Low-carbon power system multi-stage collaborative planning method considering wind power and coal power transformation

Abstract

The invention provides a low-carbon power system multi-stage collaborative planning method considering wind power and coal power transformation, and the method comprises the steps: building a total cost model of a low-carbon power system through the sum of the transformation cost and the operation cost, and enabling the transformation cost to comprise the wind power orderly decommissioning cost, the wind power reconstruction cost and the coal power transformation cost; the operation cost comprises coal power operation cost, wind curtailment punishment cost and load shedding cost; and by taking the minimum total cost as an objective function, constructing a multi-stage collaborative planning model under the planning constraint and the system operation constraint, and solving to obtain a multi-stage collaborative planning scheme of the low-carbon power system. According to the method, the wind power decommissioning and rebuilding modes are reasonably and orderly arranged in a mathematical modeling mode, the coal power unit is correspondingly and flexibly transformed, the decommissioning path after the old wind power unit reaches the service life can be reasonably arranged, reasonable connection of wind power and coal power transformation is achieved, and the carbon emission of the system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power system stability and security, and in particular to a multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation. Background Art

[0002] As a vital component of the renewable energy power sector, the wind power industry plays a crucial role in achieving the "dual carbon" goals. However, my country's early wind turbines are approaching or exceeding their 20-year design lifespans. China is poised for its first large-scale wind power retirements, with over 1 GW of wind power capacity reaching 20 years of service. By 2030, the cumulative wind power retirements will exceed 60 GW, representing approximately 7.5% of total installed capacity. This has necessitated a more urgent planning process for wind power retirements and reconstruction. In June 2023, the National Energy Administration issued the "Management Measures for Wind Farm Renovation, Upgrading, and Decommissioning," encouraging the upgrading of older wind turbines. However, wind farms currently face numerous challenges, including developing decommissioning strategies and ensuring reliable operation after reaching their grid-connected lifespans. Retiring a large number of wind turbines in a short period of time could lead to power shortages and other stability issues for the power grid. Furthermore, to accommodate the increased capacity of wind farms, flexible retrofitting of coal-fired power plants is urgently needed. Therefore, solving the problem of coordinated planning of wind power decommissioning, reconstruction and coal-fired power transformation has important engineering value for achieving low-carbon transformation of the power system. Summary of the Invention

[0003] In response to the problems existing in the prior art, the present invention provides a method for rationally and orderly arranging the decommissioning and reconstruction of wind power by using mathematical modeling, and carrying out corresponding flexibility transformation of coal-fired power units. This method can rationally arrange the decommissioning path of old wind turbines after they reach the end of their service life, achieve a reasonable connection between wind power and coal-fired power transformation, and reduce the carbon emissions of the system. It is a multi-stage collaborative planning method for low-carbon power systems that takes into account wind power and coal-fired power transformation.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation, comprising the following steps: constructing a total cost model for the low-carbon power system, wherein the total cost model is the sum of transformation cost and operating cost;

[0005] The transformation costs include the orderly decommissioning costs of wind power, wind power reconstruction costs and coal power transformation costs;

[0006] The operating costs include coal-fired power operating costs, wind power curtailment penalty costs, and load shedding costs;

[0007] Constructing a multi-stage collaborative planning model for the low-carbon power system based on the total cost model, wherein the objective function of the multi-stage collaborative planning model is to minimize the total cost within the collaborative planning stage, and the constraints of the multi-stage collaborative planning model include planning constraints and system operation constraints;

[0008] The multi-stage collaborative planning model is solved to obtain a multi-stage collaborative planning scheme for the low-carbon power system.

[0009] In some embodiments, the orderly decommissioning costs of wind power include direct decommissioning costs and life extension and transformation costs.

[0010] In some embodiments, the direct decommissioning cost is an expression of a decommissioning decision variable; and the life extension modification cost is an expression of a life extension modification decision variable.

[0011] In some embodiments, the wind power reconstruction cost includes the cost of isocapacity reconstruction and the cost of capacity expansion reconstruction.

[0012] In some embodiments, the isochoric transformation cost is an expression of isochoric transformation decision variables; the capacity expansion transformation cost is an expression of capacity expansion transformation decision variables.

