Reservoir benefit-making scale determination method based on double-layer step-by-step trial calculation

Abstract

The invention provides a reservoir benefit-making scale determination method based on double-layer step-by-step trial calculation, which comprises the steps of collecting basic data of a reservoir and determining constraint conditions of a benefit-making reservoir capacity, and further comprises the following steps of: determining a maximum benefit-making reservoir capacity V0 required when various water supplies are completely not damaged by adopting a dichotomy; 2, calculating the number of possible damage time periods of each water supply object, and drawing up the damage sequence of the water supply objects; establishing an optimization model I by taking the maximum minimum storage capacity Vmin of the damaged long series as a target, and discounting the water demand process of each water supply object period by period by using a successive optimization algorithm to solve the optimization model I; a bisection method is adopted to determine that the required benefit-making storage capacity Vop is not damaged at all after the water demand of each water supply object is discounted; drawing up a water supply quantity optimization sequence of the water supply objects; and establishing an optimization model II by taking the maximum long-series water supply amount W as a target, optimizing the discount coefficient by using a successive optimization algorithm, solving the optimization model II, and calculating the optimized long-series water supply amount W.

Description

Technical Field

[0001] The invention relates to the technical field of reservoir engineering planning and design, in particular to a method for determining the reservoir benefit scale based on double-layer step-by-step trial calculation. Background Art

[0002] Reservoirs for comprehensive utilization often undertake multiple tasks such as water supply, irrigation, and ecological water replenishment, and have two or more water supply objects with different requirements for guarantee rate and maximum damage depth. Under the constraints of meeting the guarantee rate and maximum damage depth requirements of each water supply object, determining the beneficial storage capacity of the reservoir through long-series adjustment calculation is a multi-dimensional, multi-constrained, and nonlinear optimization problem, and it is also the core work in the planning and design stage of comprehensive utilization reservoir projects. In specific work, long-series damage periods and damage depths are usually selected manually, and the beneficial storage capacity of the reservoir is determined by trial calculation on this basis. However, this method is often subjective and arbitrary, and the selection of different damage periods and damage depths has a great impact on the calculation results of the beneficial storage capacity of the reservoir. Therefore, how to determine a unified rule for selecting damage periods and damage depths, and propose an optimization trial calculation method for the beneficial storage capacity of comprehensive utilization reservoirs, is a problem that needs to be solved urgently.

[0003] The invention patent application with application number CN101831887A discloses a method for determining the beneficial storage capacity of a reservoir that takes into account both human and ecological needs. First, the key parameter values ​​of the ecological flow required by the river (the planned ecological flow during the flood period, the starting point of the high pulse flow, and the minimum ecological water demand) are determined, and the inflow is divided into four intervals according to the size of the reservoir inflow. When the flow is in different intervals, different ecological flow processes are adopted to meet different ecological flow requirements in different flow periods; then, through simulation calculation, the maximum water supply that can be provided to humans under the condition of meeting the formulated ecological flow process is determined; finally, the planned water supply is selected within the water supply range, and combined with the formulated ecological flow process, and the continuous peak algorithm that takes into account both human and ecological water supply is adopted to obtain the required reservoir beneficial storage capacity that simultaneously meets the planned water supply and ecological flow. The disadvantage of this method is that the water provided to humans is considered as a uniform process, and the uneven water demand such as irrigation is not considered, and the water supply guarantee rate and damage depth requirements are not considered.

[0004] The invention patent application with application number CN107784454A discloses a method, device and equipment for regulating the benefits of reservoirs in high-cold areas. The method includes: determining the change law of the frozen layer in the high-cold areas; obtaining the freezing loss water volume caused by the freezing of water in winter and the increased water volume caused by the melting of ice in spring according to the change law of the frozen layer in the high-cold areas; combining the freezing loss water volume and the increased water volume of the melting ice, and calculating the benefit scale and maximum water supply capacity of the reservoir according to the water balance principle. The method of the present invention solves the problem that the existing reservoir project has a large benefit scale, is biased towards safety, and has a large project investment. By calculating the frozen layer of the reservoir in the high-cold area to participate in the benefit regulation, it is possible to minimize the benefit scale of the reservoir project, increase the water supply efficiency, and reduce the cost. The disadvantage of this method is that the water supply is considered as full guarantee, and the water supply guarantee rate and the damage depth requirements are not considered. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a method for determining the scale of reservoir benefits based on double-layer step-by-step calculation. Under the premise of meeting the guarantee rate of each water supply object and the maximum damage depth requirements, the destruction order of different water supply objects is determined, and the minimum reservoir beneficial storage capacity that meets various constraints is obtained through double-layer step-by-step calculation, and the reservoir water supply process is optimized, so as to reasonably determine the reservoir beneficial storage capacity and water supply.

[0006] The purpose of the present invention is to provide a method for determining the scale of reservoir benefits based on double-layer step-by-step trial calculation, which includes collecting basic reservoir information and constraint conditions for determining the beneficial storage capacity, and also includes the following steps:

[0007] Step 1: Use the dichotomy method to determine the maximum beneficial storage capacity V0 required for each water supply to be completely undamaged; Step 2: Calculate the number of time periods during which each water supply object may be damaged, and formulate the damage order of the water supply objects;

[0008] Step 3: Take the minimum storage capacity V after the destruction min The maximum is the goal, and the optimization model I is established. The water demand process of each water supply object is discounted in each period by using the successive optimization algorithm to solve the optimization model I:

[0009] V min =min(v1,v3,v2,…,v n )

[0010] Among them, V min is the minimum storage capacity of the long series reservoir, v i is the storage capacity of the reservoir at the end of the i-th period;

[0011] Step 4: Use the dichotomy method to determine the required beneficial storage capacity V after the water demand of each water supply object is discounted. op ;

[0012] Step 5: Formulate the optimal order of water supply to water supply objects;

[0013] Step 6: Taking the maximum long-series total water supply W as the goal, establish optimization model II, use the successive optimization algorithm to optimize the discount coefficient in each time period, solve optimization model II, and calculate the optimized long-series total water supply W.

[0014] Preferably, the basic data of the reservoir include at least one of inflow runoff, various water supply demands, water level-area-storage capacity curve, evaporation increase and loss curve, time period leakage coefficient, dead water level and ecological flow decentralization demand.

