Cascade reservoir group water storage scheduling method under ultra-low water condition

Abstract

The invention relates to a cascade reservoir group water storage scheduling method under an extra-low water condition, which comprises the following steps of: judging whether a cascade reservoir group has a risk of insufficient storage according to incoming water prediction, a minimum water level constraint, a minimum output flow constraint and a water storage target of each reservoir at the end of a water storage period, and if so, starting the cascade reservoir group water storage scheduling under the extra-low water condition; taking the minimum weighted sum of the difference between the highest water level of the cascade reservoir group in the scheduling period and the water storage target as a first scheduling target, taking the maximum sum of the generating capacity and the energy storage value of the cascade reservoir group as a second scheduling target, and establishing a cascade reservoir group water storage scheduling model without setting the end water level of the scheduling period; and solving to obtain a scheduling scheme with the maximum water storage satisfaction degree of the cascade reservoir group. The method can be used for coordinating the water storage processes of all the reservoirs under the ultra-low water condition, the cascade reservoirs can complete the water storage task to the maximum extent, and the overall cascade power generation benefits are considered.

Description

Technical Field

[0001] The invention belongs to the technical field of reservoir group dispatching, and in particular relates to a method for dispatching water storage of a cascade reservoir group under extremely low water conditions. Background Art

[0002] For reservoirs with strong regulation performance, their annual scheduling is usually divided into the drawdown period, flood season, and water storage period. Different periods have different scheduling goals and tasks. Water storage usually occurs at the end of the flood season. Reservoirs use flood resources to store water to meet the needs of water supply, irrigation, power generation, etc. in the later period, and give full play to the comprehensive benefits of reservoirs. In recent years, extreme weather has occurred frequently, bringing a series of risks and challenges to reservoir scheduling. Extreme drought events have gradually highlighted the risk of reservoirs not being fully filled, especially after the establishment of large-scale reservoir groups. The reservoir groups are large in scale and large in number, and the water storage pressure has further increased. Some reservoirs need to store water in advance, while others need to postpone water storage. How to take into account the water storage needs of each reservoir and coordinate the water storage process while meeting the downstream flow demand, so as to maximize the completion of the water storage task of the cascade reservoirs and maintain a high storage capacity is a key technical issue facing the field of reservoir scheduling. In the research on water storage and scheduling of reservoir groups, most studies focus on the scheduling problems that take into account both flood control tasks and water storage targets under normal or abundant water conditions, but rarely involve research on water resource scheduling strategies for reservoir groups under extremely low water conditions, and there is also a lack of corresponding water storage scheduling models and methods to support them. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for water storage scheduling of a cascade reservoir group under extremely low water conditions, so as to coordinate the water storage progress of each reservoir and improve the water storage rate of the cascade reservoir group.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] A method for water storage dispatching of cascade reservoirs under extremely low water conditions, comprising the following steps:

[0006] S1: Based on the water inflow forecast, minimum water level constraint, minimum outflow constraint and the water storage target of each reservoir at the end of the water storage period, determine whether the cascade reservoir group has the risk of not being fully stored. If so, activate the water storage dispatch of the cascade reservoir group under the extremely low water condition;

[0007] S2, in the case of insufficient storage risk, the first scheduling target is to minimize the weighted sum of the gaps between the highest water level of the cascade reservoir group during the scheduling period and the water storage target, and the second scheduling target is to maximize the sum of the power generation and energy storage value of the cascade reservoir group. Without setting the water level at the end of the scheduling period, a water storage scheduling model for the cascade reservoir group is established, and the scheduling plan with the maximum water storage satisfaction of the cascade reservoir group is solved.

[0008] Preferably, the method for determining the risk of insufficient storage is:

[0009] (1) The reservoir group is composed of reservoir 1, reservoir 2, ..., reservoir n from upstream to downstream;

[0010] (2) For any reservoir i, the maximum available water volume of reservoir i is calculated as the total natural water inflow from upstream during the impoundment period of reservoir i – the minimum water storage volume of the reservoir group above reservoir i at the end of the impoundment period – the minimum total water discharge volume of reservoir i; where i = 1, 2, ..., n;

[0011] (3) Calculate the water storage capacity of reservoir i = the storage target corresponding to reservoir i – the storage capacity corresponding to the initial water level of reservoir i;

[0012] (4) If the maximum available water volume of reservoir i is less than the water volume to be stored in reservoir i, it means that reservoir i is at risk of not being fully stored;

[0013] (5) If the proportion of reservoirs at risk of not being fully filled exceeds a given threshold, the cascade reservoir group is judged to be at risk of not being fully filled.

