Arrangement structure of underground lower reservoir of small and medium-sized pumped storage power station

Abstract

The utility model discloses an arrangement structure of an underground lower reservoir of a small and medium-sized pumped storage power station, which mainly comprises an underground cavern group, a water inlet / outlet, a ventilation hole and a slag collecting pool, and the underground cavern group comprises a water storage hole, a connecting hole and a water inlet / outlet hole; the underground cavern group is arranged in a two-section mode, each section is composed of four axis equidistant water storage holes and two connecting holes, and each water inlet / outlet hole is provided with a slag collecting pool close to a water inlet / outlet. The water inlet / outlet adopts a vertical shaft type, the elbow pipe section adopts an elbow-shaped elbow pipe type, and a tail water tunnel is connected behind the water inlet / outlet. According to the utility model, the mineral industry and the hydropower industry are innovatively combined, and the final abandoned underground space such as the underground roadway and the cavern of the mine is reasonably utilized to build (reform) the underground lower reservoir of the pumped storage power station, so that a large amount of territorial space is saved, and the damage to the ecological environment can be reduced; meanwhile, a new choice is provided for the reservoir under the pumped storage power station.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydroelectric power generation, and in particular relates to an arrangement structure of an underground lower reservoir of a small and medium-sized pumped storage power station. Background Art

[0002] In order to ensure the safe, stable and economical operation of the power system, the demand for pumped-storage power stations, as an important component of the new power system with new energy as the main body, continues to grow. They mainly undertake tasks such as peak-shaving and valley-filling of the power grid, energy storage, frequency and phase regulation, and emergency standby. Summary of the invention

[0003] The technical problem to be solved by the utility model is to provide an energy-saving, environmentally friendly and environmentally friendly layout structure of an underground lower reservoir of a small and medium-sized pumped storage power station, so as to develop and utilize existing idle, under-construction or planned mines, and provide a new option for the construction of the lower reservoir of a pumped storage power station.

[0004] The technical problem to be solved by the utility model is to provide a layout structure of an underground lower reservoir of a small and medium-sized pumped storage power station.

[0005] The layout structure of the underground lower reservoir of small and medium-sized pumped storage power stations is mainly composed of underground cavern groups, water inlets / outlets, ventilation holes and slag collection pools. The underground cavern groups include water storage caverns, connecting holes and water inlets / outlets; the underground cavern groups adopt a two-section layout, each section consists of 4 axially equidistant water storage caverns and 2 connecting holes, a ventilation hole is provided at the end of each water storage cavern near the connecting cavern, and two adjacent water storage caverns are merged into an inlet / outlet cavern in an arc-shaped and symmetrical manner. The 4 inlet / outlet caverns are symmetrically arranged on both sides of the inlet / outlet, and a slag collection pool is provided near the inlet / outlet for each inlet / outlet; the inlet / outlet adopts a vertical shaft type and the bend section adopts an elbow-shaped bend pipe type, and the inlet / outlet is connected to a tailwater tunnel.

[0006] The four axes are equidistant and parallel to the water storage cave.

[0007] The water storage cave is tall and narrow, and the bottom is a horseshoe-shaped section of "middle horizontal section + two side arc sections".

[0008] The water inlet / outlet holes are arranged symmetrically at the water inlet / outlet.

[0009] Three submersible diversion partitions are installed in the turning section of the inlet / outlet tunnel, and pointed round piers are used at both ends of the partitions.

[0010] An inclined reinforced concrete beam is set on the top of the upstream end of the slag collecting pool, and a 1:3 bottom slope is adopted at the downstream end.

[0011] The elbow section of the vertical shaft inlet / outlet adopts an elbow type.

[0012] A submersible diversion pier is arranged at an equal distance of 15° on the circumference of the platform of the inlet / outlet, and pointed round pier heads are used at both ends of the pier.

