Cascade reservoir hydro-fluctuation period abandoned water risk analysis method based on abandoned water prevention guide line

Abstract

The invention discloses a cascade reservoir hydro-fluctuation period water abandoning risk analysis method based on a water abandoning prevention guide line. The method comprises the following steps: collecting data; generalizing the maximum power generation flow constraint matrix of the most downstream reservoir in the hydro-fluctuation period; obtaining a cascade reservoir inflow runoff process after runoff recalculation calculation; determining the threshold value of the removable reservoir capacity on the abandoned water prevention guide line and the reservoir capacity boundary condition at the end of the hydro-fluctuation period; deducing abandoned water prevention guide line clusters of the cascade reservoirs over the years; and forming a water abandoning risk probability query chart. The method provided by the invention has the advantages of being simple, practical, reasonable, reliable, easy to popularize and the like, and according to the characteristics of cascade reservoir dispatching application, an anti-abandoned water dispatching operation guide line under different incoming water conditions of the cascade reservoir and the probability of the water abandoning risk of different to-be-eliminated reservoir capacities in the hydro-fluctuation period are quickly given; the method and the device accord with the operation characteristics of actual reservoir scheduling, and can provide support for a reservoir operation management department to adjust a scheduling strategy in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of water conservancy and hydropower, and in particular to a method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on a water abandonment prevention guide line. Background Art

[0002] Reducing the amount of water discarded is a key goal of cascade reservoir power stations during the drawdown period. Typically, cascade reservoir power stations maintain higher water levels during the early stages of the drawdown period to improve their water resource utilization efficiency. Drawdown is then accelerated toward the end of the drawdown period, reducing reservoir water levels to within the prescribed operating range for the flood season. Due to the long drawdown period, the power generation capacity of cascade reservoir power stations is subject to certain constraints due to factors such as hydropower station maintenance, line maintenance, grid peak regulation, water supply scheduling, and ecological scheduling. Due to the relatively low accuracy of medium- and long-term water inflow forecasts, if water inflows are excessive in the later stages, reservoirs will be forced to open sluice gates and discard water to reduce the reservoir level to the prescribed operating range by the end of the drawdown period.

[0003] Currently, traditional reservoir operation diagrams often use full-power or fixed-flow discharge as the derivation of power generation flow. In reality, power generation flow at reservoir power stations often fluctuates during the drawdown period due to the influence of these factors. Therefore, traditional reservoir operation diagrams are not very effective in guiding actual operation. Furthermore, there are currently no comprehensive anti-abandonment guidelines for cascade reservoirs to guide their operation, resulting in the inability to provide real-time dynamic warnings of the possibility of subsequent water abandonment risks.

[0004] Therefore, there is an urgent need to reasonably characterize the power generation flow of cascade reservoirs under the influence of multiple factors at different stages of the drawdown period, deduce the guidance line for preventing water abandonment of cascade reservoirs, reduce the amount of water abandoned during the drawdown period, and timely calculate and warn the probability of water abandonment risk, so as to provide a strong reference for the scheduling and operation decision-making of cascade reservoirs. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned technology, the present invention provides a method for analyzing the risk of water abandonment in the drawdown period of cascade reservoirs based on the water abandonment prevention guide line, so as to deduce the water abandonment prevention guide line of cascade reservoirs, reduce the amount of water abandoned in the drawdown period, and timely calculate and warn the probability of water abandonment risk, providing a powerful reference for the scheduling and operation decision-making of cascade reservoirs.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on a water abandonment prevention guideline comprises the following steps:

[0008] 1) Collect engineering characteristic data, operation data and long-term runoff data of cascade reservoirs; the cascade reservoirs are A1, A2, ..., A s , s is the total reservoir capacity of the cascade reservoirs;

[0009] 2) Using time series analysis method to generalize the maximum power generation flow constraint matrix at different time periods under the influence of multiple factors during the drawdown period of the downstream reservoir;

[0010] 3) Construct a joint runoff regulation model for the upstream reservoir group of the cascade reservoirs, perform current calculations based on long-series runoff data, and obtain the inflow process of the cascade reservoirs after the current runoff calculations;

[0011] 4) Determine the threshold of the available storage capacity on the water abandonment prevention guideline and the storage capacity boundary conditions at the end of the drawdown period; based on the determined maximum power generation flow constraint matrix and the inflow and runoff process of the cascade reservoirs, calculate the available storage capacity distribution matrix of the cascade reservoirs in different typical years and at different time nodes, and deduce the water abandonment prevention guideline clusters of the cascade reservoirs over the years;

[0012] 5) Calculate the two-dimensional probability distribution of water abandonment risk at different time points for cascade reservoirs with different storage capacities to be eliminated, and form a water abandonment risk probability query chart.

