A dispatching method for cascade hydropower stations based on real-time collaborative fault response model

Abstract

The present application relates to the technical field of optimized dispatching of hydropower stations, and discloses a dispatching method of a water diversion series cascade power station based on a real-time collaborative fault response model, which aims to solve the problem of existing dispatching schemes that affect the stability of the power grid. The scheme mainly includes: constructing an objective function and constraint conditions of the planned load and actual output of the water diversion series cascade power station, and establishing a hybrid quadratic programming model based on the objective function and constraint conditions to obtain a real-time collaborative fault response model of the water diversion series cascade power station; when a generator set of the water diversion series cascade power station fails, obtaining the boundary conditions of the water diversion series cascade power station; solving the real-time collaborative fault response model based on the boundary conditions and using a solver to obtain the planned output of each generator set, and dispatching the water diversion series cascade power station in real time according to the planned output of each generator set. The present application improves the accuracy of dispatching of water diversion series cascade power stations and the stability of the power grid.

Description

Technical Field

[0001] The present application relates to the technical field of optimized dispatching of hydropower stations, and in particular to a method for dispatching water-diverting series cascade power stations based on a real-time collaborative fault response model. Background Art

[0002] Traditional cascade power stations are arranged along the main stream of the river according to the river drop and topographic and geological conditions. Each power station generally has a certain regulating reservoir capacity and is more flexible in scheduling and operation. The layout of the water diversion series cascade power station is unique. The main stream is dammed to form a reservoir. The first-level power station draws water from the reservoir to generate electricity. Two or more power stations are arranged along the water diversion line. The power stations at each level are hydraulically connected through the regulating pool. The next-level power station receives the tail water of the previous power station for power generation, and the tail water of the last-level power station returns to the main stream. Since the water diversion and power generation system of the water diversion series cascade power station is not arranged along the main stream and is restricted by the construction conditions, the storage capacity of the regulating pool connecting the upstream and downstream cascades is very limited. If the power generation flow of the upstream and downstream power stations is not coordinated, causing the surplus water of a certain power station to overflow, it will cause a series of secondary disasters. Therefore, compared with the traditional water diversion series cascade power station, the biggest feature of the water diversion series cascade power station in terms of operation is that the power generation flow of the upstream and downstream power stations needs to be matched in real time. At the same time, due to the large installed capacity of the water diversion series cascade power station, the power supply range may be multiple power grids.

[0003] When some generators fail to operate and shed load in traditional cascade hydropower stations, the scheduling scheme usually adopted is to increase the output of other generators in the cascade to compensate for the insufficient output of the faulty generators as much as possible, and to supplement it with the spare capacity of the power transmission grid. However, this regulation method is not applicable to water diversion cascade power stations in series. Since the power generation flow of each power station must be matched during operation, when the generator set of a power station fails and sheds load, increasing the output of the generator sets of other cascades will further increase the deviation of the power generation flow of the upstream and downstream power stations; if the corresponding generator sets of the downstream power station are considered to reduce the output synchronously to ensure flow matching, the load shedding in this case is large, which has a strong impact on the stability of the power grid. Summary of the invention

[0004] The present application aims to solve the problem that the existing scheduling scheme of water diversion series cascade power stations affects the stability of the power grid, and proposes a scheduling method for water diversion series cascade power stations based on a real-time collaborative fault response model.

[0005] The technical solution adopted by this application to solve the above technical problems is:

[0006] A method for dispatching a series of cascade power stations using water diversion based on a real-time collaborative fault response model, the method comprising:

[0007] Constructing the objective function and constraint conditions of the planned load and actual output of the water diversion series cascade power station, and establishing a hybrid quadratic programming model based on the objective function and constraint conditions to obtain a real-time collaborative fault response model of the water diversion series cascade power station;

[0008] When the generator set of the water diversion series cascade power station fails, the boundary conditions of the water diversion series cascade power station are obtained;

[0009] Based on the boundary conditions and using a solver, the real-time collaborative fault response model is solved to obtain the planned output of each generator set, and the water diversion series cascade power stations are dispatched in real time according to the planned output of each generator set.