[0013] In some embodiments, the coal-fired power transformation cost includes a first flexibility transformation cost and a second flexibility transformation cost; the first flexibility transformation cost is the flexibility transformation cost of the pure condensing unit, and the second flexibility transformation cost is the flexibility transformation cost of the CHP unit.

[0014] In some embodiments, the first flexibility transformation cost is an expression of a flexibility transformation decision variable of a pure condensing unit, and the second flexibility transformation cost is an expression of a flexibility transformation decision variable of a CHP unit.

[0015] In some embodiments, the coal-fired power operating cost includes a first operating cost and a second operating cost; the first operating cost is the operating cost of the pure condensing unit after flexibility modification, and the second operating cost is the operating cost of the CHP unit after flexibility modification.

[0016] In some embodiments, the planning constraints include wind power retirement constraints, constant capacity transformation constraints, capacity expansion transformation constraints, CHP unit transformation constraints, system investment cost upper limit constraints and new energy power generation proportion constraints.

[0017] In some embodiments, the system operation constraints include system power balance constraints, carbon emission constraints, wind power operation constraints, pure condensing unit operation constraints, and CHP unit operation constraints.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] By constructing and solving a multi-stage collaborative planning model, the present invention can obtain the most economically optimal wind turbine orderly decommissioning plan, reconstruction capacity configuration, and coal-fired power collaborative transformation plan under the premise of meeting system safety and stability. It can not only reasonably arrange the retirement path of old wind turbines after they reach the end of their service life, but also achieve a reasonable connection between wind power and coal-fired power transformation, reduce the system's carbon emissions, ensure the stability of the power system, reduce carbon emissions, and provide ideas for the development path of old wind farms. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to the present invention;

[0021] Figure 2 This is a structural diagram of a thermal-electric decoupling system of a cogeneration unit in an embodiment of the present invention;

[0022] Figure 3 A diagram of a feasible operating area of a cogeneration unit in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of a multi-stage collaborative planning model framework in an embodiment of the present invention;

[0024] Figure 5(a) shows the wind power and coal power output diagram for Scheme 1 from 2025 to 2027 in the calculation example;

[0025] Figure 5(b) shows the wind power and coal power output diagram for Scheme 1 from 2028 to 2030 in the calculation example;

[0026] Figure 6 This is the wind power and coal power output diagram for 2025 in the second scenario in the calculation example;

[0027] Figure 7 This is a comparison chart of low-carbon power system transformation indicators for each scheme in the example;

[0028] Figure 8 This is the wind farm capacity change diagram for Scheme 1 in the calculation example;

[0029] Figure 9 This is a comparison chart of wind farm capacity of each scheme in the example. DETAILED DESCRIPTION

[0030] To clearly illustrate the technical features of this solution, the following detailed description of the implementation methods of this application will be given in conjunction with the accompanying drawings and examples, so that the implementation process of how this application applies technical means to solve technical problems and achieve corresponding technical effects can be fully understood and implemented accordingly. The embodiments of this application and the various features therein can be combined with each other as long as they do not conflict with each other, and the resulting technical solutions are all within the scope of protection of this application.

[0031] See also Figure 1 , an embodiment of the present disclosure provides a multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation, comprising the following steps: constructing a total cost model of the low-carbon power system, where the total cost model is the sum of the transformation cost and the operating cost;

[0032] Transformation costs include the orderly decommissioning of wind power, the rebuilding of wind power, and the transformation of coal-fired power. Wind and coal-fired power transformation is part of medium- to long-term power generation planning and is considered to be completed in phases. Wind power generation equipment typically considered in wind power refers to wind turbines, which are decommissioned in an orderly manner, taking into account their grid-connected years and costs. Wind power is then rebuilt on top of these decommissioned equipment. Transformation costs for wind power include both the orderly decommissioning of wind power and the rebuilding of wind power. To increase the peak-shaving capacity of coal-fired power equipment and facilitate the absorption of new energy, it is necessary to transform coal-fired power equipment.