[0013] Preferably, in step 1), the characteristic data of the cascade reservoir project include the normal water storage level, flood limit water level, dead water level, water level and storage capacity curve, start and end time of the drawdown period, full discharge, and reservoir water level requirements for flood control safety at the end of the drawdown period of each reservoir; the scheduling operation data include the power generation flow process, power grid maintenance schedule, and power station maintenance schedule of each reservoir during the drawdown period in previous years since its operation; in the long series runoff data, the time scale of the annual runoff series is the ten-day average or the daily average.

[0014] Preferably, the step 1) includes:

[0015] 1.1) Collect engineering characteristic data, operation data, and long-term runoff data of cascade reservoirs; the long-term runoff data series should be y years, with y ≥ 30 years;

[0016] 1.2) Based on the time scale of the long series of natural runoff data, determine the time step dt for the simulation calculation of the drawdown period;

[0017] 1.3) Calculate the duration of the ebb period T according to the starting time node T0 and the ending time node T1 of the ebb period S , set the duration of the decline period to T S Divide into n calculation periods, where n = T S / dt.

[0018] Preferably, in step 2), the multiple factors include grid absorption, hydropower station maintenance, line maintenance, water supply scheduling, and ecological scheduling.

[0019] Preferably, the step 2) includes:

[0020] 2.1) For the most downstream reservoir A in the cascade reservoir s , collect the typical dispatching event data of hydropower station maintenance, line maintenance, and ecological dispatch in previous years, analyze the calculation period v when hydropower station maintenance, line maintenance, and ecological dispatch occur, and extract the outflow flow constraints under the influence of hydropower station maintenance in the corresponding calculation period v Outbound flow constraints under line maintenance Outbound flow constraints required by ecological scheduling Reservoir A s The maximum power generation flow constraint in the calculation period v for:

[0021]

[0022] Where: All are reservoir A s The average flow rate during the calculation period v;

[0023] 2.2) For the other calculation periods w except calculation period v within n calculation periods, collect and calculate the downstream reservoir A of the drawdown period in previous years. s The actual average outbound flow process during this period m is the most downstream reservoir A s The actual operating years of reservoir A, m≤y; s The maximum power generation flow constraint in the calculation period w for:

[0024]

[0025] 2.3) Combine steps 2.1) and 2.2) and Constructing Reservoir A s The maximum power generation flow constraint matrix in different calculation periods during the drawdown period is:

[0026]

[0027] Preferably, the step 3) includes:

[0028] 3.1) For the upstreammost reservoir A1 in the cascade, obtain the engineering characteristics and operation methods of the reservoir group upstream of Reservoir A1 and construct a joint runoff regulation model for the reservoir group upstream of Reservoir A1;

[0029] 3.2) Based on the long series of runoff data, the runoff restoration calculation is carried out using the constructed joint runoff regulation model of the upstream reservoir group, and the inflow runoff process of the upstream reservoir A1 after the runoff restoration calculation is proposed. and A1~A2、A2~A3、...、A s-1~A s Runoff process in each interval

[0030] Preferably, the step 4) includes:

[0031] 4.1) According to A1, A2, ..., A s Normal water level Z of each reservoir 1,nsl , Z 2,nsl ,…,Z s,nsl , meet the reservoir water level requirements for flood control safety at the end of the drawdown period Flood limit water level Z 1,fcl , Z 2,fcl ,…,Z s,fcl , based on the water level and storage capacity curves of each reservoir f r (Z~V), r=1, 2, …, s-1, s, calculate the storage capacity value V corresponding to the normal water level of each reservoir 1,nsl 、V 2,nsl ,…,V s,nsl , the storage capacity value required by the corresponding reservoir water level at the end of the drawdown period The reservoir capacity value V corresponding to the flood limit water level 1,fcl 、V 2,fcl ,…,V s,fcl , and calculate the threshold value V of the depletable storage capacity 消,max and the dissipative storage capacity of the cascade reservoirs at the end of the drawdown period and the water abandonment prevention guideline

[0032] 4.2) Using the runoff process after the drawdown period of any year i determined in step 3.2), the overall water dispatch calculation of the cascade reservoirs is performed in reverse chronological order from the end of the drawdown period to obtain the available storage capacity of the kth calculation period of the water abandonment prevention guideline in year i.

