Hydropower station generating capacity deviation risk assessment method based on runoff uncertainty

Abstract

The invention discloses a hydropower station generating capacity deviation risk assessment method based on runoff uncertainty, and the method comprises the following steps: collecting power generation dispatching basic parameters of a hydropower station, and determining constraint conditions; establishing a hydropower station power generation dispatching generating capacity calculation model according to the hydropower station power generation dispatching mode; inputting a current reservoir water level and a scheduling end water level of the hydropower station; taking historical runoff data as a calculation boundary, and inputting a hydropower station reservoir runoff process from a current time period to the end of a scheduling period in historical years; calculating the generating capacity of the hydropower station under each historical runoff process condition; and analyzing the generating capacity implementation risk of the hydropower station by applying a probability analysis method. According to the method, the hydropower station power generation dispatching model is established, the uncertainty of runoff is reflected through the historical runoff process, the hydropower station power generation capacity probability distribution from the current time period to the end of the dispatching period is established under the dispatching period end water level control target condition, and guidance is provided for power station dispatching period target power generation capacity deviation evaluation and power station power generation plan making.

Description

Technical Field

[0001] The invention relates to the technical field of water conservancy and hydropower, and in particular to a method for assessing the risk of power generation deviation of a hydropower station based on runoff uncertainty. Background Art

[0002] In medium- and long-term power trading, power generation companies need to estimate the power generation in the future trading period to provide support for participating in medium- and long-term power trading contracts. However, the power generation of hydropower stations is closely related to the inflow. Affected by the uncertainty of runoff distribution and the error of medium- and long-term runoff forecasts, the power generation forecast fluctuates greatly, which can easily cause a large surplus or shortage of actual power generation, leading to deviation assessment and affecting the power generation income of hydropower stations.

[0003] In view of this, there is an urgent need for a hydropower station power generation deviation risk assessment method based on runoff uncertainty to reduce the power generation forecast error, make full use of water resources, and provide technical support for the formulation and implementation of hydropower station power generation plans. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art and provide a risk assessment method for the deviation of hydropower station power generation based on runoff uncertainty, so as to evaluate the deviation of the target power generation during the scheduling period of the hydropower station, provide support for the formulation of the power generation plan of the hydropower station, and make full use of water resources.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

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

[0007] 1) Collect basic parameters of hydropower station power generation dispatch and determine constraints;

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

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

[0010] 4) Using historical runoff data as calculation conditions, the runoff process of the hydropower station from the current period to the end of the dispatching period in N years of history is calculated. Input into the hydropower station power generation scheduling and power generation calculation model as the inflow flow for the hydropower station power generation calculation; is the measured average flow rate in the t period of the nth year, n=1,2,......,N; t=1,2,......,T, T is the total dispatching period;

[0011] 5) Calculating the power generation of the hydropower station in each period under the historical runoff process conditions year by year through the power generation scheduling and power generation calculation model of the hydropower station, and calculating the total power generation in the total scheduling period;

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

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

[0014] Preferably, the constraints include:

[0015] ① Reservoir water level constraints

[0016] z t ∈[Z min ,Z max ]

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

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

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

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

[0021] Q out,min ≤Q out,t

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

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

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

[0025] Preferably, in step 5), the calculation formula for the total power generation in each calculation period in the N-year history is: in, is the calculated power generation of the hydropower station in the tth period of the nth year, obtained by the power generation scheduling calculation model of the hydropower station; It is the calculated power generation of the hydropower station under the runoff sequence conditions in the nth year to the end of the dispatch period.

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

[0027]

[0028] In the formula, The target power generation of the hydropower station at the end of the dispatch period;

[0029] ΔE is the deviation between the calculated power generation of the hydropower station and the target power generation at the end of the dispatch period;

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

[0031] To calculate the power generation The probability of a certain deviation range ΔE from the target power generation;

[0032] The calculated power generation of the hydropower station at the end of the dispatch period is greater than the target power generation number of years;

[0033] It is the number of years during which the calculated power generation of the hydropower station by the end of the dispatch period is within a certain deviation range of the target power generation.

