Hydropower station water inlet stoplog gate layered water taking effect evaluation method

Abstract

The invention provides a hydropower station water inlet stoplog gate layered water taking effect evaluation method, and the method comprises the steps: obtaining the real-time water temperature of different water level elevations through a vertical water temperature monitoring temperature chain disposed in front of a hydropower station water inlet stoplog gate, and combining the water inlet water taking influence elevation range under the stoplog gate state / non-stoplog gate state; the energy hybrid model is adopted to calculate the real-time energy difference under the stoplog gate state and / or the stoplog gate state, the equivalent mixed water temperature is used for characterization, the layered water taking effect under the stoplog gate state and / or the stoplog gate state can be directly compared and evaluated, meanwhile, the water taking effects under the operation working conditions of different stoplog gate layer numbers at different time can be directly simulated and calculated, and dispatching operation of the stoplog gate is effectively guided. The method also considers the influence of different operation stages of the stoplog gate, dynamically adjusts the water intake influence elevation range, draws a whole-process improvement effect curve, provides a basis for optimizing the dispatching operation of the stoplog gate, and effectively improves the water temperature regulation and control capability of a hydropower station.

Description

Technical Field

[0001] The present invention relates to the fields of water conservancy and hydropower engineering technology and ecological environment protection, and in particular to a method for evaluating the effect of layered water intake based on stoplog gates at a water inlet of a hydropower station. Background Art

[0002] With the deepening of ecological and environmental protection concepts and technologies, and the arrival of many large and medium-sized hydropower stations in years of stable operation, the phenomenon of water temperature stratification within and in front of high dams and reservoirs has attracted increasing attention. Furthermore, due to the high specific heat capacity of water, the large volumes of water stored in these reservoirs act as giant temperature regulators. Compared to natural water bodies, these reservoirs release higher temperatures in winter and lower temperatures in summer, significantly impacting the existing ecological environment of downstream rivers.

[0003] To minimize the impact on the downstream river ecosystem and protect the growth and reproduction of native fish, stratified water intake is a key engineering measure to mitigate the adverse effects of low-temperature water discharged from reservoirs. Stratified water intake is now widely used in large and medium-sized hydropower stations. Currently, the design of stratified water intake structures for large and medium-sized hydropower stations mostly utilizes either stoplog gates or multi-layer intakes. The stoplog gate stratified intake model, compared to the multi-layer intake model, has less impact on the dam structure and unit operating hydraulic conditions, and offers advantages such as the ability to adjust the stoplog gate height according to actual conditions, making it more widely used.

[0004] Stratified water intake with stoplog gates involves technical challenges such as inlet layout, hydraulic characteristic simulation, and evaluation of the improvement in outflow water temperature. The former can be addressed through specialized research such as hydraulic model tests and flow pattern analysis. The evaluation of the effectiveness of stratified water intake with stoplog gates primarily relies on formulas, experimental methods, and equivalent elevation methods. These methods primarily rely on extensive basic data to establish empirical relationships between reservoir water temperature, intake elevation, and outflow water temperature, thereby providing a preliminary estimate of outflow water temperature. However, the formula method relies on a single actual project or operating condition, which has certain limitations. The equivalent elevation method assumes a relatively stable elevation in front of the dam that represents the overall effect of the discharge water temperature. The vertical temperature distribution of the discharge water temperature of each unit with and without stoplog gates is measured using a vertical temperature chain. The corresponding temperature position is the equivalent discharge water temperature elevation for the unit with and without stoplog gates. The average temperature difference at this elevation represents the improvement effect of stratified water intake with stoplog gates. The equivalent elevation method has a certain degree of universality and can be applied to various power plants. However, it is less effective when the water temperature stratification in front of the dam is not clear. Furthermore, the determination of the equivalent elevation relies on human judgment, which may vary from person to person, leading to inaccurate results. Furthermore, the equivalent elevation is not static, with results varying under different annual operating conditions and even under different temperature fields within the same year. This requires annual operation of the stoplog gates to obtain the corresponding results. However, some stoplog gate operating conditions are relatively demanding, making them difficult to implement. Furthermore, due to the long operation time of the stoplog gates, the difficulty of dynamic water pumping and release, and conflicts between water and electrical regulation, strict adherence to stoplog gate scheduling procedures is not possible. All of these factors significantly impact the effectiveness of stratified water intake.

[0005] Patent number CN 110849580 A discloses a monitoring method for stratified water intake using stoplog gates based on a vertical temperature chain in the remote dam area. The method uses the remote dam area vertical temperature chain to obtain the vertical temperature structure in front of the dam, and obtains a cloud map of water temperature and water temperature gradient over elevation and time. Information such as the equivalent elevation of the downstream water temperature of units with and without stoplog gates and the elevation of the stoplog gate top are also simultaneously incorporated. This method can intuitively identify the relationship between the temperature structure in front of the reservoir dam and the downstream water temperature of the hydropower station with and without stoplog gate stratified water intake measures. This allows for the intuitive identification of the expansion space for the stoplog gate stratified water intake effect with and without stoplog gates, helping to guide the dispatching and operation of the stoplog gates. Summary of the Invention

[0006] In view of the current research status and various application restrictions of the evaluation method of stratified water intake in hydropower stations, the present invention aims to provide a method for evaluating the stratified water intake effect of the stoplog gates at the water inlet of a hydropower station based on energy mixing. The technical solution adopted by the present invention is: a method for evaluating the stratified water intake effect based on the stoplog gates at the water intake of a hydropower station, the method comprising: S1. Obtain real-time water temperature data at different water levels before the water inlet of the hydropower station; S2. Determine the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates; S3. Using an energy mixing model, based on the real-time water temperature data and the water intake impact elevation range, respectively calculate the equivalent mixed water temperature in the state with and without stoplog gates; S4. Determine the improvement effect of the stoplog gate stratified water intake based on the difference in the equivalent mixed water temperature.

[0007] In the preferred embodiment, in step S1, According to the specific layout of the water inlet of the hydropower station, a vertical water temperature monitoring temperature chain is arranged in front of the water inlet stoplog slot or in front of the dam body; Through the vertical water temperature monitoring temperature chain, real-time water temperature data covering the water inlet bottom plate elevation and above the water level is obtained; Regarding the arrangement position of the vertical water temperature monitoring temperature chain, if there is a single water inlet, it is arranged at the front end of the side wall; If there are multiple water inlets, it should be arranged at the front end of the partition pier between adjacent water inlets; If the arrangement conditions are not met in front of the water inlet, it should be arranged near the water inlet; The real-time water temperature data is obtained by evenly arranged thermometers, ensuring that the spacing between adjacent thermometers meets the preset standards, the monitoring accuracy meets the preset requirements, and the monitoring frequency meets the preset period; Regarding the fixing method of the vertical water temperature monitoring temperature chain, its overall verticality is maintained by a counterweight device.