[0014] Preferably, the minimum water storage capacity of the reservoir group above reservoir i at the end of the water storage period is calculated as follows:

[0015] (The storage capacity corresponding to the minimum water level constraint of reservoir j at the end of the impoundment period - the storage capacity corresponding to the initial water level of reservoir j).

[0016] Preferably, the minimum total water discharge of reservoir i is the sum of the water volumes corresponding to the minimum outflow flow of reservoir i from the initial moment to the end of the water storage period.

[0017] Preferably, the first scheduling objective of the cascade reservoir group water storage scheduling model is:

[0018]

[0019] In the formula, Z i,j represents the final water level of power station i in dispatch period j; represents the water storage target of power station i; n represents the number of power stations; J represents the total dispatching period; ω i represents the weight of power station i. The larger the weight, the more important the water storage task of power station i is.

[0020] The above formula is further transformed into:

[0021]

[0022] In the formula, a i is an auxiliary variable, which is a non-negative number; i,j is a 0-1 variable; M represents a large constant, and any constant greater than Z i max The number of .

[0023] Preferably, the second scheduling objective of the cascade reservoir group water storage scheduling model is specifically:

[0024]

[0025] Where P i,j represents the output of power station i in dispatch period j; Δt j represents the number of hours in the scheduling period j; S k (Z k,J ) indicates that the water level of power station k at the end of the dispatch period is Z k,J Available water volume at time; i () represents the energy storage function of power station i.

[0026] Preferably, the constraints of the cascade reservoir group water storage scheduling model include water level constraints, flow constraints, output constraints and other constraints that can be converted into water level, flow or output.

[0027] The invention discloses a water storage dispatching model for a cascade reservoir group under extremely low water conditions, and adopts a water storage dispatching method for a cascade reservoir group under extremely low water conditions.

[0028] The present invention can achieve the following beneficial effects:

[0029] In view of the problem that the existing optimization scheduling model of cascade reservoir groups does not take into account the risk of insufficient storage of cascade reservoir groups under extremely low water conditions, the present invention provides a water storage scheduling method for cascade reservoir groups specifically for extremely low water conditions, which optimizes the allocation of water resources, coordinates the water storage progress and the order of water storage of each reservoir, and maximizes the fullness rate of the cascade reservoir groups; when the cascade reservoir groups cannot be fully stored, water storage weights are set to ensure that important reservoirs are given priority in water storage; while considering the water storage task, the power generation during the water storage period and the cascade energy storage at the end of the water storage period are taken into account, so as to improve the utilization rate of water energy resources and achieve coordination and balance between water storage and power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0031] Figure 1 The figure is a flow chart of a method for water storage and dispatching of a cascade reservoir group under extremely low water conditions.

[0032] Figure 2 This is a diagram of the dispatching process of power station A calculated by the present invention in Example 1.

[0033] Figure 3 This is a diagram of the dispatching process of power station B calculated by the present invention in Example 1.

[0034] Figure 4 This is a diagram of the dispatching process of power station C calculated by the present invention in Example 1.

[0035] Figure 5 This is a diagram of the dispatching process of power station D calculated by the present invention in Example 1.

[0036] Figure 6 This is a diagram of the dispatching process of the E power station calculated by the present invention in Example 1.

[0037] Figure 7 This is a diagram of the dispatching process of power station A calculated by the present invention in Example 2.

[0038] Figure 8 This is a diagram of the dispatching process of power station B calculated by the present invention in Example 2.

[0039] Fig. 9 This is a diagram of the dispatching process of power station C calculated by the present invention in Example 2.

[0040] Fig.10 This is a diagram of the dispatching process of power station D calculated by the present invention in Example 2.

