A cascade reservoir drawdown and storage period scheduling risk early warning method

Abstract

The application discloses a kind of cascade reservoir drawdown and storage period scheduling risk early warning method, belong to water conservancy engineering scheduling and water resources management technical field, method includes: defining site section in research area, constraint demand, forecast hydrology time series, period division, inflow frequency and inflow condition;Variable and variable boundary are assigned: the value of each site section constraint demand and its upper and lower limit boundary are determined;Time period judgment early warning: define the variables and constraints related to reservoir scheduling;In drawdown period, based on the forecast results, judge whether the to-be-discharged reservoir capacity is over the threshold under different inflow scenarios, and early warning of risks such as water discharge, insufficient or excessive reservoir capacity;In storage period, judge whether the storage capacity and to-be-stored reservoir capacity are over the threshold under different inflow scenarios, and early warning of risks such as water discharge and insufficient storage;The application realizes fine and forward-looking early warning of cascade reservoir scheduling risk by coupling dynamic prediction and multiple constraint conditions, significantly improves the safety and intelligent level of reservoir group joint scheduling.

Description

Technical Field

[0001] This invention belongs to the field of water conservancy project scheduling and water resources management technology, and in particular relates to a method for early warning of risks during the drawdown and water storage period of cascade reservoirs. Background Technology

[0002] The coordinated operation of cascade reservoir groups is crucial for efficient water resource utilization and risk prevention. During the drawdown period (usually before the flood season) and the impoundment period (usually at the end of the flood season), reservoirs face multiple constraints, including water level fluctuations, flow rates, and storage capacity. Improper operation can lead to risks such as water wastage, insufficient impoundment, navigation disruptions, and ecological damage. Existing technologies primarily focus on operation models for single reservoirs or single indicators, lacking a systemic risk early warning mechanism for cascade reservoir groups under multiple time periods, constraints, and inflow scenarios.

[0003] The integration of forecast information and dispatch rules is not close enough, and the warning thresholds are static, making it difficult to adapt to complex and ever-changing hydrological conditions and dispatch needs, resulting in insufficient accuracy and timeliness of warnings. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for risk early warning of cascade reservoir drawdown and water storage period scheduling in order to address the shortcomings of the prior art. The method aims to achieve refined and forward-looking risk early warning based on dynamic forecasting and multiple constraints, thereby improving the safety and intelligence level of cascade reservoir scheduling.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for early warning of risks in the drawdown and water storage period scheduling of cascade reservoirs, specifically including the following steps; Step 1, Define variables: Define the station cross sections, constraint requirements, forecast hydrological time series, period division, water inflow frequency and water inflow conditions within the study area; Step 2, Assigning Variables and Determining Variable Boundaries: Determine the values ​​of various constraint requirements for each station section and their upper and lower limits; Step 3, determine and issue warnings based on time periods: During the drawdown period, based on the drawdown forecast results, it is determined whether the reservoir capacity to be drained under different inflow frequencies exceeds the first threshold, and whether the reservoir capacity to be drained under different inflow conditions is lower than the less-than-ideal threshold or higher than the more-than-ideal threshold, and a set of drawdown period early warning results is generated. During the water storage period, based on the water storage period forecast results, it is determined whether the water storage volume under different water inflow frequencies exceeds the water abandonment risk threshold or is lower than the under-storage risk threshold, and whether the storage capacity under different water inflow conditions exceeds the excessive warning threshold, and a set of water storage period warning results is generated. Step 4: Output the set of early warning results for the drawdown period and the set of early warning results for the water storage period.

[0006] As a further preferred embodiment of the method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to the present invention, the definition of variables in step 1 specifically includes the following steps: The station cross-sections within the study area are counted as j , j =1,2,…, J , J The total number of station cross-sections within the study area; the constraint requirements for each station cross-section are calculated as follows: k , k =1,2,…, K , K The total number of site cross-sectional constraints; the time series of forecasted inflow is counted as The unit is m 3 / s, t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water level time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted water level changes is counted as... The unit is m / d. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted upstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted downstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water depth time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted reservoir capacity to be dissipated is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, TThe total number of time periods; the time series of the forecasted storage capacity of cascade reservoirs is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted cascade reservoir water storage is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the set of forecast results is counted as , including time series , , , , , , , , The entire research timeframe is divided into... TT The periods are numbered as follows: tt , tt =1, 2, ..., TT , TT For the total number of periods, the first tt The start time of each period is counted as The end time is counted as ; Future water frequency meter , No. n The water frequency meter is , n Number the water inflow frequency. n =1, 2, ..., N , N This represents the total frequency of incoming water. Future water availability will be counted as... , No. m The water inflow situation is counted as follows: , m Number the water inflow conditions. m =1, 2, ..., M , M This represents the total number of water inflows.

