A method for fast operation simulation of reversible hydropower station considering unit vibration zone constraints

Abstract

The present application relates to a kind of reversible hydroelectric station fast operation simulation method considering unit vibration area constraint, comprising the following steps: S1, according to reversible hydroelectric station operation, considering output, water head, flow and storage capacity constraint condition, with power station total output maximization as objective function, establishes reversible hydroelectric station operation simulation model;S2, based on unit aggregation and integer variable linear relaxation method, the vibration area operation constraint part in operation simulation model is linearized, and the model is simplified into linear programming model;S3, according to the runoff data and operating parameters of upstream reversible hydroelectric station, solve operation simulation model, obtain operation simulation result.The present application is by introducing equivalent variable and constraint to approximate original mixed integer constraint, in the form of linear programming solution, improve solving speed when guaranteeing simulation accuracy, better consider the operation flexibility of hydroelectric station, improve energy utilization efficiency, reduce operating cost.

Description

Technical Field

[0001] The present invention relates to the field of electrical engineering, and more particularly to a method for simulating the rapid operation of a reversible hydropower station taking into account unit vibration zone constraints. Background Art

[0002] Reversible hydropower plants are capable of both power generation and energy storage, and have the ability to regulate grid load, store energy, and balance power supply and demand. Accurate and efficient hydropower plant operation simulation is crucial for the economic operation and management of power plants. Traditional operation simulation methods often require solving nonlinear, non-convex optimization problems, making it difficult to guarantee a global optimal solution. Furthermore, the simulation process must consider a variety of complex constraints, including operational constraints in vibration zones. These factors increase the model's operational state variables, making the solution difficult. Furthermore, overly simplified models fail to reflect the actual operation of hydropower plants, resulting in significant operational simulation deviations. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for simulating the rapid operation of a reversible hydropower station taking into account the vibration zone constraints of the unit, which can simulate the operation of a cascade reversible hydropower station more quickly and accurately.

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct a reversible hydropower station rapid operation simulation method considering the vibration zone constraints of the unit, comprising the following steps:

[0005] S1. Establishment of operation simulation model: Based on the operation status of the reversible hydropower station, taking into account constraints such as output, head, flow and reservoir capacity, and taking maximization of the total output of the power station as the objective function, an operation simulation model of the reversible hydropower station is established;

[0006] S2. Model linearization: Based on unit aggregation and integer variable linear relaxation method, the nonlinear part of the operation simulation model is linearized and the model is simplified into a linear programming model;

[0007] S3. Model solution: Based on the runoff data and operation parameters upstream of the reversible hydropower station, the operation simulation model is solved to obtain the operation simulation results.

[0008] According to the above scheme, in step S1, the conventional cascade power station model formula is as follows:

[0009]

[0010] in, Indicates the total output, Indicates the unit output. represents the total power generation flow, Indicates the power generation flow of the unit, Indicates total increase in reserve. Indicates that the unit is on standby. Indicates total downgrade reserve. Indicates that the unit is downgraded to standby, ρ indicates the density of water, g indicates the acceleration of gravity, η hydro Indicates the conversion efficiency of conventional cascade power stations. represents the generating head, Indicates the maximum output of the operating range in the vibration zone, H i,t Indicates the water level of the upper reservoir, Indicates the tailwater height, represents the head loss, Indicates the discharge flow, f HQ represents the tailwater height-total discharge curve, where the subscripts i, x, and t represent the power station, unit, and time number, respectively;

[0011] The operating constraint formula for conventional power station units is as follows:

[0012]

[0013] in, Indicates the minimum output in the operating range under the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output in the operating range under the vibration zone. Indicates the maximum output of the operating range in the vibration zone, A state variable indicating whether the unit is operating in the lower operating range of the vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, Indicates the maximum power generation flow, f QH Represents the maximum discharge flow-upper reservoir water level curve, H min,i,x Indicates the minimum head, H max,i,x Indicates the maximum water head;

[0014] The operating model formula of the reversible power station is as follows:

[0015]

