Flexible supply and demand balance optimization method and device for source-load-storage resources

Abstract

The invention discloses a flexible supply and demand balance optimization method and device for source-load-storage resources. The method comprises the following steps: calculating a flexibility demand of a power system in real time; carrying out two-stage robust scheduling; wherein in the first stage, the flue gas split ratio of the carbon capture unit and the CO2 rich solution amount released by the rich solution storage tank are used for regulating and controlling the operation cost, the carbon transaction cost and the flexible supply capability; wherein in the second stage, the flue gas split ratio of the carbon capture unit and the CO2 rich solution amount released by the rich solution storage tank are used for regulating and controlling the flexibility vacancy punishment cost. The carbon capture power plant provides greater flexibility for supply and demand balance of a power system.

Description

Technical Field

[0001] The invention relates to a method and a device for optimizing the flexibility supply and demand balance of source, load and storage resources. Background Art

[0002] Traditional thermal power plants contribute little to the flexibility of the power system. For example, refer to the optimization configuration method that considers the synergy and complementarity of multiple types of flexibility resources proposed in Chinese invention patent application CN116154863A. Carbon capture power plants can provide greater flexibility, so it is necessary to quantitatively describe the flexibility of carbon capture power plants and then use it for the scheduling of the power system.

[0003] In addition, the characterization of flexibility needs to be improved. For example, Chinese invention patent application CN117937428A proposes a two-stage robust capacity optimization configuration method that considers flexibility demand constraints. Since this method is a static resource configuration rather than a dynamic resource scheduling, the characterization of flexibility demand does not take into account the uncertainty of net load at the start time. Summary of the invention

[0004] The present invention provides a method and device for optimizing the flexible supply-demand balance of source, load and storage resources.

[0005] The technical solution of the present invention is as follows: a method for optimizing the supply and demand balance of source-load-storage resources, wherein the source of electricity includes a carbon capture power plant, and the method comprises:

[0006] Calculate power system flexibility requirements in real time;

[0007] Perform two-stage robust scheduling;

[0008] Among them, in the first stage, the operating parameters of the source end are determined with the first cost as the optimization target and the first constraint as the constraint, the first cost includes the start-up and shutdown cost, the operating cost and the carbon trading cost, the first constraint includes the flexibility balance constraint and the rich liquid processing capacity constraint of the carbon capture power plant, the storage tank liquid balance constraint, and the storage tank volume limit constraint, the operating parameters of the source end include the flue gas diversion ratio of the carbon capture unit in the carbon capture power plant and the amount of CO2 rich liquid released by the rich liquid storage tank, the flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released by the rich liquid storage tank are used to regulate the operating cost, carbon trading cost and flexibility supply capacity;

[0009] Among them, in the second stage, the operating parameters of the source end are determined with the second cost as the optimization target and the second constraint as the constraint. The second cost includes the flexibility deficiency penalty cost. The second constraint includes the rich liquid processing volume constraint of the carbon capture power plant, the liquid balance constraint of the storage tank, and the volume limit constraint of the storage tank. The flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released from the rich liquid storage tank are used to regulate the flexibility deficiency penalty cost.

[0010] Alternatively, the flue gas split ratio of the sth carbon capture power plant at time t is recorded as The amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t is recorded as

[0011] The contribution of the carbon capture unit of the sth carbon capture power plant to the operating cost of the power system at time t is expressed as The unit cost for transporting and storing CO2, is the amount of CO2 contained in the CO2-rich liquid being processed by the sth carbon capture power plant at time t, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

[0012] Alternatively, the flue gas split ratio of the sth carbon capture power plant at time t is recorded as

[0013] The contribution of the sth carbon capture power plant to the carbon trading cost at time t is expressed as is the carbon emission rights trading price; is the free carbon quota of the s-th carbon capture power plant at time t, is the amount of CO2 captured by the sth carbon capture power plant at time t, E s，t is the total carbon emissions of the sth carbon capture power plant at time t, represents the carbon emissions captured by the sth carbon capture power plant at time t, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

[0014] Alternatively, the flue gas split ratio of the sth carbon capture power plant at time t is recorded as The amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t is recorded as The upward flexibility supply provided by the carbon capture unit in the s-th carbon capture power plant at time t is denoted as The downward flexibility supply provided by the carbon capture unit in the s-th carbon capture power plant at time t is denoted as

[0015] in is the energy consumption of the carbon capture unit of the sth carbon capture power plant at time t, is the lower limit of energy consumption of the carbon capture unit of the sth carbon capture power plant, is the energy consumption cap of the carbon capture unit of the sth carbon capture power plant;

[0016]

[0017] is the fixed energy consumption of the carbon capture unit, which is a negative value, is the operating energy consumption of the carbon capture unit of the sth carbon capture power plant at time t, which is a negative value, φ is the energy consumption for processing unit CO2, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

[0018] Optionally, in both the first and second stages, the flexibility demand of the power system is determined according to the following formula:

[0019] in, is the upward flexibility demand at time t, is the downward flexibility demand at time t, is the upper bound of the net load fluctuation at time t-1, is the lower bound of the net load fluctuation at time t-1, is the upper bound of the net load fluctuation at time t, is the lower bound of the net load fluctuation at time t.

