Risk analysis method for abandoned water of cascade reservoirs based on abandoned water guideline

Abstract

The application discloses a kind of based on the risk analysis method of abandoned water of cascade reservoir drawdown period according to abandoned water guideline, comprising the following steps: collecting data;Generalize the maximum power generation flow constraint matrix of the most downstream reservoir drawdown period;Obtain the cascade reservoir inflow process after runoff reappears calculation;Determine the threshold of the available storage capacity on the abandoned water guideline and the reservoir capacity boundary condition at the end of drawdown period;Derive the cluster of abandoned water guideline of cascade reservoir in years;Form the abandoned water risk probability query chart.The method provided by the application has the advantages of being simple and practical, reasonable and reliable, easy to popularize, etc.According to the characteristics of cascade reservoir dispatching, the abandoned water dispatching operation guideline under different inflow conditions of cascade reservoir and the probability of different storage capacity in drawdown period to occur abandoned water risk are quickly given, the risk of abandoned water in reservoir dispatching is timely warned, which meets the operation characteristics of actual reservoir dispatching, and can provide support for real-time adjustment of dispatching strategy for reservoir operation and management department.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water conservancy and hydropower, and particularly refers to a cascade reservoir drawdown period water abandonment risk analysis method based on a water abandonment prevention guide line. BACKGROUND

[0002] Reducing water abandonment is an important goal of cascade reservoir power station operation during the drawdown period. Generally, cascade reservoir power stations maintain a high water level before the drawdown period to improve the water resource utilization efficiency of cascade power stations; and then the drawdown is accelerated to reduce the reservoir water level to the specified operating range during the flood period. Due to the long time span of the drawdown period, the power generation flow of cascade reservoir power stations is restricted by multiple factors such as power station maintenance, line maintenance, power grid peak regulation, water supply scheduling, and ecological scheduling. Due to the relatively low accuracy of medium and long-term inflow prediction, once the late inflow is large, the reservoir will have to abandon water through the opening of the gate to reduce the reservoir water level to the specified operating range at the end of the drawdown period.

[0003] At present, the traditional reservoir scheduling diagram water abandonment prevention line is usually obtained by taking the full-load flow or fixed flow as the power generation flow. In fact, the power generation flow of reservoir power stations usually changes during the drawdown period due to the influence of multiple factors. Therefore, the traditional reservoir scheduling diagram has weak guidance for actual scheduling. At the same time, there is no overall water abandonment prevention guide line for cascade reservoirs to guide the scheduling operation of cascade reservoirs, which leads to the inability to dynamically and timely calculate and warn the probability of the occurrence of water abandonment risk.

[0004] Therefore, it is urgent to reasonably depict the power generation flow of cascade reservoirs under the influence of multiple factors at different stages of the drawdown period, to obtain the water abandonment prevention guide line of cascade reservoirs, to reduce the water abandonment during the drawdown period, and to timely calculate and warn the probability of the occurrence of water abandonment risk, thereby providing a strong reference for the scheduling operation decision of cascade reservoirs. SUMMARY

[0005] In order to overcome the above technical deficiencies, the present application provides a cascade reservoir drawdown period water abandonment risk analysis method based on a water abandonment prevention guide line, to obtain the water abandonment prevention guide line of cascade reservoirs, to reduce the water abandonment during the drawdown period, and to timely calculate and warn the probability of the occurrence of water abandonment risk, thereby providing a strong reference for the scheduling operation decision of cascade reservoirs.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A cascade reservoir drawdown period water abandonment risk analysis method based on a water abandonment prevention guide line, comprising the following steps:

[0008] 1) Collecting cascade reservoir engineering characteristic data, scheduling operation data and long series runoff data; the cascade reservoirs are A1, A2,..., An respectively. s s is the total reservoir capacity of the cascade reservoirs.