[0010] Furthermore, it is characterized in that the objective function is as follows:

[0011] ;

[0012] in, Indicates deviation, Indicates the minimum value, Indicates the number of power grids connected in series with cascade power stations. Indicates the total number of time periods, Indicates The power grid is The planned load of the time period, Indicates The power grid is The actual output during the period.

[0013] Furthermore, the constraints include water balance constraints, water level constraints, unit power generation flow constraints, unit output constraints, climbing constraints, unit start and shutdown constraints, water level storage capacity curves and unit power generation characteristic curves.

[0014] Furthermore, the water balance constraint is as follows:

[0015] ;

[0016] in, Indicates The power station is The storage capacity of the time period, Indicates The power station is The inbound flow of the time period, Indicates The power station is The outbound flow of the time period, is the length of a period;

[0017] The water level constraints are as follows:

[0018] ;

[0019] ;

[0020] In the formula, Indicates The power station is The water level during the period, Indicates The upstream regulating pond of the power station is The water level during the period, Indicates The lower limit of the water level of a power station, Indicates The upper limit of the water level of a power station.

[0021] Furthermore, the power generation flow constraints of the unit are as follows:

[0022] , ;

[0023] in, Indicates The first power station The generator set is in The power generation flow during the period, Indicates The first power station The lower limit of the power generation flow of each generator set, Indicates The first power station The upper limit of the power generation flow of each generator set, Indicates The first power station The generator set is in The operation status identification of the time period;

[0024] The unit output constraints are as follows:

[0025] ;

[0026] in, Indicates The first power station The generator set is in Output during the period, Indicates The first power station The lower limit of the output of each generator set, Indicates The first power station The output limit of each generator set;

[0027] The climbing constraints are as follows:

[0028] ;

[0029] in, Indicates The first power station The generator set is in The ramp rate limit for the time period;

[0030] The unit start and stop constraints are as follows:

[0031] ;

[0032] , ;

[0033] ;

[0034] ;

[0035] ;

[0036] in, Indicates The first power station The generator set is in The power-on status indicator of the time period, Indicates The first power station The generator set is in The shutdown status indicator of the time period, Indicates The first power station The maximum start-up time of each generator set, Indicates The first power station The duration of the outage of the generator set.

[0037] Furthermore, the water level storage capacity curve is as follows:

[0038] ;

[0039] in, Indicates Water level storage capacity function of each power station;

[0040] The power generation characteristic curve of the unit is as follows:

[0041] ;

[0042] in, Indicates The first power station The characteristic curve function of a generator set, Indicates The first power station The generator set is in The power generation head during the period.

[0043] Furthermore, the method further comprises:

[0044] The water level of each power station is divided into After the discrete values ​​corresponding to each water level interval are determined, the water level storage capacity curve is linearly converted. The conversion formula is as follows:

[0045] ;

[0046] ;

[0047] , ;

[0048] , ;

[0049] ;

[0050] in, Indicates The first power station The water level interval is The weight coefficient of the time period, Indicates The first power station The discrete value corresponding to the water level interval is Indicates The first power station The storage capacity of each water level interval, Indicates the auxiliary variable introduced. If The power station is The water level during this period fell into water level interval, then ,otherwise .

[0051] Furthermore, the method further comprises:

[0052] The power generation flow of each power station’s generator set is divided into flow intervals, and determine the discrete values ​​corresponding to each flow interval, and divide the generating head of the generator set of each power station into After the discrete values ​​corresponding to each head interval are determined, the power generation characteristic curve of the unit is linearly converted. The conversion formula is as follows:

[0053] ;

[0054] ;

[0055] ;

[0056] ;

[0057] ;

[0058] in, Indicates The power station is The power characteristic curve of the generator set during the period ( , ) corresponding to the output; Indicates The power characteristic curve of the generator set of the power station The discrete value corresponding to each flow interval; Indicates The power characteristic curve of the generator set of the power station The discrete value corresponding to the head interval is Indicates The generator set of the power station is The dynamic characteristic curve of the time period ( , ) corresponding to the weight value.

[0059] Furthermore, the boundary conditions of the water diversion series cascade power stations include at least the number of power grids, the number of power stations, the number of generator sets of each power station, the scheduling period of the water diversion series cascade power stations and the corresponding planned load, the lower and upper water level limits of each power station, the lower and upper output limits of each generator set, the upper and lower output limits, the lower and upper power generation flow limits and the climbing rate limit, the parameters of the water level storage capacity curve and the unit characteristic curve, the current water level of each power station, and the current power generation flow and current output of each generator set.