[0007] As a further preferred embodiment of the method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to the present invention, step 2, assigning values ​​to variables, specifically includes the following steps: express j Station cross-section k The flow corresponding to the constraint demand; express j Station cross-section kThe water level corresponding to the constraint requirements; express j Station cross-section k Constraints on demand should be based on the corresponding water level fluctuations; express j Station cross-section k The upstream water level corresponding to the constraint demand; express j Station cross-section k The downstream water level corresponding to the constraint demand; express j Station cross-section k The water depth corresponding to the constraint requirements; Indicates water inflow frequency The downstream reservoirs are awaiting drawdown. Indicates water inflow frequency The storage capacity of downstream reservoirs; Indicates water inflow frequency Water storage capacity of downstream reservoirs; Indicates water supply status The downstream reservoirs are awaiting drawdown. Indicates water supply status The storage capacity of the downstream reservoirs.

[0008] As a further preferred embodiment of the method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to the present invention, step 2, assigning variable boundaries, specifically includes the following steps: express j Station cross-section k Constraints on the required flow rate limit; express j Station cross-section k The lower limit of the flow rate corresponding to the constraint demand; express j Station cross-section k The upper limit of the water level corresponding to the constraint requirements; express j Station cross-section k The lower limit of the water level corresponding to the constraint demand; express j Station cross-section k Constraints are based on the corresponding upper limit of water level fluctuation; express j Station cross-section k Constraints are based on the lower limit of the corresponding water level fluctuation. express j Station cross-section k The upper limit of the upstream water level corresponding to the constraint demand; express j Station cross-sectionk The lower limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The upper limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The upper limit of water depth corresponding to the constraint requirements; express j Station cross-section k The lower limit of water depth corresponding to the constraint requirements.

[0009] As a further preferred embodiment of the method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to the present invention, step 3, the early warning judgment during the drawdown period, specifically includes the following steps: The start time of the drawdown period is The end time is .when This is the drawdown period; the forecast result for the drawdown period is calculated as follows: The scheduling risk warning indicators include the reservoir capacity to be reduced in cascade reservoirs at different inflow frequencies and the reservoir capacity to be reduced in cascade reservoirs under different inflow conditions; and the inflow frequency. The threshold for the undiminished storage capacity of the downstream reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for insufficient or excessive reservoir capacity in the next tier is calculated as follows: , ,when Timely warning; the warning results will be counted as , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results; Y This is a collection of early warning results for the drawdown period, including the early warning results. , ; ; Constraints: ; .

[0010] As a further preferred embodiment of the method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to the present invention, step 3, the water storage period judgment and early warning, specifically includes the following steps: The water storage period begins at the following time: The end time is .when The period is the water storage period; the forecast results for the water storage period are counted as follows: The scheduling risk warning indicators include the water storage capacity of cascade reservoirs at different inflow frequencies, the cascade storage capacity under different inflow conditions, and the inflow frequency. The risk threshold for water release from the storage capacity of the lower-level reservoirs is calculated as follows: Future water frequency The risk threshold for insufficient water storage in the lower-level reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for excessive storage capacity in lower-level reservoirs is calculated as follows: ,when Timely warning; the warning results will be counted as , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results; This is a collection of early warning results for the water storage period, including the early warning results. , ; ; Constraints: ; .

[0011] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: This invention provides a method for early warning of scheduling risks during the drawdown and impoundment periods of cascade reservoirs. It defines variables and constraints related to reservoir scheduling. During the drawdown period, based on forecast results, it determines whether the reservoir capacity to be drained exceeds the threshold under different inflow scenarios, providing early warning of risks such as water release, insufficient or excessive reservoir capacity. During the impoundment period, it determines whether the water storage volume and the reservoir capacity to be impounded exceed the threshold under different inflow scenarios, providing early warning of risks such as water release and insufficient impoundment. This invention achieves refined and forward-looking early warning of scheduling risks for cascade reservoirs by coupling dynamic forecasting and multiple constraints, significantly improving the safety and intelligence level of joint scheduling of reservoir groups. Systematic: It comprehensively considers multiple scheduling objectives and constraints of cascade reservoir groups during the two key periods of drawdown and impoundment. The system incorporates constraints to achieve full-chain risk monitoring; it closely integrates with hydrological forecast time series to enable future-scenario-based early warning, rather than relying solely on static rules, resulting in more timely warnings; by differentiating different inflow frequencies and conditions and setting multi-level early warning thresholds, the system makes early warning information more accurate and instructive; it provides clear constraints and early warning threshold examples for specific projects (such as the Jinxia cascade and the Three Gorges cascade), making the method highly operable and easy to integrate into existing scheduling systems; and it uses "reservoir capacity to be depleted" and "reservoir capacity to be stored" as core early warning indicators, directly linking them to various risk consequences (water abandonment, insufficient storage, navigation restrictions, etc.), thus constructing a new early warning logic framework. Attached Figure Description