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

[0035] The present invention provides a method for assessing the risk of power generation deviation in a hydropower station based on runoff uncertainty. The method establishes a power generation dispatching model for the hydropower station, uses the historical runoff process to reflect the uncertainty of future inflow runoff, and then analyzes the power generation distribution law of the hydropower station through the historical runoff distribution law. The probabilistic relationship between the power generation of the hydropower station from the current period to the end of the dispatching period and the water level at the end of the dispatching period is established, which provides support for the formulation of the power generation plan of the power station, 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, and makes the power generation deviation risk assessment more diverse and reliable. The method has the advantages of being scientific, reasonable and highly reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is an implementation flow chart of a method for risk assessment of power generation deviation of a hydropower station based on runoff uncertainty according to the present invention;

[0037] Figure 2 This is the dispatching diagram of the A hydropower station in the embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following is a detailed description of the implementation of the present invention in conjunction with the accompanying drawings, but they do not constitute a limitation of the present invention and are only given as examples. At the same time, the advantages of the present invention will become clearer and easier to understand through the description.

[0039] like Figure 1 The present invention shows a method for assessing the risk of deviation in power generation of a hydropower station based on runoff uncertainty. First, the basic parameters of power generation dispatch of the hydropower station are sorted and verified, including characteristic water level, reservoir capacity curve, expected output curve, tail water level relationship curve of downstream flow, output coefficient, etc., and a power generation dispatch calculation model of the hydropower station is established according to the power generation dispatch mode of the hydropower station. The current reservoir water level of the hydropower station is used as the input condition, and the water level control target at the end of the dispatch period is used as the dispatch constraint. The long series of historical runoff data is used as the calculation condition to reflect the uncertainty of the runoff. The runoff process of the hydropower station from the current period to the end of the dispatch period in the historical year is input into the power generation calculation model, and the power generation of the hydropower station under the conditions of each historical runoff process is calculated. The probability analysis method is applied to analyze the deviation risk of the power generation of the hydropower station.

[0040] The specific steps include:

[0041] Step 1: Collect basic parameters of hydropower station power generation scheduling and determine constraints.

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

[0043] ① Reservoir water level constraints

[0044] z t ∈[Z min ,Z max ]

[0045] Among them, z t is the reservoir water level at the end of the hydropower station period t;

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

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

[0048] ② The outflow of the hydropower station meets the minimum discharge flow requirements

[0049] Q out,min ≤Q out,t ;

[0050] Among them, Q out,min is the minimum discharge flow of the hydropower station;

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

[0052] Step 2: According to the power generation dispatching mode of the hydropower station, establish a calculation model for the power generation dispatching of the hydropower station. The power generation dispatching mode of the hydropower station generally includes dispatching according to the dispatching diagram, water level control mode, and optimization dispatching mode. The difference between different dispatching modes mainly lies in solving the different outflow flows in each dispatching period. Taking the dispatching diagram dispatching mode as an example, a calculation model for the power generation dispatching 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] Among them, z t is the reservoir water level of the hydropower station at the end of the tth period, z t-1 is the reservoir water level of the hydropower station at the end of the t-1 period;

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

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

[0062] Δt is the calculation time interval;

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

[0064] f1(Q in,t ,z t-1 ) is a function relationship established by the dispatching diagram to calculate the water level at the end of a period based on the inflow of the hydropower station and the water level at the beginning of the period;

[0065] f2(z t ) and f2(z t-1 ) is the functional relationship between the water level of the hydropower station reservoir and the water storage capacity established according to the hydropower station water level-reservoir capacity curve, which can generally be calculated by interpolation based on the reservoir capacity curve;

[0066] f3(Q out,t ,z t-1 ,z t , Δt) is the reservoir water level z of the hydropower station t and z t-1 , Downflow flow Q out,t And calculate the functional relationship between the time interval Δt and the cumulative power generation during the period.

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

[0068] z0=Z current ;

[0069] z T =Z set ;

[0070] Among them, z0 is the initial hydropower station reservoir water level at the 0th period;

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

[0072] T is the total dispatch period;

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

[0074] Z set It is given as the water level at the end of the hydropower station's dispatching period, and is given according to the medium- and long-term dispatching water level control target of the hydropower station.

[0075] Step 4: Using historical runoff data as calculation conditions, the hydropower station runoff process from the current period to the end of the scheduling period in the N-year history is input into the hydropower station power generation scheduling power generation calculation model as the inflow flow for the hydropower station power generation calculation.

[0076]

[0077] In the formula, is the average inflow of the hydropower station in the nth year and the tth period; n=1,2,......,N; t=1,2,......,T; is the measured average runoff in period t in year n.