[0020] Optionally, in the first stage and the second stage, the rich liquid processing capacity is constrained as follows: is the amount of CO2 in the CO2-rich liquid being processed by the sth carbon capture power plant at time t, ω is the maximum working coefficient of carbon capture, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the maximum power of the power generation unit in the sth carbon capture power plant.

[0021] Optionally, the liquid balance constraint in the storage tank in the first stage is: V s，t is the volume of rich liquid released from the rich liquid storage tank of the sth carbon capture power plant, are the rich liquid volumes of the rich liquid storage tank of the sth carbon capture power plant at time t, time t-1, the initial time of the scheduling decision cycle, and the end time of the scheduling decision cycle, respectively. The lean liquid volume of the lean liquid storage tank of the sth carbon capture power plant at time t, time t-1, the initial time of the scheduling decision cycle, and the end time of the scheduling decision cycle respectively;

[0022] M is the amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank at time t, MEA is the molar mass of the absorbent, is the molar mass of CO2, q re is the analytical volume of the regeneration tower, l R is the absorbent solution concentration, ρ R is the density of absorbent solution;

[0023] In the second stage, the liquid balance constraint of the storage tank is: is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment, is the amount of rich liquid flowing out at time t after adjustment in the second stage; is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment, are respectively the rich liquid volume of the rich liquid storage tank of the sth carbon capture power plant at the initial moment of the scheduling decision cycle and the end moment of the scheduling decision cycle, are the lean liquid volumes of the lean liquid storage tank of the sth carbon capture power plant at the initial moment of the scheduling decision cycle and the end moment of the scheduling decision cycle respectively;

[0024] M is the amount of CO2 in the CO2 rich liquid released from the rich liquid storage tank at time t after the second stage adjustment, MEA is the molar mass of the absorbent, is the molar mass of CO2, q re is the analytical volume of the regeneration tower, l R is the absorbent solution concentration, ρ R is the density of the absorbent solution.

[0025] Optionally, the storage tank volume limit constraint in the first stage is: is the volume of the rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t, is the lean liquid volume of the lean liquid storage tank of the sth carbon capture power plant at time t, V max is the maximum volume of the storage tank;

[0026] The storage tank volume limit constraint in the second stage is: is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, V max The maximum volume of the storage tank.

[0027] The technical solution of the present invention is as follows: a flexible supply and demand balance optimization device for source, load and storage resources, including a memory and a processor, the memory stores a program, and the processor runs the program to execute the above method.

[0028] The technical solution of the present invention is as follows: a program product, which executes the above method when running.

[0029] In the present invention, the carbon capture power plant provides greater flexibility for the power system. No matter it is the first stage of flexibility supply and demand balance or the second stage of flexibility supply and demand imbalance, by adjusting the flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released from the rich liquid storage tank, the flexibility supply capacity of the power system can be effectively improved, thereby maximizing the overall economic benefits of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a working flow diagram of the carbon capture unit of the carbon capture power plant.

[0031] Figure 2 It is a flow chart of the flexible supply and demand balance optimization method of source, load and storage resources of the present invention.

[0032] Figure 3 It is a structural schematic diagram of the flexible supply and demand balance optimization device of source, load and storage resources of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0034] Note: The following description is based on a carbon capture power plant as a shutdown unit. It should be understood that a single generator unit in a carbon capture power plant can also be used as a shutdown unit. A carbon capture power plant, for example, includes multiple generator units and one carbon capture unit. Multiple generator units are independently controlled to be shut down or started.

[0035] Note: The following shows the design ideas and operation process of the flexible supply and demand balance optimization method of source-load-storage resources of the present invention.

[0036] Note: The concentration of the rich liquid is stable, and the amount of rich liquid released from the rich liquid storage tank (such as the volume of the rich liquid) is proportional to the amount of CO2 contained in the released rich liquid. The two are essentially the same control parameter.

[0037] The present invention divides the carbon capture power plant into a power generation unit and a carbon capture unit. The working process of the carbon capture unit is shown in Figure 1 .