[0015] In any of the above solutions, preferably, the constraint conditions include reservoir water level constraint, guarantee rate constraint and maximum damage depth constraint.

[0016] In any of the above solutions, preferably, the reservoir water level constraint is

[0017] Z i ∈[Z min ,Z max ]

[0018] Among them, Z i is the water level of the reservoir in period i, Z min is the dead water level of the reservoir, Z max This is the normal water level of the reservoir.

[0019] In any of the above solutions, preferably, the guaranteed rate constraint is

[0020] P j ∈[P min,j ,1]

[0021] Among them, P j is the guaranteed rate of water supply object j, P min,j Allow a minimum guaranteed rate for water supply object j.

[0022] In any of the above solutions, preferably, the maximum damage depth constraint is

[0023] B i,j ∈[0,B max,j ]

[0024] Among them, B i,j is the damage depth of water supply object j in time period i, B max,j The maximum damage depth allowed for water supply object j.

[0025] In any of the above schemes, preferably, step 1 includes the following sub-steps:

[0026] Step 11: Preliminary calculation of the maximum beneficial storage capacity V 0max and the minimum beneficial storage capacity V0min , V 0max and V 0min V 0max ≥V0 and V0≥V 0min ≥0;

[0027] Step 12: Let the beneficial storage capacity V0 = (V 0max +V 0min ) / 2, using the undiscounted water demand series for reservoir regulation calculations;

[0028] Step 13: If the minimum storage capacity of the series reservoir is V min >V dead , then let V 0max =V0, if the minimum storage capacity of the long series reservoir is V min ≤V dead , then let V 0min =V0, where V dead It is the dead storage capacity of the reservoir;

[0029] Step 14: Determine V 0max -V 0min Whether the calculation accuracy is achieved, when V 0max -V 0min If it is greater than the calculation accuracy, then re-execute step 12. 0max -V 0min When it is less than or equal to the calculation accuracy, V0 is confirmed to be the maximum beneficial storage capacity required for all water supply items not to be damaged.

[0030] In any of the above schemes, preferably, in step 2, the number of discounted time periods is divided into the number of discounted years N according to the different requirements of the water supply object for the guarantee rate. byear and the number of discounted durations N bdia ,

[0031] N byear =(1-P)NP

[0032] N bdia =(1-P)nP

[0033] Among them, N is the number of long series years, P is the design guarantee rate, and n is the number of time periods.

[0034] The destruction order is arranged according to the importance of the water supply objects, and water supply objects with low water supply priorities are destroyed first.

[0035] In any of the above schemes, preferably, step 3 includes the following sub-steps:

[0036] Step 31: Set the discounted water supply object j=1;

[0037] Step 32: Find the storage capacity V at the end of the minimum period in the long seriesmin and its corresponding time period t;

[0038] Step 33: Starting from time period t, discount the water demand of water supply object j forward;

[0039] Step 34: Conduct long - series regulation calculation using the discounted water demand series, and find the storage capacity V at the end of the smallest time period in the long series min and its corresponding time period t. When the time period corresponding to the smallest storage capacity at the end of the time period remains unchanged, execute Step 35. When the time period corresponding to the smallest storage capacity at the end of the time period changes, update the minimum storage capacity and its corresponding time period, and execute Step 36;

[0040] Step 35: Determine whether the water level at the beginning of the discounted time period is the normal storage level corresponding to the maximum beneficial storage capacity V0,

[0041] When it has been discounted to the normal storage level, execute Step 37;

[0042] When it has not been discounted to the normal storage level, update t. When the required guarantee rate type is the duration guarantee rate, let t = t - 1. When the required guarantee rate type is the annual guarantee rate, t is updated to the end of the previous year;

[0043] Step 36: Calculate the number of discounted time periods. When the number of discounted time periods is less than the number of time periods that can be discounted, re - execute Step 32. When the number of discounted time periods is equal to the number of time periods that can be discounted, execute Step 37;

[0044] Step 37: When j < m, then j = j + 1, and re - execute Step 32. When j = m, then end Step 3, where m is the number of water supply objects.

[0045] Preferably, in any of the above - mentioned schemes, Step 33 includes:

[0046] 1) When the required guarantee rate type of the current water supply object is the annual guarantee rate, discount from time period t to the beginning of the year in which time period t is located according to the maximum damage depth,

[0047] 2) When encountering a time period with the normal storage level at the beginning of the time period, abort the forward discount,

[0048] 3) When the required guarantee rate type of the current water supply object is the duration guarantee rate, discount time period t.

[0049] Preferably, in any of the above - mentioned schemes, Step 4 includes the following sub - steps:

[0050] Step 41: Preliminarily estimate the maximum beneficial storage capacity V for trial calculation maxop and the minimum beneficial storage capacity V minop , where V maxop = V0, and V minop needs to satisfy V op ≥Vminop ≥0;

[0051] Step 42: Set the storage capacity V op =(V maxop +V minop ) / 2, using the discounted water demand series to calculate reservoir regulation;

[0052] Step 43: If the minimum storage capacity of the series reservoir is V min >V dead , then let V maxop =V op , if the minimum storage capacity of the Chang series reservoir is V min ≤V dead , then let V minop =V op ;

[0053] Step 44: Determine V maxop -V minop Whether the calculation accuracy is achieved, when V maxop -V minop If it is greater than the calculation accuracy, step 42 is executed again. maxop -V minop If it is less than or equal to the calculation accuracy, then confirm V op This is the beneficial storage capacity of the reservoir that needs to be determined.

[0054] In any of the above schemes, preferably, in step 5, the optimization order of water supply quantity to the water supply objects is arranged according to the importance of the water supply objects, and water supply objects with high water supply priority are optimized first.

[0055] In any of the above solutions, preferably, step 6 includes the following sub-steps:

[0056] Step 61: Set the water demand discount coefficient of each water supply object in the discount period between [0,B max,j ] interval, they are discretized into r water demands, where r is the discrete number of water demands;

[0057] Step 62: Let optimized water supply object j=1, calculation period i=1;

[0058] Step 63: Determine whether the water demand of the water supply object in the current period is discounted. If it is discounted, set k=r and execute step 64.