[0016]

[0017] in, Indicates the total output of the reversible power station, Represents the generating power of the reversible unit, Indicates the pumping power of the reversible unit, represents the total flow of the reversible power station, represents the power generation flow of the reversible unit, Indicates the pumping flow of the reversible unit, Indicates that the reversible power station is always on standby. Indicates that the generator set is put on standby. Indicates that the pumping unit is on standby. Indicates that the reversible power station is always in reserve. Indicates that the generator set is lowered to standby mode. Indicates that the pumping unit is lowered to standby, η gen Indicates the power generation energy conversion efficiency, represents the generating head, η pump represents the pumping energy conversion efficiency, Indicates the pumping head, Indicates the maximum power output. Indicates the maximum pumping power, H i,t Upstream reservoir water level, H i+1,t represents the water level of the downstream reservoir, Indicates head loss;

[0018] The operating constraints of a reversible power plant are as follows:

[0019]

[0020]

[0021] in, Indicates the minimum power output, Indicates the maximum power output. represents the minimum pumping power, Indicates the maximum pumping power, Indicates the state variable of the unit working in power generation condition, Indicates the state variable of the unit working in pumping condition, represents the minimum generating head, represents the maximum generating head, Indicates the minimum pumping head, Indicates the maximum pumping head;

[0022] The reservoir operation model and constraint formula are as follows:

[0023]

[0024] Among them, f HV represents the water level-reservoir capacity curve, Represents the average storage capacity of the reservoir during the period, V i,t represents the reservoir capacity at the beginning of the period, V i,t+1 Represents the reservoir capacity at the end of the period, V min Indicates the minimum storage capacity, V nax Indicates the maximum storage capacity, It represents the total discharge of the reservoir to the lower level reservoir, Δt represents the length of the time period, represents natural runoff;

[0025] The formula for maximizing the total output optimization objective function is as follows:

[0026]

[0027] Where T represents the total time period and N represents the total number of power stations.

[0028] According to the above scheme, in step S2, the aggregation of cascade hydropower units and the linear relaxation of integer variables are as follows:

[0029]

[0030]

[0031] in, It represents the total capacity of the units operating above the vibration zone in hydropower station i, It represents the total capacity of the units operating below the vibration zone of hydropower station i, It represents the total capacity of the units of hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of hydropower station i that pass through the vibration zone downwards, It represents the total capacity of the units operating in the vibration zone of hydropower station i, C v It represents the cost of a unit of unit capacity passing through the vibration zone, represents the total cost of hydropower station i crossing the vibration zone.

[0032] According to the above scheme, in step S3, the model solving process is as follows: the simplified cascade reversible hydropower station operation model based on unit aggregation and integer variable linear relaxation method is a linear programming model, which can be solved by calling gurobipy solving software in Python.

[0033] According to the above scheme, the specific process of converting the simplified cascade reversible hydropower station operation model into a linear programming model based on unit aggregation and integer variable linear relaxation method includes the following steps:

[0034] S301. Define non-decision variables in the model based on actual data, including natural runoff, water flow time lag, output, head, head, upper and lower flow limits, and energy conversion efficiency;

[0035] S302, input the objective function and constraints of the model into the solver, and define the solution parameters, including the number of iterations and tolerance error;

[0036] S303. Output the model solution results to obtain the operation simulation results of the cascade reversible hydropower station.

[0037] The implementation of the reversible hydropower station rapid operation simulation method considering the unit vibration zone constraint of the present invention has the following beneficial effects:

[0038] 1. The present invention carefully considers all aspects of the operation of cascade reversible hydropower stations and uses unit aggregation and integer variable linear relaxation methods to transform nonlinear problems into linear problems. By introducing equivalent variables and constraints to approximate the original mixed integer constraints, the problem can be solved in the form of linear programming. This greatly improves the solution speed while ensuring simulation accuracy, better considers the operational flexibility of the hydropower station, improves energy utilization efficiency, and reduces operating costs.

