Low-carbon economic dispatching method for wind power-containing system in consideration of liquid storage type carbon capture power plant

Abstract

The invention belongs to the technical field of power grid low-carbon optimization scheduling, and particularly provides a wind power-containing system low-carbon economic scheduling method considering a liquid storage type carbon capture power plant, and the method comprises the steps: additionally installing a liquid storage tank based on a post-combustion carbon capture technology, and constructing a liquid storage type carbon capture power plant operation model; carrying out quantitative analysis on the net output of the carbon capture unit; the method comprises the following steps: introducing a pumped storage unit model and a wind turbine generator model, taking unit output conditions as decision variables, taking system comprehensive cost optimization as a target, considering unit operation constraints and system safety constraints, and constructing a low-carbon scheduling model of wind power-carbon capture combined operation considering carbon transaction; a relaxation technology and a piecewise linearization method are adopted to carry out piecewise linearization on the expected value of electricity shortage and the expected value of wind curtailment. According to the method, a liquid storage type carbon capture power plant participates in system peak regulation to solve the problem of wind power absorption in a wind power access scene, and the stability and economical efficiency of system operation are improved;

Description

Technical Field

[0001] The present invention belongs to the technical field of low-carbon optimization dispatching of power grids, and in particular, relates to a low-carbon economic dispatching method for a wind power system taking into account a liquid storage carbon capture power plant. Background Art

[0002] According to data released by the China Electricity Council, China's thermal power generation will still dominate the country by 2023, accounting for 47.63% and 69.95% of the country's cumulative installed capacity and cumulative power generation, respectively. Despite the growing global attention to environmental issues and the urgent need to take action to address the challenges of climate change, thermal power generation still plays an indispensable role in China.

[0003] As the international community pays more and more attention to the green and low-carbonization of industrial production, the pressure to slow down the continued deterioration of the greenhouse effect is becoming more and more urgent. As a pillar of the national economy with high carbon dioxide emissions, the power industry urgently needs to improve the clean level of coal-fired units. In recent years, the use of carbon capture and storage (CCS) technology to convert thermal power generating units into carbon capture units has become an effective means to achieve low-carbonization of electricity, which is crucial to ensuring that global temperature rise is controlled within 2 degrees Celsius. A research report by the International Energy Agency (IEA) pointed out that CCS technology is currently one of the only solutions that can significantly reduce fossil fuel emissions in power generation and industrial processes. It is estimated that by 2060, 14% of the world's cumulative carbon emissions reduction will be attributed to this technology.

[0004] Although China has abundant wind energy resources, wind power generation is characterized by randomness and volatility. Its large-scale grid connection will increase the peak load pressure of the power system, resulting in a large amount of wind energy being abandoned. This may not only affect the stability of the power system, but also require carbon capture units to frequently participate in the system peak load regulation, increase the system's coal burning costs and start-up and shutdown costs, thereby reducing its operating economy and environmental protection.

[0005] Although some studies have begun to explore the role of carbon capture technology in suppressing wind power uncertainty at different time scales, there are still some challenges. For example, during high load periods, carbon capture units need to increase net output to meet demand, but at this time the operation of carbon capture is restricted and cannot effectively reduce carbon dioxide emissions, which is not good for the system environment.

[0006] Currently, there are a series of challenges in the operation of carbon capture units, including insufficient backup capacity during peak load periods, frequent ramping and reduced operating efficiency, etc. Therefore, we need to seek solutions to ensure that the economy and environmental protection of the power system are taken into account while maintaining high carbon capture energy consumption. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant, and to utilize the liquid storage carbon capture power plant to participate in system peak regulation to solve the problem of wind power consumption in the wind power access scenario, thereby improving the stability and economy of the system operation.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is: a low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant, comprising the following steps: Step 1: Based on the post-combustion carbon capture technology, a liquid storage tank is installed to build a liquid storage carbon capture power plant operation model; Step 2: Quantify the net output of the carbon capture unit; Step 3: Introduce pumped storage units and wind turbine models, take unit output as the decision variable, optimize the system comprehensive cost as the goal, consider unit operation constraints and system safety constraints, and build a low-carbon dispatch model for wind power-carbon capture joint operation that considers carbon trading; Step 4: Use relaxation technology and piecewise linearization method to piecewise linearize the expected value of power shortage and the expected value of wind curtailment.