[0038] All flue gas generated by power generation in the power generation unit is discharged into the carbon capture unit. Part of the flue gas is cooled by the cooler and then directly discharged through the bypass of the absorber. The rest of the flue gas is cooled by the cooler and pretreated to remove particulate matter, sulfur compounds and other substances in the flue gas that may interfere with the CO2 capture process. The pretreated flue gas is introduced into the absorber, where CO2 contacts and reacts with ethanolamine (MEA, an absorbent) solution to absorb CO2 to form a rich liquid, which is then sent to the regeneration tower through a rich liquid pump. The excess rich liquid is stored in a rich liquid storage tank. The rich liquid and the lean liquid are heat exchanged in a heat exchanger. In the regeneration tower, the CO2 in the rich liquid is released by heating or reducing the pressure, thereby realizing the regeneration of the rich liquid and the separation of CO2. After the CO2 is separated, the MEA solution changes from a rich liquid to a lean liquid. After the lean liquid is pumped by the lean liquid pump, the absorbent is added to the mixer and can participate in the next CO2 flue gas absorption, thereby realizing recycling. The excess lean liquid is stored in a lean liquid storage tank.

[0039] The ethanolamine in the present invention is used as an example of an absorbent for capturing carbon dioxide in flue gas. The absorbent reacts chemically with CO2, and then desorbs by heating to release CO2, thereby capturing CO2.

[0040] The operation of the carbon capture power plant is modeled as follows:

[0041]

[0042] Where: is the total power output of the sth carbon capture power plant at time t; is the power output of the power generation unit in the sth carbon capture power plant at time t; is the fixed energy consumption of the carbon capture unit in the sth carbon capture power plant (negative value); is the operating energy consumption of the carbon capture unit in the sth carbon capture power plant at time t (negative value); φ is the energy consumption for processing unit CO2; is the amount of CO2 contained in the CO2-rich liquid being processed by the sth carbon capture power plant at time t; is the amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t; e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant; σcap is the capture efficiency; is the flue gas split ratio of the sth carbon capture power plant at time t.

[0043] The flexibility provision capability of the carbon capture plant is modelled as follows:

[0044]

[0045] Where: is the upward flexible supply of the sth carbon capture plant at time t; is the downward flexible supply of the sth carbon capture plant at time t; The upward flexible supply of the generation unit of the sth carbon capture plant at time t; The downward flexible supply of the power generation unit of the sth carbon capture power plant at time t; is the upward flexible supply of the carbon capture unit of the sth carbon capture power plant at time t, is the downward flexible supply of the carbon capture unit of the sth carbon capture power plant at time t; is the power of the power generation unit of the sth carbon capture power plant at time t; is the upper limit of the power generation unit of the sth carbon capture power plant; is the lower power limit of the power generation unit of the sth carbon capture power plant; is the ramp-up rate of the power generation unit of the sth carbon capture power plant; is the ramp-down rate of the power generation unit of the sth carbon capture power plant; Δt is the scheduling duration; is the energy consumption of the carbon capture unit of the sth carbon capture power plant at time t (negative value); is the upper limit of energy consumption of the carbon capture unit of the sth carbon capture power plant (negative value); is the lower limit of energy consumption of the carbon capture unit of the sth carbon capture power plant (negative value).

[0046] The present invention regards the carbon capture power plant as a flexible resource on the power supply side. In addition, it fully taps the flexibility potential of resources such as pumped storage and adjustable loads, and calls on multiple types of flexible resources to meet flexibility needs. Some embodiments of the present invention characterize the flexibility supply capacity of the power system from the three perspectives of source-load-storage. In other embodiments, the control methods of the load end and the energy storage end are designed according to other known technologies.

[0047] In addition to carbon capture power plants, power supply flexibility is mainly provided by thermal power plants (especially thermal power plants without carbon capture units); pumped storage has the advantage of large storage capacity and stronger supply capacity for power system flexibility, so it is selected as the energy storage resource. The power system controls the contracted transferable load users by issuing dispatch instructions, and can transfer the users' electricity demand to other time periods to provide flexibility, such as electric vehicles and some industrial loads. The mathematical expression of the flexibility supply capacity of the above resources is as follows.

[0048]

[0049] Where: The upward flexibility supply capacity of thermal power plant i at time t, Provide downward flexibility for thermal power plant i at time t; is the power of thermal power plant i at time t, is the upper limit of power of thermal power plant i, is the lower power limit of thermal power plant i, is the upward climbing rate of thermal power plant i; is the downward ramp rate of thermal power plant i, and Δt is the scheduling duration.

[0050]

[0051] Where: Provides the upward flexibility of the transferable load at time t, Provides downward flexibility for the transferable load at time t; P t TL is the power of the transferable load at time t, is the upper limit of the power of the transferable load, is the lower power limit of the transferable load.