[0059] When no discount is made, let i=i+1 and execute step 65, wherein k is the discrete sequence number of water demand, when k=r, the water demand is discounted according to the maximum damage depth, and when k=0, the water demand is not discounted;

[0060] Step 64: Calculate the minimum storage capacity V of the long series min , if V min <Vdead , then let k = k + 1, let i = i + 1, if V min ≥V dead , then let k = k-1, and repeat this step until k = 0 and let i = i+1;

[0061] Step 65: if i>n, set j=j+1, if i≤n, execute step 63, where n is the number of time periods;

[0062] Step 66: If j≤m, execute step 63; if i>n, calculate the total water supply W of the long series and end step 6.

[0063] In any of the above schemes, preferably, the k-th discrete water demand of the j-th water supply object in the i-th period is w i,j,k for

[0064] w i,j,k =(1-k / r·B max,j ) i,j,r

[0065] Among them, r is the discrete quantity of water demand, w i,j,r It is the undiscounted water demand of the jth water supply object in the i-th period.

[0066] In any of the above schemes, preferably, the calculation formula for the total water supply W of the long series is:

[0067]

[0068] Among them, w i,j The water supply volume for the jth water supply object in the i-th period.

[0069] The present invention proposes a method for determining the scale of reservoir benefits based on double-layer step-by-step trial calculation. On the basis of water supply not completely destroying the required beneficial storage capacity, by gradually finding the water supply destruction period, the required beneficial storage capacity of the reservoir is reduced, and the minimum beneficial storage capacity of the reservoir under the given water supply priority can be obtained while meeting the guarantee rate and destruction depth requirements of various water supply tasks; on this basis, the discount coefficients of each water supply object and each time period are optimized, and the water supply of the reservoir can be increased under the condition of unchanged beneficial storage capacity. The reliability and rationality of the method proposed by the present invention are proved by testing and analyzing the method proposed by the present invention, which is of great significance for determining the economically reasonable scale of the reservoir, meets the needs of determining the scale of the reservoir, and the results obtained are intuitive and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a flow chart of a preferred embodiment of a method for determining the scale of reservoir benefits based on double-layer step-by-step calculation according to the present invention.

[0071] Figure 2It is a flow chart of another preferred embodiment of the method for determining the scale of reservoir benefits based on double-layer step-by-step calculation according to the present invention.

[0072] Figure 3 The present invention is a flow chart of an embodiment of a method for solving the optimization model I of the method for determining the scale of reservoir benefits based on double-layer step-by-step trial calculations according to the present invention.

[0073] Figure 4 The present invention is a flow chart of an embodiment of a method for solving the optimization model II of the method for determining the scale of reservoir benefits based on double-layer step-by-step trial calculation according to the present invention. DETAILED DESCRIPTION

[0074] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0075] Embodiment 1

[0076] like Figure 1 As shown, a method for determining the scale of reservoir benefits based on double-layer step-by-step calculation executes step 100 to collect basic reservoir data and constraints for determining the beneficial storage capacity, wherein the basic reservoir data includes at least one of inflow runoff, various water supply demands, water level-area-capacity curve, evaporation increase and loss curve, time period leakage coefficient, dead water level and ecological flow decentralization demand.

[0077] The constraints include reservoir water level constraints, guarantee rate constraints and maximum damage depth constraints. The reservoir water level constraints are:

[0078] Z i ∈[Z min ,Z max ]

[0079] Among them, Z i is the water level of the reservoir in period i, Z min is the dead water level of the reservoir, Z max This is the normal water level of the reservoir.

[0080] The guaranteed rate constraint is

[0081] P j ∈[P min,j ,1]

[0082] Among them, P j is the guaranteed rate of water supply object j, P min,j Allow a minimum guaranteed rate for water supply object j.

[0083] The maximum damage depth constraint is

[0084] B i,j ∈[0,B max,j ]

[0085] Among them, B i,j is the damage depth of water supply object j in time period i, B max,j The maximum damage depth allowed for water supply object j.

[0086] Step 110 is executed to determine the maximum beneficial storage capacity V0 required for each water supply to not damage the water supply, using a dichotomy method, including the following sub-steps:

[0087] Execute step 111 to preliminarily calculate the maximum beneficial storage capacity V 0max and the minimum beneficial storage capacity V 0min , V 0max and V 0min V 0max ≥V0 and V0≥V 0min ≥0.

[0088] Execute step 112, set the beneficial storage capacity V0 = (V 0max +V 0min ) / 2, using the undiscounted water demand series for reservoir regulation calculations.

[0089] Execute step 113, if the minimum storage capacity of the long series reservoir V min >V dead , then let V 0max =V0, if the minimum storage capacity of the long series reservoir is V min ≤V dead , then let V 0min =V0, where V dead It is the dead storage capacity of the reservoir.

[0090] Execute step 114 to determine V 0max -V 0min Whether the calculation accuracy is achieved, when V 0max -V 0min If it is greater than the calculation accuracy, step 112 is executed again. 0max -V 0min When it is less than or equal to the calculation accuracy, V0 is confirmed to be the maximum beneficial storage capacity required for all water supply items not to be damaged.

[0091] Execute step 120 to calculate the number of time periods that each water supply object may be damaged, and formulate the damage order of the water supply objects. The number of time periods that can be discounted is divided into the number of discountable years N according to the different guarantee rate requirements of the water supply objects. byear and the number of discounted durations N bdia ,

[0092] N byear =(1-P)NP

[0093] N bdia =(1-P)nP

[0094] Among them, N is the number of long series years, P is the design guarantee rate, and n is the number of time periods.

[0095] The destruction order is arranged according to the importance of the water supply objects, and water supply objects with low water supply priorities are destroyed first.

[0096] Step 130 is executed to destroy the minimum storage capacity V of the subsequent long series. min The maximum is the goal, and the optimization model I is established. The water demand process of each water supply object is discounted in each period by using the successive optimization algorithm to solve the optimization model I:

[0097] V min =min(v1,v3,v2,…,v n )

[0098] Among them, V min is the minimum storage capacity of the long series reservoir, v i is the storage capacity of the reservoir at the end of the i-th period.

[0099] The step 130 includes the following sub-steps:

[0100] Execute step 131 to set the discounted water supply object j=1.

[0101] Execute step 132 to find the storage capacity V at the end of the minimum period of the long series min and the time period t in which it is located.

[0102] Execute step 133 to discount the water demand of water supply object j starting from time period t.