[0033] Operating costs include coal-fired power operating costs, wind curtailment penalty costs, and load shedding costs. After the coal-fired power equipment is retrofitted, it will operate differently than before the retrofit, at least due to peak load regulation, thus generating coal-fired power operating costs.

[0034] A multi-stage collaborative planning model for low-carbon power systems is constructed based on the total cost model. The objective function of the multi-stage collaborative planning model is to minimize the total cost within the collaborative planning stage. Figure 4 As shown, the constraints of the multi-stage collaborative planning model include planning constraints and system operation constraints;

[0035] The objective function of the multi-stage collaborative planning model is:

[0036] minC total =C ROS +C OC ;

[0037]

[0038] In the formula, min is the minimization function, C total is the total cost, C ROS is the transformation cost, C ROS is the operating cost, s is the stage number, that is, the collaborative planning cycle number, N 1 is the total number of wind farms, g is the wind farm number, N 2 is the total number of pure condensing units, r is the sequence number of the pure condensing unit, N 3 is the total number of CHP units, n is the CHP unit number, N load is the total number of nodes, d is the node number, is the direct decommissioning cost of wind farm g in stage s, is the life extension and transformation cost of wind farm g in stage s, is the isovolumetric transformation cost of wind farm g in stage s, is the expansion and transformation cost of wind farm g in stage s, is the transformation cost of the rth pure condensing unit in the sth stage, is the renovation cost of the nth CHP unit in the sth stage, T s is the number of days in stage s, X T is the total number of scheduling periods, π c is the ratio of typical day c, c is the typical day number, is the operating cost of the rth pure condensing unit after flexibility modification at time t on a typical day c in stage s, is the operating cost of the nth CHP unit after flexibility modification at time t on a typical day c in phase s, D curt is the unit wind curtailment penalty cost coefficient, is the amount of wind power abandoned by wind farm g at time t on a typical day c in period s, C load is the load shedding cost, is the load shedding power of node d at time t on a typical day c in phase s, ε2 is the discount rate of coal-fired power equipment, and Y is the number of years of each collaborative planning cycle;

[0039] The multi-stage collaborative planning model is solved to obtain a multi-stage collaborative planning scheme for the low-carbon power system. Preferably, the multi-stage collaborative planning model is optimized and solved using a Gurobi solver.

[0040] By constructing and solving a multi-stage collaborative planning model, we can obtain the most economically optimal wind turbine orderly decommissioning plan, reconstruction capacity configuration, and coal-fired power collaborative transformation plan under the premise of meeting system safety and stability. The wind farm decommissioning and reconstruction process, and the collaborative transformation of wind power and coal-fired power can be arranged reasonably and orderly, which is of great significance to the safe, stable and low-carbon transformation of the power system.

[0041] In some of the embodiments, the orderly decommissioning costs of wind power include direct decommissioning costs and life extension modification costs, that is, the orderly decommissioning of wind power includes two methods: direct decommissioning and life extension modification, and the corresponding modeling is performed considering the grid-connected years and costs of the wind turbines.

[0042] The direct decommissioning costs of a wind turbine consist of two parts: equipment removal costs and asset recovery costs. The asset recovery costs can partially offset the removal costs. The steps to construct the direct decommissioning costs are:

[0043] Based on the low-carbon power system, the first total number, the net value decline rate of wind power equipment, the equipment dismantling cost, the asset recovery cost, the capacity of retired wind power equipment, the wind power equipment discount rate, the design life of wind power equipment, the first total number of years and the number of years in each collaborative planning cycle are obtained respectively; the first total number is the total number of wind power equipment in the wind farm; the first total number of years is the total number of years from the commissioning year to the retirement year of retired wind power equipment;

[0044] The direct decommissioning cost is constructed based on the first total, the net value decline rate of wind power equipment, the equipment dismantling cost, the asset recovery cost, the capacity of retired wind power equipment, the wind power equipment discount rate, the design life of wind power equipment, the first total number of years, and the number of years in each collaborative planning cycle. The direct decommissioning cost is an expression of the decommissioning decision variables, see formula (1):

[0045]