[0009] In a preferred embodiment, in step 1, the operation model of the liquid storage carbon capture power plant includes: 1) Energy consumption expression of carbon capture system: ; ; Where: , They are The total power generation output and net power generation output of thermal power units during the period; for Carbon capture energy consumption during the period, including basic energy consumption Energy consumption , The captured unit mass of CO 2 The operating energy consumption generated; For the regeneration tower CO processed in time 2 quantity; 2) Absorption tower and regeneration tower CO processed in time 2 quantity: ; ; ; Where: is the flue gas split ratio, indicating The proportion of flue gas entering the carbon capture device in the total flue gas during the period; The carbon emission intensity coefficient per unit of electricity generated by the unit; , are the inflow and outflow of the rich liquid storage in period t, respectively; For CO 2 capture rate; For the absorption tower CO processed in time 2 quantity.

[0010] In a preferred solution, in step 2, the quantitative analysis of the net output of the carbon capture unit includes analyzing the net output of the carbon capture unit without a solution storage and the carbon capture unit with liquid storage, and the expression is: 1) For a carbon capture unit without solution storage, the net output expression is: ; 2) For the liquid storage carbon capture unit, the net output expression is: .

[0011] In a preferred solution, in step 3, the low-carbon dispatch model of wind power-carbon capture combined operation considering carbon trading includes the following steps: Step 3.1: Establishment of objective function: Construct an objective function that minimizes the overall system cost. The expression is: ; In the formula, The cost of coal consumption for power generation; is the start-stop cost; For carbon trading costs; They are system load shedding and wind abandonment risk costs respectively; Step 3.2: Construct unit operation constraints and system safety constraints, including: 1) Power balance constraints: ; In the formula, For the j Carbon capture units in Net output during the period; For the Conventional thermal power units in Total power generation output during the time period; for The actual wind power output during the period; for Forecasted load for the time period; is the total number of carbon capture units; is the total number of conventional thermal power units; 2) Constraints on total generating output of the unit: ; In the formula, , are the maximum and minimum technical outputs of the unit respectively; 3) Carbon capture system operation constraints: ; ; In the formula, Carbon capture unit The upper limit of operating energy consumption; 4) Reserve constraints of rich liquid and lean liquid storage: Rich liquid and lean liquid storage The reserves of a period are related to the reserves of the period and the inflow and outflow of the period, that is: ; In the formula, , Respectively Carbon capture units in , The amount of rich liquid storage in the time period; , Respectively Carbon capture units in , The lean liquid storage capacity for each period; , The first Carbon capture units The amount of liquid flowing into and out of the rich liquid storage during the period, , The first Carbon capture units The amount of lean liquid storage inflow and outflow during the period; In the above formula, each quantity satisfies: ; In the formula, , are the maximum storage capacity of the rich liquid and lean liquid storages respectively; In order to ensure the long-term operation of the day-ahead periodic dispatching system, the remaining capacity of the rich liquid storage and the lean liquid storage at the beginning and end of each day must be consistent, expressed as: .

[0012] In a preferred solution, in step 3.1, the expression of each variable in the objective function is: 1) The cost expression of coal consumption for power generation is: ; In the formula, is the total number of time periods in the scheduling cycle; is the total number of conventional thermal power units and carbon capture units, that is ; , , For the crew Cost coefficient of For the crew Total power generation output; 2) The expression of start-stop cost is: ; In the formula, , For each unit exist , The on / off status of the segment, 1 indicates the on state, 0 indicates the off state; For the crew The start-stop costs; 3) The carbon trading cost expression is: ; In the formula, is the carbon trading price coefficient; is the actual carbon emissions of the system; For CO 2 Capture volume; ; In the formula, Free allowances for carbon emissions; is the initial allocation coefficient of carbon emissions per unit of electricity; , The calculation methods are: ; ; In the formula, For the crew The actual carbon emission intensity coefficient; , Respectively Carbon capture units in CO captured during the period 2 Quantity and operating energy consumption; 4) The calculation expression of system load shedding and wind abandonment risk cost is: ; ; In the formula, is the unit loss load value; The expected value for insufficient power; is the wind abandonment penalty coefficient; is the expected value of wind power abandonment, represents the prediction error of wind power output; is the probability density function of wind power output prediction error; , They are the system's upper and lower reserve capacity respectively; , They are respectively the reasonable upper and lower limits of wind power prediction error.