[0039] 2. In order to improve the simulation solution efficiency while considering the vibration zone constraints of the hydropower station units, the present invention adopts unit aggregation and integer variable linear relaxation method to transform the nonlinear problem into a linear problem. By introducing equivalent variables and constraints to approximate the original mixed integer constraints, the problem can be solved in the form of linear programming, thereby greatly improving the solution speed while ensuring the simulation accuracy, better considering the operational flexibility of the hydropower station, improving energy utilization efficiency, and reducing operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0041] Figure 1 It is a flow chart of the method for simulating the rapid operation of a reversible hydropower station taking into account the vibration zone constraints of the unit according to the present invention. DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0043] like Figure 1 As shown, the method for simulating the rapid operation of a reversible hydropower station considering the vibration zone constraints of the unit of the present invention includes the following steps:

[0044] S1. Run simulation model establishment

[0045] According to the operation status of the reversible hydropower station, considering the constraints such as output, head, flow and reservoir capacity, and taking the maximization of the total output of the power station as the objective function, a reversible hydropower station operation simulation model is established;

[0046] The formula for the conventional cascade power station model is as follows:

[0047]

[0048] in, Indicates the total output, Indicates the unit output. represents the total power generation flow, Indicates the power generation flow of the unit, Indicates total increase in reserve. Indicates that the unit is on standby. Indicates total downgrade reserve. Indicates that the unit is downgraded to standby, ρ indicates the density of water, g indicates the acceleration of gravity, η hydro Indicates the conversion efficiency of conventional cascade power stations. represents the generating head, Indicates the maximum output of the operating range in the vibration zone, H i,t Indicates the water level of the upper reservoir, Indicates the tailwater height, represents the head loss, Indicates the discharge flow, f HQ represents the tailwater height-total discharge curve, where the subscripts i, x, and t represent the power station, unit, and time number, respectively;

[0049] The operating constraint formula for conventional power station units is as follows:

[0050]

[0051]

[0052] in, Indicates the minimum output in the operating range under the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output in the operating range under the vibration zone. Indicates the maximum output of the operating range in the vibration zone, A state variable indicating whether the unit is operating in the lower operating range of the vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, Indicates the maximum power generation flow, f QH Represents the maximum discharge flow-upper reservoir water level curve, H min,i,x Indicates the minimum head, H max,i,x Indicates the maximum water head;

[0053] The operating model formula of the reversible power station is as follows:

[0054]

[0055] in, Indicates the total output of the reversible power station, Represents the generating power of the reversible unit, Indicates the pumping power of the reversible unit, represents the total flow of the reversible power station, represents the power generation flow of the reversible unit, Indicates the pumping flow of the reversible unit, Indicates that the reversible power station is always on standby. Indicates that the generator set is put on standby. Indicates that the pumping unit is on standby. Indicates that the reversible power station is always in reserve. Indicates that the generator set is lowered to standby mode. Indicates that the pumping unit is lowered to standby, η gen Indicates the power generation energy conversion efficiency, represents the generating head, η pump represents the pumping energy conversion efficiency, Indicates the pumping head, Indicates the maximum power output. Indicates the maximum pumping power, H i,t Upstream reservoir water level, H i+1,t represents the water level of the downstream reservoir, Indicates head loss;

[0056] The operating constraints of a reversible power plant are as follows:

[0057]

[0058] in, Indicates the minimum power output, Indicates the maximum power output. represents the minimum pumping power, Indicates the maximum pumping power, Indicates the state variable of the unit working in power generation condition, Indicates the state variable of the unit working in pumping condition, represents the minimum generating head, represents the maximum generating head, Indicates the minimum pumping head, Indicates the maximum pumping head;

[0059] The reservoir operation model and constraint formula are as follows:

[0060]

[0061]

[0062] Among them, f HV represents the water level-reservoir capacity curve, Represents the average storage capacity of the reservoir during the period, V i,t represents the reservoir capacity at the beginning of the period, V i,t+1Represents the reservoir capacity at the end of the period, V min Indicates the minimum storage capacity, V max Indicates the maximum storage capacity, It represents the total discharge of the reservoir to the lower level reservoir, Δt represents the length of the time period, represents natural runoff;

[0063] The formula for maximizing the total output optimization objective function is as follows:

[0064]

[0065] Where T represents the total time period and N represents the total number of power stations.