[0012] Figure 1 This is a flowchart of a method for early warning of risks in the drawdown and water storage period scheduling of cascade reservoirs according to the present invention; Figure 2 This invention is a schematic diagram of the guideline for preventing water wastage based on different inflow frequencies during the ten-day average power generation flow process of Xiangjiaba. Figure 3 This is a schematic diagram illustrating the risk warning of water wastage during the four cascade reservoirs in the lower reaches of the Jinsha River. Figure 4 This is a schematic diagram illustrating the risk warning of under-storage at four cascade reservoirs in the lower reaches of the Jinsha River. Figure 5 This is a schematic diagram of the risk warning line for water release from the Three Gorges-Gezhouba cascade hydropower project from August to October. Figure 6 This is a schematic diagram of the Three Gorges Reservoir's under-storage risk warning line at the end of October. Detailed Implementation

[0013] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings: The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The purpose and effects of the present invention will become clearer. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0014] This invention provides a method for early warning of risks related to drawdown and water storage period scheduling in cascade reservoirs, such as... Figure 1 As shown, the specific steps include: Step 1: Define variables. The station cross-sections within the study area are counted as... j , j =1,2,…, J , J The total number of station cross-sections within the study area; the constraint requirements for each station cross-section are calculated as follows: k , k =1,2,…, K , K The total number of site cross-sectional constraints; the time series of forecasted inflow is counted as The unit is m 3 / s, t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water level time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted water level changes is counted as... The unit is m / d. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted upstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted downstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, TThe total number of time periods; the forecast water depth time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted reservoir capacity to be dissipated is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted storage capacity of cascade reservoirs is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted cascade reservoir water storage is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T This represents the total number of time periods. The set of forecast results is counted as... , including time series , , , , , , , , The entire research timeframe is divided into... TT The periods are numbered as follows: tt , tt =1, 2, ..., TT , TT For the total number of periods, the first tt The start time of each period is counted as The end time is counted as The future water frequency meter will be... , No. n The water frequency meter is , n Number the water inflow frequency. n =1, 2, ..., N , N This represents the total frequency of incoming water. Future water availability will be counted as... , No. m The water inflow situation is counted as follows: , m Number the water inflow conditions. m =1, 2, ..., M ,M This represents the total number of water inflows.

[0015] Step 2: Assign values ​​to variables. express j Station cross-section k The flow corresponding to the constraint demand; express j Station cross-section k The water level corresponding to the constraint requirements; express j Station cross-section k Constraints on demand should be based on the corresponding water level fluctuations; express j Station cross-section k The upstream water level corresponding to the constraint demand; express j Station cross-section k The downstream water level corresponding to the constraint demand; express j Station cross-section k The water depth corresponding to the constraint requirements. Indicates water inflow frequency The downstream reservoirs are awaiting drawdown. Indicates water inflow frequency The storage capacity of downstream reservoirs; Indicates water inflow frequency Water storage capacity of downstream reservoirs. Indicates water supply status The downstream reservoirs are awaiting drawdown. Indicates water supply status The storage capacity of the downstream reservoirs.

[0016] Step 3: Assign variable boundaries. express j Station cross-section k Constraints on the required flow rate limit; express j Station cross-section k The lower limit of the flow rate corresponding to the constraint demand. express j Station cross-section k The upper limit of the water level corresponding to the constraint requirements; express j Station cross-section k The lower limit of the water level corresponding to the constraint demand. express j Station cross-section k Constraints are based on the corresponding upper limit of water level fluctuation; express j Station cross-section kThe constraint requirement corresponds to the lower limit of the water level fluctuation range. express j Station cross-section k The upper limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the upstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the downstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of water depth corresponding to the constraint requirements; express j Station cross-section k The lower limit of water depth corresponding to the constraint requirements.

[0017] Step 4: Determine and issue warnings based on time periods.

[0018] Step 4.1: Determine and warn of the decline period.

[0019] The start time of the drawdown period is The end time is .when This is the period of water level drawdown. The predicted drawdown period is calculated as follows: The dispatch risk early warning indicators include the reservoir capacity to be reduced in cascade reservoirs at different inflow frequencies and the reservoir capacity to be reduced in cascade reservoirs under different inflow conditions. (Incoming inflow frequency...) The threshold for the undiminished storage capacity of the downstream reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for insufficient or excessive reservoir capacity in the next tier is calculated as follows: , ,when Timely warning. The warning result will be recorded as... , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results. Y This is a collection of early warning results for the drawdown period, including the early warning results. , . ; Constraints: Step 4.2: Water storage period judgment and early warning.