[0060] Furthermore, based on the boundary conditions and using a solver, the real-time collaborative fault response model is solved, specifically including:

[0061] After the boundary conditions are input into the hybrid quadratic programming model, the Gurobi solver is called to automatically perform optimization calculations to obtain the planned output of each generator set when the deviation of the objective function is minimized.

[0062] The beneficial effects of the present application are as follows: the present application provides a method for dispatching a water diversion series cascade power station based on a real-time collaborative fault response model, by constructing the objective function and constraint conditions of the water diversion series cascade power station, and then constructing a real-time collaborative fault response model of the water diversion series cascade power station. When some generator sets fail to operate, the solver is used to obtain the planned output of each generator set on the real-time collaborative fault response model, and the output of the generator sets of each power station is dynamically adjusted according to the planned output, thereby accurately realizing the dynamic real-time dispatching of the water diversion series cascade power station, and improving the accuracy of the dispatching of the water diversion series cascade power station. In addition, multiple power grids can jointly bear the load shedding caused by the fault, reducing the impact on a single power grid and improving the stability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A flow chart of a method for dispatching a series of cascade power stations using water diversion based on a real-time collaborative fault response model provided in an embodiment of the present application;

[0064] Figure 2 A schematic diagram of a three-dimensional interpolation calculation provided in an embodiment of the present application;

[0065] Figure 3 A schematic diagram of the structure of a water diversion series cascade power station provided in an embodiment of the present application;

[0066] Figure 4 A schematic diagram of the system load, residual load and planned output of the power grid 1 provided in an embodiment of the present application;

[0067] Figure 5 A schematic diagram of changes in the system load, residual load, and planned output of the power grid 2 provided in an embodiment of the present application;

[0068] Figure 6 A schematic diagram of output variation of the power grid 1 when a generator set fails provided in an embodiment of the present application;

[0069] Figure 7 A schematic diagram of output variation of the power grid 2 when a generator set fails provided in an embodiment of the present application;

[0070] Figure 8 A schematic diagram of output changes of each generator set when one generator set fails provided in an embodiment of the present application;

[0071] Fig. 9 A schematic diagram of output variation of the power grid 1 when two generator sets fail according to an embodiment of the present application;

[0072] Fig.10 A schematic diagram of output variation of the power grid 2 when two generator sets fail according to an embodiment of the present application;

[0073] Fig.11A schematic diagram of the output change of each generator set when two generator sets fail in an embodiment of the present application. DETAILED DESCRIPTION

[0074] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0075] In some of the processes described in the specification of this application and the above-mentioned figures, multiple operations appearing in a specific order are included, but it should be clearly understood that these operations may not be executed in the order in which they appear in this article or may be executed in parallel. The sequence numbers of the operations are only used to distinguish different operations, and the sequence numbers themselves do not represent any execution order. In addition, these processes may include more or fewer operations, and these operations may be executed in sequence or in parallel.

[0076] The technical solution of the embodiment of the present application is applicable to a water diversion series cascade power station having multiple power grids.

[0077] At present, when some generators in the cascade power station are faulty and load shedding occurs, the scheduling scheme usually adopted is that other generators in the cascade increase their output to compensate for the insufficient output of the faulty generators as much as possible, and the spare capacity of the power transmission grid is used to supplement it. After research, the inventor found that if this scheduling method is applied to the cascade power station in series, it may increase the deviation of the power generation flow of the upstream and downstream power stations and have a strong impact on the stability of the power grid.

[0078] Based on this, the technical solution of the present application is proposed. In an embodiment of the present application, by constructing the objective function and constraints of the planned load and actual output of the water diversion series cascade power station, and establishing a hybrid quadratic programming model according to the objective function and constraints, a real-time collaborative fault response model of the water diversion series cascade power station is obtained; when a generator set of the water diversion series cascade power station fails, the boundary conditions of the water diversion series cascade power station are obtained; based on the boundary conditions and using a solver, the real-time collaborative fault response model is solved to obtain the planned output of each generator set, and the water diversion series cascade power station is dispatched in real time according to the planned output of each generator set.

