Reversible hydropower station rapid operation simulation method considering unit vibration area constraint

Abstract

The invention relates to a reversible hydropower station rapid operation simulation method considering unit vibration area constraints, which comprises the following steps: S1, according to the operation condition of a reversible hydropower station, considering constraint conditions of output, water head, flow and reservoir capacity, and taking maximization of the total output of the power station as a target function, establishing an operation simulation model of the reversible hydropower station; s2, based on a unit aggregation and integer variable linear relaxation method, linearizing a vibration area operation constraint part in the operation simulation model, and simplifying the model into a linear programming model; and S3, according to the upstream runoff data and the operation parameters of the reversible hydropower station, solving the operation simulation model to obtain an operation simulation result. According to the method, the equivalent variable and the constraint approximate original mixed integer constraint are introduced, solving is carried out in a linear programming mode, the solving speed is improved while the simulation precision is guaranteed, the operation flexibility of the hydropower station is better considered, the energy utilization efficiency is improved, and the operation cost is reduced.

Description

Technical Field

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

[0002] Reversible hydropower stations are capable of generating electricity and storing energy, and have the ability to regulate grid load, store energy, and balance electricity supply and demand. Accurate and efficient hydropower station operation simulation is crucial for the economic operation and management of power stations. In traditional operation simulation methods, it is often necessary to solve nonlinear and non-convex optimization problems, and it is difficult to ensure that the global optimal solution is found. In addition, a variety of complex constraints need to be considered during the simulation process, including vibration zone operation constraints. On the one hand, these factors increase the number of operating state variables in the model, making it difficult to solve. On the other hand, overly simplified models cannot reflect the actual operation of hydropower stations, and the operation simulation has large 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: 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, 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: According to 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 It represents 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, represents the tailwater height, represents the head loss, Indicates the discharge flow, f HQ It represents the tailwater height-total discharge flow curve, and the subscripts i, x, and t represent the power station, unit, and time number respectively;

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

[0012]

[0013] in, Indicates the minimum output of the operating range in the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output of the operating range in 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 vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, represents the maximum power generation flow, f QH Represents the maximum discharge flow-upper reservoir water level curve, H min,i,x Indicates the minimum water 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, Represents the total output of the reversible power station, Represents the power generation of the reversible unit, represents 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 rate of the reversible unit, Indicates that the reversible power station is always adjusted to 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 down-regulated for standby. Indicates that the generator set is downgraded to standby. Indicates that the pumping unit is lowered to standby, η gen It represents the energy conversion efficiency of power generation. 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, It represents the head loss;

[0018] The operating constraints of the 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, represents the maximum pumping power, The state variable representing 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 operation model and constraint formula of the reservoir 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 initial reservoir capacity of the time period, V i,t+1 represents the reservoir capacity at the end of the period, V min Represents the minimum storage capacity, V nax represents the maximum storage capacity, It represents the total discharge of the reservoir to the lower reservoir, Δt represents the length of the time period, represents natural runoff;

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

[0026]

[0027] Wherein, 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 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 the 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 the hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of the hydropower station i that pass through the vibration zone downwards, represents the total capacity of the units in operation 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, It 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 simplifying the cascade reversible hydropower station operation model based on unit aggregation and integer variable linear relaxation method into a linear programming model includes the following steps:

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

[0035] S302, inputting the objective function and constraint conditions of the model into the solver, and defining the solution parameters, including the number of iterations and tolerance error;

[0036] S303, outputting the model solution result to obtain the operation simulation result 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 convert 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, thereby greatly improving the speed of solution while ensuring the simulation accuracy, and can better consider the operational flexibility of the hydropower station, improve energy utilization efficiency, and reduce 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 convert 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, thereby greatly improving the solution speed while ensuring the simulation accuracy, and can better consider the operational flexibility of the hydropower station, improve energy utilization efficiency, and reduce 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 fast operation simulation method of a reversible hydropower station considering 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 reversible hydropower station rapid operation simulation method considering the unit vibration zone constraint of the present invention comprises the following steps:

[0044] S1. Run simulation model establishment

[0045] According to the operation 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 It represents 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, represents the tailwater height, represents the head loss, Indicates the discharge flow, f HQ It represents the tailwater height-total discharge flow curve, and the subscripts i, x, and t represent the power station, unit, and time number respectively;

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

[0050]

[0051]