[0046] Where, is the direct decommissioning cost of wind farm g in the sth stage, i is the serial number of the wind power equipment in the wind farm, N is the first total number, that is, the total number of wind power equipment in the wind farm, is the retirement decision variable of the i-th wind turbine in the (s-1) stage, is the retirement decision variable of the i-th wind turbine in stage s, c u is the decommissioning and dismantling cost of each MW wind power equipment, c s is the cost of recovering dismantled materials after decommissioning each MW of wind turbine equipment, i.e., the asset recovery cost of each decommissioned wind turbine equipment, b rt is the net value decline rate of wind power equipment, is the design life of the i-th wind turbine equipment in stage s, is the capacity of the i-th wind turbine retired in stage s, ε1 is the wind turbine discount rate, and y is the first total number of years, that is, the total number of years from the commissioning year to the retirement year of the retired wind turbine. When the value of the retirement decision variable is 0, the wind turbine is retired, and when the value of the retirement decision variable is 1, the wind turbine remains in the power system.

[0047] The life extension transformation of a wind farm only involves upgrading and optimizing some components. The cost is the installation cost of the life extension transformation equipment. The steps to construct the life extension transformation cost are:

[0048] Based on the low-carbon power system, the first total, the installation cost of the life-extending and retrofitted wind power equipment, the capacity of the life-extending and retrofitted wind power equipment, the discount rate of the wind power equipment and the number of years of each collaborative planning cycle are obtained respectively;

[0049] The life extension transformation cost is constructed based on the first total, the installation cost of the life extension transformation wind power equipment, the capacity of the life extension transformation wind power equipment, the wind power equipment discount rate, and the number of years in each collaborative planning cycle. The life extension transformation cost is an expression of the life extension transformation decision variable, see formula (2):

[0050]

[0051] Where, is the life extension and transformation cost of wind farm g in stage s, is the life extension and transformation decision variable of the i-th wind power equipment in the (s-1) stage, is the decision variable for the life extension transformation of the i-th wind power equipment in the s-th stage, c re The installation cost of life extension transformation for each megawatt of wind power equipment is: is the capacity of the life extension transformation of the i-th wind turbine in the s-th stage; some wind turbines need to be transformed to extend their life and remain in the system due to system requirements and other reasons. When the value of the life extension transformation decision variable is 0, the wind turbine has reached its service life and is retired. When the value of the life extension transformation decision variable is 1, the wind turbine chooses to remain in the system after the life extension transformation;

[0052] In some embodiments, the wind power reconstruction cost includes the cost of isocapacity reconstruction and the cost of capacity expansion reconstruction.

[0053] The steps to construct the isovolumetric renovation cost are:

[0054] Based on the low-carbon power system, the first total, the installation cost of wind power equipment equal capacity transformation, the capacity of wind power equipment equal capacity transformation, the discount rate of wind power equipment and the number of years of each collaborative planning cycle are obtained respectively;

[0055] The cost of isotropic transformation is constructed based on the first total, the installation cost of isotropic transformation of wind power equipment, the capacity of isotropic transformation wind power equipment, the discount rate of wind power equipment, and the number of years in each collaborative planning cycle. The cost of isotropic transformation is an expression of the decision variable of isotropic transformation, see formula (3):

[0056]

[0057] Where, is the isovolumetric transformation cost of wind farm g in stage s, is the decision variable for the constant capacity transformation of the i-th wind turbine in the (s-1) stage, is the decision variable for the constant capacity transformation of the i-th wind power equipment in the s-th stage, c ec The cost of installation and transformation of wind power equipment of equal capacity per MW is: is the constant capacity transformation capacity of the i-th wind turbine in the s-th stage; when the value of the constant capacity transformation decision variable is 0, the wind turbine undergoes constant capacity transformation; when the value of the constant capacity transformation decision variable is 1, the wind turbine does not undergo constant capacity transformation;

[0058] The steps to construct the expansion and transformation costs are:

[0059] Based on the low-carbon power system, the first total, the installation cost of wind power equipment expansion and transformation, the capacity of wind power equipment expanded with the same capacity, the discount rate of wind power equipment and the number of years of each collaborative planning cycle are obtained respectively;

