Design method of mixed pumped storage power station layered inlet / outlet

Abstract

The application provides a design method of a layered inlet / outlet of a hybrid pumped storage power station, and relates to the technical field of water conservancy and hydropower engineering. The application is characterized in that the original ground line is excavated and constructed, the contour of the bottom of the original ground line is reserved as a reserved rock ridge, the layered inlet / outlet is arranged downstream of the reserved rock ridge, the layered inlet / outlet comprises a group of lower-layer gates of layered water intakes arranged below, and a group of upper-layer gates of layered water intakes is arranged above the lower-layer gates of layered water intakes. When the hybrid pumped storage power station is in the water pumping condition, water is discharged from the upper-layer gates of layered water intakes, the water pumping head range of the water pump turbine is reduced, and the design and manufacturing difficulty of the water pump turbine is reduced. In addition, the reserved rock ridge is used for water retaining, and a stilling basin is formed in front of the inlet / outlet to dissipate the water drop.

Description

Technical Field

[0001] This invention relates to the field of water conservancy and hydropower engineering technology, and in particular to a design method for a layered inlet / outlet of a hybrid pumped storage power station. Background Technology

[0002] With the introduction of the "dual carbon" target, the low-carbon and green transformation of the national energy sector is imperative. Pumped storage, as a relatively mature, economically optimal, and large-scale clean energy source, is experiencing rapid development. Hybrid pumped storage power stations have advantages over conventional pumped storage power stations, such as less land acquisition and resettlement and shorter construction periods. However, their upper reservoirs are often located in high dams and large reservoirs. To minimize the impact of the reservoir water on the downstream river's ecological environment, the design of the inlet / outlet must meet the conditions for drawing water from the upper reservoir layer.

[0003] To mitigate the impact of drawing low-temperature water from the lower layers on the downstream ecosystem and irrigated crops, stratified intakes are needed to draw water from the upper layers of the reservoir. Meanwhile, the large fluctuations in reservoir water levels pose significant challenges to the design and manufacture of pump turbines, and the stability and efficiency of the units during operation are difficult to guarantee. Summary of the Invention

[0004] This invention provides a design method for stratified inlet / outlet of a hybrid pumped storage power station. The purpose is to reduce the pump head variation of the pump turbine during pumping operation, thereby reducing the design and manufacturing difficulty of the pump turbine. Furthermore, this invention utilizes a reserved rock retaining wall to impede water flow, forming an energy dissipation pool in front of the inlet / outlet to dissipate energy from the drop flow. The dissipated water then flows through the reserved rock retaining wall into the upper reservoir.

[0005] The present invention provides the following technical solution to achieve the above objectives: A design method for a hybrid pumped storage power station with stratified inlets / outlets includes excavation and construction at the original ground line, retaining a pre-reserved rock embankment based on the bottom outline of the original ground line, and setting up stratified inlets / outlets downstream of the pre-reserved rock embankment. The stratified inlets / outlets include a set of lower gates for the stratified intakes located below, and a set of upper gates for the stratified intakes located above the lower gates for the stratified intakes.

[0006] In the aforementioned design method for the stratified inlet / outlet of a hybrid pumped storage power station, the distance L2 from the downstream side of the reserved rock embankment to the upstream side of the lower gate of the stratified intake is calculated as follows: ; In the formula, L0 is the water drop range. ; The outflow from the upper gate of the stratified intake is considered as the outflow from a broad-crested weir. ; Lj The length of the hydraulic jump. , h c For the depth of the water before the jump; h A The water depth at the top of the sill is m; the flow coefficient is P2; the height of the downstream sill is H. O It is the total head of the drop-off water inlet.

[0007] In the aforementioned design method for the stratified inlet / outlet of a hybrid pumped storage power station, the height of the reserved rock retainer is H1, and the calculation formula is as follows: ; In the formula: σ s h is the inundation coefficient. C " is the conjugate water depth; H represents the effective head at the drop inlet. ; H 01 For the full head of the stilling basin sill, ; q is the unit width flow rate; m1 is the flow rate coefficient.

[0008] In the aforementioned design method for the layered inlet / outlet of a hybrid pumped storage power station, the bottom width L1 of the reserved rock sill is greater than or equal to the height H1 of the reserved rock sill, and the bottom width L1 of the reserved rock sill is the distance H3 from the bottom of the upper gate of the layered intake to the bottom of the lower gate, which is greater than or equal to 0.5.

[0009] In the aforementioned design method for the stratified inlet / outlet of a hybrid pumped storage power station, a breast wall is provided between the upper gate of the stratified intake and the lower gate of the stratified intake; an emergency gate well is provided downstream of the stratified inlet / outlet.

