Reservoir water level optimization regulation and control method for elastic risk balance of cascade dam group system

Abstract

The invention discloses a reservoir water level optimization regulation and control method for elastic risk balance of a cascade dam group system, and the method comprises the steps: determining a difference W between an inflow flood amount and an outflow flood amount, and calculating the risk elastic coefficient of each unit dam in the cascade dam group system in an initial state; the unit dams are grouped, the dam with the minimum risk elastic coefficient is classified as G, and the remaining dams are classified as H; repeatedly carrying out flood volume distribution on each reservoir in the G and calculating the risk elastic coefficient of the unit dam after distribution until all the risk elastic coefficients in the G are smaller than or equal to the minimum risk elastic coefficient in the H; and judging the distribution completion of the flood volume W, and if the total flood volume distribution is not equal to the flood volume W, re-grouping the unit dams, distributing the flood volume and calculating the risk elastic coefficient until the total flood volume distribution is equal to the flood volume W. Compared with the prior art, from the perspective of combination of system risk minimization and risk elastic coefficient balance, optimization regulation and control of the reservoir water level in the cascade environment are achieved, and the service risk of the cascade dam group is prevented and controlled as a whole on the system level.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of safety prevention and control of cascade reservoir dam group in river basin, and particularly relates to a reservoir water level optimization regulation method for risk elasticity balance of cascade dam group system. BACKGROUND

[0002] In order to fully develop and utilize water energy and water resources, in the same river or river basin, through the step-by-step layout and construction of multiple reservoir dam projects, an interconnected and coordinated cascade reservoir dam group system is formed, which plays an extremely important role in unified deployment of water resources, improvement of extreme water condition response capability and promotion of regional coordinated development. However, in the cascade dam group system, the water power connection between the reservoirs and dams at all levels is close, and the safety states of each unit dam are related to each other. The failure or breach of any unit dam can easily cause a chain effect and systemic risk, which may cause disastrous consequences in the entire river basin. Scientifically formulating and implementing precise and dynamic regulation strategies for the cascade dam group system can effectively weaken the cumulative effect of system risk, ensure the long-term stable operation of the cascade dam group system under complex hydro-meteorological conditions, geological environment changes and unexpected events, and is not only an important means to reduce the service risk rate and risk loss of the cascade dam group system, but also an important way to improve the overall safety of the system, enhance the anti-risk ability of the system and optimize the allocation of resources. To achieve the above goals, the most commonly used measure is scientific regulation of reservoir water level, which aims to utilize the regulation and storage capacity of each reservoir, reasonably store and discharge the inflow in a certain period of time, so as to balance the risk distribution of the reservoir group and reduce the overload failure risk rate of individual dams.

[0003] The traditional cascade reservoir storage rules mainly include "top-down" storage rule and "flood control capacity equal proportion" storage rule. The "top-down" storage rule refers to when the flood comes, the upper reservoir of the cascade stores more water in order to generate more power benefits under the condition of ensuring the safety of the dam, and then the downstream reservoir is stored in turn. The "flood control capacity equal proportion" storage rule refers to when the flood comes, according to the total flood control capacity of each reservoir, the flood storage task is allocated in proportion. The main purpose of the "top-down" storage strategy is to utilize the storage capacity of the upstream reservoir to optimize the operation efficiency of the cascade reservoir, and at the same time, to fully utilize the water resources under the multi-objective demand of flood control, ecology and power generation, which is beneficial to improve the power generation efficiency of the cascade reservoir, but it will bring the problem that the flood control function of the downstream reservoir of the cascade is not fully played, the overall benefit of the cascade dam system is lost, and the total risk of the system is increased. The "flood control capacity equal proportion" storage rule reflects the cooperation of each unit dam of the cascade dam system, so that the storage state of each reservoir is more balanced, the risk of affecting the stability of the whole cascade reservoir system due to the overload of a single reservoir is reduced, and the reliability of the overall operation of the system is improved. However, this rule mainly controls according to the flood control capacity of each reservoir, and the dam failure risk is not only determined by the storage capacity, but also affected by factors such as structural characteristics. Only allocating water according to the proportion of the capacity may cause individual weak projects to bear too much pressure, and the cascade dam system has a significant risk transfer effect. If the scheduling is only based on water balance, it may lead to insufficient burden of the upstream reservoir in flood control, and increase the flood control pressure of the downstream reservoir, and aggravate the systemic failure risk. SUMMARY

