CN104392142A - Generation method of power generation scheme for preventing sustained damage of hydropower station group - Google Patents

Abstract

A generation method of a power generation scheme for preventing sustained damage of a hydropower station group includes the steps of 1, determining an optimization target and constraint conditions and establishing a statin optimizing and scheduling module; 2, considering uncertainty of hydrological forecasting and conversion of forecasting runoff; 3, calculating potential output of each phase; 4, determining a pattern of power generation constraint rules; 5, acquiring optimized power generation constraint rules and a power generation scheme set by means of an optimization algorithm; and 6, establishing an evaluation index system to evaluate optimal scheduling results. The generation method has the advantages that sustainability of the power generation process is ensured, a minimum of damage is ensured, and the simple and universal power generation constraint scheduling rules are provided to guide optimization of hydropower stations; the influence of hydrological forecasting errors upon scheduling results is fully considered, the power generation constraint scheduling rules are optimized by means of forms of energy, and more accurate decision basis is provided for decision makers.

Description

Prevent the electricity generating plan generation method that GROUP OF HYDROPOWER STATIONS continuation is destroyed

Technical field

The present invention relates to reservoir operation technical field, a kind of with the Reservoir Operation Scheme generation method ensureing that the continuity generated electricity is target with the continuation avoiding generating to destroy specifically.

Background technology

GROUP OF HYDROPOWER STATIONS Optimized Operation passes through hydraulic power and the storage capacity compensating action of storehouse group, space-time redistributes water resource, reaches the object of bringing good to and remove all evil.Usually because the uncertainty of runoff and the distribution in year are uneven, the destruction (being mainly reflected on hydropower station fraction) that the generating in power station is suffered to a certain degree is usually caused.At present, the scheduling rule run for power station (group) has usually: graph of reservoir operation, neural network, discriminant method etc.

Graph of reservoir operation is the basis of reservoir routine dispactching, the principle that the difference that it reflects each department requires and dispatches, and is used to the conventional measure instructing Hydropower Plant Reservoir to run; Neural network determines suitable network structure and parameter combinations according to the specific requirement of practical application, comprise the network number of plies, the neuron number of every layer and all connection weights, threshold value, may be used for multiple regression analysis, obtain the determination principle of optimality of implicit stochastic optimization, instruct reservoir to run; Store the order discriminant method that discharges water be exactly make power station not pondage banish under head large as far as possible, reach the object that gross generation is large as far as possible.

Current methods Problems existing is: 1. scheduling graph can only be used for single reservoir usually, is not easy to process complicated Cascade Reservoirs scheduling problem.Scheduling result is not optimum, fails to consider that the period becomes a mandarin, and merges Optimized Operation rule.2. the determination of Parameters of Neural Network Structure also lacks systematized method, and usually adopt the method for repetition test to carry out, it is slow that algorithm exists pace of learning, is easily absorbed in the defect of local minimum.3. use and store water supply discriminant method when dispatching, only considered the distribution of exerting oneself and do not consider the distribution of the water yield, only be conceived to the optimization in the period, and do not consider the impact of operation on following sessions of this period, the possibility that stepped system abandons water is very large.

Summary of the invention

The object of the invention is the present situation for above-mentioned background technology, according to examination benchmark (optimization aim), ensure generating continuity and homogeneity, at utmost make hydropower station process avoid destroying as target, a kind of electricity generating plan generation method preventing GROUP OF HYDROPOWER STATIONS continuation from destroying is provided.

A kind of electricity generating plan generation method preventing GROUP OF HYDROPOWER STATIONS continuation from destroying, comprises the steps:

(1) determine optimization aim and constraint condition, set up Optimized Scheduling of Hydroelectric Power model;

(2) uncertainty of hydrologic forecast and the conversion of forecasting runoff is considered;

(3) calculate the potential of each period to exert oneself;

(4) form of generating restriction rule is determined;

(5) optimized algorithm is adopted to be optimized generating restriction rule and electricity generating plan set;

(6) the preferred scheduling result of assessment indicator system evaluation is set up;

The restriction rule that generates electricity described in step (4) is as follows,

Potential exerting oneself is greater than 0 and equals and be less than MAXP ₁, adopt exert oneself into mW generates electricity;

Potential exerting oneself is more than or equal to MAXP ₁and be less than MAXP ₂, adopt exert oneself into mW generates electricity;

Potential exerting oneself is more than or equal to MAXP ₂and be less than MAXP ₃, adopt exert oneself into mW generates electricity;

……

Potential exerting oneself is more than or equal to MAXP _n-1and be less than MAXP _n, adopt and exert oneself as N MW generates electricity;

In formula, MAXP ₁, MAXP ₂..., MAXP _nrepresent potential the exerting oneself in period initial time power station respectively, unit is MW; N is the total installed capacity in power station, and unit is MW; T is installation number of units; According to the installed capacity of every platform unit by its m decile, when unit installed capacity is less, m gets 1 or 2; When unit installed capacity is larger, m gets 2 or 3.

