water flow into kinetic energy through its gradually narrowing cross-section, and delivers it to the guide vane 30 area with a uniform circulation distribution. The guide vane 30, located inside the volute, directly receives the water flow exiting the volute, and further controls the direction and flow rate of the water flow by adjusting the blade angle. At the inlet of guide vane 30, the water flow is constrained by the volute and flows centripetally, resulting in a relatively uniform velocity distribution and a flow direction that matches the curvature of the guide vane 30's leading edge, leading to minimal energy loss. However, at the outlet, after the water flow leaves the constraint of guide vane 30, if the opening of guide vane 30 is mismatched with the flow rate (e.g., closing the opening slightly under low flow conditions), the abrupt change in the contact area between guide vane 30 and the water flow leads to an increased velocity gradient, exacerbating flow turbulence and making it more prone to inducing flow separation and eddies. Therefore, the induction of flow separation and eddies occurs near the outlet of guide vane 30.

[0052] In this embodiment, by placing the rectifier plate 10 on the side of the guide vane 30 closest to the impeller 20 along its rotation center line, the rectifier plate 10 can be positioned closer to the area where flow separation and eddy current phenomena occur, thereby effectively alleviating pressure pulsation and improving the operational stability of the pumped storage unit 100. Simultaneously, it can reduce the obstruction of the rectifier plate 10 to the water flow at the inlet of the guide vane 30.

[0053] In particular, it alleviates pressure pulsation under low flow conditions and improves the operational stability of the pumped storage unit 100 under low flow conditions.

[0054] Reference Figure 2 and Figure 3 In some embodiments, the rectifier plate 10 has a first end 14 near the outlet of the guide vane 30 and a second end 15 away from the guide vane 30, and the width of the rectifier plate 10 gradually narrows from the second end 15 to the first end 14.

[0055] It is understandable that the end of the rectifier plate 10 closer to the impeller 20 is narrower, and the end farther away from the impeller 20 is wider.

[0056] Because the guide vane 30 outlet is close to the impeller 20, there is a risk of interference between the first end 14 of the rectifier plate 10 and the guide vane 30 during the rotation of the guide vane 30. In this embodiment, the end of the rectifier plate 10 furthest from the impeller 20 is designed to be wider, which can improve the rectification effect and thus improve the operational stability of the pumped storage unit 100; while the end closer to the impeller 20 is set to be narrower, which can avoid interference with the impeller 20 and reduce the degree of obstruction of the water flow by the rectifier plate 10, thereby reducing energy loss. Therefore, from the second end 15 to the first end 14, the width of the rectifier plate 10 gradually narrows, which can balance the operational stability and energy loss of the pumped storage unit 100.

[0057] The first side 11 is the main body of the rectifier plate 10, which is mainly used to interfere with the flow pattern of the bladeless zone and achieve the rectification effect. Under the condition of low flow rate, the guide vane 30 has a small opening and the pressure pulsation in the bladeless zone is large. The narrower first end 14 can reduce the degree of interference of the rectifier plate 10 with the flow pattern in the bladeless zone under the condition of low flow rate. At the same time, the wider second end 15 can increase the degree of interference of the rectifier plate 10 with the flow pattern in the bladeless zone under the condition of low flow rate.

[0058] Reference Figure 3 In one possible implementation, the rectifier plate 10 has a first side 11 facing away from the guide vane 30, and the first side 11 and the water-facing surface of the guide vane 30 have a first included angle α, satisfying 12°≤α≤16°. By controlling the first included angle between 12° and 16°, the operational stability and energy loss of the pumped storage unit 100 can be further balanced.

[0059] For example, the first included angle between the first side 11 and the water-facing surface of the guide vane 30 can be 12°, 13°, 14°, 15°, 16° and any value between these.

[0060] In order to avoid interference caused by the rectifier plate 10 being too close to the impeller 20 and thus aggravating pressure pulsation, the first included angle is controlled between 12° and 16°. In this way, when the flow rate is low, the tilt angle of the first side 11 is close to the opening of the guide vane 30, so that the rectifier plate 10 will not rapidly approach the impeller 20 due to the rotation of the guide vane 30.

[0061] Reference Figure 3 In some embodiments, the rectifier plate 10 has a first side 11, a second side 12 and a third side 13, the second side 12 and the third side 13 are spaced apart along the length direction of the rectifier plate 10, one end of the first side 11 is connected to the second side 12 and the other end is connected to the third side 13.

[0062] In some embodiments, the first side 11 and the water-facing surface of the guide vane 30 are smoothly transitioned through the second side 12.