[0009] 2) Adopting time series analysis method to generalize the maximum power generation flow constraint matrix of the lowermost reservoir in different periods under the influence of various factors in drawdown period;

[0010] 3) Constructing the joint runoff regulation model of the upstream reservoir group of cascade reservoirs, and carrying out the calculation of the present for a long series of runoff data to obtain the runoff process into the reservoir of cascade reservoirs after the calculation of the present;

[0011] 4) Determining the threshold of the available storage capacity on the water loss prevention guideline and the reservoir capacity boundary condition at the end of the drawdown period; based on the determined maximum power generation flow constraint matrix and the runoff process into the reservoir of cascade reservoirs, calculating the available storage capacity distribution matrix of cascade reservoirs in different typical years and different time nodes, and deriving the cluster of water loss prevention guidelines of cascade reservoirs in years;

[0012] 5) Calculating the two-dimensional probability distribution of the risk of water loss of different storage capacities of cascade reservoirs at different time nodes, and forming the water loss risk probability query chart.

[0013] Preferably, in step 1), the engineering characteristics of cascade reservoirs include the normal water level, the flood control water level, the dead water level, the water level-storage capacity curve, the start and end time of the drawdown period, the full-flow discharge, and the water level requirement meeting the flood control safety at the end of the drawdown period; the dispatching operation data include the power generation flow process of the drawdown period since the operation of each reservoir, the power grid maintenance arrangement, and the power station maintenance arrangement; in the long series of runoff data, the time scale of the annual runoff series is ten-day average or daily average.

[0014] Preferably, step 1) comprises:

[0015] 1.1) Collecting the engineering characteristics of cascade reservoirs, dispatching operation data, and long series of runoff data of cascade reservoirs; wherein the long series of runoff data series has y years, and y≥30;

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

[0017] 1.3) For the starting time node T0 of the drawdown period and the ending time node T1 of the drawdown period, calculating the duration T of the drawdown period S , and dividing the duration T of the drawdown period S into n calculation periods, wherein n=T S / dt.

[0018] Preferably, in step 2), the various factors include power grid consumption, power station maintenance, line maintenance, water supply dispatching, and ecological dispatching.

[0019] Preferably, step 2) comprises:

[0020] 2.1) for the lowermost reservoir A in the cascade reservoirs s collecting typical dispatching event data of power station maintenance, line maintenance, and ecological dispatching in previous years, analyzing the calculation period v when the power station maintenance, line maintenance, and ecological dispatching occur, and extracting the outflow constraint under the influence of power station maintenance in the corresponding calculation period v outflow constraint under the influence of line maintenance outflow constraint required by ecological dispatching then the reservoir A s the maximum power generation flow constraint of the reservoir A is:

[0021]

[0022] in the formula: are all the reservoir A s the average flow of the reservoir A

[0023] 2.2) for other calculation periods w except the calculation period v in n calculation periods, collecting and calculating the lowermost reservoir A s the actual average outflow process of the reservoir A m is the actual operation years of the lowermost reservoir A s , m≤y; then the reservoir A s the maximum power generation flow constraint of the reservoir A in the calculation period w is:

[0024]

[0025] 2.3) combining the maximum power generation flow constraints of the reservoir A and in different calculation periods in steps 2.1) and 2.2) to construct the maximum power generation flow constraint matrix of the reservoir A s in the drawdown period:

[0026]

[0027] Preferably, the step 3) comprises:

[0028] 3.1) for the uppermost reservoir A1 in the cascade reservoirs, obtaining the engineering characteristic data and dispatching mode of the upper reservoir group of the reservoir A1, and constructing a joint runoff regulation model of the upper reservoir group of the reservoir A1;

[0029] 3.2) for a long series of runoff data, using the constructed joint runoff regulation model of the upper reservoir group to carry out runoff reappearance calculation, and proposing the inflow process of the uppermost reservoir A1 after runoff reappearance calculation and A1~A2, A2~A3,..., A s-1~ A s Runoff process of each interval

[0030] Preferably, the step 4) comprises:

[0031] 4.1) According to A1, A2,..., A s Normal water level Z of each reservoir 1,nsl , Z 2,nsl ,..., Z s,nsl , and the reservoir water level requirement meeting the flood control safety at the end of drawdown period and the flood control limit water level Z 1,fcl , Z 2,fcl ,..., Z s,fcl , the reservoir capacity value V corresponding to the normal water level of each reservoir is calculated based on the water level-capacity curve f r (Z~V) of each reservoir, r=1, 2,..., s-1, s 1,nsl , V 2,nsl ,..., V s,nsl , the reservoir capacity value corresponding to the reservoir water level requirement at the end of drawdown period and the reservoir capacity value V corresponding to the flood control limit water level 1,fcl , V 2,fcl ,..., V s,fcl , and the threshold value V of the dischargeable reservoir capacity is calculated 消,max and the dischargeable reservoir capacity of the cascade reservoir drawdown period end guideline