[0060] The expansion and transformation cost is constructed based on the first total, the installation cost of wind power equipment expansion and transformation, the capacity of the wind power equipment expanded and transformed, the discount rate of wind power equipment, and the number of years in each collaborative planning cycle. The expansion and transformation cost is an expression for the expansion and transformation decision variable, see formula (4):

[0061]

[0062] Where, is the expansion and transformation cost of wind farm g in stage s, is the decision variable for capacity expansion and transformation of the i-th wind power equipment in the (s-1) stage, is the decision variable for capacity expansion and transformation of the i-th wind power equipment in the s-th stage, c kr The cost of wind power equipment expansion and renovation per megawatt is is the expansion and transformation capacity of the i-th wind turbine in the s-th stage; when the value of the expansion and transformation decision variable is 0, the wind turbine is expanded and transformed; when the value of the expansion and transformation decision variable is 1, the wind turbine is not expanded and transformed;

[0063] Coal-fired power plants typically include condensing units and combined heat and power (CHP) units, i.e., cogeneration units. In some embodiments, the coal-fired power transformation cost includes a first flexibility transformation cost and a second flexibility transformation cost. The first flexibility transformation cost is the flexibility transformation cost of the condensing unit. The flexibility transformation of the condensing unit typically includes optimizing the unit's thermal system, control system, and other components, lowering its output limit to provide a wider load regulation range, thereby "making way" for renewable energy and improving the system's off-peak peak regulation capability. In some embodiments, the first flexibility transformation cost is an expression for the flexibility transformation decision variable of the condensing unit:

[0064]

[0065] Where, is the cost of transformation of the rth pure condensing unit in the sth stage, c pcup is the unit transformation cost, is the transformation decision variable of pure condensing unit r in stage s, is the maximum output of the pure condensing unit; if the value of the transformation decision variable is 1, the pure condensing unit will undergo flexibility transformation; if the value of the transformation decision variable is 0, the pure condensing unit will not undergo flexibility transformation;

[0066] The second flexibility transformation cost is the flexibility transformation cost of the CHP unit. The CHP unit has a significant operating characteristic of "determining electricity by heat". Under the condition of high thermal power in the heating season, the minimum power is high, the adjustment range is small, and the peak-shaving capacity is insufficient, which is not conducive to the consumption of new energy. By adding electric boilers and heat storage tanks to perform thermal and electrical decoupling, the minimum power can be reduced and the peak-shaving capacity of the unit can be improved. Figure 2 In some embodiments, the second flexibility modification cost is an expression of the CHP unit flexibility modification decision variable.

[0067]

[0068] Where, is the cost of the transformation of the nth CHP unit in the sth stage, c EB is the unit cost of the electric boiler, x n,s is the decision variable for whether to carry out thermal storage tank renovation for the nth CHP unit in the sth stage, x n,s If it is equal to 1, the thermal storage tank will be transformed. n,s If it is equal to 0, no thermal storage tank modification will be performed. is the capacity of the electric boiler added to the nth CHP unit in the sth stage, c HST is the unit cost of the heat storage tank, y n,s is the decision variable for whether the nth CHP unit should undergo electric boiler transformation at stage s, y n,s If it is equal to 1, then the electric boiler will be transformed. n,s If it is equal to 0, no electric boiler transformation will be carried out. The capacity of the heat storage tank added to the nth CHP unit in stage s;

[0069] In some embodiments, the coal-fired power operation cost includes a first operation cost and a second operation cost; the first operation cost is the operation cost of the pure condensing unit after flexibility modification, and the second operation cost is the operation cost of the CHP unit after flexibility modification.

[0070] After the flexibility transformation of the pure condensing unit, the operating range can be divided into the basic peak regulation stage and the deep peak regulation stage. The first operating cost is determined by the output power range, as shown in formula (7):

[0071]

[0072] Where, is the operating cost of the rth pure condensing unit after flexibility transformation in the sth stage, c fr1 is the unit power generation cost in the basic peak regulation stage, is the power output of the rth pure condensing unit in the sth stage after flexibility transformation, c fr2 is the unit power generation cost during the deep peak regulation stage;

[0073] When constructing the second operating cost, the vertex convex combination method is first used to construct the CHP unit operation model, such as Figure 3 As shown, the model is shown in formula (8):

[0074]