[0052]

[0053]

[0054] Where: The upward flexibility supply capacity of pumped storage at time t, The downward flexibility supply capacity of pumped storage at time t; P t PS is the power of pumped storage at time t (when the value is positive, it indicates power generation, and when the value is negative, it indicates pumping), is the upper limit of the power generation capacity of pumped storage. The upper limit of pumping power for pumped storage; is the storage capacity of pumped storage at time t, E max is the upper limit of pumped storage capacity, Emin is the lower limit of pumped storage capacity; η C is the pumping efficiency of pumped storage, η D is the power generation efficiency of pumped storage; Δt is the scheduling time.

[0055]

[0056] Where: is the total upward flexibility supply of the power system at time t, is the total downward flexibility supply of the power system at time t; A G is the number of thermal power plants, A ICCPP is the number of carbon capture power plants, s is the number of carbon capture power plants, and i is the number of thermal power plants.

[0057] Affected by the dual uncertainty of renewable energy generation and load, the net load presents the characteristics of variability and uncertainty. Variability is due to the change in predicted load demand and renewable energy generation output, which causes the net load to change over time; uncertainty refers to the forecast deviation of renewable energy generation and load output, which will cause unpredictable fluctuations in the net load. The system needs to have sufficient regulation capacity to cover the fluctuation range of the net load, which creates a demand for flexibility.

[0058] The present invention assumes that the forecast errors of wind power and load obey normal distribution, as shown below:

[0059]

[0060] Where: P L，t is the actual power of the load at time t, is the predicted power of the load at time t, δ L，t is the load prediction error at time t; P W，t is the actual power of wind power at time t, is the predicted power of wind power at time t, δ W，t is the prediction error of wind power at time t, P W，total is the total installed capacity of wind power. The above 0.03, 1 / 5, and 1 / 50 are typical values ​​of the set coefficients, and these set coefficients are represented by k, l, and m respectively. The formula can be written as follows:

[0061]

[0062] Based on the day-ahead forecast values ​​of wind power and load, according to the established probability distribution model, the upward and downward forecast error rates of wind power and load output at each time series can be sampled to obtain the forecast error interval range. Decision makers can select the confidence level in the [0, 1] interval to adjust the forecast error interval range according to their own risk preferences. In the embodiment of the present invention, the forecast error interval is obtained with a conservative preference and a confidence level of 0.9 to obtain the final forecast error interval:

[0063]

[0064] Where: is the upper bound of the load prediction error at time t, is the lower bound of the load prediction error at time t, is the upper bound of the wind power prediction error at time t, is the lower bound of the prediction error of wind power at time t.

[0065] The essence of flexibility demand is caused by the uncertainty of net load. Therefore, before describing flexibility demand, the uncertainty interval of net load should be described first. When the positive deviation of load is the largest and the negative deviation of wind power is the largest, the upper limit of net load is obtained; when the negative deviation of load is the largest and the positive deviation of wind power is the largest, the lower limit of net load is obtained.

[0066]

[0067] Where: P net，t is the actual value of the net load at time t, is the predicted value of net load at time t; is the upper bound of the net load fluctuation at time t, is the lower bound of the net load fluctuation at time t.

[0068] Considering that flexibility has directional characteristics, it can be divided into two directions: upward and downward. The flexibility demand is described as follows:

[0069]

[0070] Where: is the upper bound of the net load fluctuation at time t-1, is the lower bound of the net load fluctuation at time t-1; is the upward flexibility demand at time t, is the downward flexibility demand at time t.

[0071] When determining the upward flexibility demand and the downward flexibility demand, both the upper and lower bounds of the net load fluctuation at the current moment and the upper and lower bounds of the net load fluctuation at the previous moment are considered. This processing method takes into account the uncertainty of the prediction of the net load at the current moment and the previous moment, and ensures sufficient climbing capacity in the subsequent real-time scheduling operation.

[0072] In the conventional interval method, the upward flexibility demand at time t is calculated based on the upper limit of the net load fluctuation at time t and the value of the net load at time t-1, and the downward flexibility demand at time t is calculated based on the lower limit of the net load fluctuation at time t and the value of the net load at time t-1. The conventional interval method only considers the uncertainty of the end time (t), but ignores the uncertainty of the starting time (t-1), which will cause the calculated flexibility demand interval to deviate from the actual demand.

[0073] With the goal of minimizing the comprehensive operating cost of the system, a two-stage robust optimization scheduling model of source, load and storage taking into account flexibility is established. In the first stage, the operating status and output of thermal power plants, carbon capture power plants, and pumped storage are obtained in a deterministic scenario based on the net load forecast value of the day before; in the second stage, based on the optimization results of the first stage, the "extremely severe scenario" with the largest net load forecast error is considered, and the output of carbon capture equipment, pumped storage and transferable loads that can quickly respond to scheduling instructions is adjusted with the minimum adjustment cost as the objective function to deal with uncertainties in the system; the results are then fed back to the first stage to iterate and obtain the optimal day-ahead scheduling strategy.