[0032] 4.2) The runoff process of any year i after the drawdown period is calculated and determined by step 3.2), and the whole water quantity regulation calculation of the cascade reservoir is carried out in reverse time sequence from the end of the drawdown period, to obtain the dischargeable reservoir capacity of the k calculation period of the i year flood control guideline

[0033] 4.3) Check whether the dischargeable reservoir capacity is overflowed, and if overflowed, the upper and lower limits are corrected;

[0034] 4.4) On the basis of steps 4.1)~4.3), the dischargeable reservoir capacity of the cascade reservoir at different calculation periods of the drawdown period flood control guideline of each year is obtained by traversing calculation of long series runoff data year by year;

[0035] 4.5) The cascade reservoir drawdown period flood control guideline cluster of each year is drawn with time as the horizontal axis and the dischargeable reservoir capacity of the cascade reservoir as the vertical axis;

[0036] 4.6) According to the cascade reservoir drawdown period flood control guideline cluster, the dischargeable reservoir capacity V max of the maximum power generation flow constraint matrix Q 消 process is obtained:

[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 of 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 application further provides a computer device comprising a memory and a processor, the memory is used for storing at least one program, and the processor is used for loading the at least one program to execute the above-mentioned method for analyzing the risk of abandoned water in the drawdown period of a cascade reservoir based on the abandoned water prevention guideline.

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

[0066] The method provided by the application has the advantages of being simple and practical, reasonable and reliable, easy to popularize, and the like, and according to the characteristics of cascade reservoir operation, the method quickly gives the abandoned water prevention operation guideline of the cascade reservoir under different inflow conditions and the risk probability of abandoned water under different to-be-discharged reservoir capacities in the drawdown period, timely gives a warning for the risk of abandoned water in reservoir operation, conforms to the operation characteristics of actual reservoir operation, and can provide support for real-time adjustment of the operation strategy of the reservoir operation and management department.

[0067] The application fully combines the actual law and operation requirements, reasonably induces the maximum power generation flow constraint in different periods under the influence of multiple factors such as maintenance of the hydropower station in the drawdown period, line maintenance, power grid peak regulation, and ecological operation, and conforms to the actual operation characteristics of the reservoir.

[0068] The application takes the dischargeable reservoir capacity as the target, provides a method for deriving the abandoned water prevention guideline of the cascade reservoir, the method is simple and practical, reasonable and reliable, conforms to the actual operation characteristics, can quickly give the abandoned water prevention operation guideline of the cascade reservoir under different inflow conditions, and provides a reference for the control of the drawdown reservoir capacity of the cascade reservoir.

[0069] The application can quickly give the probability distribution of the risk of abandoned water in the real-time operation of the cascade reservoir under different inflow conditions and in subsequent different periods and the abandoned water risk probability query chart, timely gives a warning for the risk of abandoned water in the reservoir operation, and provides effective support for the operation strategy of the reservoir. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 It is an implementation flowchart of the method for analyzing the risk of abandoned water in the drawdown period of a cascade reservoir based on the abandoned water prevention guideline;

[0071] Figure 2 It is a calculation flowchart of the dischargeable reservoir capacity of the cascade reservoir in different calculation periods in the drawdown period;

[0072] Figure 3 It is a calculation flowchart of the risk probability of abandoned water of different magnitudes of to-be-discharged reservoir capacity;

[0073] Figure 4 It is a cluster chart of the abandoned water prevention guideline of the cascade reservoir in different years;

[0074] Figure 5 It is an abandoned water risk probability query chart of the cascade reservoir from May 1 to June 21 in the embodiment. DETAILED DESCRIPTION

[0075] In order to better explain the present application, the main content of the present application is further illustrated below in combination with specific examples, but the content of the present application is not limited to the following examples only.