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

[0079]

[0080] In the formula, is the calculated power generation of the hydropower station in period t in year n;

[0081] It is the calculated power generation of the hydropower station under the runoff sequence conditions in the nth year to the end of the dispatch period.

[0082] Step 6: Calculate the power generation of the hydropower station at the end of the scheduling period under the conditions of the historical runoff under the water level at the end of the scheduling period The probability of being greater than or equal to the target power generation, and the calculated power generation The probability of a certain deviation range ΔE from the target power generation.

[0083]

[0084] In the formula, The target power generation of the hydropower station at the end of the dispatch period;

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

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

[0087] To calculate the power generation The probability of a certain deviation range ΔE from the target power generation;

[0088] The calculated power generation of the hydropower station at the end of the dispatch period is greater than the target power generation number of years;

[0089] It is the number of years during which the calculated power generation of the hydropower station by the end of the dispatch 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 at the end of the scheduling period is greater than the target power generation under the given water level at the end of the scheduling period, and the probability that the calculated power generation is within a certain deviation range ΔE of the target power generation, the power generation deviation risk is obtained, which can provide support for the power station operation and management unit to formulate a power generation plan. If the probability of predicted power generation exceeding the target power generation is low, that is, the possibility of achieving the target power generation index is low, the possibility of achieving the target power generation can be increased by lowering the water level at the end of the scheduling period and changing the scheduling plan; If the power generation capacity is smaller, the risk of power generation deviation is greater, that is, the probability that the power generation is within a certain deviation range of the target power generation is low. The power generation can be adjusted by adjusting the water level at the end of the scheduling period and changing the scheduling plan to meet the power generation requirements of the hydropower station while improving the utilization rate of water resources.

[0091] The method of the present invention is further described below by means of specific examples.

[0092] Example 1

[0093] Taking a large hydropower station A in the Yangtze River Basin of my country as an example, a method for assessing the risk of power generation deviation of a hydropower station based on runoff uncertainty according to the present invention is applied, comprising the following steps:

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

[0095] First, basic parameters such as the water level-reservoir capacity curve, reservoir water level-discharge capacity curve, discharge flow-tailwater level relationship curve, power generation scheduling diagram, upper and lower limits of water level, minimum discharge flow, and power generation scheduling method of Hydropower Station A are collected to provide boundary conditions for the construction of the power generation scheduling model of the hydropower station and the evaluation of power generation. Among them, the water level-reservoir capacity curve, reservoir water level-discharge capacity curve, discharge flow-tailwater level relationship curve, power generation scheduling diagram, upper and lower limits of water level, and power generation scheduling method are all related parameters determined in the design stage of the hydropower station. The minimum discharge flow is the discharge requirement during the operation of the hydropower station proposed by the comprehensive utilization requirements such as water supply, ecology or shipping. The minimum discharge flow of Hydropower Station A is 401m 3 / s, that is, under normal circumstances, the discharge flow of the hydropower station should be greater than or equal to 401m 3 / s.

[0096] For power plants that do not have a power generation dispatch diagram in the design phase, the dispatch diagram of the power plant can be calculated first for use in building a power generation dispatch model. This part is an existing technology and will not be elaborated on here.

[0097] Step 2: Apply the dispatching diagram to establish a hydropower station power generation dispatching and power generation calculation model. This part is the existing technology and will not be described in detail here. According to the power station dispatching plan, its dispatching diagram is as follows Figure 2 shown.

[0098] Depend on Figure 2 It can be seen that the scheduling diagram defines the water level process of the hydropower station in each period. By applying this scheduling diagram, the reservoir water level, outflow, power generation flow, power generation, etc. of the hydropower station at the end of the scheduling period can be calculated based on the current reservoir inflow and the hydropower station reservoir water level at the beginning of the scheduling period.

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

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

[0101] z0=1155;

[0102] z T =1198;

[0103] T=24.

[0104] Step 4: Using historical runoff data as calculation conditions, from the runoff data of the dam site of hydropower station A from 1959 to 2014 (N=56), select the end of April to the end of December as the hydropower station reservoir runoff process from the current period to the end of the dispatch period, and input it into the hydropower station power generation dispatch power generation calculation model as the reservoir flow for the calculation of the hydropower station power generation. The historical runoff sequence takes the runoff data of each decade from the end of April to the end of December from 1959 to 2014 as n=1,2,……,N (N is the total number of years for calculation, here N=56, that is The runoff data for each decade from the end of April to the end of December 1959) are used as reservoir inflow data to input into the dispatching model.