[0063] The second side 12 allows for a smooth transition between the first side 11 of the rectifier plate 10 and the water-facing surface of the guide vane 30, thus enabling the water flow to smoothly transition from the first side 11 to the second side 12. This reduces stress concentration caused by the impact on the rectifier plate 10, lowering the risk of the rectifier plate 10 falling off. On the other hand, it allows the width of the rectifier plate 10 to narrow rapidly, reducing the blocking effect of the rectifier plate 10 on the bladeless area (i.e., the liquid inlet channel 40 described later), and reducing energy loss.

[0064] In some embodiments, the first side 11 and the water-facing surface of the guide vane 30 are smoothly transitioned through the third side 13.

[0065] The third side 13 is the water-facing rib of the guide vane 30 when the pumped storage unit 100 is running. The first side 11 and the water-facing surface of the guide vane 30 are smoothly transitioned through the third side 13, which allows the water flow to smoothly transition from the third side 13 to the first side 11. This can reduce the stress concentration caused by the impact of the water flow on the rectifier plate 10 when the pumped storage unit 100 is running, and reduce the risk of the rectifier plate 10 falling off. On the other hand, it can make the width of the rectifier plate 10 increase rapidly and extend into the bladeless area, so that the rectifier plate 10 can quickly cut into the water flow, interfere with the flow pattern of the water flow in the bladeless area, and alleviate the vortex formed by the flow separation at the outlet of the guide vane 30.

[0066] In some embodiments, the rectifier plate 10 has a first end 14 near the outlet of the guide vane 30 and a second end 15 away from the outlet of the guide vane 30. From the second end 15 to the first end 14, the distance between the first side surface 11 and the upstream surface of the guide vane 30 gradually decreases. This arrangement can alleviate flow separation and stress concentration caused by the abrupt change in size of the first end 14 of the rectifier plate 10.

[0067] In some embodiments, the rectifier plate 10 has a first end 14 near the outlet of the guide vane 30 and a second end 15 away from the outlet of the guide vane 30. From the second end 15 to the first end 14, the distance between the third side surface 13 and the upstream surface of the guide vane 30 gradually increases. This arrangement can alleviate stress concentration caused by the abrupt change in size of the second end 15 of the rectifier plate 10.

[0068] Reference Figure 2 In some embodiments, multiple rectifier plates 10 are provided, and the multiple rectifier plates 10 are spaced apart along the height direction of the guide vanes 30. This arrangement can further improve the operational stability of the pumped storage unit 100.

[0069] For example, two rectifier plates 10 are provided. For example, the top rectifier plate 10 is spaced apart from the upper edge of the guide vane 30, and the bottom rectifier plate 10 is spaced apart from the lower edge of the guide vane 30.

[0070] In some embodiments, the height of the guide vane 30 is H1, and the thickness of the rectifier plate 10 is H2, satisfying 0.02H1≤H2≤0.03H1. This configuration can improve the structural strength of the rectifier plate 10 while reducing the obstruction effect of the rectifier plate 10 on the bladeless region.

[0071] For example, H2 can be 0.02H1, 0.022H1, 0.024H1, 0.026H1, 0.028H1, 0.03H1, and any value between these.

[0072] In some embodiments, the length of the guide vane 30 is L1, and the length of the rectifier plate 10 is L2, satisfying 0.65L1≤L2≤0.75L1. This arrangement can also improve the structural strength of the overall rectifier plate while reducing the obstruction effect of the rectifier plate 10 on the bladeless region.

[0073] For example, L2 can be 0.65L1, 0.67L1, 0.69L1, 0.7L1, 0.72L1, 0.75L1, and any value between these.

[0074] In some embodiments, 2mm ≤ H2 ≤ 30mm.

[0075] For example, H2 can be 2mm, 4mm, 6mm, 15mm, 19mm, 23mm, 26mm, 29mm, 30mm, or any value between these values. This configuration can also improve the structural strength of the overall flow plate while reducing the obstruction effect of the flow plate 10 on the bladeless region.

[0076] In some embodiments, the distance between the rectifier plate 10 and the upper edge of the guide vane 30 is between 0.25H1 and 0.3H1.

[0077] In some embodiments, the distance between the rectifier plate 10 and the lower edge of the guide vane 30 is between 0.25H1 and 0.3H1.

[0078] By controlling the distance between the rectifier plate 10 and the upper and / or lower edge of the guide vane 30, the rectifier plate 10 can be made closer to and adapted to the position where the water flow forms a vortex before the rectifier plate 10 is installed, thereby improving the rectification effect.