[0076] As shown in the Figure 1 , the present application provides a cascade reservoir drawdown period draw-off water risk analysis method based on a draw-off water prevention guideline, specifically comprising the following steps:

[0077] 1) Collecting cascade reservoir engineering characteristic basic data, scheduling operation data and long series runoff data. Specifically including:

[0078] 1.1) Collecting data

[0079] The cascade reservoir engineering characteristic data includes normal water level, flood control water level, dead water level, water level-storage capacity curve, start and end time of drawdown period, full-flow, drawdown period end reservoir water level requirement meeting flood control safety of each reservoir, etc.

[0080] The scheduling operation data includes power generation flow process of each reservoir since operation, power grid maintenance arrangement, power station maintenance arrangement, etc.

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

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

[0083] 1.3) For the drawdown period start time node T0 and the drawdown period end time node T1, calculate the drawdown period duration T S , divide the drawdown period duration T S into n calculation periods, where n=T S / dt.

[0084] 2) Using time series analysis method to generalize the maximum power generation flow constraint matrix of different periods of the lowermost reservoir drawdown period under the influence of power grid consumption, hydropower station maintenance, line maintenance, water supply scheduling, ecological scheduling, etc. Assuming that from upstream to downstream are reservoirs A1, A2,..., A s , s is the number of cascade reservoirs.

[0085] Specifically including:

[0086] 2.1) For the lowermost reservoir A s, collect typical scheduling event data of power station maintenance, line maintenance, ecological scheduling and other factors affecting the maximum power generation flow of reservoir power station in previous years, analyze the calculation period of water power station maintenance, line maintenance, ecological scheduling and other factors v.

[0087] Extract the outflow constraint under the influence of power station maintenance in the corresponding calculation period v Outflow constraint under the influence of line maintenance Outflow constraint required by ecological scheduling Then the reservoir A s The maximum power generation flow constraint in the calculation period v is:

[0088]

[0089] In the formula: are the reservoir A s The average flow in the calculation period v.

[0090] 2.2) For other calculation periods w except the calculation period v in n calculation periods, collect and calculate the actual average outflow process of the downstream reservoir A s in the period m is the actual operation years of the downstream reservoir A s , m≤y; then the reservoir A s The maximum power generation flow constraint in the calculation period w is:

[0091]

[0092] 2.3) Merge the maximum power generation flow constraints of reservoir A and in different calculation periods in steps 2.1) and 2.2) s to construct the maximum power generation flow constraint matrix of reservoir A

[0093]

[0094] 3) Construct the joint runoff regulation model of the reservoir group, carry out runoff return calculation for long series of runoff data, and propose the reservoir inflow runoff process after runoff return calculation. Specifically includes:

[0095] 3.1) For the uppermost reservoir A1 in the cascade reservoir, obtain the engineering characteristics data and scheduling mode of the reservoir group in the upstream area of reservoir A1, and construct the joint runoff regulation model of the related 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 Overflow, if overflow, upper and lower limit correction. Details as follows:

[0103]

[0104] 4.4) On the basis of steps 4.1) ~ 4.3), the long series of runoff data are calculated year by year, and the cascade reservoirs can be consumed reservoir capacity of different calculation period of the guiding line of the falling period of the year.

[0105] 4.5) With time as the horizontal axis and the cascade reservoirs can be consumed reservoir capacity as the vertical axis, draw the cascade reservoirs of the year's defense water guiding line cluster.

[0106] 4.6) According to the cascade reservoirs of the defense water guiding line cluster, the distribution matrix of the cascade reservoirs can be consumed reservoir capacity V max based on the process is obtained: 消

[0107]

[0108] 5) Calculate the two-dimensional probability distribution of the risk of abandoning water of different to-be-consumed reservoir capacity at different time nodes, and form the risk probability query chart. As shown in Figure 3 , specifically including:

[0109] 5.1) Introducing the to-be-consumed reservoir capacity distribution matrix V ds for evaluating the risk of abandoning water:

[0110]

[0111] In the formula: p is the dimension of the to-be-consumed reservoir capacity distribution matrix V ds

[0112] 5.2) Based on the cascade reservoirs of the defense water guiding line cluster, select the calculation period k, and extract the kth row vector of V 消 :

[0113]

[0114] 5.3) For the to-be-consumed reservoir capacity ds in the matrix V , the years y0 greater than are counted, and the to-be-consumed reservoir capacity in the calculation period k is the risk probability of abandoning water :

[0115]

[0116] 5.4) Further traverse other calculation periods to obtain the to-be-consumed reservoir capacity ​​​In different calculated water abandonment risk probability distribution