[0013] In the preferred solution, in step 4, the expected value of power shortage and the expected value of wind curtailment are piecewise linearized using relaxation technology and piecewise linearization method, and the expression is: ; ; In the formula, , , , is the linearization coefficient for each segment.

[0014] The present invention provides a low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant, which has the following beneficial effects: 1. The present invention constructs a comprehensive and flexible carbon capture working mechanism. Compared with the traditional post-combustion carbon capture technology, the comprehensive and flexible carbon capture technology can achieve partial decoupling of carbon capture and power generation, realize the time shift of wind power energy consumption, and the energy consumption time shift feature can greatly alleviate the peak load reduction and standby pressure of the unit. This comprehensive and flexible operation mechanism not only improves the overall operation flexibility of the power plant, but also significantly reduces the dependence on the high energy consumption links of the traditional carbon capture unit. By adding a liquid storage tank, the technology can capture carbon during the low load period of the power grid, effectively balance the power load, and reduce the energy consumption of carbon capture during peak hours, achieving a win-win situation of economic and environmental benefits.

[0015] 2. The method of the present invention constructs a low-carbon economic dispatch model for wind power systems that takes into account liquid storage carbon capture power plants, explores the joint operation mechanism of carbon capture units and wind turbines, and compares it with traditional thermal power dispatch strategies and non-liquid storage carbon capture-wind power dispatch strategies. It is concluded that the wind power-liquid storage carbon capture joint operation power generation system obtains better economic and environmental benefits than the other two scenarios with the support of the carbon trading mechanism. The carbon capture unit of this method can focus more on carbon capture work. In one dispatch cycle, the total cost is reduced by 4.80% and the carbon emissions are reduced by 20.64%.

[0016] 3. The method of the present invention closely combines liquid storage carbon capture technology with the wind power system, significantly improving the wind power absorption capacity. The use of liquid storage tanks enables the system to flexibly adjust the timing of carbon capture during periods when wind power output is high and grid load is low, thereby reducing the amount of wind power abandoned. At the same time, this optimization strategy not only improves the utilization rate of wind power resources, but also effectively reduces the dependence on grid peak regulation, achieving the dual goals of wind power absorption and carbon emission reduction.

[0017] 4. The present invention adopts relaxation technology and piecewise linearization method to piecewise linearize the expected value of power shortage and the expected value of wind power abandonment to solve the mixed integer nonlinear programming problem. Through advanced mathematical technology, the system can more accurately describe and optimize complex power dispatching problems. This method greatly reduces the difficulty of calculation, improves the convergence speed and stability of the algorithm, and provides technical guarantee for the economic operation of large-scale wind power access to the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 A schematic flow chart of a low-carbon dispatch strategy method for a new energy power grid taking into account flexible operation of carbon capture according to an embodiment of the present invention; Figure 2 A schematic diagram of a flexible operation carbon capture structure according to an embodiment of the present invention; Figure 3 Relationship diagram between gross power generation output and net output of carbon capture unit; Figure 4 is the probability density function of wind power prediction error; Figure 5 It is the prediction curve of load and wind power. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Carbon capture technology is a technology used to absorb carbon dioxide produced by conventional thermal power units and store it in a specific way to prevent it from being discharged to the outside. Currently, carbon capture technology can be divided into three categories: oxygen-enriched combustion capture technology, pre-combustion carbon capture technology, and post-combustion carbon capture technology. The present invention selects the more mature post-combustion carbon capture technology.

[0021] The post-combustion carbon capture unit is composed of a conventional thermal power unit and a carbon capture device. The main working process of a typical carbon capture device includes absorption, regeneration, and compression. The main energy consumption of the carbon capture system is used in the regeneration and compression stages. The comprehensive flexible operation carbon capture technology is to add a liquid storage tank to the post-combustion carbon capture technology to enable it to flexibly adjust the carbon capture power.