[0052] in, Indicates the minimum output of the operating range in the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output of the operating range in 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 vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, represents the maximum power generation flow, f QH Represents the maximum discharge flow-upper reservoir water level curve, H min,i,x Indicates the minimum water 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, Represents the total output of the reversible power station, Represents the power generation of the reversible unit, represents 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 rate of the reversible unit, Indicates that the reversible power station is always adjusted to 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 down-regulated for standby. Indicates that the generator set is downgraded to standby. Indicates that the pumping unit is lowered to standby, η gen It represents the energy conversion efficiency of power generation. 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, It represents the head loss;

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

[0057]

[0058] in, Indicates the minimum power output, Indicates the maximum power output. represents the minimum pumping power, represents the maximum pumping power, The state variable representing 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 operation model and constraint formula of the reservoir 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 initial reservoir capacity of the time period, V i,t+1represents the reservoir capacity at the end of the period, V min Represents the minimum storage capacity, V max represents the maximum storage capacity, It represents the total discharge of the reservoir to the lower reservoir, Δt represents the length of the time period, represents natural runoff;

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

[0064]

[0065] Wherein, 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 the aggregation and integer variables of cascade hydropower units is as follows:

[0069]

[0070]

[0071] in, It represents the total capacity of the units operating above the vibration zone in the 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 the hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of the hydropower station i that pass through the vibration zone downwards, represents the total capacity of the units in operation 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, It 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 of the 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 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 gurobipy solver in Python. First, the non-decision variables in the model are defined according to the actual data, including natural runoff, water flow time lag, output, head, head, upper and lower flow limits, energy conversion efficiency, etc., and then the objective function and constraints of the model are input into the solver, and the solution parameters are defined, including the number of iterations, tolerance error, etc. Finally, the model solution results are output to obtain the operation simulation results of the cascade reversible hydropower station.

[0076] Example

[0077] The example analysis is carried out with simulated simplified 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[Maximum flow rate (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[Maximum storage capacity (100 million m 3 )]]> 43.12 30.18 / <![CDATA[Minimum reservoir capacity (100 million 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 enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of 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. According to the operation of the reversible hydropower station, considering the constraints of 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; S2. Based on the 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 operation simulation model according to 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, ρ indicates the density of water, g indicates the acceleration of gravity, η hydro represents 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, represents the tailwater height, represents the head loss, Indicates the discharge flow, f HQ It represents the tailwater height-total discharge flow curve, and the subscripts i, x, and t represent the power station, unit, and time number respectively; The operating constraint formula of conventional power station units is as follows: in, Indicates the minimum output of the operating range in the vibration zone. Indicates the minimum output of the operating range in the vibration zone. Indicates the maximum output of the operating range in 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 vibration zone. The state variable indicating whether the unit is operating in the vibration zone. Indicates the maximum downstream flow rate, represents the maximum power generation flow, f QH Represents the maximum discharge flow-upper reservoir water level curve, H min,i,x Indicates the minimum water head, H max,i,x Indicates the maximum water head; The operating model formula of the reversible power station is as follows: in, Represents the total output of the reversible power station, Represents the power generation of the reversible unit, represents 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 rate of the reversible unit, Indicates that the reversible power station is always adjusted to 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 down-regulated for standby. Indicates that the generator set is downgraded to standby. Indicates that the pumping unit is lowered to standby, η gen It represents the energy conversion efficiency of power generation. 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, It represents the head loss; The operating constraints of the reversible power plant are as follows: in, Indicates the minimum power output, Indicates the maximum power output. represents the minimum pumping power, represents the maximum pumping power, The state variable representing 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 operation model and constraint formula of the reservoir are as follows: In min ≤V i,t ≤V max 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 Represents the minimum storage capacity, V max represents the maximum storage capacity, It represents the total discharge of the reservoir to the lower reservoir, Δt represents the length of the time period, represents natural runoff; The formula for optimizing the objective function of maximizing the total output is as follows: Wherein, T represents the total time period and N represents 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 1 is characterized in that: In step S2, the method formula for linear relaxation of cascade hydropower units aggregation and integer variables is as follows: in, It represents the total capacity of the units operating above the vibration zone of 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 the hydropower station i that pass through the vibration zone upwards, It represents the total capacity of the units of the hydropower station i that pass through the vibration zone downwards, represents the total capacity of the units in operation 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, It 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: 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.

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 specific process of simplifying the 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: S301. Define non-decision variables in the model according to actual data, including natural runoff, water flow time lag, output, water head, head, upper and lower flow limits, and energy conversion efficiency; S302, inputting the objective function and constraint conditions of the model into the solver, and defining the solution parameters, including the number of iterations and tolerance error; S303, outputting the model solution result to obtain the operation simulation result of the cascade reversible hydropower station.

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