[0117] 5.5) Based on steps 5.2) to 5.4), the V ds The two-dimensional probability distribution of the water abandonment risk of different magnitudes of the to-be-discharged reservoir capacity at different time nodes is calculated through a traversal cycle of other magnitudes of the to-be-discharged reservoir capacity

[0118] 5.6) Between the starting time node T0 of the drawdown period and the ending time node T1 of the drawdown period, z important control time nodes are selected according to the scheduling operation needs And:

[0119]

[0120] 5.7) The water abandonment risk probabilities of different magnitudes of the to-be-discharged reservoir capacity at the time nodes in step 5.6) are counted, and a two-dimensional water abandonment risk probability query chart is drawn. ds

[0121] Through the above method, the probability distribution of the water abandonment risk of the cascade reservoirs at different water inflow conditions and in subsequent time periods in real-time scheduling and the water abandonment risk probability query chart can be quickly given, the water abandonment risk in reservoir scheduling is warned in time, and effective support is provided for the reservoir scheduling strategy.

[0122] The application further provides a cascade reservoir drawdown period water abandonment risk analysis system for realizing the above-mentioned cascade reservoir drawdown period water abandonment risk analysis method based on the water abandonment prevention guide line, comprising:

[0123] A data acquisition module is configured to perform step 1) in the above-mentioned method, acquire the cascade reservoir engineering characteristic data, the scheduling operation data and the long-series runoff data, and acquire the scheduling period.

[0124] A data processing module is configured to perform steps 2) to 5) in the above-mentioned method, process the data collected by the data collection module, obtain the two-dimensional probability distribution of the water abandonment risk of different to-be-discharged reservoir capacities of the cascade reservoirs at different time nodes, and form a water abandonment risk probability query chart.

[0125] A result output module is configured to output the water abandonment risk probability query chart.

[0126] The application further provides a computer device comprising a memory and a processor, wherein the memory is configured to store at least one program, and the processor is configured to load the at least one program to execute the above-mentioned cascade reservoir drawdown period water abandonment risk analysis method based on the water abandonment prevention guide line.

[0127] The application scheme is further described through the following 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 illustrated cascade reservoirs of the years of the abandoned water guide line cluster. According to the cascade reservoirs of the abandoned water guide line cluster, the distribution matrix of the available storage V 消 is obtained.

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

[0139]

[0140] 5) Introducing the evaluation of the abandoned water risk distribution matrix of the available storage V ds

[0141]

[0142] The V ds The two-dimensional probability distribution of the occurrence of the abandoned water risk of different orders of the available storage at different time nodes is calculated by traversing the loop of each order of the available storage in V Between the starting time node of the calculation of the drawdown period December 31 and the end time node of the drawdown period June 30, according to the needs of the scheduling operation, the important control time nodes May 1, May 11, May 21, June 1, June 11 and June 21 are selected.

[0143] The abandoned water risk probability of different orders of the available storage at the above-mentioned time nodes in V ds is counted, and the two-dimensional abandoned water risk probability query chart is drawn, which is shown in Figure 5 and Table 3, respectively.

[0144] Table 3: Abandoned water risk probability query table of each time node from May 1 to June 21

[0145]

[0146] Through the above method, the probability distribution of the abandoned water risk of the cascade reservoirs in real-time scheduling under different inflow conditions and in subsequent different periods and the abandoned water risk probability query chart can be quickly given, the risk of the occurrence of the abandoned water in the reservoir scheduling can be timely warned through Table 3, and effective support is provided for the reservoir scheduling strategy.