[0105]

[0106] Step 5: Use the above model to calculate the power generation of the hydropower station in each period under the historical runoff process year by year, and calculate the total power generation in the period. Take n = 1 as an example, that is, calculate the power generation of Hydropower Station A from the end of April to the end of December during the runoff sequence in 1959. t=1,2,……,T (T is the total calculation period. In this example, the calculation period is 8 months, and the calculation period is ten days, so T is 24) is the input data. According to the dispatching diagram of hydropower station A, Q can be obtained out,t ,z t-1 ,z t , and then according to and The power generation of hydropower station A in each period during the runoff sequence in 1959 can be calculated And the cumulative power generation from the end of April to the end of December In this example, the power generation in early May A similar method can be used to obtain And the cumulative power generation from the end of April to the end of December

[0107] Similarly, the cumulative power generation of hydropower station A from the end of April to the end of December under other runoff sequence conditions can be obtained:

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

[0109] The annual target power generation of hydropower station A is 18 billion kW·h. The actual power generation from January to the end of April is 3.86 billion kW·h. Therefore, the power generation from the end of April to the end of December should be greater than 14.14 billion kW·h to achieve the target power generation. Distribution of power generation of hydropower station A calculated based on historical runoff series The probability of achieving the target power generation can be obtained as:

[0110]

[0111] Assuming the target power generation deviation is 1 billion kW·h, that is, ΔE = 10, the probability that the calculated power generation is within the deviation range is:

[0112]

[0113] Other parts not described belong to the prior art.

Claims

1. A method for assessing the risk of power generation deviation of a hydropower station based on runoff uncertainty, characterized by: The following steps are involved: 1) Collect basic parameters of hydropower station power generation dispatch and determine constraints; 2) According to the power generation dispatching mode of the hydropower station, based on the basic parameters and constraints, a power generation dispatching and power generation calculation model of the hydropower station is established; 3) The current measured reservoir water level Z of the hydropower station current Input the hydropower station power generation scheduling and power generation calculation model as the initial calculation reservoir water level, and set the end-of-scheduling reservoir water level Z set ; Z set The reservoir water level at the end of a given dispatching period is given according to the reservoir medium- and long-term dispatching water level control target; 4) Using historical runoff data as calculation conditions, the runoff process of the hydropower station from the current period to the end of the dispatching period in N years of history is calculated. Input into the hydropower station power generation scheduling and power generation calculation model as the inflow flow for the hydropower station power generation calculation; is the measured average flow rate in the t period of the nth year, n=1,2,......,N; t=1,2,......,T, T is the total dispatching period; 5) Calculating the power generation of the hydropower station in each period under the historical runoff process conditions year by year through the power generation scheduling and power generation calculation model of the hydropower station, and calculating the total power generation in the total scheduling period; 6) Calculate the probability that the calculated power generation of the hydropower station at the end of the scheduling period is greater than or equal to the target power generation under the historical runoff conditions under the set water level conditions at the end of the scheduling period, and the probability that the calculated power generation is within a certain deviation range of the target power generation, and obtain the power generation deviation risk.

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

3. The method for risk assessment of power generation deviation of a hydropower station based on runoff uncertainty according to claim 1 is characterized by: The constraints include: ① Reservoir water level constraints With t ∈[Z min ,WITH max ] Among them, z t is the reservoir water level at the end of the hydropower station period t; Z min It is the lower limit of the reservoir water level of the hydropower station, generally the dead water level; Z max It is the upper limit of the reservoir water level of the hydropower station, which is generally the normal water storage level; ② The discharge flow of the hydropower station meets the minimum discharge flow requirements Q out,min ≤Q out,t Among them, Q out,min is the minimum discharge flow of the hydropower station; Q out,t is the average outflow flow of the hydropower station in period t.

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

5. The method for risk assessment of power generation deviation of a hydropower station based on runoff uncertainty according to claim 1 is characterized by: In step 5), the calculation formula for the total power generation in each calculation period in the N-year history is: in, is the calculated power generation of the hydropower station in the tth period of the nth year, obtained by the power generation scheduling calculation model of the hydropower station; It is the calculated power generation of the hydropower station under the runoff sequence conditions in the nth year to the end of the dispatch period.

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

Images