A method for evaluating deviation risk of power generation of a hydropower station based on runoff uncertainty

Abstract

The application discloses a hydropower station power generation deviation risk assessment method based on runoff uncertainty, and comprises the following steps: collecting basic parameters of hydropower station power generation scheduling, and determining constraint conditions; according to the hydropower station power generation scheduling mode, a hydropower station power generation scheduling power generation calculation model is established; inputting the current reservoir water level and the scheduling final water level of the hydropower station; taking historical runoff data as a calculation boundary, inputting the hydropower station inflow runoff process from the current period to the scheduling final period in the historical years; calculating the power generation of the hydropower station under each historical runoff process condition; and applying a probability analysis method to analyze the power generation realization risk of the hydropower station. Through the establishment of the hydropower station power generation scheduling model, the uncertainty of the runoff is reflected by the historical runoff process, the probability distribution of the hydropower station power generation from the current period to the scheduling final period under the condition of the scheduling final water level control target is established, and the method can provide guidance for the assessment of the target power generation deviation of the power station scheduling period and the establishment of the power station power generation plan.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water conservancy and hydropower, and particularly relates to a method for evaluating deviation risk of power generation of a hydropower station based on runoff uncertainty. BACKGROUND

[0002] In a medium and long term power transaction, a power generation enterprise needs to estimate power generation in a future transaction period, so as to provide support for participating in a medium and long term power transaction contract. However, the power generation of a hydropower station is closely related to reservoir inflow, and is affected by uncertainty of runoff distribution and error of medium and long term runoff prediction, so that the power generation prediction fluctuates greatly, and actual power generation is easily greatly abundant or insufficient, thereby causing deviation evaluation and affecting power generation income of the hydropower station.

[0003] Therefore, a method for evaluating deviation risk of power generation of a hydropower station based on runoff uncertainty is needed, so as to reduce error of power generation prediction, and provide technical support for making and executing a power generation plan of the hydropower station. SUMMARY

[0004] The present application aims at the above-mentioned deficiencies of the prior art, and provides a method for evaluating deviation risk of power generation of a hydropower station based on runoff uncertainty, so as to evaluate deviation of target power generation of the hydropower station in a dispatching period, and provide support for making a power generation plan of the hydropower station, so as to fully utilize water energy resources.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] A method for evaluating deviation risk of power generation of a hydropower station based on runoff uncertainty comprises the following steps:

[0007] 1) Collecting basic parameters of power generation dispatching of the hydropower station, and determining constraint conditions;

[0008] 2) According to a power generation dispatching mode of the hydropower station, establishing a power generation dispatching power generation calculation model of the hydropower station based on the basic parameters and the constraint conditions;

[0009] 3) Inputting a current measured reservoir water level Z current of the hydropower station as an initial calculation reservoir water level in the power generation dispatching power generation calculation model of the hydropower station, and setting a reservoir water level Z set at the end of a dispatching period; set Zis a given reservoir water level at the end of the dispatching period, and is given according to a medium and long term water level control target of the reservoir;

[0010] 4) Inputting a measured average inflow of the hydropower station from a current period to the end of the dispatching period in N years of historical runoff data as a calculation condition into the power generation dispatching power generation calculation model of the hydropower station, as inflow for calculating power generation of the hydropower station; The measured average inflow for the nth period t, n = 1, 2,..., N; t = 1, 2,..., T, T is the total scheduling period;

[0011] 5) Calculate the power generation of the hydropower station in each period under the historical runoff process condition by the power generation scheduling power generation calculation model of the hydropower station year by year, and calculate the total power generation in the total scheduling period;

[0012] 6) Calculate the probability that the calculated power generation of the hydropower station to the end of the scheduling period under the historical runoff condition is greater than or equal to the target power generation under the condition that the water level at the end of the scheduling period is set, and the probability that the calculated power generation is within a certain deviation range of the target power generation, to obtain the power generation deviation risk.