[0008] In the preferred solution, in step S2, the minimum submerged height for safe and stable operation of the stoplog gate is determined through hydraulic model tests and water flow pattern analysis; For a state without stoplog gates, the water intake impact elevation range is determined to be from the water inlet bottom plate elevation to the minimum flooding height; For a stoplog gate state, the water intake impact elevation range is determined to be from the stoplog gate top plate elevation to the minimum submergence height; The specific limits of the elevation range affected by the water intake are obtained by combining the limiting conditions of the minimum flooding height with the operational safety boundaries of the stoplog gate and trash rack. If the minimum flooding height is limited by vibration or flow rate, it is adjusted based on the results of special research.

[0009] In a preferred embodiment, the determining of the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates comprises: In order to determine the elevation range affected by water intake, a segmented analysis is conducted in combination with different stages of stoplog gate operation; If the stopgate operation phase is the stopgate falling phase, the water intake influence elevation range is adjusted according to the stopgate falling process; If the stoplog gate operation stage is a stable operation period, determining the water intake impact elevation range according to the stoplog gate top plate elevation; If the stopgate operation phase is the stopgate lifting phase, the water intake influence elevation range is dynamically adjusted according to the stopgate lifting process; Through the segmented analysis, the changing pattern of the elevation range affected by water intake in each stage is obtained.

[0010] In the preferred embodiment, in step S3, the real-time water temperature data within the water intake influence elevation range is recorded in order from bottom to top. The water body is evenly stratified according to a preset assumption, and the flow rate of each layer is determined to decrease according to a preset rule. Calculating the energy value of each layer of water body through the water temperature value of each layer and the water flow rate of each layer; Summarizing the total energy and total flow within the water intake impact elevation range, and calculating the equivalent mixed water temperature; If there is a portion of the real-time water temperature data that exceeds the water intake influence elevation range, it is determined whether to include it in the calculation according to preset rules.

[0011] In a preferred embodiment, in step S3, an energy mixing model is used to calculate the equivalent mixed water temperature in the state with and without stoplog gates according to the real-time water temperature data and the water intake influence elevation range, including: For the energy mixing model, it is assumed that the water temperature stratification is uniformly distributed in layers in the vertical direction; The water flow state before the water inlet is set to a non-turbulent state, and the streamlines follow a preset distribution pattern; The water inlet volume is set to decrease from bottom to top within the water intake influence elevation range; Based on the above assumptions, a temperature-based energy calculation method for stratified water bodies is constructed; If the distribution of the real-time water temperature data does not conform to the assumption, the calculation method is adjusted according to the flow field analysis results.

[0012] In the preferred solution, select the vertical water temperature monitoring chain at a certain moment in the water intake influence elevation range Temperature data within, From bottom to top, they are , the number is recorded as , divide the water body evenly into layer, and the water flow rate of the lowest layer is ; According to the triangle similarity principle, starting from the bottom plate elevation of the stoplog door, Laminar flow rate According to the formula ( ) calculation, which is used to determine the flow rate of each layer of water body based on the assumed law of decreasing water inflow; Energy per layer of water based on temperature According to the formula Calculate, where , is the energy coefficient constant. This formula is used to calculate the energy of each layer of water based on temperature and flow; When there is a stoplog gate, the elevation range affected by water intake Total energy of internal water bodies According to the formula Calculation, total flow According to the formula The total energy formula is used to calculate the total energy of all water bodies within the elevation range affected by the water intake, and the total flow formula is used to calculate the total flow of water within this range; Equivalent mixed water temperature with stoplog doors According to the formula calculate; Similarly, the corresponding water intake influence elevation range and temperature data are replaced with the data in the state without stoplog gates, and the equivalent mixed water temperature in the state without stoplog gates can be calculated. ; If the real-time water temperature data exceeds the water intake elevation range, if the thermometer elevation exceeds H 影响 The part that is less than half of the distance between two adjacent thermometers should be included; The difference in equivalent mixed water temperature with and without stoplog gates at the same time is the improvement effect of stoplog gate stratified water intake at that moment, i.e., T 改善 =T 有 -T 无； According to the calculated improvement effects at different moments, a process line diagram of the improvement effect of the whole stratified water intake scheduling cycle can be drawn; In the preferred solution, the following situations are handled when the distribution of real-time water temperature data does not conform to the assumptions: When the real-time water temperature data distribution does not conform to the assumption, the numerical simulation method is used to simulate the flow field before the water inlet to obtain the water velocity distribution and temperature distribution; Adjust the calculation method according to the flow field analysis results. If the water velocity distribution does not conform to the decreasing law of the triangle similarity principle, an exponential function can be used. Describe the water flow rate at each layer, where are parameters determined based on flow field analysis; At this time, the energy of each layer of water , total energy , total traffic , equivalent mixed water temperature .

[0013] In the preferred solution, in step S4, the equivalent mixed water temperature in the state with the stoplog door and the state without the stoplog door at the same time is obtained; By calculating the difference between the equivalent mixed water temperatures, the improvement effect of the stoplog gate stratified water intake at that moment is determined; Calculate the average difference of the equivalent mixed water temperature for different operation periods and durations, and obtain the average improvement effect in each period; If the operation period includes multiple stages, the average improvement effect is calculated for each stage respectively; The average improvement effect is used to analyze the stratified water intake performance of the stoplog gate in different time periods.

[0014] In the preferred solution, a process line diagram of the improvement effect of the stratified water intake scheduling cycle is drawn based on the calculated improvement effect of the stratified water intake by the stoplog gate at each moment; Determine the time point when the stratified water extraction effect begins to appear and the moment when the maximum improvement effect occurs through the process line diagram of the whole process improvement effect; Based on the process line diagram of the improvement effect of the whole process, combined with the water level change data, the correlation between the stratified water intake effect and the water level is analyzed; If the overall improvement effect process line diagram shows multiple cycles, then the improvement effect characteristics in each cycle are obtained respectively; The optimized timing of the stoplog door scheduling operation is obtained through the process line diagram of the improvement effect of the whole process.