[0041] Fig.11 This is a diagram of the dispatching process of the E power station calculated by the present invention in Example 2. DETAILED DESCRIPTION

[0042] The preferred solution is Figure 1 As shown, a method for water storage scheduling of cascade reservoirs under extremely low water conditions comprises the following steps:

[0043] (1) Based on the water inflow forecast, minimum water level constraint, minimum outflow constraint, and the water storage target of each reservoir at the end of the water storage period, determine whether the cascade reservoir group has the risk of not being fully stored. If so, activate the cascade reservoir group water storage scheduling under the extremely low water condition;

[0044] (1.1) The method for determining the risk of underfilling of cascade reservoirs is as follows:

[0045] (1.1.1) The reservoir group is composed of reservoir 1, reservoir 2, ..., reservoir n from upstream to downstream;

[0046] (1.1.2) For any reservoir i (i = 1, 2, ..., n), calculate the maximum available water volume of reservoir i = the total natural water inflow from upstream during the storage period of reservoir i - the minimum water storage volume of the reservoir group above reservoir i at the end of the storage period - the minimum total water discharge volume of reservoir i;

[0047] The calculation method for the minimum water storage capacity of the reservoir group above reservoir i at the end of the water storage period is:

[0048] (storage capacity corresponding to the minimum water level constraint of reservoir j at the end of the impoundment period - storage capacity corresponding to the initial water level of reservoir j);

[0049] The minimum total discharge of reservoir i is the sum of the water volume corresponding to the minimum outflow of reservoir i from the initial moment to the end of the water storage period;

[0050] (1.1.3) Calculate the water storage capacity of reservoir i = the storage target corresponding to reservoir i - the storage capacity corresponding to the initial water level of reservoir i;

[0051] (1.1.4) If the maximum available water volume of reservoir i is less than the water volume to be stored in reservoir i, it means that reservoir i is at risk of being under-stored;

[0052] (1.1.5) If the proportion of reservoirs at risk of not being fully filled exceeds a given threshold, the cascade reservoir group is judged to be at risk of not being fully filled.

[0053] (2) In the case of insufficient water storage risk, the first scheduling target is to minimize the weighted sum of the gaps between the highest water level of the cascade reservoir group during the scheduling period and the water storage target, and the second scheduling target is to maximize the sum of the power generation and energy storage value of the cascade reservoir group. Without setting the water level at the end of the scheduling period, a water storage scheduling model for the cascade reservoir group is established, and the scheduling plan with the maximum water storage satisfaction of the cascade reservoir group is solved.

[0054] (2.1) The first scheduling objective of the cascade reservoir group water storage scheduling model is:

[0055]

[0056] In the formula, Z i,j represents the final water level of power station i in dispatch period j; represents the water storage target of power station i; n represents the number of power stations; J represents the total dispatching period; ω i It represents the weight of power station i. The larger the weight, the more important the water storage task of power station i is.

[0057] The above formula is further transformed into

[0058]

[0059] In the formula, a i is an auxiliary variable, which is a non-negative number; i,j is a 0-1 variable; M represents a large constant, taking any value greater than The number of .

[0060] (2.2) The second scheduling objective of the cascade reservoir group water storage scheduling model is as follows:

[0061]

[0062] Where P i,j represents the output of power station i in dispatch period j; Δt j represents the number of hours in the scheduling period j; S k (Zk,J ) indicates that the water level of power station k at the end of the dispatch period is Z k,J Available water volume at time; i () represents the energy storage function of power station i.

[0063] (2.3) The constraints of the cascade reservoir group water storage scheduling model include water level constraints, flow constraints, output constraints and other constraints that can be converted into water level, flow or output.

[0064] Embodiment 1:

[0065] The following is a cascade reservoir group consisting of five reservoirs A, B, C, D, and E as an embodiment to further illustrate the water storage scheduling method of the cascade reservoir group under extremely low water conditions provided by the present invention. The five reservoirs are Reservoir A, Reservoir B, Reservoir C, Reservoir D, and Reservoir E from upstream to downstream. The scheduling period is from July 1 to October 31, and the scheduling scale is ten days. The constraints are shown in Table 1. The initial water levels are 951.5m, 786.8m, 560.7m, 371.6m, and 148.1m, respectively. The water storage targets are 974m, 824m, 599m, 379m, and 175m, respectively. The threshold of the proportion of reservoirs that are at risk of not being fully stored is set to 0.