[0013] Preferably, the basic parameters of the power generation scheduling of the hydropower station include the water level-storage capacity curve, the reservoir water level-discharge capacity curve, the discharge flow-tail water level relationship curve, the power generation scheduling diagram, the upper and lower limits of the reservoir water level, the minimum discharge flow, and the power generation scheduling mode.

[0014] Preferably, the constraint conditions include:

[0015] ① Reservoir water level constraint

[0016] z t ∈[Z min ,Z max ]

[0017] Wherein, z t is the reservoir water level at the end of period t of the hydropower station;

[0018] Z min is the lower limit of the reservoir water level of the hydropower station, generally the dead water level;

[0019] Z max is the upper limit of the reservoir water level of the hydropower station, generally the normal storage level;

[0020] ② The discharge flow of the hydropower station meets the minimum discharge flow requirement

[0021] Q out,min ≤Q out,t

[0022] Wherein, Q out,min is the minimum discharge flow of the hydropower station;

[0023] Q out,t is the average outflow of the hydropower station in period t.

[0024] Preferably, in step 2), the power generation scheduling mode of the hydropower station includes scheduling diagram scheduling, water level control mode, and optimization scheduling mode.

[0025] Preferably, in the step 5), the calculation formula of the total power generation in each year of the N-year history is: Wherein, is the calculated power generation of the hydropower station at the t period of the n year, which is calculated by the power generation scheduling model of the hydropower station; is the calculated power generation of the hydropower station under the runoff sequence condition of the n year to the end of the scheduling period.

[0026] Preferably, in the step 6), the calculation formula of each probability is as follows:

[0027]

[0028] Wherein, is the target power generation of the hydropower station to the end of the scheduling period;

[0029] ΔE is the deviation of the calculated power generation of the hydropower station to the end of the scheduling period and the target power generation;

[0030] is the probability that the calculated power generation of the hydropower station to the end of the scheduling period is greater than or equal to the target power generation;

[0031] is the calculated power generation within the deviation range of the target power generation;

[0032] is the number of years that the calculated power generation of the hydropower station to the end of the scheduling period is greater than the target power generation .

[0033] is the number of years that the calculated power generation of the hydropower station to the end of the scheduling period is within the deviation range of the target power generation.

[0034] Compared with the prior art, the present application has the following beneficial effects:

[0035] The method for evaluating the power generation deviation risk of a hydropower station based on runoff uncertainty provided by the present application reflects the uncertainty of future reservoir inflow through the historical runoff process by establishing a power generation scheduling model of the hydropower station, and then analyzes the power generation distribution law of the hydropower station through the historical runoff distribution law, establishes the probability relationship between the power generation of the hydropower station from the current period to the end of the scheduling period and the water level at the end of the scheduling period, and provides support for the power generation planning of the power station. The method effectively combines the water level control target and the historical hydrological data, analyzes the medium and long-term power generation capacity of the hydropower station, makes the power generation deviation risk evaluation more diversified and reliable, and has the advantages of scientific rationality and high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is the implementation flowchart of the method for evaluating the power generation deviation risk of a hydropower station based on runoff uncertainty.

[0037] Figure 2 A water power station dispatching diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0038] The embodiments of the present application will be described in detail below with reference to the drawings, but they do not constitute limitations on the present application, and are only examples. At the same time, the advantages of the present application will become clearer and easier to understand through the description.

[0039] As Figure 1 shown is a water power station power generation deviation risk assessment method based on runoff uncertainty of the present application. First, the basic parameters of water power station power generation dispatching are collated and reviewed, including characteristic water level, reservoir capacity curve, expected output curve, discharge flow tail water level relationship curve, output coefficient, etc., and a water power station power generation dispatching power generation calculation model is established according to the water power station power generation dispatching mode. With the current reservoir water level of the water power station as the input condition, and according to the dispatching period end water level control target as the dispatching constraint, the long series of historical runoff data is used as the calculation condition to reflect the uncertainty of runoff. The current period to the dispatching period end water power station inflow runoff process in the historical year is input in the power generation calculation model to calculate the power generation of the water power station under each historical runoff process condition. The probability analysis method is applied to analyze the deviation risk of the water power station power generation.