[0015] The present invention provides a method for evaluating the stratified water intake effect of stoplog gates at a hydropower station water intake based on energy mixing. Compared with the prior art, the method for evaluating the stratified water intake effect of stoplog gates at a hydropower station water intake based on energy mixing has the following beneficial effects: 1. The present invention utilizes a vertical water temperature monitoring chain arranged in front of the stoplog gates of a hydropower station to obtain real-time water temperatures at different water level elevations. Combined with the elevation range affecting water intake at the water inlet with and without stoplog gates, an energy mixing model is used to calculate the real-time energy difference between the two states. This is characterized by equivalent mixed water temperatures. This allows for direct comparison and evaluation of the stratified water intake effects with and without stoplog gates. Furthermore, the present invention can directly simulate and calculate the water intake effects at different times under operating conditions with different numbers of stoplog gate layers, effectively guiding the scheduling and operation of the stoplog gates.

[0016] 2. The present invention mainly arranges a vertical water temperature monitoring temperature chain in front of the stoplog gate slot (trash rack slot) of the left / right bank water inlet of the hydropower station or in front of the dam body. There is no need to set up an additional control group. The data on the same temperature chain are used for both the presence and absence of stoplog gates, which can avoid differences in control groups caused by inconsistencies in terrain, location, flow field, operating conditions, etc.

[0017] 3. The present invention is mainly based on the water temperature monitoring data of the vertical temperature monitoring chain in front of the stoplog gate. There is no need to deduce the equivalent water temperature or elevation on the upstream side based on the tailwater temperature data. This can reduce the layout of tailwater temperature monitoring equipment and avoid inaccurate improvement effect evaluation caused by inaccurate tailwater temperature monitoring data due to factors such as overflow of the dam unit.

[0018] 4. This invention, based primarily on real-time water temperature monitoring data in front of the stoplog gates and an energy hybrid model, eliminates the need for manual search for equivalent elevations, effectively reducing inaccurate assessments due to human variability. Furthermore, this invention is applicable to all stages of water temperature stratification, effectively avoiding the drawback of the equivalent elevation method, which is ineffective when water temperature stratification in front of the stoplog gates is not obvious.

[0019] 5. The present invention is mainly based on real-time water temperature monitoring data in front of the stoplog gate and an energy hybrid model. It can calculate the possible improvement effect of stratified water intake based on the real-time water temperature data in front of the stoplog gate without actually putting the stoplog gate into operation. It can effectively guide the operating height and operating timing of the stoplog gate and maximize the water temperature improvement effect.

[0020] 6. The present invention can calculate the improvement effect of the stoplog gate stratified water intake at any time scale based on the frequency of water temperature monitoring data and draw the corresponding full-cycle process line. This can better show when the stoplog gate stratified water intake begins to take effect, when the improvement effect is the greatest, and in which period the average improvement effect is the best, thereby realizing the improvement effect evaluation of the entire process of the stoplog gate stratified water intake. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and examples: Figure 1 This is a schematic diagram of the state of the stratified water intake at the hydropower station with stoplog gates according to the present invention (front view); Figure 2 This is a schematic diagram (side view) of the state of the water inlet of the hydropower station with stratified water intake and no stoplog gates according to the present invention; Figure 3 This is a schematic diagram (side view) of the state of the stratified water intake at the hydropower station of the present invention with stoplog gates; Figure 4 This is a process line diagram of the improvement effect of the stratified water intake scheduling of two-layer laminated beam gates in a hydropower station in a certain year according to an embodiment of the present invention; Figure 5 This is a process line diagram of the improvement effect of layered water intake scheduling of a single-layer stacked beam gate under the same conditions in a certain year at a hydropower station according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] Example 1 like Figure 1-3 As shown, a method for evaluating the effect of stratified water intake based on stoplog gates at a hydropower station water intake comprises: S1. Obtain real-time water temperature data at different water levels before the water inlet of the hydropower station; S2. Determine the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates; S3. Using an energy mixing model, based on the real-time water temperature data and the water intake impact elevation range, respectively calculate the equivalent mixed water temperature in the state with and without stoplog gates; S4. Determine the improvement effect of the stoplog gate stratified water intake based on the difference in the equivalent mixed water temperature.

[0023] In the preferred embodiment, in step S1, According to the specific layout of the water inlet of the hydropower station, a vertical water temperature monitoring temperature chain is arranged in front of the water inlet stoplog slot or in front of the dam body; Through the vertical water temperature monitoring temperature chain, real-time water temperature data covering the water inlet bottom plate elevation and above the water level is obtained; Regarding the arrangement position of the vertical water temperature monitoring temperature chain, if there is a single water inlet, it is arranged at the front end of the side wall; If there are multiple water inlets, it should be arranged at the front end of the partition pier between adjacent water inlets; If the arrangement conditions are not met in front of the water inlet, it should be arranged near the water inlet; The real-time water temperature data is obtained by evenly arranged thermometers, ensuring that the spacing between adjacent thermometers meets the preset standards, the monitoring accuracy meets the preset requirements, and the monitoring frequency meets the preset period; Regarding the fixing method of the vertical water temperature monitoring temperature chain, its overall verticality is maintained by a counterweight device.

[0024] Hydropower station inlets can be categorized as shore-type, dam-type, or tower-type, depending on their layout. The stoplog slot (trash rack slot) in front of the inlet should be located a certain distance from the inlet to maintain the width of the vertical flow channel behind the stoplog slot. This can improve the hydraulic characteristics of the inlet and reduce the impact of the flow field in front of the inlet on the temperature field. The vertical temperature chain should be positioned based on the specific inlet configuration. It is generally required to be placed a certain distance in front of the inlet stoplog slot (trash rack slot) to ensure that the temperature chain does not affect the safe operation of the trash rack. The end of the temperature chain should be equipped with necessary metal or concrete counterweights to maintain the overall verticality of the wire rope and temperature chain.

[0025] In step S1, for a single water inlet at a power station, a vertical temperature monitoring chain should be deployed at the front of the sidewall. For multiple water inlets, it should be deployed at the front of the intermediate pier between adjacent water inlets. If a temperature chain is not available in front of the water inlet, it can be deployed near the water inlet, but the deployment distance should not exceed 1 km. The monitoring data or monitoring meters on the temperature chain should be evenly distributed, with spacing of at least 5 meters between adjacent thermometers. The monitoring accuracy should be no less than 0.1°C, and the monitoring data frequency should be once per hour. The higher the monitoring accuracy and the denser the thermometer layout, the better the analysis and evaluation results.

