Water intake and sand prevention composite structure for power stations on sediment-laden rivers

Abstract

The present invention discloses a water intake and sand prevention composite structure, in particular, a water intake and sand prevention composite structure for a power station on a sediment-laden river, belonging to the technical field of the design and construction of water conservancy and hydropower engineering buildings. A water intake and sand prevention composite structure for a power station on a sediment-laden river is provided, which has and can maintain a certain regulating storage capacity for a long time, and at the same time meets the requirements of water intake and sand prevention. The water intake and sand prevention composite structure includes a water volume regulating reservoir, a sand prevention system and a water intake system. The sand prevention system is arranged on the upstream side of the water volume regulating reservoir, and the water intake system is arranged on the downstream side of the water volume regulating reservoir. The sediment mixed in the river channel water is preliminarily filtered by the sand prevention system, and the filtered water body in the water volume regulating reservoir is output to the power station through the water intake system.

Description

Technical Field

[0001] The present invention relates to a water intake and sand prevention composite structure, and in particular to a water intake and sand prevention composite structure for a power station on a sediment-laden river, belonging to the technical field of design and construction of water conservancy and hydropower engineering buildings. Background Art

[0002] 1. Glossary of Terms

[0003] 1) The regulating storage capacity refers to the reservoir volume that provides regulated runoff for hydropower generation, usually referring to the reservoir volume between the normal storage level and the lowest operating level.

[0004] 2) A run-of-river hydropower station generally refers to a hydropower station that does not have a regulating storage capacity and cannot perform runoff regulation. A run-of-river hydropower station can only generate electricity corresponding to the natural river inflow and time period within the installed capacity of the hydropower station, cannot meet the requirements of the power system load change, and cannot store excess runoff, resulting in poor power quality.

[0005] 3) A runoff peak-regulating hydropower station refers to a hydropower station that, based on a run-of-river hydropower station, obtains a regulating storage capacity by increasing the height of the water retaining dam, thus having a regulating storage capacity.

[0006] Regarding the differences between a run-of-river hydropower station and a runoff peak-regulating hydropower station, an example is given: 1) A run-of-river hydropower station does not have a regulating storage capacity and generates electricity according to the amount of water coming in the river every day. When the incoming flow is less than the diverted flow, it generates electricity whenever water comes. The time period for providing electricity is not necessarily the time period required by the power grid load because its power quality is poor; 2) A runoff peak-regulating hydropower station obtains a regulating storage capacity by increasing the dam height. Therefore, it can store all the river inflow in a day in the reservoir and generate electricity concentratedly during the time period when the power grid needs it most in a day, such as the peak electricity consumption period from the end of work to evening rest in developing countries, so the power quality is better.

[0007] 2. Conventional Layout Scheme

[0008] The structural features of the conventional layout scheme of the headwork of a runoff hydropower station with prominent sediment problems in mountainous areas are as follows: 1) The headwork consists of an overflow dam, a sediment flushing sluice, a water intake, an underground sedimentation tank, a sediment discharge channel, a diversion tunnel, etc.; 2) The elevation of the crest of the overflow dam is basically the same as the lowest operating water level of the hydropower station, that is, the reservoir does not have a regulating storage capacity. The advantages of this structure are: 1) The height of both the overflow dam and the water intake is relatively low, and the engineering quantity of the retaining and discharging structures of the headwork is relatively small; 2) It only needs to operate in the runoff mode, and the operation is relatively simple. The main problems of this structure are: 1) It does not have the regulating performance and the power quality is poor; 2) The height of the overflow dam is relatively low, and the water intake can only take water at a position relatively low from the riverbed in the elevation direction. When the sediment content in the diverted flow during the flood season is relatively high, special sedimentation tank buildings need to be set up to meet the requirements of water intake and sediment prevention, and the engineering quantity of the water intake and sediment prevention buildings of the headwork is relatively large. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a water intake and sediment prevention composite structure for a sediment-laden river power station, which has and can maintain a certain regulating storage capacity for a long time, and at the same time meets the requirements of water intake and sediment prevention.