[0103] 1) When the current water supply object requires an annual guarantee rate, the maximum damage depth is discounted from period t to the beginning of the year in which period t is located.

[0104] 2) When the water level at the beginning of the period is normal, the forward discount is stopped.

[0105] 3) When the current water supply object requires a guarantee rate type of time guarantee rate, the t period is discounted.

[0106] Execute step 134, use the discounted water demand series to perform long series regulation calculation, and find the minimum storage capacity V at the end of the long series period min and the time period t in which it is located. When the time period in which the minimum storage capacity at the end of the time period is located has not changed, execute step 135. When the time period in which the minimum storage capacity at the end of the time period is located has changed, update the minimum storage capacity and the time period in which it is located, and execute step 136.

[0107] Execute step 135 to determine whether the initial water level during the discount period is the normal water level corresponding to the maximum beneficial storage capacity V0.

[0108] When the water level has been reduced to the normal level, execute step 137;

[0109] When it is not discounted to the normal storage level, update t. When the required guarantee rate type is the duration guarantee rate, let t = t - 1. When the required guarantee rate type is the annual guarantee rate, t is updated to the end of the previous year.

[0110] Execute step 136 to calculate the number of discounted periods. When the number of discounted periods is less than the number of periods that can be discounted, re - execute step 132. When the number of discounted periods is equal to the number of periods that can be discounted, execute step 137.

[0111] Execute step 137. When j < m, then j = j + 1 and re - execute step 132. When j = m, then end step 130, where m is the number of water supply objects.

[0112] Execute step 140 and use the bisection method to determine the required beneficial storage capacity V after water demand discounting for each water supply object op , including the following sub - steps:

[0113] Execute step 141 to initially estimate the maximum beneficial storage capacity V for trial calculation maxop and the minimum beneficial storage capacity V minop , where V maxop = V0, V minop needs to satisfy V op ≥V minop ≥0.

[0114] Execute step 142 and let the beneficial storage capacity V op =(V maxop +V minop ) / 2, and use the discounted water demand series to perform reservoir regulation calculations.

[0115] Execute step 143. If the minimum storage capacity V of the long - series reservoir min >V dead , then let V maxop =V op . If the minimum storage capacity V of the long - series reservoir min ≤V dead , then let V minop =V op .

[0116] Execute step 144 to judge whether V maxop −V minop reaches the calculation accuracy. When V maxop −V minop is greater than the calculation accuracy, then re - execute step 142. When V maxop −V minop is less than or equal to the calculation accuracy, then confirm that V op is the required beneficial storage capacity of the reservoir.

[0117] Execute step 150 to formulate an optimization sequence of water supply quantity for water supply objects. The optimization sequence of water supply quantity for water supply objects is arranged according to the importance of water supply objects, and water supply objects with high water supply priority are optimized first.

[0118] Execute step 160, take the maximum long series total water supply W as the goal, establish optimization model II, use the successive optimization algorithm to optimize the discount coefficient in each time period, solve optimization model II, and calculate the optimized long series total water supply W, including the following sub-steps:

[0119] Execute step 161, set the water demand discount coefficient of each water supply object in the discount period between [0,B max,j ] interval, they are discretized into r water demands, where r is the discrete number of water demands;

[0120] Execute step 162, set the optimized water supply object j=1, and the calculation period i=1;

[0121] Execute step 163 to determine whether the water demand of the water supply object is discounted during the current period. If it is discounted, set k=r and execute step 164.

[0122] When there is no discount, let i=i+1 and execute step 65, where k is a discrete number;

[0123] Execute step 164 to calculate the minimum storage capacity V of the long series min , if V min <V dead , then let k = k + 1, let i = i + 1, if V min ≥V dead , then let k = k-1, and repeat this step until k = 0 and let i = i+1;

[0124] Execute step 165, if i>n, set j=j+1, if i≤n, execute step 163, where n is the number of time periods;

[0125] Execute step 166. If j≤m, execute step 163. If i>n, calculate the total water supply W of the long series and end step 160.

[0126] The k-th discrete water demand of the j-th water supply object in the i-th period w i,j,k for

[0127] w i,j,k =(1-k / r·B max,j ) i,j,r

[0128] Among them, r is the discrete quantity of water demand, w i,j,r It is the undiscounted water demand of the jth water supply object in the i-th period.

[0129] The calculation formula for the total water supply W of the long series is:

[0130]

[0131] Among them, w i,j The water supply volume for the jth water supply object in the i-th period.

[0132] Embodiment 2

[0133] The purpose of the present invention is to provide an optimization method for determining the beneficial storage capacity of a comprehensive utilization reservoir based on a double-layer step-by-step trial calculation. Under the premise of meeting the guarantee rate of each water supply object and the maximum damage depth requirements, the destruction order of different water supply objects is determined. Through a double-layer step-by-step trial calculation, the minimum beneficial storage capacity of the reservoir that meets various constraints is obtained, and the reservoir water supply process is optimized, thereby reasonably determining the beneficial storage capacity and water supply of the reservoir.

[0134] The technical solution adopted by the present invention is as follows:

[0135] like Figure 2 As shown, a method for optimizing the storage capacity of comprehensive reservoir utilization based on double-layer step-by-step trial calculation includes the following steps.

[0136] S1. Collect basic information of reservoirs and constraints for determining the beneficial storage capacity;

[0137] S2. Use the dichotomy method to determine the maximum beneficial storage capacity V0 required for each water supply to be completely undamaged;

[0138] S3. Calculate the number of time periods during which each water supply object may be damaged and formulate the order of damage to the water supply objects;

[0139] S4. Minimum storage capacity V after destruction min The maximum is the goal, and the optimization model I is established. The water demand process of each water supply object is discounted in each period by using the successive optimization algorithm to solve the optimization model I:

[0140] V min =min(v1,v3,v2,…,v n )

[0141] Among them, V min is the minimum storage capacity of the long series reservoir, v i is the storage capacity of the reservoir at the end of the i-th period;

[0142] S5. Use the dichotomy method to determine the water demand of each water supply object after the discount does not completely destroy the required beneficial storage capacity V op ;

[0143] S6. Formulate an optimal sequence of water supply to water supply objects;

[0144] S7. Taking the maximum total water supply W in the long series as the goal, establish optimization model II, use the successive optimization algorithm to optimize the discount coefficient in each period, solve optimization model II, and calculate the total water supply W in the long series:

[0145]

[0146] Among them, n is the number of time periods, m is the number of water supply objects, and w i,j The water supply volume for the jth water supply object in the i-th period.