[0079] Specifically, this application constructs a real-time collaborative fault response model for cascade power stations connected in series with water diversion. The real-time collaborative fault response model can minimize the power output deviation caused by generator failures, thereby ensuring the stability of the power grid. The new output plan obtained by solving can minimize the negative impact caused by unit failures, ensure the stability and reliability of power grid operation, and minimize the impact on the power grid.

[0080] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0081] Figure 1 A flow chart of a method for dispatching a series of cascade power stations based on a real-time collaborative fault response model is shown in FIG. Figure 1 , the method comprises the following steps:

[0082] S1. Construct an objective function and constraint conditions for the planned load and actual output of the water diversion cascade power station in series, and establish a hybrid quadratic programming model based on the objective function and constraint conditions to obtain a real-time collaborative fault response model for the water diversion cascade power station in series.

[0083] In the embodiment of the present application, the objective function is as follows:

[0084] ;

[0085] in, Indicates deviation, Indicates the minimum value, Indicates the number of power grids connected in series with cascade power stations. Indicates the total number of time periods, Indicates The power grid is The planned load of the time period, Indicates The power grid is The actual output during the period.

[0086] In an embodiment of the present application, the constraints include water balance constraints, water level constraints, unit power generation flow constraints, unit output constraints, climbing constraints, unit start and shutdown constraints, water level storage capacity curves and unit power generation characteristic curves.

[0087] The water balance constraints are as follows:

[0088] ;

[0089] in, Indicates The power station is The storage capacity of the time period, Indicates The power station is The inbound flow of the time period, Indicates The power station is The outbound flow of the time period, is the length of a period;

[0090] The water level constraints are as follows:

[0091] ;

[0092] ;

[0093] In the formula, Indicates The power station is The water level during the period, Indicates The upstream regulating pond of the power station is The water level during the period, Indicates The lower limit of the water level of a power station, Indicates The upper limit of the water level of a power station.

[0094] The power generation flow constraints of the unit are as follows:

[0095] , ;

[0096] in, Indicates The first power station The generator set is in The power generation flow during the period, Indicates The first power station The lower limit of the power generation flow of each generator set, Indicates The first power station The upper limit of the power generation flow of each generator set, Indicates The first power station The generator set is in The operation status identification of the time period;

[0097] The unit output constraints are as follows:

[0098] ;

[0099] in, Indicates The first power station The generator set is in Output during the period, Indicates The first power station The lower limit of the output of each generator set, Indicates The first power station The output limit of each generator set;

[0100] The climbing constraints are as follows:

[0101] ;

[0102] in, Indicates The first power station The generator set is in The ramp rate limit for the time period;

[0103] The unit start and stop constraints are as follows:

[0104] ;

[0105] , ;

[0106] ;

[0107] ;

[0108] ;

[0109] in, Indicates The first power station The generator set is in The power-on status indicator of the time period, Indicates The first power station The generator set is in The shutdown status indicator of the time period, Indicates The first power station The maximum start-up time of each generator set, Indicates The first power station The duration of the outage of the generator set.

[0110] The water level storage capacity curve is as follows:

[0111] ;

[0112] in, Indicates Water level storage capacity function of each power station;

[0113] The power generation characteristic curve of the unit is as follows:

[0114] ;

[0115] in, Indicates The first power station The characteristic curve function of a generator set, Indicates The first power station The generator set is in The power generation head during the period.

[0116] The embodiment of the present application aims at the linearization of complex constraint problems, and adopts piecewise linearization or the method of introducing 0-1 variables to convert the nonlinear functions corresponding to the water level storage capacity curve and the unit power generation characteristic curve into linear functions.

[0117] Specifically, the water level storage capacity curve is usually in the form of a quartic polynomial, so the embodiment of the present application adopts a piecewise linearization method to approximate it. After determining the discrete values ​​corresponding to each water level interval, the water level storage capacity curve is piecewise linearly interpolated by introducing auxiliary variables to achieve linear conversion of the water level storage capacity curve. The conversion formula is as follows:

[0118] ;

[0119] ;

[0120] , ;

[0121] , ;

[0122] ;

[0123] in, Indicates The first power station The water level interval is The weight coefficient of the time period, Indicates The first power station The discrete value corresponding to the water level interval is Indicates The first power station The storage capacity of each water level interval, Indicates the auxiliary variable introduced. If The power station is The water level during this period fell into water level interval, then ,otherwise .