Described in step (6), assessment indicator system mainly comprises following index:

(1) reliability index:

$\mathrm{\γ}=\frac{\mathrm{int\Σ}(P_i\≥{\mathrm{TP}}_i)}{n}$

In formula, P _ifor i period output of power station, TP _iexert oneself for i period power station is given, hop count when n is total activation, int Σ (P _i>=TP _i) to represent in scheduling result that the i period exerts oneself P _ibe more than or equal to TP _inumber of times;

(2) restorability index:

$\mathrm{\&beta;}=\frac{\mathrm{int\&Sigma;}(P_i<{\mathrm{TP}}_i\&\&P_{i+1}\&GreaterEqual;{\mathrm{TP}}_{i+1})}{n-\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}$

In formula, int Σ (P _i< TP _iaMP.AMp.Amp & P _i+1>=TP _i+1) represent that the i period exerts oneself P _ibe less than TP _ithe P and the i+1 period exerts oneself _i+1be more than or equal to TP _i+1number of times;

(3) vulnerability inder:

$\mathrm{\&zeta;}=\frac{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\max ({\mathrm{TP}}_i-P_i;0)}{n-\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}.$

In formula, for P _ibe less than TP _inumber of times.

The advantage of the electricity generating plan generation method that the present invention prevents GROUP OF HYDROPOWER STATIONS continuation from destroying is:

1, scheduling rule is considered less to runoff prediction error in the past, and institute of the present invention extracting method takes into full account the uncertainty of hydrologic forecast, can be decision maker and provides reference frame more accurately;

2, the energy that the unit water yield has under different head is different, and the optimization generating restriction scheduling rule that the present invention carries obtains based on energy mode, fully takes into account the energy variation rule that change of water level causes;

3, the present invention is applicable to the multiobject mid-long runoff for reservoir power generation run solution formulation of GROUP OF HYDROPOWER STATIONS, instructs the medium-term and long-term optimizing operation in power station.

Provided by the invention a kind of with the generation method of the Reservoir Operation Scheme preventing power generation process progressive failure from being target, make the continuity of power generation process and the destruction of minimum degree, and then provide a kind of generating of simple general-purpose to limit scheduling rule to instruct optimal operation.The present invention takes into full account the impact of hydrologic forecast error on scheduling result, and employing form of energy is optimized to generate electricity and limits scheduling rule, for decision maker provides decision-making foundation more accurately simultaneously.

Accompanying drawing explanation

Fig. 1 is the flow diagram of the inventive method.

Fig. 2 is the schematic diagram of generating restriction rule.

Embodiment

The present invention considers the uncertainty of mid-and-long term hydrologic forecast, adopts the mode of energy to formulate generating restriction rule, by given goal condition, adopts optimized algorithm to be optimized generating restriction rule.This rule can take into full account generating continuity and homogeneity, at utmost makes GROUP OF HYDROPOWER STATIONS power generation process avoid destroying as target, provides a kind of GROUP OF HYDROPOWER STATIONS medium-term and long-term electricity generating plan generation method.Idiographic flow refers to Fig. 1.

Prevent the electricity generating plan generation method that GROUP OF HYDROPOWER STATIONS continuation is destroyed, specifically comprise following process:

1 determines optimization aim and constraint condition, sets up Model on Formulate Operation of Reservoir

1.1 optimization aim determining reservoir operation

For generating, flood control and ecology, determine the objective function that medium-term and long-term optimization of hydroelectric generation is dispatched, as follows:

(1) gross generation of GROUP OF HYDROPOWER STATIONS is maximized:

$\begin{array}{cc}\mathrm{Max}& \underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\underset{j=1}{\overset{m}{\mathrm{\&Sigma;}}}{P}_{i,j}\text{\&Delta;t---}\left(1\right)\end{array}$

In formula: n is the scheduling slot number divided; M is power station number in Cascade Reservoirs; Δ t is the Period Length of schedule periods; P _{i, j}for exerting oneself of i period j power station.