[0020] The water storage period begins at the following time: The end time is .when This is the water storage period. The forecast results for the water storage period are as follows: The dispatch risk warning indicators include the water storage capacity of cascade reservoirs at different inflow frequencies and the cascade storage capacity under different inflow conditions. (Incoming water frequency...) The risk threshold for water release from the storage capacity of the lower-level reservoirs is calculated as follows: Future water frequency The risk threshold for insufficient water storage in the lower-level reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for excessive storage capacity in lower-level reservoirs is calculated as follows: ,when Timely warning. The warning result will be recorded as... , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results. This is a collection of early warning results for the water storage period, including the early warning results. , . ; Constraints: .

[0021] Example 1: Lower Gold Tier: Step 1: Define variables. The station cross-sections within the study area are counted as... j The study area included a total of 8 station cross sections: Wudongde, Baihetan, Xiluodu, Xiangjiaba, Yibin Hejiangmen, Lizhuang, Zhutuo, and Cuntan. j =1, 2, ..., 8. The constraint requirements for the station cross-section are calculated as follows: k The constraints are divided into six aspects: ecological requirements, geological disaster requirements, power generation requirements, unit maintenance requirements, shipping requirements, and flood control requirements. k =1, 2, ..., 6. The time series of the predicted inflow is calculated as follows: The unit is m 3 / s, t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water level time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted water level changes is counted as... The unit is m / d. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted upstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted downstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water depth time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted reservoir capacity to be dissipated is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted storage capacity of cascade reservoirs is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted cascade reservoir water storage is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T This represents the total number of time periods. The set of forecast results is counted as... , including time series , , , , , , , , The entire research timeframe is divided into... TT The periods are numbered as follows: tt , tt =1, 2, ..., TT , TT For the total number of periods, the first tt The start time of each period is counted as The end time is counted as The future water frequency meter will be... , No. n The water frequency meter is , n The water inflow frequency is numbered, including P=95% (extremely dry year), P=90% (dry year), P=75% (relatively dry year), P=50% (normal year), P=25% (relatively abundant year), P=10% (abundant year), and P=5% (extremely abundant year). n =1, 2, ..., 7. Future water conditions are calculated as follows: , No. m The water inflow situation is counted as follows: , m The water inflow conditions are numbered, including -30% low water level, -10% low water level, 30-year average water level, 10% above average water level, and 30% above average water level. m =1, 2, ..., 5.

[0022] Step 2: Assign values ​​to variables. express j Station cross-section k The flow corresponding to the constraint demand; express j Station cross-section k The water level corresponding to the constraint requirements; express j Station cross-section k Constraints on demand should be based on the corresponding water level fluctuations; express j Station cross-section k The upstream water level corresponding to the constraint demand; express j Station cross-section k The downstream water level corresponding to the constraint demand; express j Station cross-section k The water depth corresponding to the constraint requirements. Indicates water inflow frequency The lower-level cascade reservoirs are awaiting capacity reduction. Indicates water inflow frequency The storage capacity of the Xiajinxia cascade reservoirs; Indicates water inflow frequency Water storage capacity of the Xiajin cascade reservoirs. Indicates water supply status The lower-level cascade reservoirs are awaiting capacity reduction. Indicates water supply status The waiting storage capacity of the Xiajinxia cascade reservoirs.

[0023] Step 3: Assign variable boundaries. express j Station cross-section k Constraints on the required flow rate limit; express j Station cross-section k The lower limit of the flow rate corresponding to the constraint demand. express j Station cross-section k The upper limit of the water level corresponding to the constraint requirements; express j Station cross-section k The lower limit of the water level corresponding to the constraint demand. express j Station cross-section k Constraints are based on the corresponding upper limit of water level fluctuation; express j Station cross-section k The constraint requirement corresponds to the lower limit of the water level fluctuation range. express j Station cross-section k The upper limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the upstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the downstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of water depth corresponding to the constraint requirements; express j Station cross-section k The lower limit of water depth corresponding to the constraint requirements.

[0024] Step 4: Determine and issue warnings based on time periods.

[0025] Step 4.1: Determine and warn of the decline period.