[0033] 4.3) Check the available storage capacity Whether there is overflow, if so, correct the upper and lower limits;

[0034] 4.4) Based on steps 4.1) to 4.3), perform annual traversal calculations on the long series of runoff data to determine the available storage capacity of the cascade reservoirs at different calculation periods on the annual drawdown period water abandonment prevention guideline;

[0035] 4.5) Using time as the horizontal axis and the available storage capacity of the cascade reservoirs as the vertical axis, draw the guidance line clusters for preventing water abandonment in the cascade reservoirs over the years;

[0036] 4.6) According to the anti-abandonment guideline cluster of cascade reservoirs, the maximum power generation flow constraint matrix Q is obtained max The process's dissipative storage capacity V 消 The distribution matrix of :

[0037]

[0038] Preferably, in step 4.1), the threshold value V of the depletable storage capacity is 消,max and the dissipative storage capacity of the cascade reservoirs at the end of the drawdown period and the water abandonment prevention guideline The calculation is as follows:

[0039]

[0040] Preferably, in step 4.2), the depletable storage capacity of the kth calculation period of the i-year anti-abandonment water guideline is The calculation method is as follows:

[0041]

[0042] Preferably, in step 4.3), the storage capacity can be eliminated The upper and lower limit correction methods are as follows:

[0043]

[0044] Preferably, the step 5) includes:

[0045] 5.1) Introducing the distribution matrix V of the storage capacity to be eliminated for assessing the risk of water abandonment ds :

[0046]

[0047] Where: For different levels of storage capacity to be consumed, p is the distribution matrix V of the storage capacity to be eliminated ds Dimensions;

[0048] 5.2) Based on the cluster of water abandonment prevention guide lines for cascade reservoirs, select the calculation period k and extract V 消 The k-th row vector of

[0049]

[0050] 5.3) For matrix V ds Different levels of storage capacity to be consumed, statistics The years that are greater than the magnitudes are used to calculate the storage capacity V of different magnitudes. ds The probability of water abandonment risk in each calculation period is used to form a water abandonment risk probability query chart.

[0051] Preferably, the step 5.3) includes:

[0052] (1) For matrix V ds Storage capacity to be consumed statistics Medium to large In the year y0, the storage capacity to be consumed is The probability of abandoning water risk in calculation period k for:

[0053]

[0054] (2) Further traverse other calculation periods to obtain the storage capacity to be consumed Probability distribution of water abandonment risk in different calculation periods

[0055] (3) V ds The other levels of storage capacity to be consumed are traversed and circulated to calculate the two-dimensional probability distribution of the risk of water abandonment at different time nodes for different levels of storage capacity to be consumed

[0056] Preferably, the step 5.3) further comprises:

[0057] (4) Between the start time node T0 of the flattening period and the end time node T1 of the flattening period, select z important control time nodes according to the scheduling operation needs. And there are:

[0058]

[0059] (5) Statistics V ds Different levels of storage capacity to be consumed at z important control time nodes The risk probability of water abandonment is calculated and a two-dimensional water abandonment risk probability query chart is drawn.

[0060] The present invention also provides a system for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs, which is used to implement the above-mentioned method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on the anti-abandonment guidance line, comprising:

[0061] Data acquisition module, used to obtain cascade reservoir engineering characteristic data, scheduling operation data and long-term runoff data;

[0062] The data processing module is used to process the data obtained by the data collection module to obtain the two-dimensional probability distribution of the risk of water abandonment at different time points for different storage capacities to be consumed in the cascade reservoirs, and to form a water abandonment risk probability query chart;

[0063] The result output module is used to output a water abandonment risk probability query chart.

[0064] The present invention also provides a computer device comprising a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load the at least one program to execute the above-mentioned method for analyzing the risk of water abandonment in the drawdown period of cascade reservoirs based on the anti-water abandonment guidance line.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] The method provided by the present invention has the advantages of being simple, practical, reasonable, reliable, and easy to promote. According to the characteristics of cascade reservoir scheduling and application, it can quickly provide the anti-water abandonment scheduling operation guide line of cascade reservoirs under different water inflow conditions and the probability of water abandonment risk occurring in different waiting-for-discharge storage capacities during the drawdown period, and timely issue early warning of the risk of water abandonment in reservoir scheduling. It conforms to the operating characteristics of actual reservoir scheduling and can provide support for reservoir operation management departments to adjust scheduling strategies in real time.

[0067] The present invention fully combines the actual laws and dispatching needs of dispatching operation, and reasonably summarizes the maximum power generation flow constraints in different time periods under the influence of multiple factors such as hydropower station maintenance, line maintenance, power grid peak regulation, and ecological dispatching during the drawdown period, which conforms to the actual dispatching and application characteristics of reservoirs.

[0068] The present invention takes the available storage capacity as the target and provides a method for deriving the water abandonment prevention guide line of cascade reservoirs. The method is simple and practical, reasonable and reliable, and conforms to the actual characteristics of scheduling. It can quickly give the water abandonment prevention scheduling operation guide line of cascade reservoirs under different water inflow conditions, and provide a reference for the control of storage capacity drawdown of cascade reservoirs.