[0010] Beneficial effects Compared with the prior art, the present invention has the following beneficial effects: This invention combines a reserved rock retaining wall with tiered intake gates. During pumping operations in a hybrid pumped-storage power station, water always exits through the upper gate of the tiered intake. This effectively reduces the head variation of the pump-turbine, thereby simplifying the design and manufacturing of the pump-turbine. Since the water exiting the upper gates at the inlet and outlet forms a cascade, the reserved rock retaining wall can impede the flow, reducing the impact of the cascade energy on the stability of the inlet / outlet. Furthermore, an energy dissipation pool is formed before the inlet / outlet to dissipate the energy of the cascade. The fully dissipated water then flows through the reserved rock retaining wall into the upper reservoir. Moreover, retaining the reserved rock retaining wall also saves on the investment required for underwater blasting to remove it. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a cross-sectional structural diagram of the present invention; Figure 2 for Figure 1 A top-view structural diagram; Figure 3 A schematic diagram illustrating the calculation of the length and width of the stilling pool formed by this invention.

[0013] Attached diagram labels: 1-Original ground line; 2-Water flow direction during pumping operation; 3-Reserved rock sill; 4-Lower gate of stratified intake; 5-Breast wall; 6-Upper gate of stratified intake; 7-Emergency gate well; Water level 1-Normal storage level; Water level 2-Minimum water level for reducing head amplitude; Water level 3-Floor elevation of inlet and outlet; H1-Height of reserved rock sill (energy dissipation sill height); L1-Bottom width of reserved rock sill; L2-Distance from downstream side of reserved rock sill to upstream side of intake (length of stilling basin); H2-Distance from bottom of lower gate of stratified intake to top of upper gate; H3-Distance from bottom of upper gate of stratified intake to bottom of lower gate. Detailed Implementation

[0014] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0015] It should be noted that in this invention: the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices; the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. These terms are primarily for better describing the invention and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation; the terms "installed," "set," "equipped with," "connected," "linked," "sleeve," etc., should be interpreted broadly; for example, they may be fixed connections, detachable connections, or integral constructions; they may be mechanical connections or electrical connections; they may be direct connections or indirect connections through an intermediate medium, or internal communication between two devices, elements, or components. Furthermore, some terms, besides indicating direction or positional relationship, may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0016] Example. A design method for stratified inlet / outlet of a hybrid pumped storage power station, referring to... Figure 1-2 As shown, the original ground line 1 is excavated and constructed, and the pre-reserved rock embankment 3 is retained based on the bottom outline of the original ground line 1. Downstream of the pre-reserved rock embankment 3, there is a layered inlet / outlet. The layered inlet / outlet includes a set of lower gates 4 of the layered water intake located below, and a set of upper gates 6 of the layered water intake is provided above the lower gates 4 of the layered water intake.

[0017] With the above design, during the pumping operation of the hybrid pumped storage power station, water exits from the upper gate 6 of the stratified intake, and is blocked by the reserved rock sill 3. An energy dissipation pool is formed before the inlet / outlet to dissipate energy from the drop flow. The energy-dissipated water flows through the reserved rock sill 3 into the upper reservoir. Water level 1 is the normal storage level, water level 2 is the lowest water level for reducing the head variation, and water level 3 is the floor elevation of the inlet / outlet. During pumping, the water flows out from the upper gate 6 of the inlet / outlet, causing the pump turbine head to decrease from water level 3 to water level 1, and then to water level 2 to water level 1.

[0018] To effectively achieve the above objectives, the dimensional requirements are as follows: The height of the reserved rock retainer 3 is H1. The distance from the bottom of the lower gate 4 of the stratified intake to the top of the upper gate 6 is H2. The distance from the downstream side of the reserved rock retainer 3 to the upstream side of the intake is L2. H1 and L2 are determined primarily to ensure sufficient energy dissipation of the water flow falling from the upper gates of the intake / outlet and to reduce the amount of work required to remove the reserved rock retainer, while also ensuring that the water flow in the water cushion can smoothly flow into the upper reservoir. Under pumping conditions, the k-flow exits from the upper gate 6 of the stratified intake, and its falling kinetic energy is relatively large. Therefore, the reserved rock retainer 3 is used to block the water, and the front end of the intake / outlet is made into a stilling basin to avoid scouring the bottom of the platform. The depth (height of the reserved rock retainer is H1) and length (distance from the downstream side of the reserved rock retainer to the upstream side of the intake is L2) of the stilling basin are sufficient to accommodate the falling water flow and simultaneously generate a submerged hydraulic jump within the stilling basin. The depth and length of the stilling basin are calculated as follows: Figure 3 As shown.