[0040] Specifically includes the following steps:

[0041] Step 1: Collect the basic parameters of water power station power generation dispatching and determine the constraint conditions.

[0042] Collect the basic parameters of water power station water level-reservoir capacity curve, reservoir water level-discharge capacity curve, discharge flow-tail water level relationship curve, power generation dispatching diagram, reservoir water level upper and lower limits, minimum discharge flow, power generation dispatching mode, etc. to provide boundary conditions for water power station power generation dispatching model construction and power generation evaluation. The boundary conditions mainly include:

[0043] ① Reservoir water level constraint

[0044] z t ∈ [Z min ,Z max ]

[0045] Wherein, z t is the reservoir water level at the end of period t of the water power station;

[0046] Z min is the lower limit of the reservoir water level of the water power station, generally the dead water level;

[0047] Z max is the upper limit of the reservoir water level of the water power station, generally the normal storage water level;

[0048] ② The discharge flow of the water power station meets the minimum discharge flow requirement

[0049] Q out,min ≤Q out,t ;

[0050] wherein, Q out,min is the minimum discharge of the hydropower station;

[0051] Q out,t is the average discharge of the hydropower station in period t.

[0052] Step 2: According to the power generation scheduling mode of the hydropower station, a power generation scheduling power generation calculation model of the hydropower station is established. The power generation scheduling mode of the hydropower station generally has scheduling according to the scheduling diagram, water level control mode, and optimization scheduling mode, etc. The difference of different scheduling modes mainly lies in the difference of solving the discharge of each scheduling period. Taking the scheduling diagram scheduling mode as an example, a power generation scheduling power generation calculation model of the hydropower station is constructed.

[0053] z t =f1(Q in,t ,z t-1 )

[0054] v t =f2(z t )

[0055] v t-1 =f2(z t-1 )

[0056] Q out,t =Q in,t +(v t -v t-1 ) / Δt

[0057] E t =f3(Q out,t ,z t-1 ,z t ,Δt)

[0058] wherein, z t is the water level of the hydropower station at the end of the t period, z t-1 is the water level of the hydropower station at the end of the t-1 period;

[0059] v t is the storage capacity of the hydropower station at the end of the t period, v t-1 is the storage capacity of the hydropower station at the end of the t-1 period;

[0060] Q in,t is the average inflow of the hydropower station in the t period;

[0061] Q out,t is the average outflow of the hydropower station in the t period;

[0062] Δt is the calculation time interval;

[0063] E t is the total power generation of the hydropower station in the t period;

[0064] f1(Q in,t ,z t-1 ) is a function relationship established by the scheduling diagram according to the inflow of the hydropower station and the initial water level of the period, to calculate the final water level of the period;

[0065] f2(z t ) and f2(z t-1 ) are function relationships between the reservoir water level and the reservoir capacity of the hydropower station established according to the water level-capacity curve of the hydropower station, which can generally be calculated by interpolation according to the capacity curve;

[0066] f3(Q out,t ,z t-1 ,z t ,Δt) is a function relationship of the reservoir water level z t and z t-1 , the outflow Q out,t and the calculation time interval Δt and the period cumulative power generation.

[0067] Step 3: input the current reservoir water level of the hydropower station into the power generation scheduling power generation calculation model of the hydropower station, and set the final water level of the scheduling period.

[0068] z0=Z current ;

[0069] z T =Z set ;

[0070] Wherein, z0 is the initial reservoir water level of the hydropower station in the 0 period;

[0071] z T is the final water level of the hydropower station in the T period;

[0072] T is the total scheduling period;

[0073] Z current is the current measured reservoir water level of the hydropower station;

[0074] Z set is the given final water level of the hydropower station in the scheduling period, which is given according to the medium and long-term scheduling water level control target of the hydropower station.