[0026] In the preferred solution, in step S2, the minimum submerged height for safe and stable operation of the stoplog gate is determined through hydraulic model tests and water flow pattern analysis; For a state without stoplog gates, the water intake impact elevation range is determined to be from the water inlet bottom plate elevation to the minimum flooding height; For a stoplog gate state, the water intake impact elevation range is determined to be from the stoplog gate top plate elevation to the minimum submergence height; The specific limits of the elevation range affected by the water intake are obtained by combining the limiting conditions of the minimum flooding height with the operational safety boundaries of the stoplog gate and trash rack. If the minimum flooding height is limited by vibration or flow rate, it is adjusted based on the results of special research.

[0027] In a preferred embodiment, the determining of the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates comprises: In order to determine the elevation range affected by water intake, a segmented analysis is conducted in combination with different stages of stoplog gate operation; If the stopgate operation phase is the stopgate falling phase, the water intake influence elevation range is adjusted according to the stopgate falling process; If the stoplog gate operation stage is a stable operation period, determining the water intake impact elevation range according to the stoplog gate top plate elevation; If the stopgate operation phase is the stopgate lifting phase, the water intake influence elevation range is dynamically adjusted according to the stopgate lifting process; Through the segmented analysis, the changing pattern of the elevation range affected by water intake in each stage is obtained.

[0028] Minimum submerged height H for safe and stable operation of stoplog gate 淹没 It should be confirmed through special studies such as hydraulic model tests of the water inlet or stoplog gate, flow field and flow pattern analysis, etc., in combination with the vibration conditions of the stoplog gate and the trash rack, the allowable flow velocity at the top of the stoplog gate, and the allowable flow velocity over the trash rack.

[0029] In the preferred embodiment, in step S3, the real-time water temperature data within the water intake influence elevation range is recorded in order from bottom to top. The water body is evenly stratified according to a preset assumption, and the flow rate of each layer is determined to decrease according to a preset rule. Calculating the energy value of each layer of water body through the water temperature value of each layer and the water flow rate of each layer; Summarizing the total energy and total flow within the water intake impact elevation range, and calculating the equivalent mixed water temperature; If there is a portion of the real-time water temperature data that exceeds the water intake influence elevation range, it is determined whether to include it in the calculation according to preset rules.

[0030] In a preferred embodiment, in step S3, an energy mixing model is used to calculate the equivalent mixed water temperature in the state with and without stoplog gates according to the real-time water temperature data and the water intake influence elevation range, including: For the energy mixing model, it is assumed that the water temperature stratification is uniformly distributed in layers in the vertical direction; The water flow state before the water inlet is set to a non-turbulent state, and the streamlines follow a preset distribution pattern; The water inlet volume is set to decrease from bottom to top within the water intake influence elevation range; Based on the above assumptions, a temperature-based energy calculation method for stratified water bodies is constructed; If the distribution of the real-time water temperature data does not conform to the assumption, the calculation method is adjusted according to the flow field analysis results.

[0031] In the preferred solution, select the vertical water temperature monitoring chain at a certain moment in the water intake influence elevation range Temperature data within, From bottom to top, they are , the number is recorded as , divide the water body evenly into layer, and the water flow rate of the lowest layer is ; According to the triangle similarity principle, starting from the bottom plate elevation of the stoplog door, Laminar flow rate According to the formula ( ) calculation, which is used to determine the flow rate of each layer of water body based on the assumed law of decreasing water inflow; Energy per layer of water based on temperature According to the formula Calculate, where , is the energy coefficient constant. This formula is used to calculate the energy of each layer of water based on temperature and flow; When there is a stoplog gate, the elevation range affected by water intake Total energy of internal water bodies According to the formula Calculation, total flow According to the formula The total energy formula is used to calculate the total energy of all water bodies within the elevation range affected by the water intake, and the total flow formula is used to calculate the total flow of water within this range; Equivalent mixed water temperature with stoplog doors According to the formula calculate; Similarly, the corresponding water intake influence elevation range and temperature data are replaced with the data in the state without stoplog gates, and the equivalent mixed water temperature in the state without stoplog gates can be calculated. ; If the real-time water temperature data exceeds the water intake elevation range, if the thermometer elevation exceeds H 影响 The part that is less than half of the distance between two adjacent thermometers should be included; The difference in equivalent mixed water temperature with and without stoplog gates at the same time is the improvement effect of stoplog gate stratified water intake at that moment, i.e., T 改善 =T 有 -T 无； According to the calculated improvement effects at different moments, a process line diagram of the improvement effect of the whole stratified water intake scheduling cycle can be drawn; The basic assumptions or generalized models are the physical and mathematical foundations required for the derivation of this method, which means that the method has the highest accuracy under this ideal state, but it does not mean that the method is not applicable to non-laminar uniform flow.

[0032] The water intake impact elevation range H 影响 If the temperature data within the temperature range exceeds H 影响 The part that is less than half of the distance between two adjacent thermometers should be taken into account.

[0033] The flow pattern of water before the water inlet is approximately exponentially distributed, and the specific exponential equation needs to be determined in combination with hydraulic model tests and flow field flow pattern analysis.

[0034] This method uses similar triangles for simulation, i.e., the lateral velocity component and stratified flow rate decrease in a regular pattern from the stoplog base upwards, with the decreasing pattern being equal to the height ratio. Although this method uses similar triangles for simulation, simulations using other exponential relationships fall within the scope of this invention.

[0035] Equivalent mixed water temperature T with / without stoplog door 有 、T 无 Only the water intake in this state affects the elevation range H 影响The specific temperature data t within the affected range is related to the number n. The denser the distribution of thermometers and the larger the number n, the more accurate the equivalent mixed water temperature. The number of power plant units and their switching on and off affect the temperature field through the inlet flow field, which in turn affects the specific temperature data reflected in the equivalent mixed water temperature. However, this does not affect the evaluation results of this method.

[0036] In the preferred solution, the following situations are handled when the distribution of real-time water temperature data does not conform to the assumptions: When the real-time water temperature data distribution does not conform to the assumption, the numerical simulation method is used to simulate the flow field before the water inlet to obtain the water velocity distribution and temperature distribution; Adjust the calculation method according to the flow field analysis results. If the water velocity distribution does not conform to the decreasing law of the triangle similarity principle, an exponential function can be used. Describe the water flow rate at each layer, where are parameters determined based on flow field analysis; At this time, the energy of each layer of water , total energy , total traffic , equivalent mixed water temperature These adjusted formulas are used to more accurately calculate the equivalent mixed water temperature when the real-time water temperature data distribution does not meet the assumptions, thereby improving the reliability of the assessment results.