[0075] Where, is the power output of the nth CHP unit at the sth stage and time t, is the first 0 / 1 variable, is the second 0 / 1 variable, is the third 0 / 1 variable, is the fourth 0 / 1 variable, is the electric output at point A in the operating range, is the electric output of point B in the operating range, is the electric output at point C in the operating range, is the electric output of point D in the operating range, A, B, C, and D are the vertices in the vertex convex combination, is the heat output of the nth CHP unit at time t in stage s, is the thermal output of point A in the operating range, is the thermal output of point B in the operating range, is the thermal output at point C in the operating range, is the thermal output of point D in the operating range, The thermal output start and stop status of the nth CHP unit at time t in stage s;

[0076] The second operating cost, i.e., the operating cost after the flexibility modification of the CHP unit, is determined by the electrical output and thermal output of the CHP unit after the flexibility modification, as shown in equations (9), (10), and (11):

[0077]

[0078] Where, is the operating cost of the nth CHP unit at time t in stage s, is the first cost coefficient, is the power output of the nth CHP unit at the sth stage and time t, E n,t,s is the conversion coefficient of the nth CHP unit at the sth stage and time t, is the heat output of the nth CHP unit at time t in stage s, is the second cost coefficient, is the third cost coefficient, is the operating capacity of the electric boiler added to the nth CHP unit at time t in the sth stage, η EB is the electricity-to-heat efficiency of the electric boiler, The operating capacity of the heat storage tank added to the nth CHP unit at time t in the sth stage, The operating capacity of the heat storage tank added to the nth CHP unit at the sth stage (t-1);

[0079] In some embodiments, the planning constraints include wind power retirement constraints, constant capacity transformation constraints, capacity expansion transformation constraints, CHP unit transformation constraints, system investment cost upper limit constraints, and new energy power generation ratio constraints.

[0080] Wind power retirement constraints are:

[0081]

[0082] Where, is the decision variable for the life of wind power equipment;

[0083] Mode It is restricted that after the wind power equipment is retired in stage (s-1), the next stage s is the retired state; Wind turbines that have reached their grid-connected age must undergo life extension modifications to remain in the power system. Indicates that the wind turbine (wind power equipment) has reached the grid connection age. Indicates that the wind turbine has not reached the grid-connected lifespan;

[0084] The constraints for isovolumetric transformation and expansion transformation are:

[0085]

[0086] Where, is the total retired capacity of wind farm g in stage s, is the total constant capacity reconstruction of wind farm g in stage s, is the total expansion and reconstruction capacity of wind farm g in stage s, N rt is the total number of retired wind power equipment, α is the serial number of retired wind power equipment, N ec is the total number of wind power equipment transformed with equal capacity, β is the serial number of wind power equipment transformed with equal capacity, N kr is the total number of wind power equipment for expansion and transformation, γ is the serial number of wind power equipment for expansion and transformation, μ kr is the proportional coefficient, μ kr Limit the upper limit of expansion capacity;

[0087] The CHP unit transformation constraints are:

[0088] x n,s +y n,s ≤1;

[0089]

[0090] Where, is the capacity of wind farm g at time t in stage s, The minimum installed capacity of wind power equipment is specified for the system of wind farm g at time t in phase s;

[0091] The upper limit constraint of system investment cost is:

[0092] C ROS ≤Π max ;

[0093] Where, π max The upper limit of investment cost;

[0094] In some embodiments, the system operation constraints include system power balance constraints, carbon emission constraints, wind power operation constraints, pure condensing unit operation constraints, and CHP unit operation constraints.