[0079] Reference Figure 1 and Figure 3 In some embodiments, multiple guide vanes 30 are provided, and the multiple guide vanes 30 are arranged circumferentially around the impeller 20. An inlet channel 40 for supplying water flow into the impeller 20 is defined between two adjacent guide vanes 30. The rectifier plate 10 is located in the inlet channel 40. The distance between the rotation center lines of two adjacent guide vanes 30 is W, and the width of the rectifier plate 10 is L, satisfying 0.3W≤L≤0.5W.

[0080] Among them, the liquid inlet channel 40 is the bladeless zone mentioned above.

[0081] The width of the rectifier plate 10 is the dimension of the widest position of the rectifier plate 10.

[0082] For example, L can be 0.3W, 0.34W, 0.37W, 0.4W, 0.43W, 0.46W, 0.48W, 0.5W, and any value in between.

[0083] It can be understood that L is the dimension of the rectifier plate 10 extending into the liquid inlet channel 40. The larger the value of L, the more the rectifier plate 10 extends in the bladeless area, the better the rectification effect, but the greater the obstruction to the water flow, resulting in increased energy loss. In this embodiment, by controlling L between 0.3W and 0.5W, both rectification effect and energy loss can be taken into account.

[0084] In the water storage and energy storage unit provided in the above embodiments of this application, the rectifier plate 10 can regulate the water flow and suppress the development of eddies. In addition, the rectifier plate 10 can be separately manufactured and fixedly connected with the guide vane 30. Separate manufacturing facilitates the separate processing of the rectifier plate 10 and the guide vane 30, reduces the manufacturing difficulty, and improves the manufacturing accuracy.

[0085] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0086] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0087] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0088] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A pumped-storage hydroelectric unit, characterized in that, include: impeller, Guide vanes, located on the outside of the impeller, are configured to be rotatable and are used to control the flow rate of water entering the impeller; A rectifier plate is disposed on the water-facing surface of the guide vane, and the rectifier plate is used to guide the flow direction of the water flow at the outlet of the guide vane.

2. The pumped storage unit according to claim 1, characterized in that, The rectifier plate is positioned on the side of the guide vane's rotation center line near the impeller.

3. The pumped storage unit according to claim 1, characterized in that, The rectifier plate has a first end near the guide vane outlet and a second end away from the guide vane inlet, and the width of the rectifier plate gradually narrows from the second end to the first end.

4. The pumped storage unit according to claim 3, characterized in that, The rectifier plate has a first side facing away from the guide vane, and the first side has a first included angle α with the water-facing surface of the guide vane, satisfying 12°≤α≤16°.

5. The pumped storage unit according to claim 1, characterized in that, The rectifier plate has a first side, a second side, and a third side. The second side and the third side are spaced apart along the length of the rectifier plate. One end of the first side is connected to the second side, and the other end is connected to the third side. The first side and the water-facing surface of the guide vane smoothly transition through the second side; and / or, The first side and the water-facing surface of the guide vane transition smoothly through the third side.

6. The pumped storage unit according to claim 5, characterized in that, The rectifier plate has a first end near the guide vane outlet and a second end away from the guide vane outlet; From the second end to the first end, the distance between the first side surface and the upstream surface of the guide vane gradually decreases; and / or, From the second end to the first end, the distance between the third side and the water-facing surface of the guide vane gradually increases.

7. The pumped storage unit according to any one of claims 1-6, characterized in that, The rectifier plate is provided in multiple ways, and the multiple rectifier plates are spaced apart along the height direction of the guide vane.

8. The pumped storage unit according to any one of claims 1-6, characterized in that, The height of the guide vane is H1, and the thickness of the rectifier plate is H2, satisfying 0.02H1≤H2≤0.03H1; and / or, The guide vane has a length of L1 and the rectifier plate has a length of L2, satisfying 0.65L1≤L2≤0.75L1.

9. The pumped storage unit according to claim 8, characterized in that, 2mm≤H2≤30mm.

10. The pumped storage unit according to any one of claims 1-6, characterized in that, The guide vanes are provided in multiple ways, and the multiple guide vanes are arranged circumferentially around the impeller. An inlet channel for water to enter the impeller is defined between two adjacent guide vanes. The rectifier plate is located in the inlet channel. The distance between the rotation center lines of two adjacent guide vanes is W, and the width of the rectifier plate is L, satisfying 0.3W≤L≤0.5W.

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