[0026] The drawdown period for the Jinxia cascade reservoirs is from April to June. The predicted drawdown period is calculated as follows: The dispatch risk early warning indicators include the reservoir capacity to be reduced in cascade reservoirs at different inflow frequencies and the reservoir capacity to be reduced in cascade reservoirs under different inflow conditions. (Incoming inflow frequency...) The threshold for the undiminished storage capacity of the downstream reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for insufficient or excessive reservoir capacity in the next tier is calculated as follows: , ,when Timely warning. The warning result will be recorded as... , No. l The number of early warning results is counted as , l The warning results are numbered, and the warning results include: water release from the Jinxia cascade reservoir, insufficient storage capacity to be drawn down in the Jinxia cascade reservoir, excessive storage capacity to be drawn down in the Jinxia cascade reservoir, water release from the cascade reservoir, excessive storage capacity to be drawn down in the Jinxia cascade reservoir, and navigation restrictions. l =1, 2, 3, 4. Y This is a collection of early warning results for the drawdown period, including the early warning results. , , , Water supply situation Warning results l The threshold for early warning of excessive storage capacity in the lower tier of the reservoir is calculated as follows: .

[0027] Constraints: Water was released from the Jinxia cascade reservoirs; The reservoir capacity of the downstream cascade reservoirs is insufficient to withstand drawdown. The reservoirs in the Jinxia cascade reservoirs have too much storage capacity to be drawn down, which restricts navigation. There is too much unused water in the cascade reservoirs below Jinxia, ​​leading to water wastage at each level.

[0028] Step 4.2: Water storage period judgment and early warning.

[0029] The water storage period for the Jinxia cascade reservoirs is from late August to October. The predicted water storage period is calculated as follows: The dispatch risk warning indicators include the water storage capacity of cascade reservoirs at different inflow frequencies and the cascade storage capacity under different inflow conditions. (Incoming water frequency...) The risk threshold for water release from the storage capacity of the lower-level reservoirs is calculated as follows: Future water frequency The risk threshold for insufficient water storage in the lower-level reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for excessive storage capacity in lower-level reservoirs is calculated as follows: ,when Warning in time. The limit is counted as g, the first... r The restrictions are counted as The restrictions include allowing Xiangjiaba to discharge water at a rated flow rate of 6400 m³ / s and meeting the ecological flow requirement of 1260 m³ / s for the lower reaches of the Jinsha River. r =1, 2. The warning results are counted as... , No. l The number of early warning results is counted as , l The warning results are numbered as follows: Jinxia cascade reservoirs are releasing water; Jinxia cascade reservoirs are under-storage; and the storage capacity of reservoirs upstream of Jinxia cascade reservoirs is excessive and under-storage. l =1, 2, 3. This is a collection of early warning results for the water storage period, including the early warning results. , , Water supply situation limit Warning results l The warning threshold for excessive storage capacity in reservoirs below the Xiajin cascade level is calculated as follows: .

[0030] Constraints: Water was released from the Jinxia cascade reservoirs; The Jinxia cascade reservoirs are under-storage; The reservoirs in the lower cascade of the Jin River have an excess of storage capacity and are under-storage. The drawdown periods are shown in Table 1.

[0031] Table 1 Based on the different inflow frequencies during the ten-day average power generation flow process of Xiangjiaba, the guideline for preventing water wastage is as follows: Figure 2 As shown in Table 2, the distribution of reservoir capacity to be depleted based on the ten-day average power generation flow rate for preventing water wastage is presented. The unit is 100 million m³. 3 : Table 2 Table 3 shows the warning thresholds for insufficient reservoir capacity in the lower reaches of the Jinsha River. The unit is 100 million cubic meters. 3 : Table 3 Table 3 shows that the total drawdown capacity of the reservoirs above the dead water level in the lower reaches of the Jinsha River is 37.5 billion m3, and the total drawdown capacity above the flood control limit water level is 21.8 billion m3. The numbers in parentheses in the table are negative, indicating that the drawdown capacity will not be excessive or insufficient, and the same applies below.

[0032] Table 4 shows the warning thresholds for excessive reservoir capacity in the lower reaches of the Jinsha River. The unit is 100 million cubic meters. 3 : Table 4 A schematic diagram illustrating the risk warning of water release during the four cascade reservoirs in the lower reaches of the Jinsha River is shown below. Figure 3 As shown in the diagram, this is a risk warning illustration of the four cascade reservoirs in the lower reaches of the Jinsha River that are experiencing insufficient water storage. Figure 4 As shown.