[0066] Table 1 Constraints

[0067]

[0068]

[0069] The water flow in typical dry years is selected from the long series of historical water flows for calculation. First, based on the water flow forecast, the minimum water level constraint, the minimum outflow constraint, and the water storage target of each reservoir at the end of the water storage period, it is determined whether the cascade reservoir group has a risk of being under-stored.

[0070] The total natural water inflow upstream of Reservoir A is 46 billion m 3 The minimum total discharge volume is 21.3 billion m 3 The maximum available water storage capacity is 24.7 billion m 3 The water storage capacity is 2.36 billion m 3 , the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of insufficient storage in reservoir A;

[0071] The total natural water inflow upstream of Reservoir B is 48.6 billion m 3 The minimum total discharge volume is 21.3 billion m 3 The minimum water storage capacity of reservoir A above reservoir B is 2.36 billion m 3 The maximum available water volume of reservoir B is 24.94 billion m 3 , the water storage capacity is 7 billion m 3, the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of insufficient storage in reservoir B;

[0072] The total natural water inflow upstream of Reservoir C is 52.2 billion m 3 The minimum total discharge volume is 31.9 billion m 3 The minimum water storage capacity of reservoirs A and B above reservoir C is 9.36 billion m 3 The maximum available water volume of reservoir C is 10.94 billion m 3 The water storage capacity is 4.45 billion m 3 , the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of insufficient storage in reservoir C;

[0073] The total natural water inflow upstream of Reservoir D is 51.1 billion m 3 The minimum total discharge volume is 31.9 billion m 3 The minimum water storage capacity of reservoirs A, B, and C above reservoir D is 13.81 billion m 3 The maximum available water volume of reservoir D is 5.39 billion m 3 The water storage capacity is 670 million m 3 , the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of reservoir D not being fully stored;

[0074] The total natural water inflow upstream of Reservoir E is 129.5 billion m 3 The minimum total discharge volume is 95.7 billion m 3 The minimum water storage capacity of reservoirs A, B, C, and D above reservoir E is 14.48 billion m 3 The maximum available water volume of reservoir D is 19.32 billion m 3 The water storage capacity is 20.6 billion m 3 , the maximum available water volume for storage is less than the water volume to be stored, and there is a risk that reservoir E will not be fully stored;

[0075] The proportion of reservoirs at risk of not being fully filled is 20%, which exceeds the threshold of 0. Therefore, it is necessary to activate water storage scheduling of cascade reservoirs under extremely low water conditions.

[0076] The first scheduling target is to minimize the weighted sum of the difference between the highest water level of the cascade reservoir group during the scheduling period and the water storage target, and the second scheduling target is to maximize the sum of the power generation and energy storage value of the cascade reservoir group. The water level at the end of the scheduling period is not set, and the water storage weight is set to 0.2. The water storage scheduling model of the cascade reservoir group is established, as follows:

[0077] The first scheduling objective of the cascade reservoir group water storage scheduling model is:

[0078]

[0079] In the formula, Z i,j represents the final water level of power station i in dispatch period j; represents the water storage target of power station i.

[0080] The above formula is further transformed into

[0081]

[0082] In the formula, a i is an auxiliary variable, which is a non-negative number; i,j It is a 0-1 variable.

[0083] The second scheduling objective of the cascade reservoir group water storage scheduling model is as follows:

[0084]

[0085] Where P i,j represents the output of power station i in dispatch period j; Δt j represents the number of hours in the scheduling period j; S k (Z k,12 ) indicates that the water level of power station k at the end of the dispatch period is Z k,12 Available water volume at time; i () represents the energy storage function of power station i.

[0086] The constraints are:

[0087] Water level constraints:

[0088] Outbound traffic constraints:

[0089] Water balance constraint: V i,j =V i,j-1 +(I i,j -Q i,j )×Δt j

[0090] I i,j =Q i-1,j +ΔI i,j

[0091] Where V i,j ,I i,j , Q i,j , ΔI i,j , Z i,j , They represent the final storage capacity, inflow, outflow, interval flow, reservoir water level, minimum water level, maximum water level, minimum outflow, and maximum outflow of power station i in dispatching period j, respectively. j represents the time interval of scheduling period j.