[0022] The process of the flexible carbon capture system is as follows: the flue gas bypass system is used to adjust the proportion of flue gas entering the carbon capture device. The flue gas that does not enter the capture device will be directly discharged into the atmosphere. The flue gas to be treated enters the absorption tower from the bottom and is countercurrently mixed with CO at an environment of 40-60℃. 2 The absorbent is fully contacted and an absorption reaction occurs, thereby producing CO 2 The rich liquid then flows into the rich liquid storage, and the rich liquid pump adjusts the rich liquid flow into the regeneration tower. The regeneration tower extracts hot steam from the working cylinder of the steam turbine of the thermal power unit, raises the temperature of the rich liquid to 100-40℃, and reacts inversely to separate the CO 2 Drain from the top of the tower to compressed storage to achieve CO in flue gas 2 The capture of CO in the absorbent flowing out of the regeneration tower 2 The content is very small, so it is called lean liquid. The lean liquid flows into the lean liquid storage and the absorption tower through the lean liquid pump for recycling. The carbon capture system adjusts the liquid pump so that the liquid inflow / outflow of the lean liquid storage is equal to the outflow / inflow of the rich liquid storage.

[0023] It can be seen from the operating mechanism of the carbon capture system that the diversion of carbon capture energy consumption is equivalent to reducing the minimum technical output of the unit, so that the carbon capture unit has a greater peak-shaving depth. During peak load periods, the liquid storage carbon capture power plant reduces the flue gas entering the capture device through the flue gas bypass system on the one hand, and increases the inflow of rich liquid storage and reduces the outflow on the other hand, effectively reducing the energy consumption of the carbon capture system, thereby increasing the net output of the carbon capture power plant; during low load periods, by improving the carbon capture level, the liquid storage carbon capture power plant can achieve low-carbon electricity production while providing space for renewable energy to access the grid. Compared with carbon capture units without liquid storage, liquid storage carbon capture units have a wider adjustable range of net output and stronger flexible operation capabilities when participating in system operation.

[0024] The present invention provides a low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant, such as Figure 1 As shown, the following steps are included: Step 1: Based on the post-combustion carbon capture technology, a liquid storage tank is installed to build an operation model of a liquid storage carbon capture power plant.

[0025] Carbon capture power plants can not only effectively control carbon emissions during electricity production, but also flexibly adjust the net output of power plants by changing capture energy consumption. Figure 2 As shown. Among them, , Indicates the CO treated by the absorption tower and regeneration tower 2 quantity, , , , The inflow / outflow CO of the rich / lean liquid storage is 2 quantity.

[0026] The liquid storage carbon capture power plant operation model includes: 1) Energy consumption expression of carbon capture system: ; ; Where: , They are The total power generation output and net power generation output of thermal power units during the period; for Carbon capture energy consumption during the period, including basic energy consumption Energy consumption , The captured unit mass of CO 2 The operating energy consumption generated; For the regeneration tower CO processed in time 2 quantity.

[0027] Basic energy consumption This is because the introduction of the carbon capture system changes the structure of the original unit, resulting in a fixed and small impact that is independent of the operating status of the capture system. It is related to the energy loss in the CO2 regeneration process of the capture device, which can generally be considered to be related to Period CO 2 Proportional to the amount captured.

[0028] 2) Absorption tower and regeneration tower CO processed in time 2 quantity: ; ; ; Where: is the flue gas split ratio, indicating The proportion of flue gas entering the carbon capture device in the total flue gas during the period; The carbon emission intensity coefficient per unit of electricity generated by the unit; , are the inflow and outflow of the rich liquid storage in period t, respectively; For CO 2 capture rate; For the absorption tower CO processed in time 2 quantity.

[0029] Step 2: Quantify the net output of the carbon capture unit.

[0030] In order to quantitatively analyze the net output characteristics of the carbon capture unit, a model reflecting the relationship between the total power output and net output of the two carbon capture units with and without liquid storage is constructed. Figure 3 shown.