[0074] The two-stage robust scheduling model takes the minimum total cost of system scheduling as the optimization goal, and the optimization objective function is as follows:

[0075]

[0076] Where: C total is the total operating cost; f1 is the first-stage objective function, f2 is the second-stage objective function, V is the uncertainty set, x is the first-stage decision variable, and y is the second-stage decision variable.

[0077] f1 is the optimization target of the first stage, which aims to determine the economic dispatch plan with the minimum operating cost in the deterministic scenario. The optimization target includes the start-up and shutdown costs, operating costs and carbon trading costs. Since the carbon capture power plant is converted from a thermal power plant, the cost and constraints of thermal power are also applicable to the carbon capture power plant. In formula (19), s is the number of the power plant in the set of thermal power plants and carbon capture power plants.

[0078]

[0079] Where: C status is the unit start-up and shutdown cost, C OPFor fuel costs, is the carbon trading cost; A S is the total number of carbon capture power plants and thermal power plants, t is time, T is the scheduling decision cycle, and in the embodiment of the present invention, T is 24h. is the startup cost coefficient of the sth power plant, is the shutdown cost coefficient of the sth power plant; is a Boolean variable representing the power-on status of power plant s at time t (a value of 1 indicates power-on, and a value of 0 indicates other statuses), is a Boolean variable representing the shutdown state of power plant s at time t (a value of 1 indicates shutdown, and a value of 0 indicates other states); is the power of the power generation unit of power plant s at time t; is the startup cost coefficient of pumped storage, is the shutdown cost coefficient for pumped storage; is the state variable of pumped storage power generation at time t (a value of 1 indicates that it is in the power generation state, and a value of 0 indicates that it is in other states), is the state variable of pumped storage at time t (a value of 1 indicates that it is in the pumping state, and a value of 0 indicates that it is in other states); a s is the coefficient of the quadratic term in the power generation cost function of the sth power plant, b s is the coefficient of the first-order term in the power generation cost function of the sth power plant, c s is the constant coefficient in the power generation cost function of the sth power plant; ρ e For pumped hydro tariffs; The unit cost of transporting and storing CO2 (e.g. the amount it costs to process one tonne of CO2); is the carbon emission rights trading price; is the free carbon quota of the sth power plant at time t, is the amount of CO2 captured by the carbon capture of the sth power plant at time t (for ordinary thermal power plants, this value is 0), E s，t is the overall carbon emissions of the sth power plant at time t.

[0080] The constraints of the first stage are as follows.

[0081] This is a power balance constraint, the power output of the source, load and storage resources should be equal to the load.

[0082] This is a flexibility balance constraint. In the first stage, flexible supply should be greater than demand.

[0083] This is the unit output constraint, and the power should be within the limit.

[0084] This is the unit climbing constraint, and the power change range should be within the limit.

[0085] This is the start-stop time constraint. Coal-fired units generally have a minimum start-up time and a minimum shutdown time. Where: t on is the minimum startup time, t off is the minimum downtime, t0 is the time the unit must be started and stopped at the beginning, It is the state variable of thermal power unit i at time t. When it is 1, it indicates startup, and when it is 0, it indicates shutdown. is the state variable of thermal power unit i at time t-1. When it is 1, it indicates startup, and when it is 0, it indicates shutdown. is the power of the power generation unit of the sth carbon capture power plant at time t-1, is the power of thermal power plant i at time t-1.

[0086] This is the constraint on the amount of rich liquid being processed. The amount of rich liquid being processed cannot be higher than the amount of rich liquid produced when the power plant is at maximum output. Where: ω is the maximum operating coefficient of carbon capture, is the maximum power of the power generation unit in the sth carbon capture power plant.

[0087] This is the volume expression of the amount of solution released from the rich liquid storage tank of the sth carbon capture power plant at time t.

[0088] This is the volume expression of the liquid in the rich liquid / lean liquid storage tank at time t; the circulation of rich liquid and lean liquid is considered to be a 1:1 relationship, and the amount of lean liquid stored is equal to the amount of rich liquid flowing out at time t. The storage tank balance expression at the beginning and end of the scheduling period, the amount at the beginning should also be balanced at the end, so that the next scheduling period can continue.

[0089] This is the volume limit that the storage tank should be within.