[0147] The basic data of step S1 include inflow runoff, various water supply requirements, water level-area-storage capacity curve, evaporation increase and loss curve, leakage coefficient during the period, dead water level, ecological flow decentralization requirements, etc.;

[0148] The constraints include:

[0149] ① Reservoir water level constraints:

[0150] Z i ∈[Z min ,Z max ]

[0151] Among them, Z i is the water level of the reservoir in period i, Z min is the dead water level of the reservoir, Z max is the normal water level of the reservoir, which changes with the calculated beneficial storage capacity;

[0152] ② Guarantee rate constraint

[0153] P j ∈[P min,j ,1]

[0154] Among them, P j is the guarantee rate of water supply object j;

[0155] P min,j Allow a minimum guaranteed rate for water supply object j;

[0156] ③ Maximum damage depth constraint

[0157] B i,j ∈[0,B max,j ]

[0158] Among them, B i,j is the damage depth of water supply object j in time period i;

[0159] B max,j The maximum damage depth allowed for water supply object j.

[0160] The specific steps of step S2 are:

[0161] S2-1. Preliminary calculation of the maximum beneficial storage capacity V 0max and the minimum beneficial storage capacity V 0min , V 0max and V 0min V 0max ≥V0 and V0≥V 0min ≥0;

[0162] S2-2. Let the benefit storage capacity V0 = (V 0max +V 0min ) / 2, using the undiscounted water demand series for reservoir regulation calculations;

[0163] S2-3. Minimum storage capacity of Ruochang series reservoirs V min >V dead , then let V 0max =V0, if the minimum storage capacity of the long series reservoir is V min ≤V dead , then let V 0min =V0,

[0164] Among them, V dead It is the dead storage capacity of the reservoir;

[0165] S2-4. Determine V 0max -V 0min Whether the calculation accuracy is met, if not, go to step S2-2, if the calculation accuracy is met, then V0 is the maximum beneficial storage capacity required for all water supplies to not damage the water supply.

[0166] In a further preferred solution, the number of discounted time periods in step S3 is divided into the number of discounted years N according to the different requirements of the water supply object for the guarantee rate. byear and the number of discounted durations N bdia ;

[0167] N byear =(1-P)NP

[0168] N bdia =(1-P)nP

[0169] Where N is the number of long series years, and P is the design guarantee rate;

[0170] The destruction order is arranged according to the importance of the water supply objects, and water supply objects with low water supply priorities are destroyed first.

[0171] like Figure 3 As shown, the specific steps of step S4 are:

[0172] S4-1. Let discounted water supply object j = 1;

[0173] S4-2. Find the minimum storage capacity V at the end of a long series of periodsmin and its corresponding time period t;

[0174] S4-3. Starting from time period t, discount the water demand of water supply object j forward. If the required guarantee rate type is annual guarantee rate, then discount from time period t to the beginning of the year of the year where time period t is located according to the maximum damage depth. If a time period with the normal storage level at the beginning of the time period is encountered, stop discounting forward; if the required guarantee rate type is duration guarantee rate, then only discount time period t;

[0175] S4-4. Use the discounted water demand series to perform long series regulation calculations, and find the minimum reservoir storage capacity V at the end of the long series min and its corresponding time period t. If the time period where the minimum reservoir storage capacity at the end of the time period has not changed, go to step S4-5. If the time period where the minimum reservoir storage capacity at the end of the time period has changed, update the minimum reservoir storage capacity and its corresponding time period, and go to step S4-6;

[0176] S4-5. Judge whether the water level at the beginning of the discounted time period is the normal storage level corresponding to the maximum beneficial storage capacity V0. If it has been discounted to the normal storage level, it means that the water demand of this water supply object cannot further reduce the beneficial storage capacity even if the water demand is further discounted, and go to step S4-7. If it has not been discounted to the normal storage level, update t. For the required guarantee rate type of duration guarantee rate, let t = t - 1. For the required guarantee rate type of annual guarantee rate, t is updated to the end of the previous year, and go to step S4-6;

[0177] S4-6. Calculate the number of discounted time periods. If the number of discounted time periods is less than the number of time periods that can be discounted, go to S4-2. If the number of discounted time periods is equal to the number of time periods that can be discounted, go to S4-7;

[0178] S4-7. If j < m, then j = j + 1, go to S4-2. If j = m, then end step S4.

[0179] Since after the aforementioned steps are completed, it is actually a process of gradually increasing the minimum reservoir storage capacity in the long series under the condition that the maximum beneficial storage capacity V0 required for complete non-destruction of each water supply is actually achieved, and the evaporation and leakage losses corresponding to different water levels are different, so the difference between V0 and V min cannot be directly used as the beneficial storage capacity. To obtain the minimum beneficial storage capacity that meets the requirements, it is necessary to further perform trial calculations under the condition of the established water demand discount series in the above steps. The specific steps of step S5 are as follows:

[0180] S5-1. Initially assume the maximum beneficial storage capacity V maxop = V0, the minimum beneficial storage capacity V maxop ,

[0181] V maxop needs to satisfy V op ≥V minop ≥0;

[0182] S5-2. Lingxingli Storage Capacity V op =(V maxop +V minop ) / 2, using the discounted water demand series to calculate reservoir regulation;

[0183] S5-3. Minimum storage capacity of Ruochang series reservoirs V min >V dead , then let V maxop =V op , if the minimum storage capacity of the Chang series reservoir is V min ≤V dead , then let V minop =V op ;

[0184] S5-4. Determine V maxop -V minop If the calculation accuracy is not met, go to step S5-2. If the calculation accuracy is met, then V op This is the beneficial storage capacity of the reservoir that needs to be determined.

[0185] In step S6, the optimization order of water supply quantity to water supply objects is arranged according to the importance of the water supply objects, and water supply objects with high water supply priority are optimized first.