(2) the generating fraction of Hydropower Stations is maximum:

$\begin{array}{cc}\max & \frac{\mathrm{num}(\underset{j=1}{\overset{m}{\mathrm{\&Sigma;}}}{P}_{i,j}\&GreaterEqual;P_{m\mathrm{in}})}{n}\end{array},---\left(2\right)$

In formula: P _minrepresent the firm output powcr of Hydropower Stations; represent that in each period, Hydropower Stations gross capability is greater than the number of times of step firm output powcr.

(3) downstream meets with the least risk of flood:

$\max \frac{\mathrm{num}(Q_{i,j}\&le;Q_{\mathrm{safe}})}{n}---\left(3\right)$

In formula: Q _safefor the safety discharge at flood control reference mark, downstream; Num (Q _i,j≤ Q _safe) represent that in each period, letdown flow is less than or equal to the number of times of safety discharge.

(4) ecological flow Service Efficiency is maximum:

$\max \frac{\mathrm{num}(Q_{i,j}\&GreaterEqual;Q_{\mathrm{eco}})}{n}---\left(4\right)$

In formula: Q _ecofor the minimum ecological discharge of downstream river course; Num (Q _i,j>=Q _eco) represent that in each period, letdown flow is more than or equal to the number of times of ecological flow.

1.2 constraint conditions determining reservoir operation

The constraint of Model on Formulate Operation of Reservoir mainly comprises: (1) water balance retrains; (2) reservoir capacity constraint; (3) reservoir storage outflow constraint; (4) water balance constraint between upstream and downstream reservoir; (5) output of power station constraint; (6) whole story state constraint etc.

2 consider the uncertainty of hydrologic forecast and the conversion of forecasting runoff

In Runoff Forecast, the generation of prediction error is difficult to avoid, and it is mainly derived from hydrologic survey error, Prediction version error, sampling error and forecasting model error etc.According to reality, the uncertainty of hydrologic forecast error can only forecast that handling situations estimates its probability distribution.One method indirectly estimates according to the forecast qualification rate in " Hydrological Information and Forecasting specification ", and another kind of method directly directly estimates according to actual prediction error data.Given sample point set inquires into its probability density function parameter estimation and non-parametric estmation two kinds of methods.The distribution pattern that parameter estimation needs prior data-oriented sample to obey, and then the parameter of this probability density function is estimated with sample; Non-parametric estmation does not then need the form supposing probability density function, utilizes sample data directly to estimate its probability density.Adopt parametric technique to carry out hydrologic forecast error analysis, need to provide error distribution pattern in advance, then estimate the parameter of corresponding distribution pattern according to operation forecast data sample.Usual supposition hydrologic forecast error Normal Distribution.Nonparametric technique does not require totally known or supposition to imposing any restrictions property of population distribution, by its probability distribution of sample data direct estimation.There are many Nonparametric Estimations at present, as histogram method, Rosenblatt method, kernel function estimation method, Nearest Neighbor Estimates method etc.

Be described for method for parameter estimation below.Just because of the outwardness of prediction error, measuring runoff can be counted as the average line of forecasting process, and forecast runoff always does random fluctuation round measuring runoff.Generally, it is 0 that hydrologic forecast error can think that it obeys average, and mean square deviation is δ ₁normal distribution.Under the prerequisite that two Phase flow process is known, the regularity of distribution of runoff process prediction error depends on the deterministic coefficient of Prediction version, and relational expression is between the two as follows:

${\mathrm{\&delta;}}_1=\sqrt{(1-R^2)\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{(I_t-\stackrel{\&OverBar;}{I})}^2/\underset{t=1}{\overset{n}{\mathrm{\&Sigma;}}}{I}_t^2}---\left(5\right)$

In formula: δ ₁for the standard deviation of prediction error; R ²for deterministic coefficient; for measured discharge I _taverage.

The deterministic coefficient of known forecasting model, can obtain the mean square deviation of this forecasting model prediction error, according to the rule of hydrologic forecast error Normal Distribution, obtains prediction error by stochastic simulation, reaches the object revised forecast numerical value.If forecast data deficiencies, when qualitatively can only determine the grade of Runoff Forecast scheme, the deterministic coefficient corresponding according to each grade can obtain the mean square deviation of prediction error, according to the rule of hydrologic forecast error Normal Distribution, by stochastic simulation, actual measurement two Phase flow process is converted into forecast two Phase flow process, the forecast two Phase flow I ' of t _tcan be calculated by following formula:

I′ _t＝(1+ε)I _t(6)

In formula: ε is random number.