[0075] Step 4: take the historical runoff data as the calculation condition, and take the inflow process of the hydropower station from the current period to the final period of the scheduling period in N years as the input of the inflow of the hydropower station into the power generation scheduling power generation calculation model of the hydropower station.

[0076]

[0077] wherein, is the average inflow of the nth year of the hydropower station at the t period; n = 1, 2,..., N; t = 1, 2,..., T; is the measured average inflow of the nth year at the t period.

[0078] Step 5: Calculate the power generation of the hydropower station at each period under the historical runoff process condition year by year through the above-mentioned power generation scheduling calculation model of the hydropower station, and calculate the total power generation in the total scheduling period.

[0079]

[0080] wherein, is the calculated power generation of the hydropower station at the nth year at the t period;

[0081] is the calculated power generation of the hydropower station at the nth year under the runoff sequence condition until the end of the scheduling period.

[0082] Step 6: Calculate the calculated power generation of the hydropower station until the end of the scheduling period under the historical runoff condition when the water level at the end of the scheduling period is set is greater than or equal to the target power generation, and the probability that the calculated power generation is within a certain deviation range ΔE of the target power generation.

[0083]

[0084] wherein, is the target power generation of the hydropower station until the end of the scheduling period;

[0085] ΔE is the deviation between the calculated power generation of the hydropower station until the end of the scheduling period and the target power generation;

[0086] is the probability that the calculated power generation of the hydropower station until the end of the scheduling period is greater than or equal to the target power generation;

[0087] is the probability that the calculated power generation is within a certain deviation range ΔE of the target power generation;

[0088] is the number of years that the calculated power generation of the hydropower station until the end of the scheduling period is greater than the target power generation ;

[0089] is the number of years that the calculated power generation of the hydropower station until the end of the scheduling period is within a certain deviation range of the target power generation.

[0090] By calculating the probability that the calculated power generation of the hydropower station to the end of the scheduling period is greater than the target power generation under the water level condition at the end of the given scheduling period, and the probability that the calculated power generation is within a certain deviation range ΔE of the target power generation, i.e., the power generation deviation risk, support can be provided for the power generation plan of the power station operation management unit. For example, if the probability that the predicted power generation is greater than the target power generation is relatively low, i.e., the possibility of achieving the target power generation index is relatively small, the possibility of achieving the target power generation can be increased by reducing the water level at the end of the scheduling period and changing the scheduling plan. If the probability is relatively small, the power generation deviation risk is relatively large, i.e., the probability that the power generation is within a certain deviation range of the target power generation is relatively low, the power generation can be adjusted by adjusting the water level at the end of the scheduling period and changing the scheduling plan, so as to meet the power generation requirements of the hydropower station and improve the utilization rate of water resources.

[0091] The method of the application will be further described below through specific examples.

[0092] Example 1

[0093] Taking a large hydropower station A in the Yangtze River Basin of China as an example, the power generation deviation risk assessment method of the hydropower station based on runoff uncertainty is applied, which includes the following steps:

[0094] Step 1: Collect basic parameters of hydropower station power generation scheduling and determine constraint conditions.

[0095] First, collect the water level-storage capacity curve, reservoir water level-discharge capacity curve, discharge flow-tail water level relationship curve, power generation scheduling diagram, water level upper and lower limit, minimum discharge flow, power generation scheduling mode and other basic parameters of A hydropower station, which provide boundary conditions for the construction of the power generation scheduling model of the hydropower station and the assessment of power generation. Among them, the water level-storage capacity curve, reservoir water level-discharge capacity curve, discharge flow-tail water level relationship curve, power generation scheduling diagram, water level upper and lower limit, power generation scheduling mode and other parameters are related parameters determined in the design stage of the hydropower station. The minimum discharge flow is the minimum discharge requirement of the hydropower station during operation due to the comprehensive utilization requirements of water supply, ecology or navigation, etc. The minimum discharge flow of A hydropower station is 401 m 3 / s, i.e. under normal circumstances, the discharge flow of the hydropower station should be greater than or equal to 401 m 3 / s.