[0010] The technical solution adopted to solve the above technical problem is: A water intake and sediment prevention composite structure for a sediment-laden river power station, the water intake and sediment prevention composite structure includes a water volume regulating reservoir, a sediment prevention system and a water intake system. The sediment prevention system is arranged on the upstream side of the water volume regulating reservoir, and the water intake system is arranged on the downstream side of the water volume regulating reservoir; the sediment mixed in the river channel water is preliminarily filtered through the sediment prevention system, and the filtered water body in the water volume regulating reservoir is output to the power station through the water intake system.

[0011] Furthermore, the sediment prevention system includes a sediment retaining and overflowing mechanism and a primary sedimentation and flushing mechanism. The sediment retaining and overflowing mechanism with the top elevation not lower than the highest water level of the water volume regulating reservoir is arranged on the upstream side of the water volume regulating reservoir, and the primary sedimentation and flushing mechanism is arranged on the river bank on the upstream side of the sediment retaining and overflowing mechanism. The flushing line of the primary sedimentation and flushing mechanism adjacent to the sediment retaining and overflowing mechanism is arranged obliquely downstream with respect to the river flow direction.

[0012] The preferred form of the above scheme is that the sediment retaining and overflowing mechanism is a sediment retaining and overflowing dam arranged in the upstream river channel, and the included angle between the flushing line and the river flow direction is between 30° and 45°.

[0013] Furthermore, the primary sedimentation and flushing mechanism includes an upstream water intake, an upstream sediment flushing sluice chamber assembly and a sediment discharge tunnel. The upstream sediment flushing sluice chamber assembly is arranged at the inlet end of the sediment discharge tunnel. The upstream sediment flushing sluice chamber assembly is communicated with the upstream river channel through the upstream water intake, and the outlet end of the sediment discharge tunnel is communicated with the river channel on the downstream side of the water intake system.

[0014] The preferred embodiment of the above solution is that the water intake system includes a downstream overflow dam, a secondary sedimentation and flushing mechanism, and a water intake mechanism. The downstream overflow dam with a top elevation not lower than the highest water level of the water volume regulation reservoir is arranged on the downstream side of the water volume regulation reservoir. The sediment carried in the water flow within the water volume regulation reservoir is discharged to the river channel on the downstream side of the downstream overflow dam through the secondary sedimentation and flushing mechanism. The water intake mechanism is arranged adjacent to the secondary sedimentation and flushing mechanism on the riverbank on the upstream side of the downstream overflow dam.

[0015] Furthermore, the secondary sedimentation and flushing mechanism includes one or two sets of downstream flushing sluice chamber assemblies. Each set of the downstream flushing sluice chamber assemblies is arranged adjacent to the water inlet of the water intake mechanism on the downstream overflow dam.

[0016] The preferred embodiment of the above solution is that the water intake mechanism includes a water intake sluice chamber assembly, a downstream water intake, and a water diversion and conveyance assembly. The water intake sluice chamber assembly is arranged at the inlet end of the downstream water intake. The water diversion and conveyance assembly is communicated with the outlet end of the downstream water intake. The water inlet of the water intake mechanism is located at the water inflow end of the water intake sluice chamber assembly.

[0017] Furthermore, the water diversion and conveyance assembly includes at least one water diversion tunnel. The water intake sluice chamber assembly includes at least two sets of water intake gates. Each set of the water intake gates is arranged side by side at the inlet end of the downstream water intake.

[0018] The preferred embodiment of the above solution is that the elevation of the bottom plate of the downstream water intake is higher than the elevation of the bottom plate of the downstream flushing sluice chamber assembly and lower than the elevation of the top of the downstream overflow dam.

[0019] Furthermore, the storage capacity of the water volume regulation reservoir formed by the sand prevention system, the water intake system, and the riverbank slopes on both sides is calculated and determined according to the regulation storage capacity required by the hydropower station.