[0124] In the embodiment of the present application, a three-dimensional curve linearization processing method is used to linearize the power generation characteristic curve of the unit. Specifically, the power generation flow of the generator set of each power station can be divided into flow intervals, and determine the discrete values ​​corresponding to each flow interval, and divide the generating head of the generator set of each power station into After the discrete values ​​corresponding to each head interval are determined, the power generation characteristic curve of the unit is linearly converted. The conversion formula is as follows:

[0125] ;

[0126] ;

[0127] ;

[0128] ;

[0129] ;

[0130] in, Indicates The power station is The power characteristic curve of the generator set during the period ( , ) corresponding to the output; Indicates The power characteristic curve of the generator set of the power station The discrete value corresponding to each flow interval; Indicates The power characteristic curve of the generator set of the power station The discrete value corresponding to the head interval is Indicates The generator set of the power station is The dynamic characteristic curve of the time period ( , ) corresponding to the weight value.

[0131] See also Figure 2 In the embodiment of the present application, the power generation flow and the power generation head are divided into multiple intervals, and then the following is constructed: Figure 2 The three-dimensional interpolation calculation is then performed using the above formula to ensure that the calculation result can only fall into one triangular area, and the weight value of the triangle vertex can be obtained and the output value can be calculated. Figure 2 The horizontal axis represents the Each head interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation head, among which, Indicates The first head interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation head. Indicates The second head interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation head. Indicates The third head interval on the power characteristic curve of the generator set of the power station corresponds to the discrete value of the power generation head. Each flow interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation flow. Indicates The first flow interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation flow. Indicates The second flow interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation flow. Indicates The third flow interval on the power characteristic curve of the generator set of a power station corresponds to the discrete value of the power generation flow.

[0132] Based on the above objective function and constraints, a mixed integer quadratic programming model (MIQP) is established to obtain a real-time coordinated fault response model for cascade hydropower stations. The mixed integer quadratic programming model is an optimization model whose objective function is a quadratic function and whose constraints are usually in a linear form.

[0133] S2. When a generator set of the water diversion series cascade power station fails, the boundary conditions of the water diversion series cascade power station are obtained.

[0134] When some of the generator sets in the water diversion series cascade power station fail and shed load, the boundary conditions of the water diversion series cascade power station are input into the real-time collaborative fault response model, and then the real-time collaborative fault response model of the water diversion series cascade power station is solved by the solver to obtain the scheduling parameters of the water diversion series cascade power station.

[0135] In an embodiment of the present application, the boundary conditions of the water diversion series cascade power stations include at least the number of power grids, the number of power stations, the number of generator sets of each power station, the scheduling period of the water diversion series cascade power stations and the corresponding planned load, the lower and upper water level limits of each power station, the lower output limit, upper output limit, lower power flow rate limit, upper power flow rate limit and climbing rate limit of each generator set, parameters of the water level storage capacity curve and the unit characteristic curve, the current water level of each power station, and the current power flow rate and current output of each generator set.

[0136] S3. Based on the boundary conditions and using a solver, the real-time collaborative fault response model is solved to obtain the planned output of each generator set, and the water diversion series cascade power stations are dispatched in real time according to the planned output of each generator set.

[0137] In the embodiment of the present application, after the boundary conditions are input into the hybrid quadratic programming model, the Gurobi solver is called to automatically perform optimization calculations to obtain the planned output of each generator set when the deviation of the objective function is minimized.

[0138] For integer programming problems, the Gurobi solver uses algorithms such as branch and bound and cutting plane method. The branch and bound method gradually decomposes the feasible solution space and uses relaxed linear programming to obtain upper and lower bounds, and then selects branches for further search until the optimal solution (that is, the minimum deviation) is found or the stopping condition is reached. The cutting plane method is a method used to accelerate integer programming solutions. It reduces the feasible solution space by continuously adding cutting planes.