[0186] like Figure 4 As shown, the specific steps of step S7 are:

[0187] S7-1. Set the water demand discount coefficient of each water supply object in the discount period between [0,B max,j ] interval, and are discretized into r water demands:

[0188] w i,j,k =(1-k / r·B max,j ) i,j,r

[0189] Among them, r is the discrete quantity of water demand;

[0190] w i,j,k is the water demand after the kth discretization for the jth water supply object in the i-th period;

[0191] w i,j,r is the undiscounted water demand of the jth water supply object in the i-th period;

[0192] S7-2. Let the optimized water supply object j = 1, calculation period i = 1;

[0193] S7-3. Determine whether the water supply object needs water at a discount in the current period. If it is discounted, let k = r and go to step S7-4. If it is not discounted, let i = i + 1 and go to step S7-5.

[0194] This step is used to avoid optimizing the undiscounted water demand period, which can increase the calculation speed;

[0195] 7-4. Calculation of the minimum storage capacity V of the long series min , if V min <V dead , then let k = k + 1, let i = i + 1, if V min ≥V dead , then let k = k-1, and repeat this step until k = 0 and let i = i+1;

[0196] S7-5. If i>n, let j=j+1, if i≤n, go to step S7-3;

[0197] S7-6. If j≤m, go to step S7-3; if i>n, calculate the total water supply W of the long series and end step S7.

[0198] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: for a comprehensive utilization reservoir that undertakes multiple tasks, the present invention proposes a method for optimizing the beneficial storage capacity of a comprehensive utilization reservoir based on a double-layer step-by-step trial calculation. On the basis of completely not destroying the required beneficial storage capacity, the required beneficial storage capacity of the reservoir is reduced by gradually finding the water supply damage period, and the minimum beneficial storage capacity of the reservoir under the given water supply priority can be obtained while meeting the guarantee rate and damage depth requirements of various water supply tasks; on this basis, the discount coefficients for each water supply object and each time period are optimized, and the water supply of the reservoir can be increased under the condition that the beneficial storage capacity remains unchanged. The reliability and rationality of the method proposed by the present invention are proved by testing and analyzing the method proposed by the present invention, which is of great significance for determining the economically reasonable scale of the reservoir, meets the needs of determining the scale of the reservoir, and the results obtained are intuitive and practical.

[0199] Embodiment 3

[0200] Take a certain reservoir as an example. The water supply objects of the reservoir are urban and rural water supply, agricultural irrigation and ecological water replenishment. The regulation calculation adopts a series of 52 years, and the regulation calculation is based on ten-day regulation. The number of time periods n = 52 × 36 = 1872. The technical solution of the method for determining the beneficial storage capacity of the reservoir and optimizing the water supply based on double-layer step-by-step trial calculation of the present invention is as follows:

[0201] The following steps are involved:

[0202] S1. Collect basic information of reservoirs and constraints for determining the beneficial storage capacity;

[0203] S2. Use the dichotomy method to determine the maximum beneficial storage capacity V0 required for each water supply to be completely undamaged;

[0204] S3. Calculate the number of time periods during which each water supply object may be damaged and formulate the order of damage to the water supply objects;

[0205] S4. Minimum storage capacity V after destruction min The maximum is the goal, and the optimization model I is established. The water demand process of each water supply object is discounted in each period by using the successive optimization algorithm to solve the optimization model I:

[0206] V min =min(v1,v3,v2,…,v n )

[0207] Among them, V min It is the minimum storage capacity of a long series of reservoirs;

[0208] v i is the storage capacity of the reservoir at the end of the i-th period;

[0209] S5. Use the dichotomy method to determine the required beneficial storage capacity V after the water demand of each water supply object is discounted. op ;

[0210] S6. Formulate an optimal sequence of water supply to water supply objects;

[0211] S7. Taking the maximum total water supply W of the long series as the goal, establish optimization model II, use the successive optimization algorithm to optimize the discount coefficient in each period, solve optimization model II, and calculate the total water supply W of the long series after optimization:

[0212]

[0213] Among them, w i,j is the water supply volume of the jth water supply object in the i-th period.

[0214] The specific steps of step S1 are:

[0215] First, we collect the reservoir runoff, various water supply requirements, water level-area-storage capacity curve, evaporation increase and loss curve, leakage coefficient during the period, dead water level, ecological flow decentralization requirements, etc. The constraints include:

[0216] ① Reservoir water level constraints:

[0217] Z i ∈[Z min ,Z max ]

[0218] Among them, Z i is the water level of the reservoir in period i, Z min is the dead water level of the reservoir, Z max is the normal water level of the reservoir, which changes with the calculated beneficial storage capacity;

[0219] ② Guarantee rate constraint

[0220] P j ∈[Pmin,j ,1]

[0221] Among them, P j is the guarantee rate of water supply object j;

[0222] P min,j Allow a minimum guaranteed rate for water supply object j;

[0223] The urban and rural water supply requires a guaranteed rate of no less than 95% over time, the agricultural irrigation requires an annual guaranteed rate of no less than 85%, and the ecological water replenishment requires a guaranteed rate of no less than 90% over time;

[0224] ③ Maximum damage depth constraint

[0225] B i,j ∈[0,B max,j ]

[0226] Among them, B i,j is the damage depth of water supply object j in time period i;

[0227] B max,j The maximum damage depth allowed for water supply object j;

[0228] The urban and rural water supply requirement is that the depth of damage is no more than 30%, the agricultural irrigation requirement is that the depth of damage is no more than 50%, and the ecological water replenishment requirement is that the depth of damage is no more than 50%.

[0229] The specific steps of step S2 are:

[0230] S2-1. Preliminary calculation of the maximum beneficial storage capacity V 0max and the minimum beneficial storage capacity V 0min , V 0max and V 0min V 0max ≥V0 and V0≥V 0min ≥0;

[0231] S2-2. Let the benefit storage capacity V0 = (V 0max +V 0min ) / 2, using the undiscounted water demand series for reservoir regulation calculations;

[0232] S2-3. Minimum storage capacity of Ruochang series reservoirs V min >V dead , then let V 0max =V0, if the minimum storage capacity of the long series reservoir is V min ≤V dead , then let V 0min =V0;

[0233] Among them, V dead It is the dead storage capacity of the reservoir;

[0234] S2-4. Determine V 0max -V 0min Whether the calculation accuracy is met, if not, go to step S2-2, if the calculation accuracy is met, then V0 is the maximum beneficial storage capacity required for all water supplies to not damage the water supply.