3 calculate the potential of each period exerts oneself

Consider that the energy that the unit water yield in power station has in different head situation is non-equivalence, be thus necessary water interactions to be unified energy.For single power station j, the potential of power station is exerted oneself according to calculating of such as giving a definition:

${\mathrm{MAXP}}_{i,j}=k_j\&CenterDot;I_{i,j}\&CenterDot;{\stackrel{\&OverBar;}{H}}_{i,j}+\frac{k_j}{\mathrm{\&Delta;t}}\underset{{\mathrm{VL}}_{i,j}}{\overset{V_{i,j}}{\&Integral;}}{H}_j\left(V\right)\mathrm{dV}---\left(7\right)$

In formula: k _jfor the comprehensive power factor in j power station, MAXP _i,jrepresent to exert oneself at the potential of i period in j power station; I _i,jfor becoming a mandarin of j power station i period; VL _i,jrepresent the minimum storage capacity of j power station in the i period, H _j(V) represent under different storage capacity V, corresponding average output head.

For series connection power station, owing to there is hydraulic connection between them, the pondage (going out stream) in upper water power station can be reused by tail water power station, and then produces more energy.Assuming that tail water power station keeps original state constant, after water,tap power station uses all water yields stored, potential the exerting oneself in tail water power station calculates according to the following formula:

${\mathrm{MAXP}}_{i,j+1}=k_{j+1}\&CenterDot;(I_{i,j}+I_{i,j+1})\&CenterDot;{\stackrel{\&OverBar;}{H}}_{i,j+1}+\frac{k_{j+1}}{\mathrm{\&Delta;t}}\&CenterDot;V_{i,j}\&CenterDot;H_{i,j+1}+\frac{k_{j+1}}{\mathrm{\&Delta;t}}\underset{{\mathrm{VL}}_{i,j+1}}{\overset{V_{i,j+1}}{\&Integral;}}{H}_{j+1}\left(V\right)\mathrm{dV}---\left(8\right)$

In formula: MAXP _{i, j+1}represent to exert oneself at the potential of i period in j+1 power station.

4 determine the form of restriction rule of generating electricity

Restriction generating rule is defined as follows:

The total installed capacity in power station is N MW, and installation number of units is catwalk, and according to the installed capacity of every platform unit by its m decile, unit installed capacity is less, m desirable 1 or 2; Unit installed capacity is comparatively large, m desirable 2 or 3.Rule format is with reference to Fig. 2.Simultaneously can according to formulating different generating restriction rules in flood season and non-flood period, month or season.The advantage of this rule is: unit can be made while simple to operate to be in efficiency higher state and run.

Potential exerting oneself is greater than 0 and equals and be less than MAXP ₁, adopt exert oneself into mW generates electricity;

Potential exerting oneself is more than or equal to MAXP ₁and be less than MAXP ₂, adopt exert oneself into mW generates electricity;

Potential exerting oneself is more than or equal to MAXP ₂and be less than MAXP ₃, adopt exert oneself into mW generates electricity;

……

Potential exerting oneself is more than or equal to MAXP _n-1and be less than MAXP _n, adopt and exert oneself as N MW generates electricity.

In formula: MAXP ₁, MAXP ₂..., MAXP _nrepresent potential exert oneself (MW) in period initial time power station respectively.

According to above-mentioned steps, can determine the generating restriction rule in each power station in GROUP OF HYDROPOWER STATIONS respectively, the final optimized algorithm that adopts is optimized result.

5 adopt optimized algorithm to be optimized limits generating rule and electricity generating plan

Above-mentioned optimization problem is a multiparameter, higher-dimension, nonlinear optimization problem, and artificial intelligence multi-objective optimization algorithm usually can be adopted to be optimized calculating.Conventional method has: NSGA-II, PSO and MODE algorithm etc.

Below for NSGA-II method, be described.NSGA-II, based on Pareto thought, can obtain the multiple noninferior solutions within population number; Have employed elitism strategy, the best solution obtained in search procedure is remained; In addition by the application to degree of crowding calculating and quick non-dominated ranking method, improve efficiency of algorithm, reduce the complexity of calculating, realize simple.NSGA-II method is adopted to optimize the key step of hydropower station restriction rule as follows: 1. encode to the horizontal stroke at reference mark, ordinate, the number at reference mark depends on the division of unit; 2. the citation form of preset schedule rule, as shown in Figure 1; 3. calculate the fitness of different scheduling line, through individual variation, intersection and selection, produce new scheduling line; 4. judge whether to meet convergence of algorithm condition, if meet, turn to next step, otherwise turn to step 2..Finally be met the Noninferior Solution Set of condition, and then obtain different Reservoir Operation Scheme.