[0066] S2. Model linearization

[0067] Based on unit aggregation and integer variable linear relaxation method, the nonlinear part of the operation simulation model is linearized and the model is simplified into a linear programming model.

[0068] The linear relaxation of aggregation and integer variables for cascade hydropower units is as follows:

[0069]

[0070]

[0071] in, It represents the total capacity of the units operating above the vibration zone in hydropower station i, It represents the total capacity of the units operating below the vibration zone of hydropower station i, It represents the total capacity of the units of hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of hydropower station i that pass through the vibration zone downwards, It represents the total capacity of the units operating in the vibration zone of hydropower station i, C v It represents the cost of a unit of unit capacity passing through the vibration zone, represents the total cost of hydropower station i crossing the vibration zone.

[0072] S3. Model solution

[0073] According to the runoff data and operation parameters upstream of the reversible hydropower station, the operation simulation model is solved and the operation simulation results are obtained.

[0074] The model solving process is as follows:

[0075] The simplified cascade reversible hydropower station operation model, based on unit aggregation and integer variable linear relaxation, is a linear programming model that can be solved using the gurobipy solver in Python. First, the non-decision variables in the model are defined based on actual data, including natural runoff, flow lag, output, head, head, upper and lower flow limits, and energy conversion efficiency. The model's objective function and constraints are then input into the solver, and solution parameters, including the number of iterations and tolerance, are defined. Finally, the model solution is output to obtain the operational simulation results of the cascade reversible hydropower station.

[0076] Example

[0077] The example analysis is performed using simplified simulated data. The data is shown in Table 1 below:

[0078] Table 1 Data of upstream and downstream conventional hydropower stations

[0079] Upstream power station Downstream power station Reversible power station Number of units 4 4 4 <![CDATA[最大流量(m / s 3 )]]> 277.6 325 198 Maximum water head (m) 203 122 150 Minimum water head (m) 147 80.7 240 Maximum output (MW) 150 80 / Lower minimum output (MW) 40 45 / Maximum output (MW) 460 300 300 Minimum output (MW) 300 180 180 <![CDATA[最大库容(亿m 3 )]]> 43.12 30.18 / <![CDATA[最小库容(亿m 3 )]]> 19.29 10.77 / Maximum water level (m) 400 200 / Minimum water level (m) 350 160 /

[0080] According to the model establishment in step S1, the model linearization in step S2, and the model solution in step S3, the results are shown in Table 2 below:

[0081] Table 2 Simulation results

[0082]

[0083]

[0084]

[0085] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A method for simulating the rapid operation of a reversible hydropower station considering the vibration zone constraints of the unit, characterized in that: The following steps are involved: S1. Based on the operation of the reversible hydropower station, considering the constraints of output, head, flow and reservoir capacity, and taking maximizing the total output of the power station as the objective function, a reversible hydropower station operation simulation model is established; The operation simulation model of a reversible hydropower station is as follows: in, Indicates the total output of the reversible power station, Represents the generating power of the reversible unit, Indicates the pumping power of the reversible unit, represents the total flow of the reversible power station, represents the power generation flow of the reversible unit, Indicates the pumping flow of the reversible unit, Indicates that the reversible power station is always on standby. Indicates that the generator set is put on standby. Indicates that the pumping unit is on standby. Indicates that the reversible power station is always in reserve. Indicates that the generator set is lowered to standby mode. Indicates that the pumping unit is lowered to standby. represents the density of water, represents the acceleration due to gravity, Indicates the power generation energy conversion efficiency, represents the generating head, represents the pumping energy conversion efficiency, Indicates the pumping head, Indicates the maximum power output. Indicates the maximum pumping power, Upstream reservoir water level, represents the water level of the downstream reservoir, Indicates head loss, subscript Respectively represent the power station, unit and time mark; S2. Based on unit aggregation and integer variable linear relaxation method, the nonlinear part of the operation simulation model is linearized and the model is simplified into a linear programming model; S3. Solve the simplified operation simulation model based on the runoff data and operation parameters upstream of the reversible hydropower station to obtain the operation simulation results.