[0031] by , Indicates the maximum and minimum technical output of thermal power, then the total output range of the unit can be expressed as When the output of the carbon capture unit changes within this range, the adjustable range of its net output also changes accordingly. The specific analysis is as follows: For a carbon capture unit without a solution storage, the relationship is satisfied and its net output can be expressed as : ; (1) When the total power output of the unit is When the unit net output range is Figure 3 The middle line segment AD shows that point A represents the smoke split ratio At this time, the net output of the unit takes the maximum value ; Point D is , corresponding to the minimum net output .

[0032] (2) When the total power output of the unit is When the unit net output range is Figure 3 As shown by line segment BC. Point B represents , the net output takes the maximum value; point C is , corresponding to the minimum net output.

[0033] (3) At a certain moment, the total power output of the unit When it is between the upper and lower limits, the maximum and minimum net outputs of the unit change linearly, as shown by line segments AB and DC, and the net output change range is shown by line segment EF.

[0034] For the liquid storage carbon capture unit, the net output meets the following requirements: ; (1) When the total power output of the unit is When the unit net output range is Figure 3 The middle line segment AD' is shown. Point A represents , the net output takes the maximum value ; D' point indicates Take the maximum value, corresponding to the minimum net output When the rich liquid storage meets When the vertical coordinate value of point D' is smaller than that of point D, the minimum technical output is reduced .

[0035] (2) When the total power output of the unit is When the unit net output range is Figure 3 The middle line segment BC' is shown. Point B represents , the net output takes the maximum value ; C' point indicates Take the maximum value, corresponding to the minimum net output Similarly, when When , the vertical coordinate value of point C' is smaller than that of point C, and the minimum technical output is reduced.

[0036] (3) At a certain moment, the total power output of the unit When it is between the upper and lower limits, the maximum and minimum net outputs of the unit change linearly, as shown by line segments AB and D'C', and the net output change range is shown by line segment EF'.

[0037] From the above analysis, it can be seen that the absorption and regeneration links of the carbon capture unit equipped with solution storage remain relatively independent. When the liquid storage carbon capture power plant has a larger net output adjustment range, it can provide more flexible capacity when participating in system peak regulation. In the future scenario of high proportion of renewable energy access, improving the operating flexibility of thermal power units will help increase the proportion of new energy consumption.

[0038] Step 3: Introduce pumped storage units and wind turbine models, take unit output as the decision variable, optimize the system comprehensive cost as the goal, consider unit operation constraints and system safety constraints, and build a low-carbon scheduling model for wind power-carbon capture joint operation considering carbon trading.

[0039] The liquid storage carbon capture system regulates the inflow and outflow of CO2 solution, decoupling the two processes of CO2 generation and purification in coal-fired power generation in time, so that the energy consumption and unit net output of the carbon capture device can be more flexibly adjusted during the dispatch period to meet the peak load changes and the peak load demand brought about by the connection of new energy to the grid. For liquid storage carbon capture power stations, it is necessary to achieve both carbon emission reduction and power generation reduction. It is necessary to take into account the carbon capture and power generation of the carbon capture system under the conditions of power balance, total unit output constraints, carbon capture system operation constraints, and rich liquid storage constraints, so as to achieve the comprehensive benefits of low carbon and economy of the system.

[0040] The low-carbon dispatch model of wind power-carbon capture combined operation considering carbon trading includes the following steps: Step 3.1: Establishment of objective function: Construct an objective function that minimizes the overall system cost. The expression is: ; In the formula, The cost of coal consumption for power generation; is the start-stop cost; For carbon trading costs; They are system load shedding and wind abandonment risk costs respectively; The expressions of each cost in the objective function are: 1) The cost expression of coal consumption for power generation is: ; In the formula, is the total number of time periods in the scheduling cycle; is the total number of conventional thermal power units and carbon capture units, that is ; , , For the crew Cost coefficient of For the crew Total power generation output; 2) The expression of start-stop cost is: ; In the formula, , For each unit exist , The on / off status of the segment, 1 indicates the on state, 0 indicates the off state; For the crew The start-stop costs; 3) The carbon trading cost expression is: ; In the formula, is the carbon trading price coefficient; is the actual carbon emissions of the system; For CO 2 Capture volume.