[0095] The system power balance constraint is:

[0096]

[0097] The operating constraints of the pure condensing unit are:

[0098]

[0099] The operating constraints of the CHP unit are:

[0100]

[0101] The carbon emission constraints are:

[0102]

[0103] Where, is the electrical load of node d at time t in the sth stage, is the electric load variable of node d at time t in the sth stage, is the lower limit of the output of the rth pure condensing unit in the sth stage, is the output upper limit of the rth pure condensing unit in the sth stage, is the continuous operating time of the rth pure condensing unit at the sth stage time (t-1), is the minimum continuous operating time of the rth pure condensing unit in the sth stage, is the continuous downtime of the rth pure condensing unit at the sth stage (t-1), is the minimum continuous downtime of the rth pure condensing unit in the sth stage, u r,t-1,s is the operating state variable of the rth pure condensing unit at the sth stage time (t-1), u r,t,s is the operating state variable of the rth pure condensing unit at the sth stage and time t, when ur,t,s =1 indicates that the rth pure condensing unit is operating at the sth stage at time t. r,t,s = 0, it means that the rth pure condensing unit is shut down at the sth stage and time t. is the downward ramp rate of the rth pure condensing unit in stage s, is the ramp-up rate of the rth pure condensing unit in the sth stage, α n,s is the unit transformation decision variable of the nth CHP unit in the sth stage, is the lower limit of the power output of the nth CHP unit before the unit transformation in stage s, is the upper limit of the electric output of the nth CHP unit before the unit transformation in stage s, is the lower limit of the electric output of the nth CHP unit after the unit transformation in stage s, is the upper limit of the electric output of the nth CHP unit after the unit transformation in stage s, is the upper limit of the thermal output of the nth CHP unit in the sth stage, is the downward ramp rate of the nth CHP unit in the sth stage before flexibility modification, is the upward climbing rate of the nth CHP unit in the sth stage before the flexibility modification, is the downward ramp rate of the nth CHP unit in the sth stage after flexibility modification, is the upward climbing rate of the nth CHP unit after flexibility modification in the sth stage, is the carbon emission intensity of the rth pure condensing unit at the sth stage and time t, is the carbon emission intensity of the nth CHP unit at the sth stage and time t, is the carbon emission limit for phase s;

[0104] In order to enable those skilled in the art to better understand the present invention and appreciate the advantages of the present invention over the prior art, further explanation is given in conjunction with specific examples.

[0105] The example system includes four wind farms with an initial installed capacity of 500MW. The installed capacities of wind farms 1 to 4 are 102MW, 203MW, 130MW, and 65MW, respectively. The wind turbines in wind farms 1 to 4 that have reached their service life, i.e., the total installed capacity of wind power equipment, are 30MW, 40.5MW, 40MW, and 40MW, respectively. The installed capacity of the coal-fired power plant is 1300MW, including three pure condensing units and six CHP units. Four schemes were set up for comparative analysis to highlight the advantages of the present invention. Scheme 1 is the scheme of the present invention, as shown in Table 1. "√" indicates that the plan is to be carried out, and "×" indicates that the plan is not to be carried out.

[0106] Table 1 Scheme settings

[0107] scene Direct retirement Life extension transformation Isometric transformation Expansion and renovation Coal-fired power transformation Option 1 √ √ √ √ √ Option 2 √ × √ √ √ Option 3 √ √ × √ √ Option 4 √ √ √ √ ×

[0108] The cost obtained through the simulation is shown in Table 2.

[0109] Table 2: Cost of the solution

[0110] Plan / 10,000 yuan Option 1 Option 2 Option 3 Option 4 Total cost 205369.38 337380.48 285105.84 312167.22 Orderly decommissioning costs 6569.86 8296.24 6569.86 6569.86 Life extension renovation cost 166.8 0 166.8 166.8 Equivolumetric transformation cost 54711.3 68119.27 0 54711.3 Expansion and transformation costs 16475.89 29542.97 79840.76 15384.89 Wind curtailment penalty costs 14167.63 17717.50 19516.31 27077.68 Load shedding cost 0 2596.46 0 0 Coal-fired power unit operating costs 109804.77 210648.15 176605.23 208256.69

[0111] Table 2 shows that Plan 1 offers better overall economic benefits for planning wind farms and coal-fired power units. This is because coal-fired power operating costs and wind curtailment costs account for a significant portion of total costs. Plan 1, with orderly wind power retirement and reconstruction and coordinated coal-fired power transformation, offers a higher degree of flexibility in coal-fired power transformation. This allows for a wider range of optimal output methods, reducing coal-fired power generation and, consequently, lowering operating costs. This also reduces the wind curtailment rate and costs.