[0235] The number of discounted time periods in step S3 is divided into the number of discounted years N according to the different guarantee rate requirements of the water supply object. byear and the number of discounted durations N bdia :

[0236] N byear =(1-P)×52-P

[0237] N bdia =(1-P)×1872-P

[0238] The number of years that urban and rural water supply can be discounted is 92 decades, the number of years that agricultural irrigation can be discounted is 11 years, and the number of years that ecological water replenishment can be discounted is 46 decades.

[0239] The discount order is arranged according to the importance of the water supply objects, and the discount order is agricultural irrigation, ecological water replenishment, and urban and rural water supply.

[0240] The specific steps of step S4 are:

[0241] S4-1. Let the discounted water supply object j = 1, giving priority to discounted agricultural irrigation water demand;

[0242] S4-2. Find the minimum storage capacity V at the end of a long series of periods min and the time period t in which it is located;

[0243] S4-3. Starting from period t, the water demand of water supply object j is discounted. If the required guarantee rate type is the annual guarantee rate, the water demand is discounted from period t to the beginning of the year of period t according to the maximum damage depth. If the beginning of the period is a period with normal water storage level, the forward discount is stopped; if the required guarantee rate type is the historical guarantee rate, only the period t is discounted;

[0244] S4-4. Use the discounted water demand series to perform long series regulation calculations and find the minimum storage capacity V at the end of the long series period min and the period t in which it is located. If the period in which the minimum storage capacity at the end of the period is located has not changed, go to step S4-5. If the period in which the minimum storage capacity at the end of the period is located has changed, update the minimum storage capacity and the period in which it is located, and go to step S4-6.

[0245] S4-5. Determine whether the initial water level of the discounted period is the normal water level corresponding to the maximum beneficial storage capacity V0. If it has been discounted to the normal water level, it means that the water supply object cannot further reduce the beneficial storage capacity by further discounting the water demand, and go to step S4-7. If it has not been discounted to the normal water level, update t. For the required guarantee rate type of the historical guarantee rate, set t = t-1. For the required guarantee rate type of the annual guarantee rate, update t to the end of the previous year, and go to step S4-6.

[0246] S4-6. Calculate the number of discounted time periods. If the number of discounted time periods is less than the number of discounted time periods, go to S4-2. If the number of discounted time periods is equal to the number of discounted time periods, go to S4-7.

[0247] S4-7. If j<3, then j=j+1, go to S4-2, continue to discount ecological water replenishment or urban and rural water supply, if j=3, end step S4.

[0248] The specific steps of step S5 are:

[0249] S5-1. Preliminary calculation of the maximum beneficial storage capacity V maxop =V0, minimum beneficial storage capacity V minop ,

[0250] V minop Need to meet V op ≥V minop ≥0;

[0251] S5-2. Lingxingli Storage Capacity V op =(V maxop +V minop ) / 2, using the discounted water demand series to calculate reservoir regulation;

[0252] S5-3. Minimum storage capacity of Ruochang series reservoirs V min >V dead , then let V maxop =V op , if the minimum storage capacity of the Chang series reservoir is V min ≤V dead , then let V minop =V op ;

[0253] S5-4. Determine V maxop -V minop If the calculation accuracy is not met, go to step S5-2. If the calculation accuracy is met, then V op This is the beneficial storage capacity of the reservoir that needs to be determined.

[0254] In step S6, the optimization order of water supply volume of water supply objects is arranged according to the importance of water supply objects, and the optimization order is urban and rural water supply, ecological water replenishment, and agricultural irrigation.

[0255] The specific steps of step S7 are:

[0256] S7-1. Set the water demand discount coefficient of each water supply object in the discount period between [0,B max,j ] interval, it is discretized into 10 water demands:

[0257] w i,j,k =(1-k / 10·B max,j ) i,j,r

[0258] Among them, w i,j,k is the water demand after the kth discretization for the jth water supply object in the i-th period;

[0259] w i,j,10 is the undiscounted water demand of the jth water supply object in the i-th period;

[0260] S7-2. Let the optimized water supply object j = 1, calculation period i = 1, first optimize the urban and rural water supply;

[0261] S7-3. Determine whether the water supply object needs water at a discount during the current period. If so, set k = 10 and go to step S7-4. If not, set i = i + 1 and go to step S7-5.

[0262] S7-4. Calculate the minimum storage capacity V of the long series min , if V min <V dead , then let k = k + 1, let i = i + 1, if V min ≥V dead , then let k = k-1, and repeat this step until k = 0 and let i = i+1;

[0263] S7-5. If i>1872, set j=j+1 and continue to optimize ecological water replenishment or agricultural irrigation. If i≤1872, go to step S7-3;

[0264] S7-6. If j≤3, go to step S7-3; if i>2, calculate the total water supply W of the long series and end step S7.

[0265] In order to better understand the present invention, the above is described in detail in conjunction with the specific embodiments of the present invention, but it is not intended to limit the present invention. Any simple modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention. Each embodiment in this specification focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other. For the system embodiment, since it basically corresponds to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

Claims

1. A method for determining the beneficial storage capacity of a reservoir based on double - layer step - by - step trial calculation, including collecting the basic data of the reservoir and the constraint conditions for determining the beneficial storage capacity, and also including the following steps: Step 1: Use the bisection method to determine the maximum beneficial storage capacity V0 required for no water supply disruption for each item, including the following sub - steps: Step 11: Preliminary calculation of the maximum beneficial storage capacity V 0max and the minimum beneficial storage capacity V 0min , V 0max and V 0min V 0max ≥V0 and V0≥V 0min ≥0; Step 12: Let the beneficial storage capacity V0 = (V 0max +V 0min ) / 2, using the undiscounted water demand series for reservoir regulation calculations; Step 13: If the minimum storage capacity of the series reservoir is V min >V dead , then let V 0max =V0, if the minimum storage capacity of the long series reservoir is V min ≤V dead , then let V 0min =V0, where V dead It is the dead storage capacity of the reservoir; Step 14: Determine V 0max -V 0min Whether the calculation accuracy is achieved, when V 0max -V 0min If it is greater than the calculation accuracy, then re-execute step 12. 0max -V 0min If it is less than or equal to the calculation accuracy, V0 is confirmed to be the maximum beneficial storage capacity required for all water supplies to not damage the water supply. Step 2: Calculate the number of periods when each water supply object may be disrupted, and draw up the disruption sequence of the water supply objects; Step 3: Take the minimum storage capacity V after the destruction min The maximum is the goal, and the optimization model I is established. The water demand process of each water supply object is discounted in each period by using the successive optimization algorithm to solve the optimization model I: V min =min(v1,v3,v2,…,v n ) Among them, V min is the minimum storage capacity of the long series reservoir, v i is the storage capacity of the reservoir at the end of the i-th period, and n is the number of periods; Step 4: Use the dichotomy method to determine the required beneficial storage capacity V after the water demand of each water supply object is discounted. op ; Step 5: Draw up the optimization sequence of the water supply amounts of the water supply objects; Step 6: Take the maximum total long - series water supply W as the goal, establish Optimization Model II, use the successive optimization algorithm to optimize the discount coefficient period by period, solve Optimization Model II, and calculate the optimized total long - series water supply W.

2. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 1, characterized in that: The constraint conditions include reservoir water level constraints, guarantee rate constraints, and maximum damage depth constraints. The reservoir water level constraint is Z i ∈[Z min ,Z max ] Among them, Z i is the water level of the reservoir in period i, Z min is the dead water level of the reservoir, Z max The normal water level of the reservoir; The guaranteed rate constraint is P j ∈[P min,j ,1] Among them, P j is the guaranteed rate of water supply object j, P min,j The minimum guarantee rate allowed for water supply object j; the maximum damage depth constraint is B i,j ∈[0,B max,j ] Among them, B i,j is the damage depth of water supply object j in time period i, B max,j The maximum damage depth allowed for water supply object j.

3. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 2, characterized in that: In step 2, the number of discounted periods is divided into the number of discounted years N according to the different guarantee rate requirements of the water supply object. byear and the number of discounted durations N bdia , N byear =(1-P)N-P N bdia =(1-P)n-P Among them, N is the number of years in the long series, and P is the design guarantee rate. The disruption sequence is arranged according to the importance of the water supply objects, and the water supply objects with lower water supply priority are preferentially disrupted.

4. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 3 is characterized in that: The said Step 3 includes the following sub - steps: Step 31: Set the discounted water supply object j = 1; Step 32: Find the storage capacity V at the end of the minimum period in the long series min and the time period t in which it is located; Step 33: Starting from period t, discount the water demand of water supply object j forward; Step 34: Use the discounted water demand series to perform long series regulation calculations and find the minimum storage capacity V at the end of the long series period min and the period t in which it is located. When the period in which the minimum storage capacity at the end of the period is located does not change, execute step 35. When the period in which the minimum storage capacity at the end of the period is located changes, update the minimum storage capacity and the period in which it is located, and execute step 36. Step 35: Judge whether the water level at the beginning of the discounted period is the normal storage level corresponding to the maximum beneficial storage capacity V0. When it has been discounted to the normal storage level, execute Step 37; When it has not been discounted to the normal storage level, update t. When the required guarantee rate type is the duration guarantee rate, let t = t - 1; when the required guarantee rate type is the annual guarantee rate, t is updated to the end of the previous year. Step 36: Calculate the number of discounted periods. When the number of discounted periods is less than the number of periods that can be discounted, re - execute Step 32. When the number of discounted periods is equal to the number of periods that can be discounted, execute Step 37; Step 37: When j < m, then j = j + 1, re - execute Step 32. When j = m, then end Step 3, where m is the number of water supply objects.

5. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 4, characterized in that: The said Step 33 includes: 1) When the required guarantee rate type of the current water supply object is the annual guarantee rate, discount from period t to the beginning of the year in which period t is located according to the maximum damage depth. 2) When encountering a period with a normal storage level at the beginning of the period, stop discounting forward. 3) When the required guarantee rate type of the current water supply object is the duration guarantee rate, discount period t.

6. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 5, characterized in that: The said Step 4 includes the following sub - steps: Step 41: Preliminary calculation of the maximum beneficial storage capacity V maxop and the minimum beneficial storage capacity V minop , where V maxop =V0,V minop Need to meet V op ≥V minop ≥0; Step 42: Set the storage capacity V op =(V maxop +V minop ) / 2, using the discounted water demand series to calculate reservoir regulation; Step 43: If the minimum storage capacity of the series reservoir is V min >V dead , then let V maxop =V op , if the minimum storage capacity of the Chang series reservoir is V min ≤V dead , then let V minop =V op ; Step 44: Determine V maxop -V minop Is it less than the calculation accuracy? maxop -V minop If it is greater than the calculation accuracy, step 42 is executed again. maxop -V minop If it is less than or equal to the calculation accuracy, then confirm V op This is the beneficial storage capacity of the reservoir that needs to be determined.

7. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 6, characterized in that: In the said Step 5, the optimization sequence of the water supply amounts of the water supply objects is arranged according to the importance of the water supply objects, and the water supply objects with higher water supply priority are preferentially optimized.

8. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 7, characterized in that: The said Step 6 includes the following sub - steps: Step 61: Set the water demand discount coefficient of each water supply object in the discount period between [0,B max,j ] interval, they are discretized into r water demands, where r is the discrete number of water demands; Step 62: Let the optimized water supply object j = 1, and calculate the period i = 1; Step 63: Judge whether the water demand of this water supply object in the current period is discounted. When it has been discounted, let k = r, and execute Step 64. When it has not been discounted, let i = i + 1, and execute Step 65, where k is the discrete serial number of the water demand. Step 64: Calculate the minimum storage capacity V of the long series min , if V min <V dead , then let k = k + 1, let i = i + 1, if V min ≥V dead , then let k = k-1, and repeat this step until k = 0 and let i = i+1; Step 65: If i > n, then let j = j + 1. If i ≤ n, execute Step 63, where n is the number of periods. Step 66: If j ≤ m, then execute Step 63. If i > n, then calculate the total long - series water supply W and end Step 6.

9. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 8, characterized in that: The k-th discrete water demand of the j-th water supply object in the i-th period w i,j,k for w i,j,k =(1-k / r·B max,j )w i,j,r Among them, r is the discrete quantity of water demand, w i,j,r It is the undiscounted water demand of the jth water supply object in the i-th period.

10. The method for determining the scale of reservoir benefits based on double-layer step-by-step calculation as claimed in claim 9, characterized in that: The calculation formula for the total long - series water supply W is Among them, w i,j The water supply volume for the jth water supply object in the i-th period.

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