[0004] The present application provides a cascade dam system risk elasticity balanced reservoir water level optimization control method, which combines "system risk minimization and risk elasticity coefficient balance". It uses the risk elasticity coefficient, which is the importance measure index of the cascade dam system unit dam considering the risk transfer effect, as a guide, and innovates a flood volume allocation decision mode based on this index, which not only effectively ensures the service safety of the unit dam, but also reduces the total risk of the cascade dam system, delays the growth rate of the system risk, and improves the overall risk controllability.

[0005] Technical scheme: In order to solve the above technical problems, the present application discloses a cascade dam system risk elasticity balanced reservoir water level optimization control method, which is carried out according to the following steps:

[0006] Step 1: Collect the engineering data, basin topographic data, social data, initial water level, water level-storage capacity curve of each unit dam in the cascade dam system, and determine the difference between the inflow flood volume of the dam system and the outflow flood volume of the system ;

[0007] Step 2: Calculate the risk elasticity coefficient of each unit dam in the cascade dam group system under the initial state. , , The number of dams in a cascade dam group system;

[0008] Step 3: Group the unit dams in the cascade dam group system, and include the dams with the lowest risk elasticity coefficients into the set. The number of statistics is , The remaining dams constitute the set of The number of statistics is ;

[0009] Step 4: For the set Each reservoir in the process repeatedly distributes floodwater. And calculate the risk elasticity coefficient of the allocated unit dam. , until the set All risk elasticity coefficients are less than or equal to the set The minimum risk elasticity coefficient in;

[0010] Step 5: Measure the flood volume Complete allocation judgment, if Repeat steps 3 and 4, including unit dam grouping, flood volume allocation, and risk elasticity coefficient calculation, until... .

[0011] Furthermore, the reservoir water level optimization and control method follows the water storage rule of "risk elasticity balance". That is, based on the risk elasticity coefficient of each unit dam, the relative risk contribution of each reservoir is analyzed, and the dam with the lower risk elasticity coefficient is given higher water storage priority in water storage scheduling, so as to balance the impact of the risk of each unit dam on the risk of the cascade dam group system and ensure that the increase of the risk of the cascade dam group system is minimized.

[0012] Furthermore, in steps 2 and 4, the risk elasticity coefficients of each unit dam within the cascade dam group system are calculated. Specifically:

[0013] (1);

[0014] In the formula: For the first Risks associated with unit dams; Risks associated with the cascade dam system; and These represent the changes in unit dam risk and system risk, respectively.

[0015] Furthermore, in step 4, the set Each of the reservoirs repeatedly performs flood allocation When the adaptive moment estimation algorithm is used to solve the flood allocation, it specifically includes:

[0016] Initialize parameters, including learning rate for controlling the step size of each update; decay rate and for controlling the decay of the first and second moments, respectively; set constant to avoid division by zero error; set the optimization variable , i.e. the flood allocation of the th reservoir at the th iteration;

[0017] Gradient calculation, set the comprehensive risk of the cascade dam group system after allocating flood as the objective function, that is:

[0018] (2) ;

[0019] In the formula: is the initial reservoir capacity of the th reservoir, ; is the allocated flood of the th reservoir; is the number of unit dams in the cascade dam group system; is the risk transmission coefficient between adjacent upstream and downstream unit dams; is the risk loss of the th unit dam, including life loss, economic loss and social environmental impact;