2. The method for rapid operation simulation of a reversible hydropower station considering unit vibration zone constraints according to claim 1 is characterized in that: In step S1, the conventional cascade power station model formula is as follows: in, Indicates the total output, Indicates the unit output. represents the total power generation flow, Indicates the power generation flow of the unit, Indicates total increase in reserve. Indicates that the unit is on standby. Indicates total downgrade reserve. Indicates that the unit is downgraded to standby mode. represents the density of water, represents the acceleration due to gravity, Indicates the conversion efficiency of conventional cascade power stations. represents the generating head, Indicates the maximum output of the operating range in the vibration zone, Indicates the water level of the upper reservoir, Indicates the tailwater height, represents the head loss, Indicates the downstream flow rate, Indicates the tailwater height-total discharge curve, subscript Respectively represent the power station, unit and time mark; The operating constraint formula for conventional power station units is as follows: in, Indicates the minimum output in the operating range under the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output in the operating range under the vibration zone. Indicates the maximum output of the operating range in the vibration zone, A state variable indicating whether the unit is operating in the lower operating range of the vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, Indicates the maximum power generation flow, Indicates the maximum discharge flow-upper reservoir water level curve, represents the minimum water head, Indicates the maximum water head; The operating constraints of a reversible power plant are as follows: in, Indicates the minimum power output, Indicates the maximum power output. represents the minimum pumping power, Indicates the maximum pumping power, Indicates the state variable of the unit working in power generation condition, Indicates the state variable of the unit working in pumping condition, represents the minimum generating head, represents the maximum generating head, Indicates the minimum pumping head, Indicates the maximum pumping head; The reservoir operation model and constraint formula are as follows: in, represents the water level-reservoir capacity curve, represents the average storage capacity of the reservoir during the period, represents the reservoir capacity at the beginning of the period, represents the reservoir capacity at the end of the period, represents the minimum storage capacity, Indicates the maximum storage capacity, Indicates the total discharge of the reservoir to the lower level reservoir. Indicates the length of the period, represents natural runoff; The formula for maximizing the total output optimization objective function is as follows: in, Indicates the total time period, Indicates the total number of power stations.

3. The method for rapid operation simulation of a reversible hydropower station considering unit vibration zone constraints according to claim 2 is characterized in that: In step S2, the method formula for aggregating the cascade hydropower units and linearly relaxing the integer variables is as follows: in, It represents the total capacity of the units operating above the vibration zone in hydropower station i, It represents the total capacity of the units operating below the vibration zone of hydropower station i, It represents the total capacity of the units of hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of hydropower station i that pass through the vibration zone downwards, It represents the total capacity of the units operating below the vibration zone of hydropower station i, It represents the cost of a unit of unit capacity passing through the vibration zone, represents the total cost of hydropower station i crossing the vibration zone.

4. The method for rapid operation simulation of a reversible hydropower station considering unit vibration zone constraints according to claim 1 is characterized in that: The simplified operation model of the cascade reversible hydropower station based on unit aggregation and integer variable linear relaxation method is a linear programming model, which can be solved by calling the gurobipy solving software in Python.

5. The method for rapid operation simulation of a reversible hydropower station considering unit vibration zone constraints according to claim 4 is characterized in that: The process of solving the simplified operational simulation model includes the following steps: S301. Define non-decision variables in the model based on actual data, including natural runoff, water flow time lag, output, head, head, upper and lower flow limits, and energy conversion efficiency; S302, input the objective function and constraints of the model into the solver, and define the solution parameters, including the number of iterations and tolerance error; S303. Output the model solution results to obtain the operation simulation results of the cascade reversible hydropower station.

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