[0037] In the preferred solution, in step S4, the equivalent mixed water temperature in the state with the stoplog door and the state without the stoplog door at the same time is obtained; By calculating the difference between the equivalent mixed water temperatures, the improvement effect of the stoplog gate stratified water intake at that moment is determined; Calculate the average difference of the equivalent mixed water temperature for different operation periods and durations, and obtain the average improvement effect in each period; If the operation period includes multiple stages, the average improvement effect is calculated for each stage respectively; The average improvement effect is used to analyze the stratified water intake performance of the stoplog gate in different time periods.

[0038] In the preferred solution, a process line diagram of the improvement effect of the stratified water intake scheduling cycle is drawn based on the calculated improvement effect of the stratified water intake by the stoplog gate at each moment; Determine the time point when the stratified water extraction effect begins to appear and the moment when the maximum improvement effect occurs through the process line diagram of the whole process improvement effect; Based on the process line diagram of the improvement effect of the whole process, combined with the water level change data, the correlation between the stratified water intake effect and the water level is analyzed; If the overall improvement effect process line diagram shows multiple cycles, then the improvement effect characteristics in each cycle are obtained respectively; The optimized timing of the stoplog door scheduling operation is obtained through the process line diagram of the improvement effect of the whole process.

[0039] In step S4, the operation of the stoplog gates is divided into a drop gate period, a stable operation period, and a lift gate period. The drop gate period refers to the time period from the first stoplog gate participating in the stratified water intake scheduling to the time the last stoplog gate falls into place; the stable operation period refers to the time period from the time all stoplog gates participating in the stratified water intake scheduling fall into place to the time the first stoplog gate starts to lift; the lift gate period refers to the time period from the time the first stoplog gate starts to lift to the time the last stoplog gate lifts into place. According to different time periods, the equivalent mixed water temperature T is calculated at each moment in the period with or without stoplog gates. 有 、T 无 The difference in the arithmetic mean of the two is the average improvement effect of the layered water sampling of the stoplog door in this period.

[0040] Based on the drawn process line diagram of the improvement effect of the stratified water intake scheduling of the beam gate and the process line diagram of the water level change, a comprehensive assessment can be made of the sustainable time of stratified water intake and the achievable improvement effect under the conditions of safe and stable operation of the beam gate.

[0041] Example 2 Further illustrate with reference to Example 1, Figure 1-3 The structure shown here determines the elevation range of water intake impacts with and without stoplogs, as well as the energy mixing model for stratified water bodies. The improvement effect of stratified water intake is characterized by the difference in equivalent mixed water temperatures. Calculating the average difference in equivalent mixed water temperatures over different time periods effectively assesses the average improvement effect of stoplog-operated stratified water intake over time, providing guidance on the timing of stoplog-operated stratified water intake. Furthermore, it directly simulates the water intake effects at different times under operating conditions with different numbers of stoplog layers, reducing reliance on actual stoplog operating conditions and downstream water temperature monitoring data.

[0042] The inventive concept of the present invention is to set up a vertical water temperature monitoring chain in front of the stoplog gate at the water inlet of a hydropower station to obtain real-time water temperature monitoring data at various water level elevations in front of the stoplog gate. By determining the elevation range of the water inlet water intake affected by the presence or absence of the stoplog gate, the real-time water temperature monitoring data within this elevation range is used to calculate the equivalent mixed water temperature in this state through an energy mixing model. The difference in equivalent mixed water temperature between the presence and absence of the stoplog gate can be used to characterize the effect of the stoplog gate stratified water intake at that moment. The average difference in equivalent mixed water temperature over different time periods is the average improvement effect of the stoplog gate stratified water intake over that time period. This method can not only quantitatively represent the effect of the stoplog gate stratified water intake without relying on downstream water temperature monitoring and manual search for equivalent elevations, but can also calculate the improvement effect of the stoplog gate stratified water intake over any time period and for any number of layers. It can effectively determine the time period when the stoplog gate stratified water intake effect is relatively good, thus better guiding the scheduling and operation of the stoplog gate.

[0043] Based on the above-mentioned inventive concept, the present invention provides a method for evaluating the stratified water intake effect of stoplog gates at a hydropower station based on energy mixing, comprising the following steps: A1. Arrange vertical water temperature monitoring temperature chain According to the specific layout of the water inlet of the hydropower station, a vertical water temperature monitoring temperature chain is arranged in front of the left / right bank water inlet stoplog gate slot (trash rack slot) or in front of the dam body.

[0044] A2. Determine the elevation range H affected by the presence or absence of stoplog gates at the water inlet. 影响 The minimum submerged height H for the safe and stable operation of the stoplog gate is determined through hydraulic model tests of the hydropower station water intake or stoplog gate and flow pattern analysis before the water intake. 淹没 Without stoplog gate in operation, water intake affects elevation range H 影响 From the water inlet bottom plate elevation to the minimum submerged height H above 淹没 ; With the stoplog gate in operation, the water intake affects the elevation range H 影响 From the top elevation of the stoplog gate to the minimum flooding height H above 淹没 .

[0045] A3. Calculate the equivalent mixed water temperature T with and without stoplog doors. 无 、T 有； A31. Energy mixing models are based on the following basic assumptions or generalized models: ① The water temperature stratification is uniform in the vertical direction; ② The flow pattern before the water inlet is non-turbulent, and the streamlines in the vertical direction are approximately exponentially distributed; ③ The water inlet volume decreases vertically along the water intake influence elevation range H from bottom to top; ④ The energy of temperature-based stratified water is proportional to the water temperature and flow rate.

[0046] A32. Select the vertical water temperature monitoring chain at a certain moment within the water intake influence elevation range H. 影响 Internal temperature data, from bottom to top, select the vertical water temperature monitoring chain at a certain moment in the water intake influence elevation range H 影响 Internal temperature data, recorded from bottom to top as 、 、 、 、 , the number is recorded as ; This will evenly divide the water into layer, the water flow rate of the bottom layer is Based on the relevant assumptions and generalized model in step A31, and the triangle similarity principle, we can get the height of the first The laminar water flow rate is , No. Layer , No. Layer , , No. Layer The energy of each layer of water based on temperature can be calculated as , , , , is the energy coefficient constant.