[0020] The beneficial effects of the present invention are as follows: In this application, a water intake and sand prevention composite structure including a water volume regulation reservoir, a sand prevention system, and a water intake system is set up. The sand prevention system is arranged on the upstream side of the water volume regulation reservoir, and the water intake system is arranged on the downstream side of the water volume regulation reservoir. Then, the sediment mixed in the river water flow is preliminarily filtered through the sand prevention system, and the filtered water body in the water volume regulation reservoir is output to the power station through the water intake system. In this way, due to the presence of the water volume regulation reservoir, when the water volume is large or when electric energy is not needed, the water is first stored in the water volume regulation reservoir, and when power generation is required, it is output through the water intake system to achieve power generation, so as to achieve the purpose of maintaining a certain regulation storage capacity for a long time. At the same time, when the water flow enters the power station, it is first preliminarily filtered through the sand prevention system, then enters the water volume regulation reservoir, and then enters the power station, so as to meet the requirements of water intake and sand prevention for the hydropower station. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the layout plan of the water intake and sand prevention composite structure for power stations in rivers with heavy sediment load of the present invention.

[0022] In the figure, the markings are: water volume regulation reservoir 1, sand prevention system 2, water intake system 3, sediment interception and overflow mechanism 4, primary sedimentation and flushing mechanism 5, flushing line 6, upstream water intake 7, upstream flushing sluice chamber assembly 8, sediment discharge tunnel 9, downstream overflow dam 10, secondary sedimentation and flushing mechanism 11, water intake mechanism 12, downstream water intake 14, water diversion and transportation assembly 15, water intake gate 16. Detailed implementation manners

[0023] As Figure 1 shown, this is a water intake and sand prevention composite structure for power stations in rivers with heavy sediment load provided by the present invention, which has and can maintain a certain regulation storage capacity for a long time, and at the same time meets the requirements of water intake and sand prevention. The water intake and sand prevention composite structure includes a water volume regulation reservoir 1, a sand prevention system 2 and a water intake system 3. The sand prevention system 2 is arranged on the upstream side of the water volume regulation reservoir 1, and the water intake system 3 is arranged on the downstream side of the water volume regulation reservoir 1; the sediment mixed in the river water flow is preliminarily filtered through the sand prevention system 2, and the filtered water body in the water volume regulation reservoir 1 is output to the power station through the water intake system 3. In this application, a water intake and sand prevention composite structure including a water volume regulation reservoir, a sand prevention system and a water intake system is set, and the sand prevention system is arranged on the upstream side of the water volume regulation reservoir, and the water intake system is arranged on the downstream side of the water volume regulation reservoir; then the sediment mixed in the river water flow is preliminarily filtered through the sand prevention system, and the filtered water body in the water volume regulation reservoir is output to the power station through the water intake system. In this way, due to the existence of the water volume regulation reservoir, when the water volume is large or when electric energy is not needed, the water is stored in the water volume regulation reservoir first, and then when power generation is required, it is output through the water intake system to achieve power generation, so as to achieve the purpose of maintaining a certain regulation storage capacity for a long time. At the same time, when the water flow enters the power station, it is first preliminarily filtered through the sand prevention system, then enters the water volume regulation reservoir, and then enters the power station, so as to meet the requirements of water intake and sand prevention of the hydropower station.