[0069] The present invention can quickly provide the probability distribution of water abandonment risks of cascade reservoirs under different water inflow conditions and in different subsequent time periods during real-time scheduling, as well as a water abandonment risk probability query chart, and timely issue early warnings for the risk of water abandonment during reservoir scheduling, providing effective support for reservoir scheduling strategies. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is a flowchart for the implementation of a method for risk analysis of water abandonment during the drawdown period of cascade reservoirs based on the water abandonment prevention guideline.

[0071] Figure 2 It is a flow chart for calculating the dissipative storage capacity of cascade reservoirs in different calculation periods during the drawdown period;

[0072] Figure 3 The flow chart for calculating the probability of water abandonment risk for different levels of storage capacity to be consumed;

[0073] Figure 4 It is a cluster map of the water abandonment prevention guidance lines of cascade reservoirs over the years;

[0074] Figure 5 This is a query map of the water abandonment risk probability of the cascade reservoirs from May 1 to June 21 in the embodiment. DETAILED DESCRIPTION

[0075] In order to better explain the present invention, the main contents of the present invention are further illustrated below in conjunction with specific examples, but the contents of the present invention are not limited to the following examples.

[0076] like Figure 1 As shown, the present invention provides a method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on a water abandonment prevention guide line, which specifically includes the following steps:

[0077] 1) Collect basic data on the characteristics of cascade reservoir projects, operation data, and long-term runoff data. Specifically, include:

[0078] 1.1) Data Collection

[0079] The characteristic data of cascade reservoir projects include each reservoir's normal water level, flood limit water level, dead water level, water level and storage capacity curve, start and end time of the drawdown period, full discharge, and reservoir water level requirements to meet flood control safety at the end of the drawdown period.

[0080] The dispatching operation data includes the power generation flow process during the drawdown period of each reservoir over the years since its operation, the grid maintenance schedule, the power station maintenance schedule, etc.

[0081] The natural runoff data of the long series of cascade reservoirs, the time scale of the annual runoff series is the ten-day average or daily average. Among them, the natural runoff data series of the long series of cascade reservoirs has a total of y years, y ≥ 30;

[0082] 1.2) Based on the time scale (ten days or ten days) of the long series of natural runoff data, determine the time step dt for the simulation calculation of the drawdown period.

[0083] 1.3) Calculate the duration of the ebb period T according to the starting time node T0 and the ending time node T1 of the ebb period S , set the duration of the decline period to T S Divide into n calculation periods, where n = T S / dt.

[0084] 2) The time series analysis method is used to generalize the maximum power generation flow constraint matrix of different periods of the downstream reservoir drawdown period under the influence of multiple factors such as power grid absorption, hydropower station maintenance, line maintenance, water supply scheduling, and ecological scheduling. Assume that from upstream to downstream, the reservoirs are A1, A2, ..., A s , s is the number of reservoirs in the cascade reservoirs.

[0085] Specifically include:

[0086] 2.1) For the most downstream reservoir A in the cascade reservoir s, collect data on typical scheduling events such as hydropower station maintenance, line maintenance, and ecological scheduling that affect the maximum power generation flow of reservoir power stations in previous years, and analyze the calculation period v when factors such as hydropower station maintenance, line maintenance, and ecological scheduling occur.

[0087] Extract the outflow constraints under the influence of hydropower station maintenance in the corresponding calculation period v Outbound flow constraints under line maintenance Outbound flow constraints required by ecological scheduling Reservoir A s The maximum power generation flow constraint in the calculation period v for:

[0088]

[0089] Where: All are reservoir A s The average flow rate during the calculation period v.

[0090] 2.2) For the other calculation periods w except calculation period v within n calculation periods, collect and calculate the downstream reservoir A of the drawdown period in previous years. s The actual average outbound flow process during this period m is the most downstream reservoir A s The actual operating years of reservoir A, m≤y; s The maximum power generation flow constraint in the calculation period w for:

[0091]

[0092] 2.3) Combine steps 2.1) and 2.2) and Constructing Reservoir A s The maximum power generation flow constraint matrix in different calculation periods during the drawdown period is:

[0093]

[0094] 3) Construct a joint runoff regulation model for a reservoir group, conduct runoff restoration calculations based on long-term runoff data, and propose the runoff process of cascade reservoirs after runoff restoration calculations. Specifically, it includes:

[0095] 3.1) For the upstreammost reservoir A1 in the cascade, obtain the engineering characteristics and operation methods of the reservoir group upstream of reservoir A1 and construct a joint runoff regulation model for the relevant upstream reservoir group.