[0041] The initial allocation of carbon quotas is an important basis for enterprises to obtain carbon emission rights. A reasonable quota allocation method can promote the optimal allocation of resources, thereby building a production model with lower carbon emissions and higher energy efficiency. On this basis, combined with the current carbon emission rights trading system, a method for calculating the free carbon quota of power generation enterprises based on the industry benchmark method is proposed.

[0042] ; In the formula, Free allowances for carbon emissions; is the initial allocation coefficient of carbon emissions per unit of electricity; , The calculation methods are: ; ; In the formula, For the crew The actual carbon emission intensity coefficient; , Respectively Carbon capture units in CO captured during the period 2 Quantity and operating energy consumption; 4) System load shedding and wind curtailment risk costs In the active dispatch of power systems containing wind power, wind power forecast errors may lead to reduced system reliability and operational losses such as power abandonment. Load shedding and wind abandonment risk costs are used to quantify the potential risks of wind power forecast errors to system operation. If the normal distribution is used to approximate the probability density curve of the forecast error, the calculation basis of the risk loss is as follows: Figure 4 As shown in the figure, represents the prediction error of wind power output; is the probability density function of wind power output prediction error; , They are the system's upper and lower reserve capacity respectively; , They are respectively the reasonable upper and lower limits of wind power prediction error.

[0043] When the actual wind power generation is smaller than the predicted value, the positive prediction error will cause a power gap. If the system regulation reserve is insufficient at this time, it is necessary to take forced load shedding measures; when the wind power generation exceeds the predicted value, the negative prediction error will lead to an increase in wind power generation. If the set reduction reserve is not enough, power abandonment will occur. Figure 4 The shaded parts on both sides represent the expected value of power shortage and the expected value of wind power abandonment caused by wind power access. The calculation expression of system load shedding and wind power abandonment risk cost is: ; ; In the formula, is the unit loss load value; The expected value for insufficient power; is the wind abandonment penalty coefficient; is the expected value of wind power abandonment, represents the prediction error of wind power output; is the probability density function of wind power output prediction error; , They are the system's upper and lower reserve capacity respectively; , They are respectively the reasonable upper and lower limits of wind power prediction error.

[0044] Step 3.2: Construct unit operation constraints and system safety constraints, including: 1) Power balance constraints: ; In the formula, For the j Carbon capture units in Net output during the period; For the Conventional thermal power units in Total power generation output during the time period; for The actual wind power output during the period; for Forecasted load for the time period; is the total number of carbon capture units; is the total number of conventional thermal power units; 2) Constraints on total generating output of the unit: ; In the formula, , are the maximum and minimum technical outputs of the unit respectively; 3) Carbon capture system operation constraints: ; ; In the formula, Carbon capture unit The upper limit of operating energy consumption; 4) Reserve constraints of rich liquid and lean liquid storage: Rich liquid and lean liquid storage The reserves of a period are related to the reserves of the period and the inflow and outflow of the period, that is: ; In the formula, , Respectively Carbon capture units in , The amount of rich liquid storage in the time period; , Respectively Carbon capture units in , The lean liquid storage capacity for each period; , The first Carbon capture units The amount of liquid flowing into and out of the rich liquid storage during the period, , The first Carbon capture units The amount of lean liquid storage inflow and outflow during the period; In the above formula, each quantity satisfies: ; In the formula, , are the maximum storage capacity of the rich liquid and lean liquid storages respectively; In order to ensure the long-term operation of the day-ahead periodic dispatching system, the remaining capacity of the rich liquid storage and the lean liquid storage at the beginning and end of each day must be consistent, expressed as: .

[0045] Step 4: Use relaxation technology and piecewise linearization method to piecewise linearize the expected value of power shortage and the expected value of wind curtailment.

[0046] The low-carbon economic dispatch of wind power system considering liquid carbon capture power plant is a mixed integer nonlinear programming problem. The load shedding risk cost in the objective function is and the risk of wind curtailment Cost is variable and The integral term is difficult to solve directly. Given that the cost term is convex and monotonic, the relaxation technique and piecewise linearization method can be used to convert the expected value of power shortage into Wind power curtailment Piecewise linearization: The expression is: ; ; In the formula, , , , is the linearization coefficient for each segment.