[0024] In the above-described embodiments, in order to simplify the structure of each component of the present application to the greatest extent, facilitate construction, and facilitate maintenance and repair during subsequent use, the sand prevention system 2 of the present application includes a sand retaining and overflowing mechanism 4 and a primary sedimentation flushing and discharging mechanism 5. The sand retaining and overflowing mechanism 4 with a top elevation not lower than the highest water level of the water volume regulation reservoir 1 is arranged on the upstream side of the water volume regulation reservoir 1, and the primary sedimentation flushing and discharging mechanism 5 is arranged on the river bank on the upstream side of the sand retaining and overflowing mechanism 4, and the flushing line 6 of the primary sedimentation flushing and discharging mechanism 5 adjacent to the sand retaining and overflowing mechanism 4 is arranged to incline downstream with respect to the river flow direction. At this time, the sand retaining and overflowing mechanism 4 of the present application is set as a sand retaining overflow dam arranged in the upstream river channel, and the included angle between the flushing line 6 and the river flow direction is between 30° and 45°. The primary sedimentation flushing and discharging mechanism 5 is set as a structure including an upstream water intake 7, an upstream flushing sluice chamber assembly 8, and a sediment discharge tunnel 9. The upstream flushing sluice chamber assembly 8 is arranged at the inlet end of the sediment discharge tunnel 9, the upstream flushing sluice chamber assembly 8 is communicated with the river channel on the upstream side through the upstream water intake 7, and the outlet end of the sediment discharge tunnel 9 is communicated with the river channel on the downstream side of the water intake system. Correspondingly, the water intake system 3 includes a downstream overflow dam 10, a secondary sedimentation flushing and discharging mechanism 11, and a water intake mechanism 12. The downstream overflow dam 10 with a top elevation not lower than the highest water level of the water volume regulation reservoir 1 is arranged on the downstream side of the water volume regulation reservoir 1. The sand carried in the water flow located in the water volume regulation reservoir 1 is discharged to the river channel on the downstream side of the downstream overflow dam 10 through the secondary sedimentation flushing and discharging mechanism 11, and the water intake mechanism 12 is arranged on the river bank on the upstream side of the downstream overflow dam 10 adjacent to the secondary sedimentation flushing and discharging mechanism 11. Similarly, the secondary sedimentation flushing and discharging mechanism includes one or two sets of downstream flushing sluice chamber assemblies, and each set of the downstream flushing sluice chamber assemblies is arranged on the downstream overflow dam adjacent to the water flow inlet of the water intake mechanism. The water intake mechanism 12 includes a water intake sluice chamber assembly, a downstream water intake 14, and a water diversion and conveying assembly 15. The water intake sluice chamber assembly is arranged at the inlet end of the downstream water intake 14, the water diversion and conveying assembly 15 is communicated with the outlet end of the downstream water intake 14, and the water flow inlet of the water intake mechanism 12 is located at the water body inflow end of the water intake sluice chamber assembly. The water diversion and conveying assembly 15 includes at least one water diversion tunnel, and the water intake sluice chamber assembly includes at least two sets of water intake gates 16, and each set of the water intake gates 16 is arranged side by side at the inlet end of the downstream water intake 14. The elevation of the bottom plate of the downstream water intake is higher than the elevation of the bottom plate of the downstream flushing sluice chamber assembly and lower than the elevation of the top of the downstream overflow dam.

[0025] Meanwhile, the storage capacity of the water volume regulation reservoir 1 formed by the sand prevention system 2, the water intake system 3, and the river bank slopes on both sides of the river in the present application is calculated and determined according to the regulation storage capacity required by the hydropower station.

[0026] Specifically, the main operation mode and working principle of the above technical solution of the present application are as follows:

[0027] 1. During the dry season, the sediment content of the upstream flow is low. The upstream gate and sand flushing gate are closed, and the downstream gate is opened. The upstream flow will cross the upstream overflow dam, be filled up by the downstream overflow dam, pass through the downstream water intake, enter the water diversion tunnel to the downstream power plant for power generation; a small amount of sediment mixed in the upstream flow will be deposited in front of the upstream overflow dam.

[0028] 2. Flood season:

[0029] 1) When the upstream flow Q1 < the power station reference flow Q2, the upstream flow has relatively less sediment content, close the upstream gate and sand flushing gate, and open the downstream gate. The upstream flow will cross the upstream overflow dam, be filled by the downstream overflow dam, enter the water diversion tunnel through the downstream water intake, and generate electricity in the downstream power plant; a small amount of sediment mixed in the upstream flow will be deposited in front of the upstream overflow dam.

[0030] 2) When the upstream flow Q1> the power station reference flow Q2, the upstream flow has a relatively high sediment content. The upstream gate is partially or completely opened, the sand flushing gate is closed, and the downstream gate is opened, so that the flow discharged through the sand flushing tunnel = the upstream flow Q1-the power station reference flow Q2; the flow that crosses the upstream overflow dam and enters the downstream water intake is Q2. Then the sediment deposited in front of the upstream overflow dam will be discharged downstream through the sand flushing tunnel, realizing the sand flushing and silting-up of the reservoir in front of the upstream overflow dam; and the water flow with relatively less sediment content that crosses the upstream overflow dam will also enter the diversion tunnel through the downstream water intake to the downstream power plant for power generation.