[0096] 3.2) Based on the long series of runoff data, the runoff restoration calculation was carried out using the constructed joint runoff regulation model of the upstream reservoir group, and the A1 inflow runoff process after the runoff restoration calculation was proposed. and A1~A2、A2~A3、...、A s-1 ~A s Runoff process in each interval

[0097] 4) Determine the threshold of the available storage capacity on the water abandonment prevention guideline and the storage capacity boundary conditions at the end of the drawdown period; based on the determined maximum power generation flow constraint matrix and long series runoff data, calculate the available storage capacity distribution matrix of the cascade reservoirs in different typical years and different time nodes, and deduce the water abandonment prevention guideline clusters of the cascade reservoirs over the years. Figure 2 As shown, specifically including:

[0098] 4.1) According to A1, A2, ..., A s Normal water level Z of each reservoir 1,nsl , Z 2,nsl ,…,Z s,nsl At the end of the drawdown period (the end of the calculation period n), the reservoir water level meets the flood control safety requirements. Flood limit water level Z 1,fcl , Z 2,fcl ,…,Z s,fcl , based on the water level and storage capacity curves of each reservoir f r (Z~V), r=1, 2, …, s-1, s, calculate the storage capacity value V corresponding to the normal water level of each reservoir 1,nsl 、V 2,nsl ,…,V s,nsl , the storage capacity required by the corresponding reservoir water level at the end of the drawdown period The reservoir capacity value V corresponding to the flood limit water level 1,fcl 、V 2,fcl ,…,V s,fcl , then the threshold value V of the depleted storage capacity 消,max and the dissipative storage capacity of the cascade reservoirs at the end of the drawdown period and the water abandonment prevention guideline They are:

[0099]

[0100] 4.2) Using the runoff process after the drawdown period of any year i determined in step 3.2), the overall water dispatch calculation of the cascade reservoirs is performed in reverse chronological order from the end of the drawdown period to obtain the available storage capacity of the kth calculation period of the water abandonment prevention guideline in year i. The details are as follows:

[0101]

[0102] 4.3) Check the available storage capacity Whether there is overflow, if so, adjust the upper and lower limits. The details are as follows:

[0103]

[0104] 4.4) Based on steps 4.1) to 4.3), the long series of runoff data is traversed and calculated year by year to obtain the available storage capacity of the cascade reservoirs at different calculation periods on the guidance line for preventing water abandonment during the drawdown period of each year.

[0105] 4.5) Using time as the horizontal axis and the available storage capacity of the cascade reservoirs as the vertical axis, draw the guidance line clusters for preventing water abandonment in the cascade reservoirs over the years.

[0106] 4.6) According to the cluster of water abandonment prevention guide lines of cascade reservoirs, the Q-based max The process's dissipative storage capacity V 消 The distribution matrix of :

[0107]

[0108] 5) Calculate the two-dimensional probability distribution of the risk of water abandonment at different time points for different storage capacities of cascade reservoirs to be eliminated, and form a water abandonment risk probability query chart. Figure 3 As shown, specifically including:

[0109] 5.1) Introducing the distribution matrix V of the storage capacity to be eliminated for assessing the risk of water abandonment ds :

[0110]

[0111] Where: p is the distribution matrix V of the storage capacity to be eliminated ds dimension.

[0112] 5.2) Based on the cluster of water abandonment prevention guide lines for cascade reservoirs, select the calculation period k and extract V 消 The k-th row vector of

[0113]

[0114] 5.3) For matrix V ds Storage capacity to be consumed statistics Medium to large In the year y0, the storage capacity to be consumed is The probability of abandoning water risk in calculation period k for:

[0115]

[0116] 5.4) Further traverse other calculation periods to obtain the storage capacity to be consumed Probability distribution of water abandonment risk in different calculations

[0117] 5.5) Based on steps 5.2) to 5.4), V ds The other levels of storage capacity to be consumed are traversed and circulated to calculate the two-dimensional probability distribution of the risk of water abandonment at different time nodes for different levels of storage capacity to be consumed

[0118] 5.6) Between the start time node T0 of the ebb and flow period and the end time node T1 of the ebb and flow period, select z important control time nodes according to the scheduling operation needs. And there are:

[0119]

[0120] 5.7) Statistics V ds The risk probability of water abandonment at each time point in step 5.6) for different levels of storage capacity to be consumed is used to draw a two-dimensional water abandonment risk probability query chart.

[0121] The above method can quickly provide the probability distribution of water abandonment risk of cascade reservoirs under different water inflow conditions and subsequent different time periods in real-time scheduling, as well as a water abandonment risk probability query chart, so as to timely issue early warning of the risk of water abandonment in reservoir scheduling and provide effective support for reservoir scheduling strategies.