[0096] For the power station whose power generation scheduling diagram is not given in the design stage, the scheduling diagram of the power station can be calculated first, which is used for the construction of the power generation scheduling model. This part is prior art and will not be described in detail here.

[0097] Step 2: Apply the power generation scheduling mode of the scheduling diagram to establish a power generation scheduling power generation calculation model. This part is prior art and will not be described in detail here. According to the scheduling scheme of the power station, the scheduling diagram is as shown in Figure 2 .

[0098] By Figure 2 It can be seen that the scheduling diagram defines the water level process of each period of the hydropower station. By applying the scheduling diagram, the hydropower station reservoir water level at the end of the scheduling period, the discharge flow, the power generation flow and the power generation capacity can be calculated according to the current reservoir inflow, the initial reservoir water level of the hydropower station at the beginning of the scheduling period.

[0099] Step 3: input the current reservoir water level of the hydropower station into the hydropower station power generation scheduling and power generation capacity calculation model, and set the water level at the end of the scheduling period.

[0100] Taking the end of April as the current calculation period as an example, the current reservoir water level of the hydropower station is input as 1155m, the end of the scheduling period is set as the end of December, the water level at the end of the scheduling period is set as 1198m, and the calculation time scale is ten days, and the number of calculation scheduling periods per year is 24. That is:

[0101] z0=1155;

[0102] z T =1198;

[0103] T=24.

[0104] Step 4: taking the historical runoff data as the calculation condition, in the dam site runoff data of A hydropower station from 1959 to 2014 (N=56), the runoff process from the end of April to the end of December is selected as the reservoir inflow of the hydropower station, and the input is input into the hydropower station power generation scheduling and power generation capacity calculation model. The historical runoff sequence is the runoff data of each ten-day period from the end of April to the end of December from 1959 to 2014 n=1, 2, …, N (N is the total number of calculation years, here N=56, i.e. is the runoff data of each ten-day period from the end of April to the end of December in 1959), as the reservoir inflow data input into the scheduling model.

[0105]

[0106] Step 5: the power generation capacity of the hydropower station in each period under the condition of historical runoff process is calculated year by year, and the total power generation capacity in the calculation period is calculated. Taking n=1 as an example, the power generation capacity of A hydropower station from the end of April to the end of December in 1959 is calculated. (T is the total calculation period, and the calculation period in this example is 8 months, and the calculation period is ten days, so T takes the value of 24) as the input data, and According to the scheduling diagram of A hydropower station, Q out,t ,z t-1 ,z t , and then according to and the power generation capacity of A hydropower station in each period in 1959 can be calculated and the cumulative power generation from the end of April to the end of December The power generation in the first ten days of May in this example Using a similar method, we can obtain and the cumulative power generation from the end of April to the end of December

[0107] Similarly, we can obtain the cumulative power generation from the end of April to the end of December of A hydropower station under other runoff sequences

[0108] Step 6: Calculate the calculated power generation of the hydropower station to the end of the dispatching period under the condition of setting the water level at the end of the dispatching period and historical runoff The probability of being greater than or equal to the target power generation, and the calculated power generation The probability of being within a certain deviation range ΔE of the target power generation.

[0109] The annual target power generation of A hydropower station is 18 billion kW·h, of which the actual power generation from January to the end of April is 3.86 billion kW·h, so the power generation from the end of April to the end of December should be greater than 14.14 billion kW·h, that is, the target power generation According to the distribution of the power generation of A hydropower station calculated based on the historical runoff sequence We can obtain the probability of reaching the target power generation:

[0110]

[0111] Suppose the target power generation deviation is 1 billion kW·h, that is, ΔE = 10, then we can obtain the probability of the calculated power generation being within the deviation range:

[0112]

[0113] The other parts not mentioned belong to the prior art.