[0092] The water storage scheme of the cascade reservoir group is obtained as follows: Figure 2-6As shown. It can be seen that when the inflow cannot fill the cascade reservoirs at the same time, the cascade reservoirs can complete the water storage task in sequence through joint optimization scheduling and coordination of the water storage progress of each reservoir. Among them, reservoir A completed water storage in early September, reservoir B completed water storage in mid-October, reservoir C completed water storage in late September, reservoir D completed water storage in early October, and reservoir E completed water storage in late October. For the insufficient water storage in reservoir E, reservoirs C and D will replenish water, and the upstream reservoirs A and B will maintain a high water level to improve the overall energy storage of the cascade.

[0093] Embodiment 2:

[0094] To highlight the effect of the present invention, based on Example 1, another typical dry year water inflow is selected from the long historical series of water inflows for calculation, wherein the initial water level, water level constraint, flow constraint and water storage target of each reservoir remain unchanged.

[0095] Firstly, based on the water inflow forecast, minimum water level constraint, minimum outflow flow constraint and the water storage target of each reservoir at the end of the water storage period, it is determined whether the cascade reservoir group has the risk of being under-filled.

[0096] The total natural water inflow upstream of Reservoir A is 37.9 billion m 3 The minimum total discharge volume is 21.3 billion m 3 The maximum available water storage capacity is 16.6 billion m 3 The water storage capacity is 2.36 billion m 3 , the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of insufficient storage in reservoir A;

[0097] The total natural water inflow upstream of Reservoir B is 40.5 billion m 3 The minimum total discharge volume is 21.3 billion m 3 The minimum water storage capacity of reservoir A above reservoir B is 2.36 billion m 3 The maximum available water volume of reservoir B is 16.84 billion m 3 , the water storage capacity is 7 billion m 3 , the maximum available water volume for storage is greater than the water volume to be stored, and there is no risk of insufficient storage in reservoir B;

[0098] The total natural water inflow upstream of Reservoir C is 44.1 billion m 3 The minimum total discharge volume is 31.9 billion m 3 The minimum water storage capacity of reservoirs A and B above reservoir C is 9.36 billion m 3 The maximum available water volume of reservoir C is 2.84 billion m 3 The water storage capacity is 4.45 billion m 3 , the maximum available water volume for storage is less than the water volume to be stored, and there is a risk that reservoir C will not be fully stored;

[0099] The total natural water inflow upstream of Reservoir D is 43.1 billion m 3 The minimum total discharge volume is 31.9 billion m 3 The minimum water storage capacity of reservoirs A, B, and C above reservoir D is 13.81 billion m 3 The maximum available water volume of reservoir D is -2.61 billion m 3 The water storage capacity is 670 million m 3 , the maximum available water volume for storage is less than the water volume to be stored, and there is a risk that reservoir D will not be fully stored;

[0100] The total natural water inflow upstream of Reservoir E is 121.2 billion m 3 The minimum total discharge volume is 95.7 billion m 3 The minimum water storage capacity of reservoirs A, B, C, and D above reservoir E is 14.48 billion m 3 The maximum available water volume of reservoir D is 11.02 billion m 3 The water storage capacity is 20.6 billion m 3 , the maximum available water volume for storage is less than the water volume to be stored, and there is a risk that reservoir E will not be fully stored;

[0101] The proportion of reservoirs at risk of not being fully filled is 60%, which exceeds the threshold of 0. Therefore, it is necessary to enable the water storage scheduling of the cascade reservoir group under the condition of extremely low water flow. By solving the model, the water storage plan of the cascade reservoir group is obtained as follows: Figure 7-11 As shown. It can be seen that under this extremely low water condition, the water inflow is small, the amount of water to be stored in the cascade reservoir group is large, and even if the cascade reservoir group is stored in sequence, it cannot be guaranteed that they will be full. In order to improve the cascade storage rate and make the highest water level of each reservoir as close to the water storage target as possible, the model enables reservoirs A, C, and D to complete the water storage task in sequence, and the highest water level of power station B reaches 818.24m, and the highest water level of power station E reaches 164.42m.