[0112] As can be seen from Figure 5, during the period of severe wind curtailment in each stage, the flexibility transformation of coal-fired power units promoted the absorption of wind power, and the amount of wind curtailment was significantly reduced after 2028. The wind curtailment rate in 2030 under Scheme 1 is 3.87%, which is 12.3% lower than that in the initial planning period and 13.72% lower than that in Scheme 4. Figure 6 It can be concluded that Plan 1 ensures the system's power supply adequacy by extending the life of WF3 and WF2 and retiring a small number of them in 2025. It can be seen that the orderly retirement of wind power can prevent safety and stability problems in the system.

[0113] Depend on Figure 7 It can be concluded that Option 1 has the highest flexibility transformation rate and lower carbon emissions. It can be seen that the transformation of wind power and coal power requires overall coordination and attention to the mutual influence between each stage.

[0114] Depend on Figure 8 and Figure 9 As can be seen, the orderly decommissioning and reconstruction of wind farms is characterized by direct decommissioning of WF1, WF2, and WF4, while WF3 adopts a life extension retrofit. Option 1 achieves the highest installed capacity in the final years of the plan and poses no system stability issues. Therefore, a rational and orderly arrangement of wind farm decommissioning and reconstruction, and the coordinated transformation of wind and coal power, are crucial for the safe, stable, and low-carbon transition of the power system.

[0115] In summary, the solution proposed in the present invention, under the premise of meeting system safety and stability, obtains the most economical wind turbine orderly decommissioning plan, reconstruction capacity configuration and coal-fired power coordinated transformation plan.

[0116] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation, characterized by: The following steps are involved: Constructing a total cost model for a low-carbon power system, wherein the total cost model is the sum of transformation costs and operating costs; The transformation costs include the orderly decommissioning costs of wind power, wind power reconstruction costs and coal power transformation costs; The operating costs include coal-fired power operating costs, wind power curtailment penalty costs, and load shedding costs; Constructing a multi-stage collaborative planning model for the low-carbon power system based on the total cost model, wherein the objective function of the multi-stage collaborative planning model is to minimize the total cost within the collaborative planning stage, and the constraints of the multi-stage collaborative planning model include planning constraints and system operation constraints; The multi-stage collaborative planning model is solved to obtain a multi-stage collaborative planning scheme for the low-carbon power system.

2. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 1 is characterized by: The orderly decommissioning costs of wind power include direct decommissioning costs and life extension and transformation costs.

3. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 2 is characterized by: The direct decommissioning cost is an expression of the decommissioning decision variable; the life extension transformation cost is an expression of the life extension transformation decision variable.

4. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 1 is characterized by: The wind power reconstruction cost includes the cost of equal capacity transformation and the cost of capacity expansion transformation.

5. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 4 is characterized by: The isovolumetric transformation cost is an expression of the isovolumetric transformation decision variables; the capacity expansion transformation cost is an expression of the capacity expansion transformation decision variables.

6. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 1 is characterized by: The coal-fired power transformation cost includes a first flexibility transformation cost and a second flexibility transformation cost; the first flexibility transformation cost is the flexibility transformation cost of the pure condensing unit, and the second flexibility transformation cost is the flexibility transformation cost of the CHP unit.

7. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 6 is characterized by: The first flexibility transformation cost is an expression of the flexibility transformation decision variable of the pure condensing unit, and the second flexibility transformation cost is an expression of the flexibility transformation decision variable of the CHP unit.

8. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 1 is characterized by: The coal-fired power operation cost includes a first operation cost and a second operation cost; the first operation cost is the operation cost of the pure condensing unit after flexibility transformation, and the second operation cost is the operation cost of the CHP unit after flexibility transformation.

9. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to any one of claims 1 to 8, characterized in that: The planning constraints include wind power retirement constraints, equal capacity transformation constraints, capacity expansion transformation constraints, CHP unit transformation constraints, system investment cost upper limit constraints and new energy power generation proportion constraints.

10. The multi-stage collaborative planning method for a low-carbon power system considering wind power and coal power transformation according to claim 9 is characterized by: The system operation constraints include system power balance constraints, carbon emission constraints, wind power operation constraints, pure condensing unit operation constraints and CHP unit operation constraints.

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