Claims

1. A cascade reservoir drawdown period abandoned water risk analysis method based on abandoned water guidelines, characterized by: The method comprises the following steps: 1) Collecting the data of cascade reservoir engineering characteristics, scheduling operation data and long series runoff data; the cascade reservoirs are A1, A2,..., A s s is the total reservoir capacity of the cascade reservoirs; 2) using time series analysis method to generalize the maximum power generation flow constraint matrix of the lowermost reservoir in different periods under the influence of various factors in the drawdown period; 3) constructing a joint runoff regulation model of the upstream reservoir group of the cascade reservoir, and carrying out the present calculation based on the long series of runoff data to obtain the reservoir inflow runoff process of the cascade reservoir after the runoff present calculation; 4) determining the threshold of the available storage capacity on the water loss prevention guide line and the reservoir capacity boundary condition at the end of the drawdown period; based on the determined maximum power generation flow constraint matrix and the reservoir inflow runoff process of the cascade reservoir, the available storage capacity distribution matrix of the cascade reservoir in different typical years and different time nodes is calculated, and the cascade reservoir annual water loss prevention guide line cluster is derived; 4.1) According to A1, A2,..., As s Normal water storage level Z of each reservoir 1,nsl , Z 2,nsl ,..., Z s,nsl , the reservoir water level requirement to meet the flood control safety at the end of drawdown period and the flood control limit water level Z 1,fcl , Z 2,fcl ,..., Z s,fcl , based on the water level-storage capacity curve f r (Z~V) of each reservoir, r=1, 2,..., s-1, s, calculate the corresponding storage capacity value V of the normal water storage level of each reservoir 1,nsl , V 2,nsl ,..., V s,nsl , the corresponding storage capacity value of the reservoir water level requirement at the end of drawdown period and the corresponding storage capacity value V of the flood control limit water level 1,fcl , V 2,fcl ,..., V s,fcl , and calculate the threshold value V of the consumable storage capacity 消,max and the consumable storage capacity of the cascade reservoir flood control line at the end of drawdown period The threshold value V of the consumable storage capacity 消,max and the consumable storage capacity of the cascade reservoir flood control line at the end of drawdown period is calculated as follows: 4.2) Using the determined runoff process after the recession period of any year i, the whole reservoir water quantity dispatching calculation is carried out in reverse time sequence from the end of the recession period, and the dischargeable reservoir capacity of the i-year discharge prevention water guide line in the kth calculation period is obtained the dischargeable reservoir capacity of the i-year discharge prevention water guide line in the kth calculation period The calculation method is as follows: 4.3) Check the available capacity whether overflow, if overflow, the upper and lower limits of the correction method of available capacity upper and lower limits of the correction method as follows: 4.4) on the basis of steps 4.1) to 4.3), the long series of runoff data is calculated year by year to obtain the available storage capacity of the cascade reservoir in different calculation periods on the annual drawdown period water loss prevention guide line; 4.5) taking time as the horizontal axis and the available storage capacity of the cascade reservoir as the vertical axis, the cascade reservoir annual water loss prevention guide line cluster is drawn; 4.6) According to the cluster of the abandoned water prevention guidelines of the cascade reservoir, the constraint matrix Q based on the maximum power generation flow is obtained max The distribution matrix of the process of the consumable reservoir V 消 ​ 5) calculating the two-dimensional probability distribution of the water loss risk of the cascade reservoir in different available storage capacities at different time nodes to form a water loss risk probability query chart.

2. The stepped reservoir drawdown period water abandonment risk analysis method according to claim 1, characterized in that: In the step 1), the cascade reservoir engineering characteristic data includes the normal water level, the flood control water level, the dead water level, the water level-storage capacity curve, the start and end time of the drawdown period, the full discharge flow, and the reservoir water level requirement meeting the flood control safety at the end of the drawdown period; the dispatching operation data includes the power generation flow process of each reservoir in the drawdown period since operation, the power grid maintenance arrangement, and the power station maintenance arrangement; in the long series of runoff data, the time scale of the annual runoff series is ten-day average or daily average.

3. The stepped reservoir drawdown period water abandonment risk analysis method according to claim 1, characterized in that: The step 1) comprises: 1.1) collecting the cascade reservoir engineering characteristic data, the dispatching operation data, and the long series of runoff data of the cascade reservoir; wherein the long series of runoff data series has y years, and y≥30; 1.2) determining the time step dt of the simulation calculation in the drawdown period based on the time scale of the long series of natural runoff data; 1.3) Calculate the duration of the drawdown period T for the starting time node T0 and the ending time node T1 of the drawdown period S , divide the duration of the drawdown period T S into n calculation periods, where n = T S / dt.

4. The stepped reservoir drawdown period water abandonment risk analysis method of claim 1, wherein: In the step 2), the various factors include power grid consumption, power station maintenance, line maintenance, water supply dispatching, and ecological dispatching.