[0090] In the above formula: V s，t is the volume of solution consumed by the rich liquid storage tank of the sth carbon capture power plant to release CO2 at time t, M MEA is the molar mass of the absorbent, is the molar mass of CO2, q re is the analytical volume of the regeneration tower, l R is the concentration of alcoholamine solution, ρ R is the density of the alcoholamine solution, are respectively the rich liquid volumes of the rich liquid storage tank of the sth carbon capture power plant at time t and time t-1, are the lean liquid volumes of the lean liquid storage tank of the sth carbon capture power plant at time t and time t-1 respectively; is the volume of solution in the rich liquid storage tank of the sth carbon capture power plant at the start time, is the volume of the lean solution storage tank of the sth carbon capture power plant at the start time, is the volume of solution in the rich liquid storage tank of the sth carbon capture power plant at the end, V is the volume of the lean solution storage tank of the sth carbon capture power plant at the end; max The maximum volume of the storage tank.

[0091] This constraint means that the pumped storage power is within the limit.

[0092] This constraint means that the pumped storage can only be in one state, either pumping water or generating electricity.

[0093]

[0094] This constraint means that pumped storage cannot be switched indefinitely and should be within the limit.

[0095] This constraint indicates that the pumped storage capacity is within the limit.

[0096] This constraint is the expression for calculating the storage capacity of pumped storage.

[0097] This constraint means that the storage capacity of pumped storage should be balanced at the beginning and end of the period.

[0098] In the above formula: is the lower limit of power generation of pumped storage, is the lower limit of pumped storage power, is the upper limit of the power generation capacity of pumped storage. is the upper limit of pumped storage power. is the power generation state variable of pumped storage at time t-1 (a value of 1 indicates that it is in the power generation state, and a value of 0 indicates that it is in other states), is the pumping state variable of pumped storage at time t-1 (a value of 1 indicates that it is in the pumping state, and a value of 0 indicates that it is in other states), N j is the maximum number of starts and stops of pumped storage in a dispatch decision cycle, The storage volume of pumped storage at 0 o'clock at the beginning of the period, The storage volume of pumped storage at the end of the period at 24 o'clock. represents the storage capacity of pumped storage at time t, represents the storage capacity of pumped storage at time t-1, E min 、E max They are the lower and upper limits of pumped storage capacity, respectively.

[0099] Note: The above is an example based on a scheduling decision cycle of 24 hours.

[0100] The optimization goal of the second stage is to find the scheduling plan with the best flexibility in the uncertain scenario. The objective function includes the flexibility shortage penalty cost, power regulation cost and the call cost of the transferable load. The specific calculation method is as follows.

[0101] f2=C punish +C adjust +C DR (35); It shows that the objective function of the second stage is to minimize the penalty cost + adjustment cost + load-side dispatching cost.

[0102] This is how the various costs are calculated.

[0103] In the above formula: C punish is the flexibility deficiency penalty cost, C adjust is the power regulation cost, C DR is the call cost of the transferable load, c up is the penalty cost coefficient for insufficient upward flexibility, c dn is the penalty cost coefficient for insufficient downward flexibility, is the upward flexibility shortfall at time t, is the downward flexibility shortfall at time t, I IC is the compensation cost coefficient of the carbon capture power plant, I PS is the compensation cost coefficient of pumped storage, is the regulation power of the sth carbon capture power plant at time t in the second stage, ΔP t PS is the regulating power of pumped storage at time t in the second stage, I TL is the compensation cost coefficient of the transferable load, P t TL is the power of the load that can be transferred at time t.

[0104] The constraints of the second stage are as follows:

[0105]

[0106] In the second stage, power readjustment is performed, and this formula is the expression for power rebalancing.

[0107] In the second stage, a flexibility shortage may occur, at which point flexibility supply + shortage should be greater than or equal to flexibility demand.

[0108] That is, the amount of rich liquid to be processed is also subject to restrictions.

[0109] is the amount of rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment.

[0110] This is an expression for the volume of solution in the re-adjusted storage tank, etc.

[0111] This is the readjusted storage tank volume limit constraint.

[0112] In the above formula: A ICCPP is the number of carbon capture plants, is the amount of CO2 contained in the CO2 rich liquid volume processed by the rich liquid pump of the sth carbon capture power plant at time t after the second stage adjustment, is the amount of CO2 contained in the rich liquid released by the sth carbon capture power plant at time t after the second stage adjustment, is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment, is the amount of rich liquid flowing out at time t after adjustment in the second stage; is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment.

[0113]

[0114]

[0115] Where: P t PS，* is the power of the pumped storage at time t after adjustment in the second stage, is the storage volume of pumped storage at time t after adjustment in the second stage, It is the storage volume of pumped storage at time t-1 after adjustment in the second stage.