[0047] A33. Elevation range affected by water intake when stoplog gates are in place at a certain moment Total energy of internal water , total traffic , equivalent mixed water temperature ,Right now Similarly, the equivalent mixed water temperature without stoplog gates at the same time can be calculated .

[0048] A4. Calculate the improvement effect of layered water intake at the lower stacked beam gate at different times according to needs. The difference in equivalent mixed water temperature with and without stoplog gates at the same time is the improvement effect of stoplog gate stratified water intake at that moment, i.e., T 改善 =T 有 -T 无 According to the different operation periods and durations of the stoplog door, the average improvement effect of the presence / absence of the stoplog door in different periods and durations can be calculated respectively.

[0049] A5. Draw a process line diagram of the improvement effect of the stoplog gate layered water intake scheduling as needed Based on the calculated improvement effects at different times, a process line diagram of the improvement effect of the entire stratified water intake scheduling cycle can be drawn. From the diagram, it can be clearly seen the specific time when the stratified water intake effect begins to appear, the maximum improvement effect within the scheduling cycle, etc.

[0050] In the above-mentioned method for evaluating the stratified water intake effect of stoplog gates at the water inlet of a hydropower station based on energy mixing, the purpose of step A1 is to obtain real-time water temperature monitoring data of each water level elevation in front of the stoplog gates.

[0051] Since hydropower station intakes can be categorized as shore-type, dam-type, and tower-type, the availability of the vertical temperature chain for installation depends on the specific inlet configuration. Furthermore, the stoplog slot (trash rack slot) in front of the hydropower station intake should be located a certain distance from the inlet to maintain the width of the vertical flow channel behind the stoplog slot. This improves the hydraulic characteristics of the inlet and reduces the impact of the flow field in front of the inlet on the temperature field. Therefore, in step A1, the vertical water temperature monitoring chain is generally required to be installed a certain distance in front of the inlet stoplog slot (trash rack slot) to ensure that the temperature chain does not affect the safe operation of the trash rack. For a single power station intake, the vertical temperature chain should be installed in front of the sidewall; for multiple intakes, it should be installed in front of the intermediate pier between adjacent intakes. If no temperature chain is available in front of the inlet, it can be installed near the inlet, but the installation distance should not exceed 1 km.

[0052] Furthermore, the vertical water temperature monitoring chain described in Step A1 can be either point-based or line-based. The monitoring range must cover the water level at or above the water inlet floor elevation. Water temperature monitors or monitoring points along the temperature chain should be evenly spaced, with the spacing between adjacent thermometers or monitoring points at least 5 meters. Monitoring accuracy should be no less than 0.1°C, and the monitoring data frequency should be no less than once per hour. The temperature chain should be tied along a steel wire rope, with a metal or concrete counterweight of no less than 300 kg at the end of the wire rope to maintain the overall verticality of the wire rope and temperature chain.

[0053] Furthermore, in step A32, in order to ensure the continuity and accuracy of the data, the water intake impact elevation range H 影响 If the temperature data within the temperature gauge exceeds (is lower than) H 影响 The part that is less than half of the distance between two adjacent thermometers should be included in the calculation, except for those that are out of water.

[0054] Further, in step A32, according to the water intake impact elevation range H 影响 After the corresponding temperature data is determined, it is necessary to first conduct a preliminary review of the temperature data to eliminate possible abnormal values, including data jumps and data anomalies that are obviously inconsistent with general rules due to abnormal operation of the thermometer. Abnormal data can be processed by linear difference between two adjacent data.

[0055] Furthermore, in steps A33 and A4, the equivalent mixed water temperature T 有 Corresponding water intake impact elevation range H 影响 The water temperature monitoring data is the minimum submerged height H above the top of the stoplog gate 淹没 , equivalent mixed water temperature T without stoplog door 无 Corresponding water intake impact elevation range H 影响 The water temperature monitoring data is the minimum submerged height H above the water inlet bottom plate 淹没.

[0056] Furthermore, in steps A33 and A4, the stratified water extraction improves the effect T 改善 The time scale is determined by the frequency of water temperature monitoring data. If the frequency of water temperature monitoring data is 1 hour / time, the improvement effect of stratified water extraction of two adjacent data is T 改善 The average value is the average improvement effect for that hour. Similarly, the improvement effect can be calculated at any time scale, even the improvement effect of layered water intake by the stoplog gates in a virtual scenario (where the stoplog gates are not actually operating).

[0057] Example 3 Further illustrate with reference to Example 1, Figure 1-3 As shown in the figure, in a certain year, the hydropower station used two layers of lapped beam gates in front of the water intake to carry out stratified water intake scheduling. The height of the single-layer lapped beam gate was 12m, and the elevation of the water intake concrete bottom plate was 518m. A vertical temperature monitoring chain was laid out 5m in front of the lapped beam gate. The total length of the temperature chain was 80m, covering water levels of 518m-598m (normal water storage level was 600m). A monitoring thermometer was laid out every 2.5m, for a total of 32 measuring points. The temperature accuracy was 0.1°C, and the temperature monitoring frequency was once per hour.

[0058] Determine whether the water inlet has / does not have a stoplog gate and the elevation range H affected by water intake 影响 After consulting the special report on stratified water intake at the hydropower station, it was determined through hydraulic model tests and flow velocity and flow pattern calculations that the minimum submerged height for the safe and stable operation of the stoplog gate is 25m, that is, the elevation range affected by water intake without stoplog gates is H. 影响 518m-543m; the elevation range affected by water intake in the presence of stoplog gates is H 影响 It is 542m-567m.

[0059] The energy mixing model is used to calculate the equivalent mixed water temperature T with and without stoplog gates. 无 、T 有 In this embodiment, the vertical water temperature monitoring chain obtained a total of 32 monitoring water temperature data at 08:00 on March 20 in a certain year, among which the water intake in the absence of the stoplog gate state affected the elevation range H. 影响 11 monitoring water temperature data were obtained within 518m-543m, which are {15.17, 15.15, 15.16, 15.20, 15.23, 15.24, 15.22, 15.24, 15.30, 15.34, 15.40}℃ from bottom to top. The equivalent mixed water temperature T 无 =15.20℃; with stoplog gate, water intake influence elevation range H 影响10 monitoring water temperature data were obtained within 542m-567m, which are {15.40, 15.50, 15.44, 15.52, 15.54, 15.54, 15.59, 15.55, 15.56, 15.64}℃ from bottom to top. The equivalent mixed water temperature T 有 =15.50℃. At this moment, the improvement effect of the stoplog gate water intake is T 改善 =T 有 -T 无 =0.30℃.