[0020] The gradient of the objective function with respect to the optimization variable is calculated as follows:

[0021] (3) ;

[0022] In the formula: is the impact of the allocated flood of the th dam at the th iteration on the comprehensive risk of the cascade dam group system ;

[0023] First and second moment calculation: as the key to guide variable optimization, the first and second moments of the gradient are calculated using the following formula:

[0024] (4) ;

[0025] (5) ; ​

[0026] In the formula: , , , The first Dam gradient In the The first-order moment estimate, second-order moment estimate, and third-order moment estimate at the nth iteration First-order moment estimation and second-order moment estimation at each iteration; and These are the decay coefficients of first-order and second-order momentum, respectively; For the first Comprehensive Risk of the Cascade Dam Group System in the Second Iteration For the The gradient of flood distribution by the dam;

[0027] Flood volume update operation: bias correction is applied to the moment estimates of equations (4) and (5):

[0028] (6);

[0029] (7);

[0030] Then, the allocatable flood is updated based on the corrected moment estimate:

[0031] (8);

[0032] In the formula: , For the moment estimation after bias correction; The learning rate; It is a constant; , The first The dam is in The second iteration and the first The flood volume allocated in the next iteration.

[0033] Furthermore, the risk transmission coefficient between adjacent upstream and downstream unit dams A and B within the cascade dam group system. Collectively referred to as The calculation formula is as follows:

[0034] (9);

[0035] In the formula: , These are events where the upstream unit dam A of the cascade is in a failed state and a reliable state, respectively. , These are events where downstream unit dam B of the cascade is in a failed state and a reliable state, respectively. Conditional probability.

[0036] Further, in step 5, the flood volume The allocation completion judgment and subsequent operation are as follows:

[0037] If , it indicates that the flood volume is allocated too much, and the flood volume ;

[0038] If , but there is no global minimum risk elasticity coefficient in the set , it indicates that the flood volume allocation of part of the dam in the set is insufficient, and the flood volume allocation of the corresponding dam should be increased , and the risk elasticity coefficient calculation, flood volume redistribution, flood volume allocation completion judgment are further cycled;

[0039] If , and there is a global minimum risk elasticity coefficient in the set , it indicates that the dam in the set is insufficient to complete the water storage task, and needs to be re-grouped according to the mode of step 3, and the flood volume allocation, risk elasticity coefficient calculation, flood volume redistribution, flood volume allocation completion judgment are further cycled;

[0040] If , then is the final water storage scheme.

[0041] Compared with the prior art, the beneficial effects of the present application are as follows:

[0042] The cascade dam group system risk reservoir water level optimization control method of the present application follows the "risk elasticity balance" water storage rule, that is, based on the risk elasticity coefficient of each unit dam, the relative risk contribution of each reservoir is analyzed, and the dam with lower risk elasticity coefficient is given higher water storage priority in water storage scheduling, the influence of the risk of each unit dam on the risk of the cascade dam group system is balanced, and the increase of the risk of the cascade dam group system is minimized, which effectively avoids the limitations of the traditional cascade dam group system reservoir water level optimization control method, such as the "top-down" water storage rule which fails to fully play the flood control function of the downstream reservoir, the "flood control reservoir capacity equal proportion" water storage rule which may lead to insufficient burden of the upstream reservoir in flood control, and both of them do not fully consider the influence of structural characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 A cascade dam group system risk elasticity balance reservoir water level optimization control decision-making process is proposed in the present application;

[0044] Figure 2 A "top-down" water storage rule schematic diagram is shown in the present application;

[0045] Figure 3 The schematic diagram of the "flood control reservoir capacity equal proportion" water storage rule;

[0046] Figure 4 The river basin plane and the location map of the cascade dams in the embodiment;

[0047] Figure 5 The dam group system risk levels obtained by the three water storage rules in the embodiment;

[0048] Figure 6 The system unit dam reliability obtained by the three water storage rules in the embodiment. DETAILED DESCRIPTION

[0049] The present application will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0050] The present application discloses a reservoir water level optimization control method for risk elasticity balance of a cascade dam group system, comprising the following steps:

[0051] Step 1, data collection. Collect the engineering data of each unit dam in the cascade dam group system, the river basin terrain data, the social data, the initial water level, the water level-storage capacity curve, and calculate the difference between the flood inflow into the dam group system and the flood outflow from the system within the calculation period .