[0116] Formula (16) is the flexibility demand interval characterized after considering the uncertainty of the two moments before and after, and formula (21) is the flexibility supply and demand balance formula in the day-ahead stage. Through the accurate characterization of flexibility demand and the supply and demand balance guarantee, the flexibility penalty cost in formula (36) can be reduced. The flexibility demand interval considering the uncertainty of the starting time and the end time proposed in the present invention can accurately describe the net load fluctuation within the allowable error range, and can also avoid the penalty caused by insufficient real-time climbing ability due to the "false balance" of day-ahead flexibility supply and demand. The present invention uses carbon capture power plants as an important provider of flexibility supply, the system carbon emissions are reduced, and there is no flexibility shortage, the total scheduling cost is reduced, and the system low-carbon and flexibility can be improved together. The two-stage robust optimization model proposed in the present invention can reduce the compensation cost and penalty cost caused by real-time deviation, and the larger the prediction error, the better the effect. In addition, by changing the uncertain parameters and confidence, the conservatism of the model can be adjusted, which is helpful for decision makers to provide a reference for the trade-off between system operation flexibility, robustness and economy.

[0117] The above wind power is an example of renewable energy power generation. Renewable energy power generation may also include solar power generation, and its mathematical description may be processed according to existing technologies.

[0118] refer to Figure 2 ,The above methods are summarized as follows: The flexibility supply and demand balancing optimization method for source load and storage resources includes: step 101, calculating the flexibility demand of the power system in real time; step 102, performing two-stage robust scheduling;

[0119] Among them, in the first stage, the operating parameters of the source end are determined with the first cost as the optimization target and the first constraint as the constraint, the first cost includes the start-up and shutdown cost, the operating cost and the carbon trading cost, the first constraint includes the flexibility balance constraint and the rich liquid processing capacity constraint of the carbon capture power plant, the storage tank liquid balance constraint, and the storage tank volume limit constraint, the operating parameters of the source end include the flue gas diversion ratio of the carbon capture unit in the carbon capture power plant and the amount of CO2 rich liquid released by the rich liquid storage tank, the flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released by the rich liquid storage tank are used to regulate the operating cost, carbon trading cost and flexibility supply capacity;

[0120] Among them, in the second stage, the operating parameters of the source end are determined with the second cost as the optimization target and the second constraint as the constraint. The second cost includes the flexibility deficiency penalty cost. The second constraint includes the rich liquid processing volume constraint of the carbon capture power plant, the liquid balance constraint of the storage tank, and the volume limit constraint of the storage tank. The flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released from the rich liquid storage tank are used to regulate the flexibility deficiency penalty cost.

[0121] Based on the same inventive concept, an embodiment of the present invention also provides a flexible supply and demand balance optimization device for source, load and storage resources, including a memory and a processor, the memory stores a program, and the processor runs the program to execute the aforementioned method.

[0122] The processor is, for example, a central processing unit (CPU), a graphics processing unit (GPU), or any other type of processor. The memory is, for example, a hard disk, a USB flash drive, a flash memory, an optical disk, or any other type of memory.

[0123] Based on the same inventive concept, an embodiment of the present invention further provides a program product, which executes the aforementioned method when running.

[0124] The various embodiments of the present invention are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0125] The protection scope of the present invention is not limited to the above-mentioned embodiments. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the scope and spirit of the present invention. If these changes and modifications fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include these changes and modifications.

Claims

1. A flexible supply and demand balance optimization method for source, load and storage resources, wherein: The source of electricity comprises a carbon capture power plant, wherein the method comprises: Calculate power system flexibility requirements in real time; Perform two-stage robust scheduling; Among them, in the first stage, the operating parameters of the source end are determined with the first cost as the optimization target and the first constraint as the constraint, the first cost includes the start-up and shutdown cost, the operating cost and the carbon trading cost, the first constraint includes the flexibility balance constraint and the rich liquid processing capacity constraint of the carbon capture power plant, the storage tank liquid balance constraint, and the storage tank volume limit constraint, the operating parameters of the source end include the flue gas diversion ratio of the carbon capture unit in the carbon capture power plant and the amount of CO2 rich liquid released by the rich liquid storage tank, the flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released by the rich liquid storage tank are used to regulate the operating cost, carbon trading cost and flexibility supply capacity; Among them, in the second stage, the operating parameters of the source end are determined with the second cost as the optimization target and the second constraint as the constraint. The second cost includes the flexibility deficiency penalty cost. The second constraint includes the rich liquid processing volume constraint of the carbon capture power plant, the liquid balance constraint of the storage tank, and the volume limit constraint of the storage tank. The flue gas diversion ratio of the carbon capture unit and the amount of CO2 rich liquid released from the rich liquid storage tank are used to regulate the flexibility deficiency penalty cost.