[0019] The distance L2 between the downstream side of the reserved rock embankment 3 and the upstream side of the lower gate 4 of the stratified water intake is calculated using the following formula: ; In the formula, L0 is the water drop range. ; The outflow from the upper gate 6 of the stratified intake is considered as the outflow from a broad-crested weir. ; L j The length of the hydraulic jump. h c For the depth of the water before the jump; h A The water depth at the top of the sill is m; the flow coefficient is P2; the height of the downstream sill is H. O It is the total head of the drop-off water inlet.

[0020] The height of the reserved rock retaining wall 3 is H1, and the calculation formula is as follows: ; In the formula: σ s h is the inundation coefficient. C " is the conjugate water depth; H is the inlet head of the drop structure." ; H 01 For the full head of the stilling basin sill, ; q is the unit width flow rate; m1 is the flow rate coefficient.

[0021] The bottom width of the reserved rock embankment 3 is L1. In order to ensure that the cascade has sufficient energy dissipation space and also to meet the stability of the reserved rock embankment 3 under the impact of the cascade, the bottom width of the reserved rock embankment is controlled to be L1≥H1. The bottom width L1 of the reserved rock embankment 3 is greater than the distance H3 between the bottom of the upper gate and the bottom of the lower gate of the upper layer water intake, that is, L1 / H3≥0.5.

[0022] A breast wall 5 is provided between the upper gate 6 and the lower gate 4 of the stratified water intake; an emergency gate well 7 is provided downstream of the stratified inlet / outlet.

[0023] Applying the above technology to the case study, in the pumping operation, the water flows out from the upper gate of the inlet / outlet, and the energy dissipation water cushion formed by the reserved rock sill reduces the pump-turbine head from water level 3 to water level 1 to water level 2 to water level 1. The ratio K of the pump-turbine's maximum head to minimum head is reduced from the original design of 1.52 to 1.27. In this example, in order to ensure sufficient energy dissipation of the water flow falling from the upper gate of the inlet / outlet and to reduce the amount of work required to remove the reserved rock sill, while also ensuring that the water flow in the water cushion can smoothly flow into the upper reservoir, H1 / H3=0.78.

[0024] To ensure that the cascade has sufficient energy dissipation space, and at the same time to meet the stability requirements of the reserved rock embankment under the impact of the cascade, L1 / H3=1.9, L2 / H3=1.2.

[0025] Obviously, the above description is only a part of the embodiments of the present invention, and not all of the embodiments. The above embodiments are not intended to limit the present invention, and various modifications and variations can be made to the present invention by those skilled in the art. Any combination, modification, equivalent substitution, improvement, and all other embodiments that can be made by those skilled in the art within the spirit and principles of the present invention should be within the protection scope of the present invention.

Claims

1. A design method for stratified inlet / outlet of a hybrid pumped storage power station, characterized in that: This includes excavation and construction at the original ground line (1), and the retention of a pre-reserved rock embankment (3) based on the bottom outline of the original ground line (1). A stratified inlet / outlet is set downstream of the pre-reserved rock embankment (3). The stratified inlet / outlet includes a set of lower gates (4) of the stratified water intake located below, and a set of upper gates (6) of the stratified water intake located above the lower gates (4).

2. The design method for the stratified inlet / outlet of a hybrid pumped storage power station according to claim 1, characterized in that: The distance L2 between the downstream side of the reserved rock embankment (3) and the upstream side of the lower gate (4) of the stratified water intake is calculated using the following formula: ; In the formula, L0 is the water drop range. ; The outflow from the upper gate (6) of the stratified intake is regarded as the outflow from the broad-crested weir. ； L j The length of the hydraulic jump. h c For the depth of the water before the jump; h A The water depth at the top of the sill is m; the flow coefficient is P2; the height of the downstream sill is H. O This represents the total head of the drop-off water inlet.

3. The design method for the stratified inlet / outlet of a hybrid pumped storage power station according to claim 1, characterized in that: The height of the reserved rock retaining wall (3) is H1, and the calculation formula is: ; In the formula: σ s h is the inundation coefficient. C "This is the conjugate water depth; H represents the effective head at the drop inlet. ; H 01 For the full head of the stilling basin sill, ; q is the unit width flow rate; m1 is the flow rate coefficient.

4. The design method for the stratified inlet / outlet of a hybrid pumped storage power station according to claim 3, characterized in that: The bottom width L1 of the reserved rock embankment (3) is greater than or equal to the height H1 of the reserved rock embankment (3). The bottom width L1 of the reserved rock embankment (3) is the distance H3 from the bottom of the upper gate of the layered water intake to the bottom of the lower gate, which is greater than or equal to 0.

5.

5. The design method for the stratified inlet / outlet of a hybrid pumped storage power station according to any one of claims 1-4, characterized in that: A breast wall (5) is provided between the upper gate (6) of the stratified water intake and the lower gate (4) of the stratified water intake; an emergency gate well (7) is provided downstream of the stratified inlet / outlet.

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