[0122] The present invention also provides a system for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs, which is used to implement the above-mentioned method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on the anti-abandonment guidance line, comprising:

[0123] A data acquisition module, configured to execute step 1) of the above method, obtain characteristic data of cascade reservoir projects, scheduling operation data and long-term runoff data, and obtain scheduling time periods;

[0124] a data processing module for executing steps 2) to 5) of the above method, processing the data acquired by the data collection module, obtaining a two-dimensional probability distribution of the risk of water abandonment at different time points for different storage capacities to be consumed in the cascade reservoirs, and forming a water abandonment risk probability query chart;

[0125] The result output module outputs a water abandonment risk probability query chart.

[0126] The present invention also provides a computer device comprising a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load the at least one program to execute the above-mentioned method for analyzing the risk of water abandonment in the drawdown period of cascade reservoirs based on the anti-water abandonment guidance line.

[0127] The present invention is further described below by way of examples.

[0128] Example 1:

[0129] Taking four cascade reservoirs in the Jinsha River Basin as an example, the proposed method was applied to generate guidance lines for preventing water abandonment in cascade reservoirs during the drawdown period and to create a two-dimensional water abandonment risk probability query chart. The method includes the following steps:

[0130] 1) Data on normal water storage levels, flood control water levels, water level and storage capacity curves, start and end times of the drawdown period, full discharge, operating water levels at the end of the drawdown period, and a ten-day average long-term natural runoff series (1959–2014) were collected for the four cascade reservoirs. Some engineering characteristic parameters, such as normal water storage levels, flood control water levels, calculated start and end times, full discharge, and operating water levels at the end of the drawdown period, are shown in Table 1. The calculation time step dt was determined to be ten days, and the calculation period n = 18.

[0131] Table 1: Some engineering characteristic parameters of the four cascade reservoirs

[0132]

[0133] 2) By collecting the historical dispatching and operation data of the most downstream reservoir A4 and the impact of different dispatching demands and maintenance on the outflow, we analyze and generalize the maximum power generation flow constraints of different reservoirs in different time periods under the influence of multiple factors such as hydropower station maintenance, line maintenance, grid peak regulation, and ecological dispatch during the drawdown period. See Table 2 for details.

[0134] 3) Data on the engineering characteristics and operation methods of the cascade reservoirs in the upper and middle reaches of the Jinsha River and the Yalong River basin above Reservoir A1 were collected to construct a joint runoff regulation model for the cascade reservoirs in the upper and middle reaches of the Jinsha River and the Yalong River basin. Runoff restoration calculations were performed using a long series of runoff data from 1959 to 2014. The runoff inflow process of Reservoir A1 after runoff restoration calculations and the runoff processes of the three intervals A1-A2, A2-A3, and A3-A4 were proposed.

[0135] 4) First, according to the normal water storage level, flood limit water level and operating water level at the end of the drawdown period of each reservoir in Table 1, combined with the water level and storage capacity curve of each reservoir, determine the V of the cascade reservoir. 消,max 15.493 billion m 3 , the dissipative storage capacity of the cascade reservoirs at the end of the drawdown period is 0.

[0136] Using the long series of runoff data after current calculation, the overall water dispatch calculation of the cascade reservoirs is carried out in reverse chronological order from the end of the drawdown period, the dissipative storage capacity of each period in previous years is obtained, and the dissipative storage capacity is tested for overflow.

[0137] With time as the horizontal axis and the available storage capacity of the cascade reservoirs as the vertical axis, plot Figure 4The shown cluster of water abandonment prevention guidance lines for cascade reservoirs over the years. Based on the water abandonment prevention guidance line clusters for cascade reservoirs, the available storage capacity V is obtained. 消 The distribution matrix of .

[0138] Table 2: Maximum power generation flow constraints of reservoir A4

[0139]

[0140] 5) Introducing the distribution matrix V of the storage capacity to be eliminated to assess the risk of water abandonment ds

[0141]

[0142] V ds The two-dimensional probability distribution of the risk of water abandonment at different time nodes of different levels of storage capacity to be consumed is calculated. Between the starting time node of the drawdown period calculation on December 31 and the ending time node of the drawdown period on June 30, important control time nodes of May 1, May 11, May 21, June 1, June 11 and June 21 are selected according to scheduling and operation needs.

[0143] Statistics V ds The risk probability of water abandonment of different levels of storage capacity to be consumed at the above time nodes is plotted, and a two-dimensional water abandonment risk probability query chart is drawn, as shown in the figure. Figure 5 and Table 3.

[0144] Table 3: Water abandonment risk probability query table for each time point from May 1 to June 21

[0145]

[0146] The above method can quickly provide the probability distribution of water abandonment risk of cascade reservoirs under different water inflow conditions and in different subsequent time periods in real-time scheduling, as well as a water abandonment risk probability query chart. Table 3 can be used to timely warn of the risk of water abandonment in reservoir scheduling, providing effective support for reservoir scheduling strategies.