[0033] Table 5 shows the warning thresholds for the risk of excessive or insufficient storage capacity in the cascade reservoirs above the Jinsha River downstream. The unit is 100 million cubic meters. 3 : Table 5 Example 2: The Three Gorges Dam; Step 1: Define variables. The station cross-sections within the study area are counted as... j The study area included eight monitoring stations: Three Gorges, Gezhouba, Miaozui, Yichang, Shashi, Songzi to Yueyang, Sankou River system, and Hankou. j =1, 2, ..., 8. The constraint requirements for the station cross-section are calculated as follows: k The constraints are divided into eight aspects: ecological requirements, geological disaster requirements, power generation requirements, unit maintenance requirements, shipping requirements, comprehensive requirements for the middle and lower reaches, water supply requirements, and water diversion and irrigation requirements. k =1, 2, ..., 8. The time series of the predicted inflow is calculated as follows: The unit is m 3 / s, t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water level time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted water level changes is counted as... The unit is m / d. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted upstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted downstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water depth time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted reservoir capacity to be dissipated is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted storage capacity of cascade reservoirs is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted cascade reservoir water storage is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T This represents the total number of time periods. The set of forecast results is counted as... , including time series , , , , , , , , The entire research timeframe is divided into... TT The periods are numbered as follows: tt , tt =1, 2, ..., TT , TT For the total number of periods, the first tt The start time of each period is counted as The end time is counted as The future water frequency meter will be... , No. n The water frequency meter is , nThe water inflow frequency is numbered, including P=95% (dry year), P=75% (partially dry year), P=50% (normal year), P=25% (partially abundant year), and P=5% (abundant year). n =1, 2, ..., 5. Future water conditions are calculated as follows: , No. m The water inflow situation is counted as follows: , m The water inflow conditions are numbered, including -30% low water level, -10% low water level, 30-year average water level, 10% above average water level, and 30% above average water level. m =1, 2, ..., 5.

[0034] Step 2: Assign values ​​to variables. express j Station cross-section k The flow corresponding to the constraint demand; express j Station cross-section k The water level corresponding to the constraint requirements; express j Station cross-section k Constraints on demand should be based on the corresponding water level fluctuations; express j Station cross-section k The upstream water level corresponding to the constraint demand; express j Station cross-section k The downstream water level corresponding to the constraint demand; express j Station cross-section k The water depth corresponding to the constraint requirements. Indicates water inflow frequency The reservoir capacity of the Lower Three Gorges cascade reservoirs is yet to be reduced. Indicates water inflow frequency The remaining storage capacity of the cascade reservoirs in the lower Three Gorges area; Indicates water inflow frequency Water storage capacity of the Three Gorges cascade reservoirs. Indicates water supply status The reservoir capacity of the Lower Three Gorges cascade reservoirs is yet to be reduced. Indicates water supply status The remaining storage capacity of the cascade reservoirs in the Lower Three Gorges area.

[0035] Step 3: Assign variable boundaries. express j Station cross-section k Constraints on the required flow rate limit; express j Station cross-section k The lower limit of the flow rate corresponding to the constraint demand. express j Station cross-section k The upper limit of the water level corresponding to the constraint requirements; express j Station cross-section k The lower limit of the water level corresponding to the constraint demand. express j Station cross-section k Constraints are based on the corresponding upper limit of water level fluctuation; express j Station cross-section k The constraint requirement corresponds to the lower limit of the water level fluctuation range. express j Station cross-section k The upper limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the upstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the downstream water level corresponding to the constraint demand. express j Station cross-section k The upper limit of water depth corresponding to the constraint requirements; express j Station cross-section k The lower limit of water depth corresponding to the constraint requirements.

[0036] Step 4: Determine and issue warnings based on time periods.

[0037] Step 4.1: Determine and warn of the decline period.

[0038] The drawdown period for the Three Gorges cascade reservoirs is from April to June. The predicted drawdown period is calculated as follows: The dispatch risk early warning indicators include the reservoir capacity to be reduced in cascade reservoirs at different inflow frequencies and the reservoir capacity to be reduced in cascade reservoirs under different inflow conditions. (Incoming inflow frequency...) The threshold for the undiminished storage capacity of the downstream reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for insufficient or excessive reservoir capacity in the next tier is calculated as follows: , ,when Timely warning. The warning result will be recorded as... , No. l The number of early warning results is counted as , lThe warning results are numbered, and the warning results include insufficient reservoir capacity to be drawn down upstream of the Three Gorges Dam, water release from the Gezhouba Dam, and water release from the Three Gorges Dam. l =1, 2, 3. Y This is a collection of early warning results for the drawdown period, including the early warning results. , , Water supply situation Warning results l The warning threshold for excessive reservoir capacity to be drawn down in the lower Three Gorges cascade reservoirs is calculated as follows: .

[0039] Constraints: The reservoir capacity above the Three Gorges Dam is relatively small and needs to be reduced. The Gezhouba Dam is releasing water because the reservoirs above the Three Gorges Dam have too much capacity to be drawn down. The Three Gorges Dam has too much water to be released from the reservoirs above the Three Gorges Dam, which is why water was released from the Three Gorges Dam.

[0040] Step 4.2: Water storage period judgment and early warning.