[0060] Calculate the improvement effect of layered water intake of the lower beam gate at different periods according to needs In this embodiment, the stoplog gate stratified water intake scheduling periods of a power station in a certain year are the stoplog gate drop period (January 6-March 5), the stoplog gate stable operation period (March 6-March 23), and the stoplog gate lift period (March 24-April 29). According to step

[0048] , the stratified water intake improvement effect at all times in the scheduling period is calculated. The average improvement effect can be calculated based on different scheduling periods, which is T during the stoplog gate drop period. 改善 =0.03℃, the stable operation period of the stoplog door is T 改善 =0.13℃, threshold period T 改善 =0.69℃.

[0061] Draw a process line diagram of the improvement effect of stoplog gate layered water intake scheduling as needed Figure 4 Process line diagram of improvement effect of 2-layer stacked beam gate layered water intake scheduling in a certain year at the hydropower station in this embodiment Combine Figure 4 , it can be seen that the effect of the layered stoplog gate water intake this year began to appear around March 18. The maximum improvement of 0.49℃ during the stable operation period of the stoplog gate (March 6-March 23) occurred at 17:00 on March 20, and the maximum improvement during the gate-lift period (March 24-April 29) was about 2℃. After the gate-lift period ended, the water level in front of the dam still met the minimum operating safety water level requirement of 567m for the stoplog gate. If the two layers of stoplog gates continue to operate stably under this condition, the maximum improvement can reach about 2.30℃. Figure 4 It can also be clearly seen that after March 18, the improvement effect of stratified water intake showed a certain negative correlation with the reservoir water level. Under the same conditions, the lower the water level, the better the improvement effect of stratified water intake by the stoplog gate.

[0062] Although the hydropower station in this embodiment uses two layers of stacked beam gates to carry out stratified water intake scheduling in a certain year, the present invention can be used to calculate the improvement effect of using one layer of stacked beam gates for stratified water intake under the same conditions. Similarly, the vertical water temperature monitoring data at 08:00 on the morning of March 20 is used. The equivalent mixed water temperature is the same T under the condition of no stacked beam gates. 无=15.20℃; 1st layer stacked beam door state water intake influence elevation range H 影响 11 monitoring water temperature data were obtained within 530m-555m, which are {15.24, 15.22, 15.24, 15.30, 15.34, 15.40, 15.50, 15.44, 15.52, 15.54, 15.54}℃ from bottom to top. The equivalent mixed water temperature T 有 =15.33℃. At this moment, the improvement effect of the stoplog gate layered water intake is T 改善 =T 有 -T 无 =0.12℃, that is, the improvement effect of the stratified water intake scheduling using one layer of laminated beam gates at 08:00 on the morning of March 20 at the hydropower station in this embodiment is 0.12℃.

[0063] Furthermore, by calculating the improvement effect of the layered water intake scheduling of the single-layer stacked beam gate at each time under the same conditions, we can obtain Figure 5 The process line diagram of the improvement effect of layered water intake scheduling of a single-layer stacked beam gate under the same conditions in a certain year at the hydropower station in this embodiment. Figure 5 It can be seen from the figure that, under the same conditions in a certain year, if the hydropower station in this embodiment adopts stratified water intake scheduling with one layer of laminated beam gates, the maximum improvement effect is about 1.50°C.

[0064] In summary, through the energy mixing-based stratified water intake effect evaluation method of the hydropower station water inlet folded beam gate provided by the present invention, the improvement effect of the folded beam gate stratified water intake scheduling at each moment can be calculated, and a process line diagram of the improvement effect for the entire period can be drawn. Not only can the average improvement effect of each stage of stratified water intake scheduling be evaluated, but the maximum improvement effect and the optimal improvement period of stratified water intake scheduling can also be intuitively seen. At the same time, the improvement effect of different folded beam gate layers under the same conditions can also be calculated, so as to better guide the folded beam gate stratified water intake scheduling and improve the scheduling effect.

[0065] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention shall be the technical solutions set forth in the claims, including equivalent alternatives to the technical features of the technical solutions set forth in the claims. In other words, equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A method for evaluating the effect of stratified water intake based on stoplog gates at the water intake of a hydropower station, characterized by: The method includes: S1. Obtain real-time water temperature data at different water levels before the water inlet of the hydropower station; S2. Determine the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates; S3. Using an energy mixing model, based on the real-time water temperature data and the water intake impact elevation range, respectively calculate the equivalent mixed water temperature in the state with and without stoplog gates; S4. Determine the improvement effect of the stoplog gate stratified water intake based on the difference in the equivalent mixed water temperature.

2. The method for evaluating the stratified water intake effect of stoplog gates at a hydropower station water intake according to claim 1 is characterized by: In step S1, According to the specific layout of the water inlet of the hydropower station, a vertical water temperature monitoring temperature chain is arranged in front of the water inlet stoplog slot or in front of the dam body; Through the vertical water temperature monitoring temperature chain, real-time water temperature data covering the water inlet bottom plate elevation and above the water level is obtained; Regarding the arrangement position of the vertical water temperature monitoring temperature chain, if there is a single water inlet, it is arranged at the front end of the side wall; If there are multiple water inlets, it should be arranged at the front end of the partition pier between adjacent water inlets; If the arrangement conditions are not met in front of the water inlet, it should be arranged near the water inlet; The real-time water temperature data is obtained by evenly arranged thermometers, ensuring that the spacing between adjacent thermometers meets the preset standards, the monitoring accuracy meets the preset requirements, and the monitoring frequency meets the preset period; Regarding the fixing method of the vertical water temperature monitoring temperature chain, its overall verticality is maintained by a counterweight device.

3. The method for evaluating the stratified water intake effect based on stoplog gates at a hydropower station water intake according to claim 1 is characterized by: In step S2, the minimum submerged height for safe and stable operation of the stoplog gate is determined through hydraulic model tests and water flow pattern analysis; For a state without stoplog gates, the water intake impact elevation range is determined to be from the water inlet bottom plate elevation to the minimum flooding height; For a stoplog gate state, the water intake impact elevation range is determined to be from the stoplog gate top plate elevation to the minimum submergence height; The specific limits of the elevation range affected by the water intake are obtained by combining the limiting conditions of the minimum flooding height with the operational safety boundaries of the stoplog gate and trash rack. If the minimum flooding height is limited by vibration or flow rate, it is adjusted based on the results of special research.