[0139] After solving the real-time collaborative fault response model with the Gurobi solver, the planned output of each generator set is obtained when the deviation of the objective function is minimized. Finally, the water diversion series cascade power station is dispatched in real time according to the planned output of each generator set, which can minimize the negative impact caused by the failure of the generator set and ensure that the impact on the operation of the power grid is minimized. In addition, by comparing and analyzing the planned output and actual output obtained by the solution, we can gain a deep understanding of the complementary relationship between the output of the generator sets and the collaborative adjustment strategy between the power grids. These analysis results will help optimize the overall dispatching plan of the water diversion series cascade power station and improve the system's risk resistance and operation efficiency.

[0140] Figure 3 The schematic diagram of a water diversion cascade power station is shown. Figure 3The water diversion cascade power station uses the water diversion tunnel to draw water from the upstream reservoir, and two power stations connected in a string are arranged along the way, namely Power Station A and Power Station B. Power Station A and Power Station B are connected by 4 tunnels, namely Tunnel I, Tunnel II, Tunnel III and Tunnel IV, forming a water diversion cascade power station with 4 tunnels per level and a total of 2 levels. In each level, each tunnel is connected to 2 generator sets, containing a total of 16 generator sets. There is a regulating tank above Power Station B to ensure that the flow at each level in each tunnel is equal. The maximum output of each generator set in Power Station A and B is 50MW, and each power station contains 4 units with a maximum output of 200MW. The power transmission area of ​​these two power stations is wide, and the combination of the receiving-end power grids and their power receiving ratios may also change. To facilitate modeling and analysis, this embodiment assumes that there are two receiving-end power grids, Power Grid 1 and Power Grid 2. Tunnel I and Tunnel II generate electricity and send it to Power Grid 1, which is the first grouping; Tunnel III and Tunnel IV generate electricity and send it to Power Grid 2, which is the second grouping. Each power grid uses equal weights when calculating the planned output.

[0141] Figure 4 A schematic diagram showing the system load, residual load and planned output of a power grid 1 is shown. Figure 5 A schematic diagram of the system load, residual load and planned output of a power grid 2 is shown. The embodiment of the present application takes 1 hour as the calculation period and the planned output of two groups on a certain day as the basis, and studies the power transmission change process of each group to each power grid after real-time scheduling using the water diversion series cascade power station scheduling method of the embodiment of the present application in two cases: one generator set failure and two generator sets failure in the same power station in a tunnel.

[0142] (1) Output comparison of two groups when one unit fails

[0143] See also Figure 6 and Figure 7, comparing the planned output and actual output of the two groups when the generator set fails, the actual total output is reduced in the time periods of 11:00-14:00 and 17:00-23:00, but the same in other time periods. Because the planned output in these time periods is greater than the maximum total output of the remaining 15 generator sets, the remaining generator sets cannot make up for the load shedding caused by the failure, resulting in a decrease in output; while the planned output in other time periods is less than the maximum total output of the remaining 15 generator sets, the remaining generator sets can compensate for the load shedding by increasing their output, so that the total output remains unchanged to ensure that the amount of electricity delivered to each power grid can remain stable. Comparing the output process of the 15 generator sets that operate normally before and after the failure, the total output of the 15 generator sets that operate normally after the failure is the same as before the failure during the full-time period, and greater than the total output before the failure in other time periods. Analyzing the reasons, when the generator set does not reach the maximum output, one generator set fails, and the remaining generator sets can fill the power gap by increasing their output to keep the total output unchanged or minimize the decline. During the period when the generator set has reached its maximum output, the output can no longer be increased and will remain at full power.

[0144] For the cascade power stations connected in series, the upstream output will decrease, and the upstream outflow will also decrease. During the peak load period, there are three generator sets upstream of the two tunnels in the first group, and four generator sets downstream. They cannot be fully powered at the same time under the flow matching requirements. Therefore, the generator sets downstream of the second group of tunnels need to reduce their output, and the surplus flow upstream is used to make up for the difference in the upstream and downstream power generation flow of the first group. Figure 8 The figure shows a schematic diagram of the output change of each generator set when a generator set fails, including 8 generator sets (1) to (8) corresponding to the upstream power station A and 8 generator sets (1) to (8) corresponding to the downstream power station B. In the output change diagram corresponding to each generator set, the horizontal axis represents time, and in the vertical axis, the solid line represents the output after the failure, and the dotted line represents the output before the failure. Figure 8 , the power generation flow of the last generator set downstream is reduced to compensate for the reduction in power generation flow of the first generator set upstream due to the fault, while the output of other generator sets does not change much.