[0041] The impoundment period for the Three Gorges cascade reservoirs is from late August to October. The predicted impoundment period is calculated as follows: The dispatch risk warning indicators include the water storage capacity of cascade reservoirs at different inflow frequencies and the cascade storage capacity under different inflow conditions. (Incoming water frequency...) The risk threshold for water release from the storage capacity of the lower-level reservoirs is calculated as follows: Future water frequency The risk threshold for insufficient water storage in the lower-level reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for excessive storage capacity in lower-level reservoirs is calculated as follows: ,when Warning in time. The limit is counted as g, the first... r The restrictions are counted as The restrictions include Gezhouba Dam releasing water at its full capacity of 18,500 m³ / s, and the Three Gorges Dam releasing water at a guaranteed output of 8,000 m³ / s. r =1, 2. The warning results are counted as... , No. l The number of early warning results is counted as , l The warning results are numbered as follows: Water release from the Three Gorges-Gezhouba cascade reservoirs; insufficient water storage in the Three Gorges Reservoir; and excessive storage capacity in reservoirs upstream of the Three Gorges Reservoir, indicating insufficient water storage. l =1, 2, 3. This is a collection of early warning results for the water storage period, including the early warning results. , , Water supply situation limit Warning results l The warning threshold for excessive storage capacity in reservoirs above the Three Gorges cascade level is calculated as follows: .

[0042] Constraints: This is for the release of water from the Three Gorges-Gezhouba cascade. Due to insufficient water storage in the Three Gorges Reservoir, The reservoirs upstream of the Three Gorges Dam have excessive storage capacity and are under-storage. The drawdown periods are shown in Table 6.

[0043] Table 6 Table 7 shows the early warning thresholds for insufficient drawdown capacity in reservoirs upstream of the Three Gorges Dam. The unit is 100 million cubic meters. 3 : Table 7 Note: The total drawdown capacity of reservoirs above the Three Gorges Dam level is 72.7 billion cubic meters. 3 The total drawdown capacity above the flood control limit is 48.4 billion cubic meters. 3 .

[0044] Table 8 shows the warning thresholds for excessive drawdown capacity in reservoirs upstream of the Three Gorges Dam. The unit is 100 million m³. 3 : Table 8 The Three Gorges-Gezhouba cascade hydropower risk warning line for August to October, such as... Figure 5 As shown, the Three Gorges Reservoir's risk warning line for under-storage at the end of October is as follows: Figure 6 As shown.

[0045] Table 9 shows the warning thresholds for the risk of insufficient water storage in reservoirs upstream of the Three Gorges Dam, indicating that the available storage capacity is too large but the actual storage capacity is insufficient. (Unit: 100 million m³) 3 : Table 9 This invention achieves refined and forward-looking early warning of risks in cascade reservoir scheduling by coupling dynamic forecasting with multiple constraints, significantly improving the safety and intelligence of joint scheduling of reservoir groups.

Claims

1. A method for early warning of risks related to drawdown and impoundment period scheduling in cascade reservoirs, characterized in that: Specifically, it includes the following steps; Step 1, Define variables: Define the station cross sections, constraint requirements, forecast hydrological time series, period division, water inflow frequency and water inflow conditions within the study area; Step 2, Assigning Variables and Determining Variable Boundaries: Determine the values ​​of various constraint requirements for each station section and their upper and lower limits; Step 3, determine and issue warnings based on time periods: During the drawdown period, based on the drawdown forecast results, it is determined whether the reservoir capacity to be drained under different inflow frequencies exceeds the first threshold, and whether the reservoir capacity to be drained under different inflow conditions is lower than the less-than-ideal threshold or higher than the more-than-ideal threshold, and a set of drawdown period early warning results is generated. During the water storage period, based on the water storage period forecast results, it is determined whether the water storage volume under different water inflow frequencies exceeds the water abandonment risk threshold or is lower than the under-storage risk threshold, and whether the storage capacity under different water inflow conditions exceeds the excessive warning threshold, and a set of water storage period warning results is generated. Step 4: Output the set of early warning results for the drawdown period and the set of early warning results for the water storage period.