[0102] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for water storage scheduling of a cascade reservoir group under extremely low water conditions, characterized in that: Based on the water inflow forecast, minimum water level constraint, minimum outflow constraint and the water storage target of each reservoir at the end of the water storage period, determine whether the cascade reservoir group has the risk of not being fully stored. If so, activate the cascade reservoir group water storage scheduling under the extremely low water condition; In the case of insufficient water storage risk, the first scheduling target is to minimize the weighted sum of the gaps between the highest water level of the cascade reservoir group during the scheduling period and the water storage target, and the second scheduling target is to maximize the sum of the power generation and energy storage value of the cascade reservoir group. Without setting the water level at the end of the scheduling period, a water storage scheduling model for the cascade reservoir group is established, and the scheduling plan with the maximum water storage satisfaction of the cascade reservoir group is solved.

2. The method for water storage dispatching of a cascade reservoir group under extremely low water conditions according to claim 1, characterized in that: The method for determining the risk of insufficient accumulation is: (1) The reservoir group is composed of reservoir 1, reservoir 2, ..., reservoir n from upstream to downstream; (2) For any reservoir i, the maximum available water volume of reservoir i is calculated as the total natural water inflow from upstream during the impoundment period of reservoir i – the minimum water storage volume of the reservoir group above reservoir i at the end of the impoundment period – the minimum total water discharge volume of reservoir i; where i = 1, 2, ..., n; (3) Calculate the water storage capacity of reservoir i = the storage target corresponding to reservoir i – the storage capacity corresponding to the initial water level of reservoir i; (4) If the maximum available water volume of reservoir i is less than the water volume to be stored in reservoir i, it means that reservoir i is at risk of not being fully stored; (5) If the proportion of reservoirs at risk of not being fully filled exceeds a given threshold, the cascade reservoir group is judged to be at risk of not being fully filled.

3. The method for water storage dispatching of a cascade reservoir group under extremely low water conditions according to claim 2, characterized in that: The calculation method for the minimum water storage capacity of the reservoir group above reservoir i at the end of the water storage period is: (The storage capacity corresponding to the minimum water level constraint of reservoir j at the end of the impoundment period - the storage capacity corresponding to the initial water level of reservoir j).

4. The method for water storage dispatching of a cascade reservoir group under extremely low water conditions according to claim 1, characterized in that: The minimum total discharge of reservoir i is the sum of the water volumes corresponding to the minimum outflow of reservoir i from the initial moment to the end of the water storage period.

5. The method for water storage scheduling of cascade reservoirs under extremely low water conditions according to claim 1, characterized in that: The first scheduling objective of the cascade reservoir group water storage scheduling model is: In the formula, Z i,j represents the final water level of power station i in dispatch period j; represents the water storage target of power station i; n represents the number of power stations; J represents the total scheduling period; ω i represents the weight of power station i. The larger the weight, the more important the water storage task of power station i is. The above formula is further transformed into: In the formula, a i is an auxiliary variable, which is a non-negative number; i,j is a 0-1 variable; M represents a large constant, taking any value greater than The number of .

6. The method for water storage dispatching of cascade reservoirs under extremely low water conditions according to claim 1, characterized in that: The second scheduling objective of the cascade reservoir group water storage scheduling model is as follows: Where P i,j represents the output of power station i in dispatch period j; Δt j represents the number of hours in the scheduling period j; S k (Z k,J ) indicates that the water level of power station k at the end of the dispatch period is Z k,J Available water volume at time; i (·) represents the energy storage function of power station i.

7. The method for water storage dispatching of cascade reservoirs under extremely low water conditions according to claim 1, characterized in that: The constraints of the cascade reservoir group water storage scheduling model include water level constraints, flow constraints, output constraints and other constraints that can be converted into water level, flow or output.

8. A water storage scheduling model for cascade reservoirs under extremely low water conditions, characterized by: A method for water storage scheduling of a cascade reservoir group under extremely low water conditions according to any one of claims 1 to 7 is adopted.

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