[0145] (2) Output comparison of two groups when two generator sets fail

[0146] See also Fig. 9 and Fig.10Before 10:00, the planned output is small. After the generator set fails, the upstream power station can increase the output to make up for the reduced output due to the failure, so the output of the two power generation groups remains basically unchanged. After 10:00, the output of the generator set increases until it is fully generated, and there is no spare capacity to make up for the load shedding caused by the failure. If other power grids still generate electricity according to the planned output, the load loss of the first power grid will be large, which will reduce the stability of the power grid, so the two power grids need to be adjusted in coordination. In summary, the first group can only increase the output as much as possible and reduce the change in flow to make the output change of the second group smaller, so the actual output of the first group will be less than the planned total output, but greater than the planned total output of the 14 generator sets in normal operation.

[0147] However, if two generators upstream of the first group fail, it is impossible for the upstream and downstream of the first group to generate full power at the same time under the flow matching requirement. Therefore, the total flow needs to be distributed, and part of the power generation flow upstream of the second group is used downstream of the first group to minimize the output change of the first group and reduce the impact of load shedding on the power grid. At this time, the output of the generators downstream of the second group will also decrease due to the decrease in flow. Fig.11 The figure shows a schematic diagram of the output change of each generator set when two generator sets fail, including 8 generator sets (1) to (8) corresponding to the upstream power station A and 8 generator sets (1) to (8) corresponding to the downstream power station B. In the output change diagram corresponding to each generator set, the horizontal axis represents time, and in the vertical axis, the solid line represents the output after the failure, and the dotted line represents the output before the failure. Please refer to Fig.11 , the output of the downstream (6th) and (8th) generator sets is reduced, and their power generation flow is used to compensate for the first group.

[0148] According to the above analysis, it can be seen that after real-time scheduling using the water diversion series cascade power station scheduling method provided by the embodiment of the present application, the power output deviation caused by the generator set failure can be reduced as much as possible, and the accuracy of water diversion series cascade power station scheduling can be improved. In addition, multiple power grids can jointly bear the load shedding caused by the failure, reducing the impact on a single power grid and improving the stability of the power grid.

Claims

1. A method for dispatching water diversion cascade power stations based on a real-time collaborative fault response model, characterized in that: The method comprises: Constructing the objective function and constraint conditions of the planned load and actual output of the water diversion series cascade power station, and establishing a hybrid quadratic programming model based on the objective function and constraint conditions to obtain a real-time collaborative fault response model of the water diversion series cascade power station; The objective function is as follows: Among them, F represents the deviation, Min represents the minimum value, N represents the number of power grids connected in series with cascade power stations, T represents the total number of time periods, and C n，t represents the planned load of the nth power grid at the tth period, p n，t represents the actual output of the nth power grid in the tth period; The constraints include water balance constraints, water level constraints, unit power flow constraints, unit output constraints, ramp constraints, unit start and stop constraints, water level storage capacity curves and unit power generation characteristic curves; The water level storage capacity curve is as follows: in, represents the water level storage capacity function of the mth power station; The power generation characteristic curve of the unit is as follows: in, represents the characteristic curve function of the jth generator set in the mth power station, h m，j，t represents the generating head of the jth generator set of the mth power station at the tth period; When the generator set of the water diversion series cascade power station fails, the boundary conditions of the water diversion series cascade power station are obtained; Based on the boundary conditions, the real-time collaborative fault response model is solved by using a solver to obtain the planned output of each generator set, and the water diversion series cascade power station is dispatched in real time according to the planned output of each generator set; The method further comprises: The water level of each power station is divided into D water level intervals, and after the discrete value corresponding to each water level interval is determined, the water level storage capacity curve is linearly converted. The conversion formula is as follows: in, represents the weight coefficient of the d-th water level interval of the m-th power station in the t-th time period, represents the discrete value corresponding to the d-th water level interval of the m-th power station, represents the storage capacity of the d-th water level interval of the m-th power station, Represents the auxiliary variable introduced. If the water level of the mth power station in the tth period falls into the dth water level interval, then otherwise 2. The method for dispatching water diversion series cascade power stations based on a real-time collaborative fault response model according to claim 1, characterized in that: The water balance constraints are as follows: Among them, V m，t represents the storage capacity of the mth power station in the tth period, represents the inflow flow of the mth power station in the tth period, represents the outflow of the mth power station in the tth period, and Δt is the length of a period; The water level constraints are as follows: In the formula, Z m，t represents the water level of the mth power station in the tth period, represents the water level of the upstream regulating pond of the mth power station at the tth period, Z m represents the lower limit of the water level of the mth power station, Represents the upper limit of the water level of the mth power station.