2. The method for early warning of drawdown and water storage period scheduling risks of cascade reservoirs according to claim 1, characterized in that: In step 1, defining variables specifically includes the following steps: The station cross-sections within the study area are counted as j , j =1,2,…, J , J The total number of station cross-sections within the study area; the constraint requirements for each station cross-section are calculated as follows: k , k =1,2,…, K , K The total number of site cross-sectional constraints; the time series of forecasted inflow is counted as The unit is m 3 / s, t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water level time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of predicted water level changes is counted as... The unit is m / d. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted upstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of forecasted downstream water levels is counted as... The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the forecast water depth time series is counted as The unit is meters. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted reservoir capacity to be dissipated is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the time series of the forecasted storage capacity of cascade reservoirs is counted as... The unit is m³. t =1, 2, ..., T , t The time period number, T Total number of time periods; The time series of predicted cascade reservoir water storage is denoted as The unit is m³. t =1, 2, ..., T , t The time period number, T The total number of time periods; the set of forecast results is counted as , including time series , , , , , , , , ; Divide the entire research timeframe into TT The periods are numbered as follows: tt , tt =1, 2, ..., TT , TT For the total number of periods, the first tt The start time of each period is counted as The end time is counted as ; Future water frequency meter , No. n The water frequency meter is , n Number the water inflow frequency. n =1, 2, ..., N , N This represents the total frequency of incoming water. Future water availability will be counted as... , No. m The water inflow situation is counted as follows: , m Number the water inflow conditions. m =1, 2, ..., M , M This represents the total number of water inflows.

3. The method for early warning of drawdown and water storage period scheduling risks in cascade reservoirs according to claim 1, characterized in that: In step 2, the variable is assigned a value, which specifically includes the following steps: express j Station cross-section k The flow corresponding to the constraint demand; express j Station cross-section k The water level corresponding to the constraint requirements; express j Station cross-section k Constraints on demand should be based on the corresponding water level fluctuations; express j Station cross-section k The upstream water level corresponding to the constraint demand; express j Station cross-section k The downstream water level corresponding to the constraint demand; express j Station cross-section k The water depth corresponding to the constraint requirements; Indicates water inflow frequency The downstream reservoirs are awaiting drawdown. Indicates water inflow frequency The storage capacity of downstream reservoirs; Indicates water inflow frequency Water storage capacity of downstream reservoirs; Indicates water supply status The downstream reservoirs are awaiting drawdown. Indicates water supply status The storage capacity of the downstream reservoirs.

4. The method for early warning of drawdown and water storage period scheduling risks of cascade reservoirs according to claim 1, characterized in that: In step 2, the variable boundaries are assigned, which specifically includes the following steps: express j Station cross-section k The upper limit of traffic volume corresponding to the constraint demand; express j Station cross-section k The lower limit of the flow rate corresponding to the constraint demand; express j Station cross-section k The upper limit of the water level corresponding to the constraint requirements; express j Station cross-section k The lower limit of the water level corresponding to the constraint demand; express j Station cross-section k Constraints are based on the corresponding upper limit of water level fluctuations; express j Station cross-section k Constraints are based on the lower limit of the corresponding water level fluctuation. express j Station cross-section k The upper limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the upstream water level corresponding to the constraint demand; express j Station cross-section k The upper limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The lower limit of the downstream water level corresponding to the constraint demand; express j Station cross-section k The upper limit of water depth corresponding to the constraint requirements; express j Station cross-section k The lower limit of water depth corresponding to the constraint requirements.

5. The method for early warning of drawdown and water storage period scheduling risks of cascade reservoirs according to claim 1, characterized in that: In step 3, the early warning for the drawdown period is determined, which specifically includes the following steps: The start time of the drawdown period is The end time is .when This is the drawdown period; the forecast result for the drawdown period is calculated as follows: The scheduling risk warning indicators include the reservoir capacity to be reduced in cascade reservoirs at different inflow frequencies and the reservoir capacity to be reduced in cascade reservoirs under different inflow conditions; and the inflow frequency. The threshold for the undiminished storage capacity of the downstream reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for insufficient or excessive reservoir capacity in the next tier is calculated as follows: , ,when Timely warning; the warning results will be counted as , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results; Y This is a collection of early warning results for the drawdown period, including the early warning results. , ; ; Constraints: ; 。 6. The method for early warning of drawdown and water storage period scheduling risks of cascade reservoirs according to claim 1, characterized in that: Step 3, the water storage period judgment and early warning, specifically includes the following steps: The water storage period begins at the following time: The end time is .when The period is the water storage period; the forecast results for the water storage period are counted as follows: The scheduling risk warning indicators include the water storage capacity of cascade reservoirs at different inflow frequencies, the cascade storage capacity under different inflow conditions, and the inflow frequency. The risk threshold for water release from the storage capacity of the lower-level reservoirs is calculated as follows: Future water frequency The risk threshold for insufficient water storage in the lower-level reservoirs is calculated as follows: ,when Early warning; water inflow situation The warning threshold for excessive storage capacity in lower-level reservoirs is calculated as follows: ,when Timely warning; the warning results will be counted as , No. l The number of early warning results is counted as , l Number the warning results. l =1, 2, ..., L , L This represents the total number of warning results; This is a collection of early warning results for the water storage period, including the early warning results. , ; ; Constraints: ; 。

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