[0013] In view of the problems existing in the construction of pumped-storage power stations, the inventors have designed a layout structure of an underground lower reservoir of a small and medium-sized pumped-storage power station, which is mainly composed of an underground cavern group, an inlet / outlet, a ventilation hole and a slag collection pool. The underground cavern group includes a water storage cavern, a connecting hole and an inlet / outlet cavern; the underground cavern group adopts a two-section layout, each section consists of 4 axially equidistant water storage caverns and 2 connecting holes, a ventilation hole is provided at the end of each water storage cavern near the connecting cavern, two adjacent water storage caverns are merged into an inlet / outlet cavern in an arc-shaped and symmetrical manner, the 4 inlet / outlet caverns are symmetrically arranged on both sides of the inlet / outlet, and a slag collection pool is provided near the inlet / outlet for each inlet / outlet; the inlet / outlet adopts a vertical shaft type and the bend section adopts an elbow-shaped bend pipe type, and the inlet / outlet is connected to a tailwater tunnel. The utility model innovatively combines the mining industry with the hydropower industry, and rationally utilizes the underground tunnels and caverns of the mines and other ultimately abandoned underground spaces to build (reconstruct) underground reservoirs of pumped-storage power stations, which not only saves a large amount of land space, but also reduces damage to the ecological environment. At the same time, the layout structure of the underground reservoir of the small and medium-sized pumped-storage power station provides a new choice for the lower reservoir of the pumped-storage power station. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a general plan view of the layout structure of the underground lower reservoir of the utility model small and medium-sized pumped storage power station.

[0015] Figure 2 yes Figure 1 Schematic diagram of the large-scale structure of the inlet / outlet and adjacent cavern plane in the layout structure.

[0016] Figure 3 yes Figure 1 Schematic diagram of the longitudinal section structure of the inlet / outlet and adjacent caverns in the layout structure.

[0017] Figure 4 yes Figure 1 Schematic diagram of the large-scale structure of the slag collecting pool in the layout structure.

[0018] Figure 5 yes Figure 1 Schematic diagram of the cross-sectional structure of the inlet / outlet water tunnel in the layout structure.

[0019] Figure 6 yes Figure 1 Schematic diagram of the cross-sectional structure of the water storage tunnel and the connecting tunnel in the layout structure.

[0020] Figure 7 yes Figure 1 Schematic diagram of the cross-sectional structure of the ventilation hole in the arrangement structure.

[0021] In the figure: 1 water storage cave; 2 water inlet / outlet; 3 water inlet / outlet cave; 4 connecting cave; 5 ventilation cave; 6 slag collecting pool; 7 diversion partition wall; 8 inclined beam; 9 diversion partition pier; 10 vertical shaft contraction / divergence section; 11 vertical shaft straight pipe section; 12 vertical shaft elbow section; 13 horizontal contraction / divergence section; 14 tailwater tunnel; 15 normal water storage level; 16 dead water level. DETAILED DESCRIPTION

[0022] 1. Basic structure

[0023] The following specifically describes the layout structure of the underground lower reservoir of the small and medium-sized pumped storage power station of the utility model in combination with the design of the planned small and medium-sized pumped storage power station.

[0024] like Figures 1 to 5 As shown in Figure 1, the underground reservoir of the project has a regulating storage capacity of about 3 million m 3 It is mainly composed of underground caverns, water inlets / outlets, ventilation holes and slag collection pools. The underground caverns include water storage holes, connecting holes and water inlets / outlets. Among them:

[0025] The underground caverns are symmetrically arranged in two sections, left and right. Each section consists of four water storage caverns with equidistant and parallel axes and two connecting caverns. Each water storage cavern is of equal length, and the ends of each section of the water storage cavern group are connected by connecting caverns. A ventilation hole (circular hole) is set at the end of each water storage cavern near the connecting cavern. The ventilation hole is arranged vertically and connected to the existing ventilation tunnel in the mining area. It leads to the ground through the tunnel, and can also lead directly to the ground according to the actual situation on site. Due to the high cavern, the cross section of the water storage cave adopts a high and narrow horseshoe cross section, and the net spacing between the caverns is about 2.2 times the maximum width of the cavern cross section.

[0026] Two adjacent water storage tunnels are combined in an arc-shaped and symmetrical manner to form a "Y"-shaped inlet / outlet tunnel (the tunnel diameter is slightly larger than the water storage tunnel), and finally form four inlet / outlet tunnels; the four inlet / outlet tunnels are vertically crossed at the inlet / outlet and arranged symmetrically on both sides. Three submersible diversion partitions are set in the turning section of the inlet / outlet tunnel, and the two ends of the partitions are pointed round piers. Each inlet / outlet tunnel is equipped with a slag collection pool in the tunnel section near the inlet / outlet. Five inclined reinforced concrete inclined beams are set on the top of the upstream end (close to the inlet / outlet end) of the slag collection pool, and the downstream end adopts a 1:3 bottom slope.

[0027] The inlet / outlet adopts a vertical shaft type and the elbow section adopts an elbow elbow type, which is composed of a vertical shaft contraction / diffusion section, a vertical shaft straight pipe section, a vertical shaft elbow section, and a horizontal contraction / diffusion section connected in sequence. A submersible diversion pier is arranged at an equidistant interval of every 15° on the platform of the inlet / outlet (at a certain distance from the orifice), and the two ends of the pier adopt a pointed round pier head. The inlet / outlet is connected to the tailwater tunnel.