3. The method for dispatching water diversion series cascade power stations based on real-time collaborative fault response model according to claim 2 is characterized in that: The power generation flow constraints of the unit are as follows: Among them, q m，j，t represents the power generation flow of the jth generator set of the mth power station in the tth period, q m，j represents the lower limit of the power generation flow of the j-th generator set in the m-th power station, represents the upper limit of the power generation flow of the jth generator set in the mth power station, Indicates the operating status of the j-th generator set of the m-th power station in the t-th period; The unit output constraints are as follows: Among them, p m，j，t represents the output of the jth generator set of the mth power station at the tth period, p m，j represents the lower limit of the output of the jth generator set in the mth power station, represents the upper limit of the output of the jth generator set in the mth power station; The climbing constraints are as follows: -R m，j，t ≤p m，j，t -p m，j，t+1 ≤R m，j，t ; Among them, R m，j，t It represents the ramp rate limit of the jth generator set of the mth power station in the tth period; The unit start and stop constraints are as follows: Open m，j，t ∈[0,1],Stop m，j，t ∈[0,1]; Open m，j，t +Stop m，j，t ≤1; Among them, Open m，j，t Indicates the startup status of the jth generator set in the mth power station in the tth period, Stop m，j，t Indicates the shutdown status of the j-th generator set of the m-th power station in the t-th period, represents the maximum startup time of the jth generator set in the mth power station, It represents the downtime duration of the j-th generator set in the m-th power station.

4. The method for dispatching water diversion series cascade power stations based on real-time collaborative fault response model according to claim 1, characterized in that: The method further comprises: The power generation flow of the generator set of each power station is divided into L flow intervals, and the discrete value corresponding to each flow interval is determined. The power generation head of the generator set of each power station is divided into G head intervals, and the discrete value corresponding to each head interval is determined. Then, the power generation characteristic curve of the unit is linearly converted. The conversion formula is as follows: ρm,t,g,l≥0; Among them, P m，g，t Indicates the power characteristic curve of the generator set of the mth power station in the tth period (Q m，l , H m，g ) corresponding to the output; Q m , l represents the discrete value corresponding to the lth flow interval on the power characteristic curve of the generator set of the mth power station; H m，g represents the discrete value corresponding to the g-th head interval on the power characteristic curve of the generator set of the m-th power station, ρ m，t，g，l Indicates the power characteristic curve of the generator set of the mth power station in the tth period (Q m，l , H m，g ) corresponding to the weight value.

5. The method for dispatching water diversion series cascade power stations based on real-time collaborative fault response model according to claim 1, characterized in that: The boundary conditions of the water diversion series cascade power stations include at least the number of power grids, the number of power stations, the number of generator sets of each power station, the scheduling period of the water diversion series cascade power stations and the corresponding planned load, the lower and upper water level limits of each power station, the lower and upper output limits of each generator set, the upper and lower output limits, the lower and upper power generation flow limits and the climbing rate limit, the parameters of the water level storage capacity curve and the unit characteristic curve, the current water level of each power station, and the current power generation flow and current output of each generator set.

6. The method for dispatching water diversion series cascade power stations based on real-time collaborative fault response model according to claim 1, characterized in that: Based on the boundary conditions, the real-time collaborative fault response model is solved by using a solver, specifically including: After the boundary conditions are input into the hybrid quadratic programming model, the Gurobi solver is called to automatically perform optimization calculations to obtain the planned output of each generator set when the deviation of the objective function is minimized.

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