5. The stepped reservoir drawdown period water abandonment risk analysis method of claim 4, wherein: The step 2) comprises: 2.1) for the lowermost reservoir A in the cascade of reservoirs s , collect typical dispatching event data of hydropower station maintenance, line maintenance, and ecological dispatching in previous years, analyze the calculation period v when the hydropower station maintenance, line maintenance, and ecological dispatching occur, and extract the outflow constraint under the influence of hydropower station maintenance in the corresponding calculation period v outflow constraint under the influence of line maintenance outflow constraint required by ecological dispatching Then, the reservoir A s The maximum power generation flow constraint in the calculation period v is: wherein: are both reservoirs A s calculate the average flow for period v; 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: 2.3) combining steps 2.1) and 2.2) and Construction of reservoir A s The maximum power generation flow constraint matrix at different calculation periods of the drawdown period:

6. The stepped reservoir drawdown period water abandonment risk analysis method of claim 1, wherein: The step 3) comprises: 3.1) for the uppermost reservoir A1 in the cascade reservoir, obtaining the engineering characteristic data and the dispatching mode of the upstream reservoir group of the reservoir A1, and constructing a joint runoff regulation model of the upstream reservoir group of the reservoir A1; 3.2) For long series of runoff data, the constructed upstream reservoir group joint runoff regulation model is used to carry out runoff restoration calculation, and the reservoir inflow process of the uppermost reservoir A1 after runoff restoration calculation is proposed and A1~A2, A2~A3,..., A s-1 ~A s Runoff process of each interval 7. The stepped reservoir drawdown period water abandonment risk analysis method of claim 1, wherein: The step 5) comprises: 5.1) Introducing the matrix V of the distribution of the reservoir volumes to be depleted to assess the risk of water abandonment ds : wherein: are different orders of magnitude of the to-be-eliminated library capacity, p is the dimension of the to-be-eliminated library capacity distribution matrix V ds . 5.2) The cascade reservoir-based abandoned water guideline cluster, select the calculation period k, extract V 消 the kth row vector: 5.3) For matrix V ds In the different orders of magnitude of the to-be-eliminated storage capacity, statistics In the years greater than each order of magnitude, the to-be-eliminated storage capacity V of different orders of magnitude is calculated ds The water abandonment risk probability of each calculation period is formed to form a water abandonment risk probability query chart.

8. The stepped reservoir drawdown period water abandonment risk analysis method of claim 7, wherein: The step 5.3) comprises: (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: (2) Further iterate over other computation periods to obtain the to-be-eliminated storage capacity Risk probability distribution of abandoned water at different computation periods (3) on V ds The two-dimensional probability distribution of the risk of abandoning water at different time nodes of different orders of magnitude of the to-be-eliminated storage capacity is calculated through a traversal cycle of other orders of magnitude of the to-be-eliminated storage capacity 9. The stepped reservoir drawdown period water abandonment risk analysis method of claim 8, wherein: The step 5.3) further comprises: (4) Between the initial time node T0 of the drawdown period and the final time node T1 of the drawdown period, according to the scheduling operation needs, select z important control time nodes And also: (5) Statistics V ds the different orders of magnitude of the reservoir capacity to be eliminated at the z important control time nodes the probability of water abandonment at the different orders of magnitude of the reservoir capacity to be eliminated at the z important control time nodes, and draw a two-dimensional probability query chart of water abandonment.

10. A cascade reservoir drawdown period abandoned water risk analysis system, characterized in that: The cascade reservoir drawdown period water loss risk analysis method based on the water loss prevention guide line as claimed in any one of claims 1 to 9 comprises: a data acquisition module for acquiring the cascade reservoir engineering characteristic data, the dispatching operation data, and the long series of runoff data; a data processing module for processing the data collected by the data collection module to obtain the two-dimensional probability distribution of the water loss risk of the cascade reservoir in different available storage capacities at different time nodes, and form a water loss risk probability query chart; a result output module for outputting the water loss risk probability query chart.

11. A computer device, characterized by: The application relates to a device for analyzing the risk of abandoned water in a cascade reservoir based on the abandoned water guideline, comprising a memory for storing at least one program and a processor for loading the at least one program to execute the method for analyzing the risk of abandoned water in a cascade reservoir based on the abandoned water guideline according to any one of claims 1-9.

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