Claims

1. A method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on a water abandonment prevention guide line, characterized in that: The following steps are involved: 1) Collect engineering characteristic data, dispatching operation data and long-term runoff data of cascade reservoirs; the cascade reservoirs are A1, A2, ..., A s , s is the total reservoir capacity of the cascade reservoirs; 2) The time series analysis method is used to generalize the maximum power generation flow constraint matrix at different time periods under the influence of multiple factors during the drawdown period of the most downstream reservoir; 3) Construct a joint runoff regulation model for the upstream reservoir group of the cascade reservoirs, carry out current calculations based on long-series runoff data, and obtain the inflow runoff process of the cascade reservoirs after the current calculations; 4) Determine the threshold of the depletable storage capacity on the water abandonment prevention guidance line and the storage capacity boundary conditions at the end of the drawdown period; based on the determined maximum power generation flow constraint matrix and the inflow and runoff process of the cascade reservoirs, calculate the depletable storage capacity distribution matrix of the cascade reservoirs in different typical years and different time nodes, and deduce the water abandonment prevention guidance line clusters of the cascade reservoirs over the years; 5) Calculate the two-dimensional probability distribution of the risk of water abandonment at different time points for cascade reservoirs with different storage capacities to be eliminated, and form a water abandonment risk probability query chart.

2. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 1 is characterized by: In the step 1), the characteristic data of the cascade reservoir project include the normal water storage level, flood limit water level, dead water level, water level and storage capacity curve, the start and end time of the drawdown period, the full discharge, and the reservoir water level requirements for flood control safety at the end of the drawdown period of each reservoir; the dispatching operation data include the power generation flow process, power grid maintenance arrangement, and power station maintenance arrangement of the drawdown period of each reservoir in the past years since its operation; in the long series runoff data, the time scale of the annual runoff series is the ten-day average or the daily average.

3. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 1 is characterized by: The step 1) comprises: 1.1) Collect engineering characteristic data, dispatching and operation data, and long-series runoff data of cascade reservoirs; the long-series runoff data has a total of y years, y ≥ 30; 1.2) Based on the time scale of the long series of natural runoff data, determine the time step dt for the simulation calculation of the drawdown period; 1.3) Calculate the duration of the decline period T for the start time node T0 and the end time node T1 of the decline period S , the duration of the decline period is T S Divided into n computing periods, where n = T S / dt.

4. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 1 is characterized by: In the step 2), the various factors include power grid absorption, hydropower station maintenance, line maintenance, water supply scheduling, and ecological scheduling.

5. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 4 is characterized by: The step 2) comprises: 2.1) For the most downstream reservoir A in the cascade reservoirs s , collect the typical dispatching event data of hydropower station maintenance, line maintenance, and ecological dispatch in previous years, analyze the calculation period v when hydropower station maintenance, line maintenance, and ecological dispatch occur, and extract the outflow flow constraints under the influence of hydropower station maintenance in the corresponding calculation period v Outbound flow constraints under line maintenance Outbound flow constraints required by ecological scheduling Reservoir A s The maximum generation flow constraint in the calculation period v x for: Where: All are reservoir A s The average flow rate during the calculation period v; 2.2) For the other calculation periods w except calculation period v in the n calculation periods, collect and calculate the downstream reservoir A of the drawdown period in previous years. s The actual average outbound flow process during this period j=1, 2, ..., m, where m is the most downstream reservoir A s The actual operating years of reservoir A, m≤y; s The maximum generation flow constraint in the calculation period w for: 2.3) Combine steps 2.1) and 2.2) and Constructing Reservoir A s The maximum power generation flow constraint matrix in different calculation periods during the drawdown period is:

6. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 1 is characterized by: The step 3) comprises: 3.1) For the upstream reservoir A1 in the cascade reservoirs, obtain the engineering characteristics and dispatching methods of the reservoir group in the upstream area of ​​reservoir A1, and build a joint runoff regulation model for the reservoir group upstream of reservoir A1; 3.2) Based on the long series of runoff data, the runoff restoration calculation is carried out using the constructed joint runoff regulation model of the upstream reservoir group, and the inflow runoff process of the upstream reservoir A1 after the runoff restoration calculation is proposed. and A1~A2、A2~A3、...、A s-1 ~A s Runoff process in each section k=1, 2,...,n, i=1, 2,...,y.

7. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 6 is characterized by: The step 4) comprises: 4.1) According to A1, A2, ..., A s Normal water level Z of each reservoir 1,nsl , Z 2,nsl , …, Z s,nsl , The reservoir water level requirements for flood control safety are met at the end of the drawdown period Flood limit water level Z 1,fcl , Z 2,fcl , …, Z s,fcl , based on the water level and storage capacity curves of each reservoir r (Z~V), r=1, 2, …, s-1, s, calculate the storage capacity value V corresponding to the normal water level of each reservoir 1,nsl 、V 2,nsl ,…,V s,nsl , the storage capacity required for the corresponding reservoir water level at the end of the drawdown period The reservoir capacity value V corresponding to the flood limit water level 1,fcl 、V 2,fcl ,…,V s,fcl , and calculate the threshold value V of the depletable storage capacity 消,max The depletable storage capacity of the cascade reservoirs at the end of the drawdown period and the water abandonment prevention guideline 4.2) Using the runoff process after the drawdown period of any year i calculated in step 3.2), the overall water dispatch calculation of the cascade reservoirs is performed in reverse chronological order from the end of the drawdown period to obtain the available storage capacity of the kth calculation period of the water abandonment prevention guideline in year i. 4.3) Check the available storage capacity Whether there is overflow, if so, correct the upper and lower limits; 4.4) Based on steps 4.1) to 4.3), the long series of runoff data is traversed and calculated year by year to obtain the available storage capacity of the cascade reservoirs at different calculation periods on the guidance line for preventing water abandonment during the drawdown period of previous years; 4.5) With time as the horizontal axis and the available storage capacity of the cascade reservoirs as the vertical axis, draw the guidance line clusters for preventing water abandonment of the cascade reservoirs over the years; 4.6) According to the cluster of water abandonment prevention guide lines of cascade reservoirs, the maximum power generation flow constraint matrix Q is obtained max The process's depletable storage capacity V 消 The distribution matrix of is:

8. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 7 is characterized by: In step 4.1), the threshold value V of the depletable storage capacity 消,max The depletable storage capacity of the cascade reservoirs at the end of the drawdown period and the water abandonment prevention guideline The calculation of is as follows:

9. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 7 is characterized by: In step 4.2), the depletable storage capacity of the kth calculation period of the water abandonment prevention guideline in year i The calculation method is as follows:

10. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 7, characterized in that: In step 4.3), the storage capacity can be eliminated The upper and lower limit correction methods are as follows:

11. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 1, characterized in that: The step 5) comprises: 5.1) Introducing the distribution matrix V of the storage capacity to be eliminated for assessing the risk of water abandonment ds : Where: For different levels of storage capacity to be consumed, p is the distribution matrix V of the storage capacity to be eliminated ds Dimensions; 5.2) Based on the cluster of water abandonment prevention guidance lines of cascade reservoirs, select the calculation period k and extract V 消 The k-th row vector of 5.3) For the matrix V ds Different levels of storage capacity to be consumed, statistics The years with a value greater than that of each magnitude are used to calculate the storage capacity V to be consumed at different magnitudes. ds The probability of water abandonment risk in each calculation period forms a water abandonment risk probability query chart.

12. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 11, characterized in that: The step 5.3) comprises: (1) For the matrix V ds Storage capacity to be consumed statistics Medium to large In the year y0, the storage capacity to be consumed is The probability of abandonment risk in calculation period k for: (2) Further traverse other calculation periods to obtain the storage capacity to be consumed Probability distribution of water abandonment risk in different calculation periods k = 1, 2, ..., n-1; (3) V ds The other magnitudes of storage capacity to be consumed are traversed and cycled to calculate the two-dimensional probability distribution of the risk of water abandonment at different time nodes for different magnitudes of storage capacity to be consumed p0=1, 2,...,p, k=1, 2,...,n-1.

13. The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs according to claim 12, characterized in that: The step 5.3) further comprises: (4) Between the start time node T0 of the decline period and the end time node T1 of the decline period, select z important control time nodes according to the scheduling operation needs. And there are: (5) Statistics V ds Different levels of storage capacity to be consumed at z important control time nodes The risk probability of water abandonment is calculated, and a two-dimensional water abandonment risk probability query chart is drawn.

14. A cascade reservoir drawdown period water abandonment risk analysis system, characterized by: The method for analyzing the risk of water abandonment during the drawdown period of cascade reservoirs based on the water abandonment prevention guidance line for realizing any one of claims 1 to 13 comprises: Data acquisition module, used to obtain cascade reservoir engineering characteristic data, dispatching operation data and long series runoff data; The data processing module is used to process the data obtained by the data collection module, obtain the two-dimensional probability distribution of the risk of water abandonment at different time points of the cascade reservoirs with different storage capacities to be eliminated, and form a water abandonment risk probability query chart; The result output module is used to output a water abandonment risk probability query chart.

15. A computer device, characterized in that: It includes a memory and a processor, the memory is used to store at least one program, and the processor is used to load the at least one program to execute the risk analysis method of water abandonment in cascade reservoirs during the drawdown period based on the water abandonment prevention guidance line as described in any one of claims 1 to 13.

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