[0047] Example In this example, the total installed capacity of thermal power is 6570MW, the maximum load is 6000MW, and the installed capacity of wind power is 1500MW. The standard deviation of the wind power prediction error is 10% of the predicted power. The prediction curve of load and wind power is as follows: Figure 5 As shown in Table 1, the initial carbon emission quota per unit of electricity and the actual carbon emission coefficient are shown in Table 1. The example analysis is carried out using 20 units, and the five 350MW thermal power units in the example are transformed into carbon capture units, with a fixed energy consumption of 3MW and a unit mass of CO captured. 2 The operating energy consumption is 0.269MWh / t, the upper limit of operating energy consumption is 96MW, CO 2 The capture rate is 0.9, the maximum storage capacity of the solution storage is 1316t, and the initial storage capacity is 658t. The carbon trading price coefficient is 120 yuan / t, the unit load loss value is 3000 yuan / (MW·h), and the wind abandonment penalty coefficient is 500 yuan / (MW·h). For the established model, CPLEX is called through the Matlab platform to solve it.

[0048]

[0049] Set up three comparison scenarios as follows: 1) Conventional thermal power units (without carbon capture system) participate in system operation and dispatch 2) Considering 4 carbon capture units without liquid storage to participate in system operation and scheduling 3) Considering 4 liquid storage carbon capture units to participate in system operation scheduling The results of the day-ahead optimization scheduling of the units under the three scenarios are shown in the following table.

[0050]

[0051] A comprehensive comparison of the dispatch results of the three scenarios shows that when the units equipped with carbon capture systems participate in system optimization, the fuel costs are increased by 7.01% and 7.25% respectively compared with traditional thermal power units, while the total dispatch costs are reduced by 4.00% and 4.80% respectively. The reason is that, unlike traditional thermal power units, carbon capture units need to provide additional carbon capture energy consumption in addition to bearing the load, which increases the system fuel cost; however, on the one hand, the carbon capture system can capture part of the CO2 emitted during the unit's electricity production process, significantly reducing carbon emissions, and then selling excess emission quotas through the market to obtain revenue; on the other hand, the carbon capture system can increase the unit's output range, so that the unit has a larger downward adjustment capacity, which not only provides power generation space for wind power output, but also avoids frequent start and stop of the unit, increases the wind power consumption, reduces the system's start and stop costs, wind abandonment and load shedding risk costs, and thus reduces the total system operation cost. Compared with the carbon capture unit without liquid storage, the liquid storage carbon capture unit decouples the amount of CO2 treated by the absorption tower and the regeneration tower by configuring a solution storage device. Its adjustable capacity and operating flexibility are greater than those of the carbon capture unit without liquid storage, and the total operating cost is further reduced.

[0052] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant, characterized in that: The following steps are involved: Step 1: Based on the post-combustion carbon capture technology, a liquid storage tank is installed to build a liquid storage carbon capture power plant operation model; Step 2: Quantify the net output of the carbon capture unit; Step 3: Introduce pumped storage units and wind turbine models, take unit output as the decision variable, optimize the system comprehensive cost as the goal, consider unit operation constraints and system safety constraints, and build a low-carbon dispatch model for wind power-carbon capture joint operation that considers carbon trading; Step 4: Use relaxation technology and piecewise linearization method to piecewise linearize the expected value of power shortage and the expected value of wind curtailment.

2. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant according to claim 1, characterized in that: In step 1, the operation model of the liquid storage carbon capture power plant includes: 1) Energy consumption expression of carbon capture system: ； ； Where: , They are The total power generation output and net power generation output of thermal power units during the period; for Carbon capture energy consumption during the period, including basic energy consumption Energy consumption , The operating energy consumption for capturing a unit mass of CO2; For the regeneration tower The amount of CO2 processed during the period; 2) Absorption tower and regeneration tower Amount of CO2 processed per period: ； ； ； Where: is the flue gas split ratio, indicating The proportion of flue gas entering the carbon capture device in the total flue gas during the period; The carbon emission intensity coefficient per unit of electricity generated by the unit; , are the inflow and outflow of the rich liquid storage in period t, respectively; is the CO2 capture rate; For the absorption tower The amount of CO2 processed during the period.

3. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant according to claim 1, characterized in that: In step 2, the quantitative analysis of the net output of the carbon capture unit includes analyzing the net output of the carbon capture unit without solution storage and the liquid storage type carbon capture unit, and the expression is: 1) For a carbon capture unit without solution storage, the net output expression is: ； 2) For the liquid storage carbon capture unit, the net output expression is: 。 4. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant according to claim 1, characterized in that: In step 3, the low-carbon dispatch model of wind power-carbon capture combined operation considering carbon trading includes the following steps: Step 3.1: Establishment of objective function: Construct an objective function that minimizes the overall system cost. The expression is: ； In the formula, The cost of coal consumption for power generation; is the start-stop cost; For carbon trading costs; They are system load shedding and wind abandonment risk costs respectively; Step 3.2: Construct unit operation constraints and system safety constraints, including: 1) Power balance constraints: ； In the formula, For the j Carbon capture units in Net output during the period; For the Conventional thermal power units in Total power generation output during the time period; for The actual wind power output during the period; for Forecasted load for the time period; is the total number of carbon capture units; is the total number of conventional thermal power units; 2) Constraints on total generating output of the unit: ； In the formula, , are the maximum and minimum technical outputs of the unit respectively; 3) Carbon capture system operation constraints: ； ； In the formula, Carbon capture unit The upper limit of operating energy consumption; 4) Reserve constraints of rich liquid and lean liquid storage: Rich liquid and lean liquid storage The reserves of a period are related to the reserves of the period and the inflow and outflow of the period, that is: ； In the formula, , Respectively Carbon capture units in , The amount of rich liquid storage in the time period; , Respectively Carbon capture units in , The lean liquid storage capacity for each period; , The first Carbon capture units The amount of liquid flowing into and out of the rich liquid storage during the period, , The first Carbon capture units The amount of lean liquid storage inflow and outflow during the period; In the above formula, each quantity satisfies: ； In the formula, , are the maximum storage capacity of the rich liquid and lean liquid storages respectively; In order to ensure the long-term operation of the day-ahead periodic dispatching system, the remaining capacity of the rich liquid storage and the lean liquid storage at the beginning and end of each day must be consistent, expressed as: 。 5. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant according to claim 4, characterized in that: In step 3.1, the expressions of the variables in the objective function are: 1) The cost expression of coal consumption for power generation is: ； In the formula, is the total number of time periods in the scheduling cycle; is the total number of conventional thermal power units and carbon capture units, that is ; , , For the crew Cost coefficient of For the crew Total power generation output; 2) The expression of start-stop cost is: ； In the formula, , For each unit exist , The on / off status of the segment, 1 indicates the on state, 0 indicates the off state; For the crew The start-stop costs; 3) The carbon trading cost expression is: ； In the formula, is the carbon trading price coefficient; is the actual carbon emissions of the system; is the amount of CO2 captured; ； In the formula, Free allowances for carbon emissions; is the initial allocation coefficient of carbon emissions per unit of electricity; , The calculation methods are: ； ； In the formula, For the crew The actual carbon emission intensity coefficient; , Respectively Carbon capture units in The amount of CO2 captured during each period and the operating energy consumption; 4) The calculation expression of system load shedding and wind abandonment risk cost is: ； ； In the formula, is the unit loss load value; The expected value for insufficient power; is the wind abandonment penalty coefficient; is the expected value of wind power abandonment, represents the prediction error of wind power output; is the probability density function of wind power output prediction error; , They are the system's upper and lower reserve capacity respectively; , They are respectively the reasonable upper and lower limits of wind power prediction error.

6. A low-carbon economic dispatch method for a wind power system taking into account a liquid storage carbon capture power plant according to claim 2, characterized in that: In step 4, the expected value of power shortage and the expected value of wind curtailment are piecewise linearized by using relaxation technology and piecewise linearization method, and the expression is: ； ； In the formula, , , , is the linearization coefficient for each segment.

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