[0052] Step 2, calculate the risk elasticity coefficient of each unit dam in the cascade dam group system in the initial state , is the number of unit dams in the cascade dam group system.

[0053] Step 3, group the unit dams in the cascade dam group system. Since there is a case that the risk elasticity coefficients of the unit dams are the same and the minimum, therefore, the dams with the minimum risk elasticity coefficient are all included in the set , the number of statistics is , the set composed of the remaining dams is , and the number of statistics is .

[0054] Step 4, flood distribution. Distribute the flood to each reservoir in the set , at the initial distribution, , is the difference between the maximum reservoir capacity and the initial reservoir capacity of the th reservoir in the set , i.e., the upper limit of the available reservoir capacity of the th reservoir.

[0055] Step 5: Calculate the risk elasticity coefficient of the unit dam after flood distribution. After the flood volume is allocated, the risk elasticity coefficient of each unit dam in the cascade dam group system is calculated. If set There exists a risk elasticity coefficient greater than the set. When the minimum risk elasticity coefficient is in the set, it indicates that the set The risk to the corresponding dam increases significantly, and the flood distribution to the dam should be reduced. Return to step 4.

[0056] Step 6, determine the flood volume Has the allocation been completed? If the set is in step 5... All risk elasticity coefficients are less than or equal to the set When determining the minimum risk elasticity coefficient, the flood volume is... Has the allocation been completed? ,but This is the final water storage plan.

[0057] Step 7, when This indicates that the flood volume has been over-allocated and needs to be reduced. .

[0058] Step 8, when The set needs to be judged. Does the set contain a globally minimum risk elasticity coefficient? If not, it indicates that the set... The flood distribution capacity of some dams in the central part of the city is insufficient, and the flood distribution capacity of the corresponding dams should be increased. Return to step 4; if it exists, it means the set... The dams in the middle are insufficient to complete the water storage task, so they need to be regrouped and returned to step 3.

[0059] Specifically, in steps 2 and 5 above, the risk elasticity coefficient of each unit dam within the cascade dam group system is calculated according to the following formula. , This refers to the number of unit dams in a cascade dam group system.

[0060] (1)

[0061] In the formula: For the first Risks associated with unit dams; Risks associated with the cascade dam system; and These represent the changes in unit dam risk and system risk, respectively.

[0062] In step 4 above, the Adaptive Moment Estimation (Adam) algorithm is used to allocate flood volume according to the following steps Solve:

[0063] ① Initialize parameters

[0064] Set the learning rate , which is used to control the step size of each update, generally taking 0.1; Set the decay rate and , which are used to control the decay of the first and second moments, respectively, usually taking 0.9 and 0.999; Set the constant , which is used to avoid division by zero errors, generally taking 10 -8 ; Set the optimization variable , which is the flood volume allocated to the th reservoir in the th iteration.

[0065] ② Calculate the gradient

[0066] Set the comprehensive risk of the cascade dam group system after allocating flood volume as the objective function, that is:

[0067] (2)

[0068] In the formula: is the initial reservoir capacity of the th reservoir, ; is the allocated flood volume of the th reservoir; is the number of unit dams in the cascade dam group system; is the risk transmission coefficient between adjacent upstream and downstream unit dams; is the risk loss of the th unit dam, including life loss, economic loss and social environmental impact.