[0031] 3) When the upstream inflow Q1 is greater than the power station's reference flow Q2, and when it is found that the silt deposited between the upstream overflow dam and the downstream overflow dam is close to the bottom plate elevation of the downstream water intake, the upstream gate and the sand flushing gate are partially or completely opened, and the downstream gate is closed, so that part of the water flow carries the silt deposited in front of the upstream overflow dam and discharges through the sand flushing tunnel, and the other part of the water flow with relatively less silt content that crosses the upstream overflow dam will carry the silt deposited between the upstream overflow dam and the downstream overflow dam and discharge to the downstream through the sand flushing gate, thereby realizing the sand flushing of the reservoir in front of the downstream overflow dam.

[0032] In summary, the water intake and sand prevention composite structure provided by the present application also has the following advantages:

[0033] 1) Through the water congestion effect of the downstream overflow dam with a higher dam height, a certain regulating reservoir capacity is obtained between the upstream overflow dam and the downstream overflow dam. The power station has a certain regulating ability and the quality of electricity is improved.

[0034] 2) Due to the interception effect of the upstream overflow dam, most of the silt carried in the upstream flow is intercepted in front of the upstream overflow dam and discharged into the downstream river channel through the sand flushing tunnel. A small amount of silt that overflows the upstream overflow dam can also be discharged into the downstream river channel through the sand flushing gate. The regulating reservoir capacity of the power station will be effectively maintained.

[0035] 3) The bottom plate elevation of the downstream water intake is higher than the bottom plate elevation of the sand flushing gate and the riverbed elevation. The silt that crosses the upstream overflow dam and arrives in front of the downstream overflow dam is mostly deposited on the riverbed in front of the dam. The water entering the downstream water intake is mostly clean water that is higher than the silt deposition elevation, and the silt content is relatively small. There is no need to arrange a special sedimentation tank to meet the water intake and sand control requirements of the power station, which greatly saves the engineering workload of the headwater hub water intake and sand control buildings.

[0036] Embodiment 1

[0037] The technical problem to be solved by the present application is to provide a composite structure for water intake and sand prevention which has and can maintain a certain regulating reservoir capacity for a long time and meets the requirements of water intake and sand prevention.

[0038] The technical solution adopted by this application to solve the technical problem is:

[0039] (1) The water intake and sand control composite structure consists of an upstream hub and a downstream hub. The upstream hub includes an upstream overflow dam, an upstream water intake, and a sand flushing tunnel; the downstream hub consists of a downstream overflow dam, a sand flushing gate, a downstream water intake, and a water diversion tunnel.

[0040] (2) The upstream overflow dam is relatively low in height and is mainly used to intercept sediment moving along the riverbed with the flow of water. The dam top elevation is higher than the normal water storage level of the hydropower station.

[0041] (3) The upstream water intake is arranged laterally on one side of the upstream overflow dam, intersecting the river flow at a small angle. An upstream gate is set at the upstream water intake to control the water flow. The sand flushing tunnel is connected to the upstream water intake, and the exit of the sand flushing tunnel is located downstream of the downstream overflow dam.

[0042] (4) The downstream overflow dam is relatively high and is mainly used to raise the water level in front of the dam to obtain the regulating storage capacity of the reservoir. The dam height is determined according to the regulating storage capacity required by the hydropower station.

[0043] (5) The sand flushing gate is arranged on one side of the downstream overflow dam. It is mainly used to discharge the silt that has crossed the upstream overflow dam and accumulated between the upstream overflow dam and the downstream overflow dam. The elevation of the bottom plate of the sand flushing gate is lower than the elevation of the bottom plate of the downstream water intake and is close to the elevation of the riverbed at this location. The sand flushing gate is equipped with a sand flushing gate to control the water flow.

[0044] (6) The downstream water intake is adjacent to the sand flushing gate and is arranged laterally on one side of the downstream overflow dam. A downstream gate is set to control the water flow. The elevation of the bottom plate of the downstream water intake is higher than the elevation of the bottom plate of the sand flushing gate and lower than the elevation of the crest of the downstream overflow dam.