4. The method for evaluating the stratified water intake effect of stoplog gates at a hydropower station water intake according to claim 3 is characterized by: Determining the elevation range affected by water intake at the water inlet in the presence and absence of stoplog gates includes: In order to determine the elevation range affected by water intake, a segmented analysis is conducted in combination with different stages of stoplog gate operation; If the stopgate operation phase is the stopgate falling phase, adjusting the water intake impact elevation range according to the stopgate falling process; If the stoplog gate operation stage is a stable operation period, determining the water intake impact elevation range according to the stoplog gate top plate elevation; If the stopgate operation phase is the stopgate lifting phase, the water intake influence elevation range is dynamically adjusted according to the stopgate lifting process; Through the segmented analysis, the changing pattern of the elevation range affected by water intake in each stage is obtained.

5. The method for evaluating the effect of stratified water intake based on stoplog gates at a hydropower station water intake according to claim 1 is characterized by: In step S3, for the real-time water temperature data within the water intake impact elevation range, the water temperature value of each layer is recorded in sequence from bottom to top; According to the preset assumptions, the water body is evenly layered, and the flow rate of each layer is determined to decrease according to the preset rules; Calculating the energy value of each layer of water body through the water temperature value of each layer and the water flow rate of each layer; Summarizing the total energy and total flow within the water intake impact elevation range, and calculating the equivalent mixed water temperature; If there is a portion of the real-time water temperature data that exceeds the water intake influence elevation range, it is determined whether to include it in the calculation according to preset rules.

6. The method for evaluating the stratified water intake effect based on stoplog gates at a hydropower station water intake according to claim 5 is characterized by: In step S3, an energy mixing model is used to calculate the equivalent mixed water temperature in the state with and without stoplog gates according to the real-time water temperature data and the water intake influence elevation range, including: For the energy mixing model, it is assumed that the water temperature stratification is uniformly distributed in layers in the vertical direction; The water flow state before the water inlet is set to a non-turbulent state, and the streamlines follow a preset distribution pattern; The water inlet volume is set to decrease from bottom to top within the water intake influence elevation range; Based on the above assumptions, a temperature-based energy calculation method for stratified water bodies is constructed; If the distribution of the real-time water temperature data does not conform to the assumption, the calculation method is adjusted according to the flow field analysis results.

7. The method for evaluating the effectiveness of stratified water intake based on stoplog gates at a hydropower station water intake according to claim 6, wherein: Select the vertical water temperature monitoring chain at a certain moment in the water intake impact elevation range Temperature data within, From bottom to top, they are , the number is recorded as , divide the water body evenly into layer, and the water flow rate of the lowest layer is ; According to the triangle similarity principle, starting from the bottom plate elevation of the stoplog door, Laminar flow rate According to the formula ( ) calculation, which is used to determine the flow rate of each layer of water body based on the assumed law of decreasing water inflow; Energy per layer of water based on temperature According to the formula Calculate, where , is the energy coefficient constant. This formula is used to calculate the energy of each layer of water based on temperature and flow; When there is a stoplog gate, the elevation range affected by water intake Total energy of internal water bodies According to the formula Calculation, total flow According to the formula The total energy formula is used to calculate the total energy of all water bodies within the elevation range affected by the water intake, and the total flow formula is used to calculate the total flow of water within this range; Equivalent mixed water temperature with stoplog doors According to the formula calculate; Similarly, the corresponding water intake influence elevation range and temperature data are replaced with the data in the state without stoplog gates, and the equivalent mixed water temperature in the state without stoplog gates can be calculated. ; If the real-time water temperature data exceeds the water intake elevation range, if the thermometer elevation exceeds H 影响 The part that is less than half of the distance between two adjacent thermometers should be included; The difference in equivalent mixed water temperature with and without stoplog gates at the same time is the improvement effect of stoplog gate stratified water intake at that moment, i.e., T 改善 =T 有 -T 无； Based on the calculated improvement effects at different moments, a process line diagram of the improvement effects during the entire stratified water intake scheduling cycle can be drawn.

8. The method for evaluating the effect of stratified water intake based on stoplog gates at a hydropower station water intake according to claim 8 is characterized by: To handle situations where the real-time water temperature data distribution does not conform to the assumptions: When the real-time water temperature data distribution does not conform to the assumption, the numerical simulation method is used to simulate the flow field before the water inlet to obtain the water velocity distribution and temperature distribution; Adjust the calculation method according to the flow field analysis results. If the water velocity distribution does not conform to the decreasing law of the triangle similarity principle, an exponential function can be used. Describe the water flow rate at each layer, where are parameters determined based on flow field analysis; At this time, the energy of each layer of water , total energy , total traffic , equivalent mixed water temperature .

9. The method for evaluating the effect of stratified water intake based on stoplog gates at a hydropower station water intake according to claim 1, characterized in that: In step S4, the equivalent mixed water temperature in the state with the stoplog door and the state without the stoplog door at the same time is obtained; By calculating the difference between the equivalent mixed water temperatures, the improvement effect of the stoplog gate stratified water intake at that moment is determined; Calculate the average difference of the equivalent mixed water temperature for different operation periods and durations, and obtain the average improvement effect in each period; If the operation period includes multiple stages, the average improvement effect is calculated for each stage respectively; The average improvement effect is used to analyze the stratified water intake performance of the stoplog gate in different time periods.

10. The method for evaluating the effect of stratified water intake based on stoplog gates at a hydropower station water intake according to claim 7, characterized in that: Based on the calculated improvement effect of the stoplog gate stratified water intake at each moment, a process line diagram of the improvement effect of the entire stratified water intake scheduling cycle is drawn; Determine the time point when the stratified water extraction effect begins to appear and the moment when the maximum improvement effect occurs through the process line diagram of the whole process improvement effect; Based on the process line diagram of the improvement effect of the whole process, combined with the water level change data, the correlation between the stratified water intake effect and the water level is analyzed; If the overall improvement effect process line diagram shows multiple cycles, then the improvement effect characteristics in each cycle are obtained respectively; The optimized timing of the stoplog door scheduling operation is obtained through the process line diagram of the improvement effect of the whole process.

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