[0069] The gradient of the objective function with respect to the optimization variable is calculated as follows:

[0070] (3)

[0071] In the formula: is the allocated flood volume of the th dam in the th iteration , which affects the comprehensive risk of the cascade dam group system.

[0072] ③ Calculate the first moment and second moment

[0073] As a key element guiding variable optimization in the Adam algorithm, the first and second moments of the gradient are calculated using the following formula:

[0074] (4)

[0075] (5)

[0076] In the formula: , , , The first Dam gradient In the The first-order moment estimate, second-order moment estimate, and... at the... iteration First-order moment estimation and second-order moment estimation at each iteration; and These are the decay coefficients of first-order and second-order momentum, respectively; For the first Comprehensive Risk of the Cascade Dam Group System in the Second Iteration For the first The gradient of flood distribution by the dam.

[0077] ④ Update flood volume

[0078] First, the moment estimates of equations (4) and (5) are corrected for bias:

[0079] (6)

[0080] (7)

[0081] Then, the allocatable flood is updated based on the corrected moment estimate:

[0082] (8)

[0083] In the formula: , For the moment estimation after bias correction; The learning rate; It is a constant; , The first The dam is in The second iteration and the first The flood volume allocated in the next iteration.

[0084] Risk transfer coefficient between adjacent upstream and downstream unit dams A and B within a cascade dam system The calculation formula is as follows:

[0085] (9)

[0086] In the formula, , respectively are the events that the upstream unit dam A of the cascade is in a failure state and a reliable state; , respectively are the events that the downstream unit dam B of the cascade is in a failure state and a reliable state; is a conditional probability.

[0087] The embodiment takes a certain 9-cascade dam group in a basin shown in Tables 1 and 2 as an example, uses the "risk elasticity balance" reservoir regulation and the model and method thereof, follows the flow shown in Table 3, studies and gives a reservoir water level regulation scheme of the dam group system, and compares the calculation results with those of the traditional "top-down" reservoir regulation shown in Table 4 and the "flood control reservoir capacity equal proportion" reservoir regulation shown in Table 5. Figure 4 Figure 1 Figure 2 Figure 3

[0088] Table 1 Engineering overview of the cascade dam group in the basin

[0089] The initial water level of each unit dam is set as the normal storage water level. Since the discharge capacity of No. 9 dam and the downstream river channel discharge are limited, when the basin encounters a rainstorm, 8x10 6 m 3 of flood volume cannot be discharged to the downstream in time and needs to be reasonably allocated to each reservoir. Table 2 shows the available reservoir capacity of each unit dam at the normal storage water level, and the upper limit of the total available reservoir capacity of the basin is 1018.38x10 4 m 3 .

[0090] Table 2 Related parameters of reservoir water level optimization regulation of the cascade dam group system

[0091] The failure risk rate of each unit dam with the change of reservoir water level is calculated, and the failure risk rate corresponding to the characteristic water level is shown in Table 3.

[0092] Table 3 Failure risk rate corresponding to the characteristic water level of each dam

[0093]

[0094] The flood volume allocation is performed, and the reservoir water level optimization regulation analysis of the 9-cascade dam group system is divided into 9 analysis periods. The flood volume allocation analysis is performed on the reservoirs in the first analysis period. ​​​​​​The cascade dam group system flood volume distribution results of the first analysis period are shown in Table 4.

[0095] Table 4 Cascade dam group system flood volume distribution of the first analysis period

[0096]

[0097] At the initial time 0, each unit dam is at the normal water level, and each reservoir has not allocated flood volume. Based on the risk elasticity coefficient calculation results, the dam number in descending order of risk elasticity coefficient is: No. 2→ No. 3→ No. 4→ No. 6→ No. 1→ No. 7→ No. 9→ No. 8→ No. 5. The smaller the risk elasticity coefficient, the smaller the influence of the unit dam risk change on the system risk change, so the flood volume is preferentially allocated to No. 2 dam. At time 1, the influence of the risk change of No. 2 dam and No. 3 dam on the system risk change is the same, so the flood volume is allocated to No. 2 dam and No. 3 dam with the smallest and equal risk elasticity coefficient, and the same is true for the subsequent time. Table 5 shows the cascade dam group system flood volume distribution of the eighth analysis period.