Claims

1. A water intake and sand prevention composite structure for a power station on a sediment-laden river, characterized in that: The described water intake and sand prevention composite structure includes a water volume regulation reservoir (1), a sand prevention system (2), and a water intake system (3). The sand prevention system (2) is arranged on the upstream side of the water volume regulation reservoir (1), and the water intake system (3) is arranged on the downstream side of the water volume regulation reservoir (1). The sediment mixed in the river water flow is preliminarily filtered through the sand prevention system (2), and the filtered water body in the water volume regulation reservoir (1) is output to the power station through the water intake system (3). The described sand prevention system (2) includes a sediment interception and overflow mechanism (4) and a primary sedimentation and flushing mechanism (5). The sediment interception and overflow mechanism (4) with a top elevation not lower than the highest water level of the water volume regulation reservoir (1) is arranged on the upstream side of the water volume regulation reservoir (1). The primary sedimentation and flushing mechanism (5) is arranged on the river bank on the upstream side of the sediment interception and overflow mechanism (4). The flushing line (6) of the primary sedimentation and flushing mechanism (5) adjacent to the sediment interception and overflow mechanism (4) is arranged to incline downstream with respect to the river flow direction. The described water intake system (3) includes a downstream overflow dam (10), a secondary sedimentation and flushing mechanism (11), and a water intake mechanism (12). The downstream overflow dam (10) with a top elevation not lower than the highest water level of the water volume regulation reservoir (1) is arranged on the downstream side of the water volume regulation reservoir (1). The sediment mixed in the water flow in the water volume regulation reservoir (1) is discharged to the river on the downstream side of the downstream overflow dam (10) through the secondary sedimentation and flushing mechanism (11). The water intake mechanism (12) is arranged adjacent to the secondary sedimentation and flushing mechanism (11) on the river bank on the upstream side of the downstream overflow dam (10). The reservoir capacity of the water volume regulation reservoir (1) enclosed by the sand prevention system (2), the water intake system (3), and the river bank slopes on both sides is calculated and determined according to the regulation reservoir capacity required by the hydropower station.

2. The water intake and sediment prevention composite structure for a power station in a sediment-laden river according to claim 1, characterized in that: The described sediment interception and overflow mechanism (4) is a sediment interception and overflow dam arranged in the upstream river course. The included angle between the flushing line (6) and the river flow direction is between 30° and 45°.

3. The water intake and sediment prevention composite structure for a power station in a sediment-laden river according to claim 1 or 2, characterized in that: The described primary sedimentation and flushing mechanism (5) includes an upstream water intake (7), an upstream flushing chamber assembly (8), and a sediment discharge tunnel (9). The upstream flushing chamber assembly (8) is arranged at the inlet end of the sediment discharge tunnel (9). The upstream flushing chamber assembly (8) is connected to the river course on the upstream side through the upstream water intake (7). The outlet end of the sediment discharge tunnel (9) is connected to the river course on the downstream side of the water intake system.

4. The water intake and sediment prevention composite structure for a power station in a sediment-laden river according to claim 3, characterized in that: The described secondary sedimentation and flushing mechanism includes one or two sets of downstream flushing chamber assemblies. Each set of the downstream flushing chamber assemblies is arranged on the downstream overflow dam adjacent to the water flow inlet of the water intake mechanism.

5. The water intake and sediment prevention composite structure for a power station in a sediment-laden river according to claim 4, characterized in that: The described water intake mechanism (12) includes a water intake chamber assembly, a downstream water intake (14), and a water diversion and transportation assembly (15). The water intake chamber assembly is arranged at the inlet end of the downstream water intake (14). The water diversion and transportation assembly (15) is connected to the outlet end of the downstream water intake (14). The water flow inlet of the water intake mechanism (12) is located at the water body inflow end of the water intake chamber assembly.

6. The water intake and sediment prevention composite structure for a power station on a sediment-laden river according to claim 5, characterized in that: The described water diversion and conveyance assembly (15) includes at least one water diversion tunnel, and the intake sluice chamber assembly includes at least two sets of intake gates (16), and each set of the intake gates (16) is arranged side by side at the inlet end of the downstream water intake (14).

7. The water intake and sediment prevention composite structure for a power station in a sediment-laden river according to claim 6, wherein: The elevation of the downstream water intake floor is higher than the elevation of the downstream sediment flushing sluice chamber assembly floor and lower than the elevation of the downstream overflow dam crest.

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