2. The method according to claim 1, characterized in that The flue gas split ratio of the sth carbon capture power plant at time t is recorded as The amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t is recorded as The contribution of the carbon capture unit of the sth carbon capture power plant to the operating cost of the power system at time t is expressed as The unit cost for transporting and storing CO2, is the amount of CO2 contained in the CO2-rich liquid being processed by the sth carbon capture power plant at time t, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

3. The method according to claim 1, characterized in that The flue gas split ratio of the sth carbon capture power plant at time t is recorded as The contribution of the sth carbon capture power plant to the carbon trading cost at time t is expressed as is the carbon emission rights trading price; is the free carbon quota of the s-th carbon capture power plant at time t, is the amount of CO2 captured by the sth carbon capture power plant at time t, E s，t is the total carbon emissions of the sth carbon capture power plant at time t, represents the carbon emissions captured by the sth carbon capture power plant at time t, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

4. The method according to claim 1, characterized in that: The flue gas split ratio of the sth carbon capture power plant at time t is recorded as The amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank of the sth carbon capture power plant at time t is recorded as The upward flexibility supply provided by the carbon capture unit in the s-th carbon capture power plant at time t is denoted as The downward flexibility supply provided by the carbon capture unit in the s-th carbon capture power plant at time t is denoted as in is the energy consumption of the carbon capture unit of the sth carbon capture power plant at time t, is the lower limit of energy consumption of the carbon capture unit of the sth carbon capture power plant, is the energy consumption cap of the carbon capture unit of the sth carbon capture power plant; is the fixed energy consumption of the carbon capture unit, which is a negative value, is the operating energy consumption of the carbon capture unit of the sth carbon capture power plant at time t, which is a negative value, φ is the energy consumption for processing unit CO2, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the power output of the power generation unit in the sth carbon capture power plant at time t.

5. The method according to claim 1, characterized in that: In both the first and second phases, the flexibility demand of the power system is determined according to the following formula: in, is the upward flexibility demand at time t, is the downward flexibility demand at time t, is the upper bound of the net load fluctuation at time t-1, is the lower bound of the net load fluctuation at time t-1, is the upper bound of the net load fluctuation at time t, is the lower bound of the net load fluctuation at time t.

6. The method according to claim 1, characterized in that In the first and second stages, the rich liquid processing capacity is constrained as follows: is the amount of CO2 in the CO2-rich liquid being processed by the sth carbon capture power plant at time t, ω is the maximum working coefficient of carbon capture, σ cap is the capture efficiency, e s is the carbon emission intensity of the power generation unit in the sth carbon capture power plant, is the maximum power of the power generation unit in the sth carbon capture power plant.

7. The method according to claim 1, characterized in that In the first stage, the liquid balance constraint of the storage tank is: V s，t is the volume of rich liquid released from the rich liquid storage tank of the sth carbon capture power plant, are the rich liquid volumes of the rich liquid storage tank of the sth carbon capture power plant at time t, time t-1, the initial time of the scheduling decision cycle, and the end time of the scheduling decision cycle, respectively. The lean liquid volume of the lean liquid storage tank of the sth carbon capture power plant at time t, time t-1, the initial time of the scheduling decision cycle, and the end time of the scheduling decision cycle respectively; M is the amount of CO2 contained in the CO2 rich liquid released from the rich liquid storage tank at time t, MEA is the molar mass of the absorbent, is the molar mass of CO2, q re is the analytical volume of the regeneration tower, l R is the absorbent solution concentration, ρ R is the density of absorbent solution; In the second stage, the liquid balance constraint of the storage tank is: is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment, is the amount of rich liquid flowing out at time t after adjustment in the second stage; is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t-1 after the second stage adjustment, are respectively the rich liquid volume of the rich liquid storage tank of the sth carbon capture power plant at the initial moment of the scheduling decision cycle and the end moment of the scheduling decision cycle, are the lean liquid volumes of the lean liquid storage tank of the sth carbon capture power plant at the initial moment of the scheduling decision cycle and the end moment of the scheduling decision cycle respectively; M is the amount of CO2 in the CO2 rich liquid released from the rich liquid storage tank at time t after the second stage adjustment, MEA is the molar mass of the absorbent, is the molar mass of CO2, q re is the analytical volume of the regeneration tower, l R is the absorbent solution concentration, ρ R is the density of the absorbent solution.

8. The method according to claim 1, characterized in that In the first stage, the storage tank volume limit constraint is: is the volume of the rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t, is the lean liquid volume of the lean liquid storage tank of the sth carbon capture power plant at time t, V max is the maximum volume of the storage tank; The storage tank volume limit constraint in the second stage is: is the amount of rich liquid in the rich liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment, is the storage capacity of the lean liquid storage tank of the sth carbon capture power plant at time t after the second stage adjustment.

9. A flexible supply and demand balance optimization device for source, load and storage resources, characterized in that: The method comprises a memory and a processor, wherein the memory stores a program, and the processor runs the program to execute the method according to any one of claims 1 to 8.

10. A program product, characterized in that The program product executes the method according to any one of claims 1 to 8 when running.

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