[0028] 2. Engineering design features and operating principles

[0029] Small and medium-sized underground reservoirs require large storage capacity (usually more than 3 million m 3 The underground space required is also large, and it belongs to the layout of large cavern groups. Combined with the characteristics of pumped-storage power stations, several key points need to be solved: first, to ensure the stability of the surrounding rock of the large cavern group; second, the hydraulic conditions for operation should be good; third, to reduce the entry of mud or slag into the tailwater tunnel.

[0030] a) Ensuring the stability of surrounding rock

[0031] Good surrounding rock conditions are a necessary condition for the construction of underground large caverns, and generally the surrounding rock conditions are required to be above Class II and Class III. In addition, for large-section caverns, reasonable cavern layout and cross-sectional shape are particularly important. The utility model adopts a multi-line parallel structure cavern layout scheme, with fewer intersections in the cavern group and a simple structure, which is especially conducive to the stability of the surrounding rock at the intersection and is also convenient for construction. The cross-sectional area of ​​the water storage tunnel is large, and it is difficult to adopt a circular cross-section. The design adopts a high and narrow horseshoe cross-section. The span of the cave top is smaller than that of the circular cross-section. The side wall of the horseshoe-shaped tunnel is an arc, which is better than the gate tunnel type with straight side walls. The rock mass has good stress conditions. Under the condition of meeting the storage capacity requirements (that is, meeting the requirements of larger cross-sections), this structure is more conducive to the stability of the surrounding rock. The bottom edge line of the horseshoe-shaped cross-section adopts the "middle horizontal section + two side arc sections" type. The middle horizontal section is 7.5m wide, the purpose is to meet the traffic needs of vehicles during construction, and the two side arc sections are to try to make the bottom plate and the side wall be connected in an arc shape, which is conducive to the stability of the surrounding rock.

[0032] This design adopts well-type inlet / outlet with simple structure, short contraction / diffusion section, small submergence depth requirement and small reservoir bottom trench excavation depth, which is conducive to the stability of surrounding rock.

[0033] The ventilation hole has a small cross-section and adopts a circular cross-section, which can better ensure the stability of the surrounding rock.

[0034] b) Ensure good hydraulic conditions

[0035] Good hydraulic conditions require smooth flow passage connections and no or few sudden changes in structure. The design of this utility model strives to make the water flow in each hole uniform and stable. Specific measures to improve water flow conditions include:

[0036] (1) The water storage tunnel adopts a multi-axis equidistant cavern layout. The equidistant axis arrangement (which can be parallel or turn with a larger radius, with a net distance of about 2.2 times the tunnel diameter) can make the water flow have no turns or fewer turns, thereby making the water flow smooth, uniform and stable with little head loss.

[0037] (2) The parts that need to be connected, such as the connecting tunnel sections at both ends of the water storage tunnel and every two confluence sections of the water storage tunnel, are connected in an arc-shaped and symmetrical manner. The front end of the water storage tunnel is close to the inlet / outlet, and the stability of the water flow has a greater impact on the flow pattern of the inlet / outlet. The two adjacent tunnels are arranged in an arc-shaped and symmetrical confluence to make the water flow velocity evenly distributed and avoid irregular flow patterns, which will lead to overall water flow obstruction, weak connectivity, increased head loss, and even local water congestion and pressure flow. The end of the water storage tunnel is far away from the inlet / outlet, and the water flow pattern has no adverse effect on the inlet / outlet. The four tunnels can be connected to the connecting tunnel in an arc shape.

[0038] (3) At the bends of the inlet / outlet tunnels, three diversion walls are set to avoid excessive unevenness of the water flow under the action of centrifugal force. Under power generation or pumping conditions, the flow in the tailwater tunnel is basically uniform without major changes. Therefore, the greater the water depth in each cavern of the lower reservoir, the smaller the flow velocity. Therefore, the diversion walls are submersible. When the water depth exceeds the top of the wall, the flow velocity is small, the centrifugal effect of the water flow is not obvious, and it will not cause large water surface fluctuations, so there is no need to raise the diversion walls.

[0039] (4) The bottom plate at the downstream end of the slag collecting pool adopts a slope of 1:3, so that the water flow can smoothly enter the slag collecting pool. The upper part of the upstream end adopts a reinforced concrete inclined beam. Under pumping conditions, the water flow can quickly return to smoothness after flowing through the inclined beam, and the flow state is better.