6 set up the preferred scheduling result of assessment indicator system evaluation

By following evaluation index (formula 9-11), set up scheduling result appraisement system, carry out the quality of thoroughly evaluating scheduling result from reliability, restorability and fragility aspect, the decision-making foundation of more science is provided to decision maker.

(1) reliability index:

$\mathrm{\&gamma;}=\frac{\mathrm{int\&Sigma;}(p_i\&GreaterEqual;{\mathrm{TP}}_i)}{n}---\left(9\right)$

In formula, P _ifor i period output of power station, TP _iexert oneself for i period power station is given, hop count when n is total activation, int Σ (P _i>=TP _i) to represent in scheduling result that the i period exerts oneself P _ibe more than or equal to TP _inumber of times;

(2) restorability index:

$\mathrm{\&beta;}=\frac{\mathrm{int\&Sigma;}(P_i<{\mathrm{TP}}_i\&\&P_{i+1}\&GreaterEqual;{\mathrm{TP}}_{i+1})}{n-\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}---\left(10\right)$

In formula, int Σ (P _i< TP _iaMP.AMp.Amp & P _i+1>=TP _i+1) represent that the i period exerts oneself P _ibe less than TP _ithe P and the i+1 period exerts oneself _i+1be more than or equal to TP _i+1number of times;

(3) vulnerability inder:

$\mathrm{\&zeta;}=\frac{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\max ({\mathrm{TP}}_i-P_i;0)}{n-\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}---\left(11\right)$

In formula, for P _ibe less than TP _inumber of times.

Claims (2)

1. the electricity generating plan generation method preventing GROUP OF HYDROPOWER STATIONS continuation from destroying, is characterized in that comprising the steps:

(1) determine optimization aim and constraint condition, set up Optimized Scheduling of Hydroelectric Power model;

(2) uncertainty of hydrologic forecast and the conversion of forecasting runoff is considered;

(3) calculate the potential of each period to exert oneself;

(4) form of generating restriction rule is determined;

(5) optimized algorithm is adopted to be optimized generating restriction rule and electricity generating plan set;

(6) the preferred scheduling result of assessment indicator system evaluation is set up;

The restriction rule that generates electricity described in step (4) is as follows,

Potential exerting oneself is greater than 0 and equals and be less than MAXP ₁, adopt exert oneself into generating;

Potential exerting oneself is more than or equal to MAXP1 and is less than MAXP ₂, adopt exert oneself into generating;

Potential exerting oneself is more than or equal to MAXP2 and is less than MAXP ₃, adopt exert oneself into generating;

……

Potential exerting oneself is more than or equal to MAXP _n-1and be less than MAXP _n, adopt and exert oneself as N MW generates electricity;

In formula, MAXP ₁, MAXP ₂..., MAXP _nrepresent potential the exerting oneself in period initial time power station respectively, unit is MW; N is the total installed capacity in power station, and unit is MW; T is installation number of units; According to the installed capacity of every platform unit by its m decile, when unit installed capacity is less, m gets 1 or 2; When unit installed capacity is larger, m gets 2 or 3.

2. the electricity generating plan generation method preventing GROUP OF HYDROPOWER STATIONS continuation from destroying as claimed in claim 1, is characterized in that described in step (6), assessment indicator system comprises following index:

(1) reliability index:

$\mathrm{\&gamma;}=\frac{\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}{n}$

In formula, P _ifor i period output of power station, TP _iexert oneself for i period power station is given, hop count when n is total activation, int Σ (P _i>=TP _i) to represent in scheduling result that the i period exerts oneself P _ibe more than or equal to TP _inumber of times;

(2) restorability index:

In formula, int Σ (P _i< TP _iaMP.AMp.Amp & P _i+1>=TP _i+1) represent that the i period exerts oneself P _ibe less than TP _ithe P and the i+1 period exerts oneself _i+1be more than or equal to TP _i+1number of times;

(3) vulnerability inder:

$\mathrm{\&zeta;}=\frac{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}\max ({\mathrm{TP}}_i-P_i;0)}{n-\mathrm{int\&Sigma;}(P_i\&GreaterEqual;{\mathrm{TP}}_i)}$

In formula, for P _ibe less than TP _inumber of times.