[0098] Table 5 Cascade dam group system flood volume distribution of the eighth analysis period

[0099]

[0100] At time 8, all the dams except No. 5 dam are allocated with flood volume, and the influence of the risk change of each unit dam on the system risk change is the same. Since the sum of the allocated storage capacity is 807.64×10 4 m 3 at this time, the flood volume is allocated too much, so there is a time in the eighth analysis period that makes the flood volume just allocated, and Table 6 shows the flood volume distribution of the total analysis period.

[0101] Table 6 Storage capacity allocation based on the “risk elasticity balance” water storage rule

[0102]

[0103] Table 7 shows the storage capacity allocation based on the “top-down” water storage rule, and Table 8 shows the storage capacity allocation based on the “flood control capacity equal proportion” water storage rule.

[0104] Table 7 Storage capacity allocation based on the “top-down” water storage rule

[0105]

[0106] Table 8 Storage capacity allocation based on the “flood control capacity equal proportion” water storage rule

[0107]

[0108] The initial moment step dam group system risk is 119.89, after different water storage rules storage, the risk increase situation is shown in Table 9. The "from top to bottom" water storage gets the dam group system risk increased to 797.85, the "equal proportion" water storage increases the risk next (512.76), the dam group system risk increase amount based on the "risk elasticity balance" water storage rule is minimum, and the final is 269.82.

[0109] Table 9 Three kinds of water storage results comparison

[0110] Appendix Figure 5 The three kinds of rules water storage after the step dam group system risk level evaluation is shown, Appendix Figure 6 The three kinds of rules water storage after the reliability level of each unit dam is shown. From Table 9 and Appendix Figure 5 , Appendix Figure 6 It can be seen that:

[0111] ① Although all are III level, the dam group system risk based on the "risk elasticity balance" water storage rule is minimum, and the level is closest to IV level.

[0112] ② The traditional water storage rule takes the available storage capacity as the main basis, and does not fully consider the structure safety, resulting in the reliability of No. 2 dam and No. 3 dam after water storage is lower than the one class damage reliability index 2.7 specified in the specification.

[0113] ③ The water level optimization scheme based on the "risk elasticity balance" water storage rule not only makes the reliability of each unit dam meet the requirements, but also the total system risk is minimum.

[0114] Obviously, the above examples are only examples for clearly illustrating, and do not limit the embodiments. For ordinary skilled in the art, on the basis of the above description, other different forms of changes or variations can be made, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A method for optimizing and regulating reservoir water level for balancing system risk elasticity of a stepped dam group, characterized in that, The following steps are taken: Step 1: Collecting engineering data of each unit dam in the stepped dam group system, basin topographic data, social data, initial water level, water level-storage capacity curve, determining the difference between the inflow flood of the dam group system and the outflow flood of the system ; Step 2: Calculate the risk elasticity coefficient of each unit dam in the stepped dam group system under the initial state , , is the number of dams in the stepped dam group system; Step 3: Group the unit dams in the stepped dam group system, and put the dam with the minimum risk elasticity coefficient into the set , the statistical number is , , the set composed of the remaining dams is , the statistical number is ; Step 4: Repeat the flood volume distribution for each reservoir in the set and calculate the risk elasticity factor for the unit dam after distribution , until all risk elasticity factors in the set are less than or equal to the minimum risk elasticity factor in the set .​ Step 5: Perform flood volume If the distribution is completed, the program proceeds to Step 6. If not, the program returns to Step 3 and Step 4 to perform unit dam grouping, flood volume distribution, and risk elasticity coefficient calculation until .