Claims

1. A method for assessing the risk of deviation of the power generation of a hydropower station based on runoff uncertainty, characterized in that: The method comprises the following steps: 1) collecting basic parameters of hydropower station generation scheduling, and determining constraint conditions; 2) establishing a hydropower station generation scheduling power generation calculation model based on the basic parameters and the constraint conditions according to a hydropower station generation scheduling mode; 3) the current measured reservoir water level Z of the hydropower station current Input the initial calculation reservoir water level in the power generation scheduling power generation calculation model of the hydropower station, and set the reservoir water level Z at the end of the scheduling period set ; Z set For a given reservoir water level at the end of the scheduling period, the long-term reservoir water level control target is given 4) with historical runoff data as the calculation condition, the average inflow of the hydropower station from the current period to the end of the dispatching period in N years of history The input of the hydropower station power generation dispatching power generation calculation model is the inflow for calculating the hydropower station power generation; is the measured average inflow of the nth year t period, n = 1, 2, …, N; t = 1, 2, …, T, T is the total dispatching period; 5) calculating, through the hydropower station generation scheduling power generation calculation model, power generation of the hydropower station in each period under a historical runoff process condition year by year, and total power generation in a total scheduling period; 6) calculating a probability that the calculated power generation of the hydropower station to the end of the scheduling period is greater than or equal to a target power generation under a historical runoff condition and a probability that the calculated power generation is in a certain deviation range of the target power generation under a condition that a water level at the end of the scheduling period is set, and obtaining a power generation deviation risk.

2. The method for assessing the risk of deviation of the power generation of a hydropower station based on runoff uncertainty according to claim 1, characterized in that: The basic parameters of the hydropower station generation scheduling include a water level-capacity curve, a reservoir water level-discharge capacity curve, a discharge flow-tail water level relationship curve, a power generation scheduling diagram, upper and lower limits of the reservoir water level, a minimum discharge flow, and a power generation scheduling mode.

3. The method for assessing the risk of deviation of the power generation of a hydropower station based on runoff uncertainty according to claim 1, characterized in that: The constraint conditions include: ① reservoir water level constraint z t ∈[Z min ,Z max ] where z t is the reservoir water level at the end of the hydropower plant period t; Z min The lower limit of the reservoir water level of the hydropower station is generally the dead water level. Z max The upper limit of the reservoir water level of the hydropower station is generally the normal storage water level. ② hydropower station discharge flow meeting a minimum discharge flow requirement Q out,min ≤Q out,t wherein Q out,min is the minimum discharge of the hydropower station; Q out,t is the average outflow of the hydropower station in the time period t.

4. The power generation deviation risk assessment method for a hydropower station based on runoff uncertainty according to claim 1, characterized in that: In the step 2), the hydropower station generation scheduling mode includes a scheduling diagram scheduling, a water level control mode, and an optimization scheduling mode.

5. The method for assessing the risk of deviation of the power generation of a hydropower station based on runoff uncertainty according to claim 1, characterized in that: In the step 5), the calculation formula of the total power generation in the calculation period of each year in N years is: wherein, is the calculated power generation of the hydropower station at the t period in the n year, which is obtained by calculation of the power generation scheduling power generation calculation model of the hydropower station; is the calculated power generation of the hydropower station under the runoff sequence condition in the n year to the end of the scheduling period.

6. The power generation deviation risk assessment method for a hydropower station based on runoff uncertainty according to any one of claims 1-5, characterized in that: In the step 6), a calculation formula of each probability is as follows: In the formula, is the target power generation of the hydropower station to the end of the dispatching period; ΔE is a deviation between the calculated power generation of the hydropower station to the end of the scheduling period and the target power generation. P is the probability that the calculated power generation of the hydropower station to the end of the dispatching period is greater than or equal to the target power generation; to calculate the generated power a probability that the target generated power is within a certain deviation range ΔE; the number of years in which the calculated power generation of the hydropower station to the end of the dispatching period is greater than the target power generation . The number of years in which the calculated power generation of the hydropower station at the end of the dispatch period is within a certain deviation range of the target power generation.

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