[0040] (5) The four inlet / outlet tunnels are symmetrically arranged at the inlet / outlet, which can ensure that the inlet / outlet flow is almost evenly distributed in each cavern and the flow rate is almost the same.

[0041] (6) A submersible diversion pier is set every 15° on the vertical shaft inlet / outlet platform to avoid water concentration and ensure that water flows evenly in / out of the vertical shaft or each inlet / outlet hole.

[0042] (7) The shaft bend section is changed from the common single arc (equal radius) bend to an elbow bend to reduce the inlet flow velocity of the bend section and weaken the strength of the centrifugal force of the water flow in the bend section, so as to facilitate the uniformity of the flow velocity distribution at the outlet end of the bend.

[0043] (8) In order to avoid the large changes in air pressure in the caverns of the lower reservoir caused by water level changes during power generation or pumping, which may affect the normal operation of the unit, ventilation holes are arranged at both ends of the caverns of the lower reservoir, with a total of 8 holes (4 on each side) with circular cross-sections, and connected to the existing ventilation tunnels in the mining area, through which they are connected to the ground (or directly to the ground according to the actual situation on site), to ensure the free flow of gas above the water surface of the lower reservoir area, without generating positive / negative pressure, and to avoid large air pressure fluctuations. c) Prevent sediment or slag from entering the tailwater tunnel.

[0044] Due to the high head characteristics of pumped storage power stations, it is necessary to avoid excessive sediment particles passing through the machine to ensure that the turbine runner does not wear out and become scrapped prematurely. Therefore, the lower reservoir project should control the sediment or slag falling into the tailwater tunnel to the maximum extent. This design is an underground lower reservoir, with almost no dirt in the reservoir area, and no trash rack is required. Unlike the ground-type reservoir, which has ground solid runoff, it is almost a reservoir without natural sediment sources. However, considering that the upper reservoir is a ground-type reservoir, there is still a certain amount of sediment in the water body. In order to prevent the sediment carried by the power generation flow from being brought into the lower reservoir and then brought back into the upper reservoir during pumping, thereby increasing the wear of the turbine, and considering that the underground reservoir caverns are not all concrete lined (the cave sections with better surrounding rock only need to use system anchor rods to hang steel mesh + concrete spraying, or even no spraying), there may be a certain amount of slag falling during operation, so it is still necessary to set a slag collection pool before the inlet / outlet in each inlet / outlet tunnel. A number of reinforced concrete inclined beams are arranged on the upper part of the upstream end of the slag collecting pool to improve the flow pattern of the water and prevent the silt from being turned up and brought into the tailwater tunnel under pumping conditions.

Claims

1. An underground reservoir layout structure for a small or medium-sized pumped storage power station, characterized in that It is mainly composed of underground cavern groups, water inlets / outlets, ventilation holes and slag collection pools. The underground cavern groups include water storage holes, connecting holes and water inlets / outlets. The underground cavern groups are arranged in two sections, and each section consists of 4 equidistant water storage holes and 2 connecting holes on the same axis. A ventilation hole is arranged at the end of each water storage hole near the connecting cavern. Two adjacent water storage holes are merged into an inlet / outlet hole in an arc-shaped and symmetrical manner. The 4 inlet / outlet holes are symmetrically arranged on both sides of the inlet / outlet, and a slag collection pool is arranged near the inlet / outlet for each inlet / outlet. The inlet / outlet adopts a vertical shaft type and the bend section adopts an elbow bend type.

2. The arrangement according to claim 1, characterized in that: The four axes are equidistant and parallel to the water storage cave.

3. The arrangement according to claim 2, characterized in that: The water storage cave is high and narrow, and the bottom is a horseshoe-shaped section of "middle horizontal section + two side arc sections".

4. The arrangement according to claim 1, characterized in that: The water inlet / outlet holes are symmetrically arranged at the water inlet / outlet.

5. The arrangement according to claim 4, characterized in that: Three submersible diversion partition walls are arranged in the turning section of the inlet / outlet tunnel, and pointed round pier heads are adopted at both ends of the partition walls.

6. The arrangement according to claim 1, characterized in that: An inclined reinforced concrete inclined beam is arranged on the top of the upstream end of the slag collecting pool, and a bottom slope of 1:3 is adopted at the downstream end.

7. The arrangement according to claim 1, characterized in that: The curved pipe section of the water inlet / outlet is an elbow-shaped curved pipe type.

8. The arrangement according to claim 7, characterized in that: A submersible diversion pier is arranged at an equal distance of every 15° on the circumference of the platform of the inlet / outlet, and pointed round pier heads are adopted at both ends of the pier.

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