2. The method of claim 1, wherein the method is characterized by, The reservoir water level optimization control method follows the "risk elasticity balance" storage rule, that is, based on the risk elasticity coefficient of each unit dam, the relative risk contribution of each reservoir is analyzed, and the dam with lower risk elasticity coefficient is given higher priority in storage scheduling, the risk of each unit dam is balanced to the influence of the risk of cascade dam group system, and the increase of the risk of cascade dam group system is minimized.

3. The method of claim 1, wherein the method is characterized by: The step 2 and step 4 calculate the risk elasticity coefficient of each unit dam in the stepped dam group system Specifically, (1)； wherein: is the first risk of the unit dam; is the risk of the stepped dam system; and denote the change in unit dam risk and system risk, respectively.

4. The method of claim 1, wherein, In step 4, the set Each reservoir in the process repeatedly distributes floodwater. At that time, the adaptive moment estimation algorithm is used to solve the flood distribution problem, specifically including: Initialization parameters, including learning rate for controlling the step size of each update; decay rate and for controlling the decay of the first and second moments, respectively; setting constant for avoiding division by zero errors; setting the variables to be optimized , i.e., the th dam's assigned flood volume at the th iteration; Gradient calculation, set the step dam group system distribution of flood volume after the comprehensive risk For the objective function, namely: (2)； In the formula: For the first The initial capacity of the reservoir, ; For the first Distribute flood volume of the reservoir; The number of unit dams in a cascade dam group system; This represents the risk transmission coefficient between adjacent upstream and downstream unit dams. For the first The risks and losses of a unit dam include loss of life, economic losses, and social and environmental impacts; The gradient of the objective function with respect to the variables to be optimized is computed as follows: ​ (3)； In the formula: For the first During the nth iteration, the 1st Distributing flood volume of the dam Comprehensive risk assessment of cascade dam system The impact; First and second moment calculation: as the key of the guiding variable optimization, the first and second moments of the gradient are calculated by the following formula: (4)； (5)； In the formula: , , , The first Dam gradient In the The first-order moment estimate, second-order moment estimate, and third-order moment estimate at the nth iteration First-order moment estimation and second-order moment estimation at each iteration; and These are the decay coefficients of first-order and second-order momentum, respectively; For the first Comprehensive Risk of the Cascade Dam Group System in the Second Iteration For the The gradient of flood distribution by the dam; The bias correction is performed on the moment estimation of formula (4) and formula (5): (6)； (7)； Then, the distributable flood is updated according to the corrected moment estimation: (8)； In the formula, , is the matrix estimate after bias correction; is the learning rate; is a constant; , are the flood volumes allocated to the first th dam at the first th iteration and the first th iteration, respectively.

5. The method of claim 4, wherein, Risk transfer coefficient between adjacent upstream and downstream unit dams A, B in a stepped dam group system , collectively referred to as , the calculation formula is as follows: (9)； wherein: , are the events that the upstream unit dam A is in a failed state and a reliable state, respectively; , are the events that the downstream unit dam B is in a failed state and a reliable state, respectively; is the conditional probability.

6. The method of claim 1, wherein, In step 5, the flood The distribution completion judgment and the subsequent operation are as follows: If , it is explained that the flood volume is distributed too much, then reduce ; like But sets The absence of a globally minimum risk elasticity coefficient in the set indicates that the set The flood distribution capacity of some dams in the central part of the city is insufficient, and the flood distribution capacity of the corresponding dams should be increased. This process then iteratively calculates the risk elasticity coefficient, redistributes flood volume, and... Complete allocation check; like and set The existence of a globally minimum risk elasticity coefficient in the set indicates that the set The existing dam is insufficient to complete the water storage task, so it is necessary to regroup the floods according to step 3, and then cyclically perform flood volume allocation, risk elasticity coefficient calculation, flood volume redistribution, and flood volume... Complete allocation check; If then is the final water storage scheme.

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