Thermal power unit primary frequency modulation control method based on economy and stability optimization

Abstract

The application discloses a thermal power unit primary frequency modulation control method based on economy and stability optimization, and belongs to the technical field of power system control, and its technical points are as follows: including the following steps: step one: detecting power grid frequency fluctuation, when the power grid frequency fluctuation exceeds the set normal range, controlling each device to perform primary frequency modulation according to the size of the power grid frequency fluctuation and the SOC state of the energy storage device; step two: performing dynamic droop coefficient optimization on the energy storage device, calculating system economy and stability, and obtaining the optimal value of the objective function; step three: setting a dynamic weight adjustment mechanism, the adjustment mechanism is to dynamically adjust the weights of economy and stability according to the size of the power grid frequency fluctuation, set the constraint condition, and determine the optimal frequency modulation strategy by using the particle swarm algorithm, which has the advantages that the calculation weights and response strategies can be adjusted in real time according to the power grid frequency fluctuation, and the economy and stability of the system are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system control, in particular to a method for primary frequency modulation control of thermal power generating units based on optimization of economy and stability. BACKGROUND

[0002] With the continuous rise of new energy installation, the uncertainty of new energy output has intensified the difficulty of balancing supply and demand during the key period of power supply. Thermal power generating units will play a more important role in bottom-up protection and system regulation in the process of promoting new-type power system, in order to maintain the task of receiving high proportion of new energy. At present, the primary frequency modulation capacity of some thermal power generating units has decreased significantly during deep peak regulation, which does not meet the requirements, resulting in a serious threat to the frequency safety of the power grid. Therefore, it is urgent to improve the dynamic response performance of the primary frequency modulation of the unit under deep peak regulation conditions, to further improve the safety and stability of the power grid.

[0003] Chinese patent application 202411415671.4 discloses a method and system for coordinated control of thermal power generating units with energy storage devices under deep peak regulation. The primary frequency modulation demand of the thermal power generating unit is obtained by determining the speed inequality formula of the thermal power generating unit. Then the current power coefficient of the energy storage device is determined. Finally, the primary frequency modulation control strategy and the load adjustment control strategy of the thermal power generating unit are determined based on the primary frequency modulation demand of the thermal power generating unit, the current power coefficient of the energy storage device, the rated output power of the energy storage device, the adjustment amount of the energy storage device and the adjustment amount of the thermal power generating unit.

[0004] However, it only considers the regulation and control strategy of frequency modulation, does not consider the response time of the system, does not consider the economy and stability of the system, and the output of each device needs to be improved. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the embodiments of the present application is to provide a method for primary frequency modulation control of thermal power generating units based on optimization of economy and stability, to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0007] The method for primary frequency modulation control of thermal power generating units based on optimization of economy and stability comprises the following steps:

[0008] Step 1: Detect the frequency fluctuation of the power grid. When the frequency fluctuation of the power grid exceeds the set normal range, control each device to perform primary frequency modulation according to the size of the frequency fluctuation of the power grid and the SOC state of the energy storage device;

[0009] Step 2: Optimize the dynamic droop coefficient of the energy storage device, calculate the economy and stability of the system, and obtain the optimal value of the objective function;

[0010] Step 3: Set up a dynamic weight adjustment mechanism. The adjustment mechanism dynamically adjusts the weights of economy and stability according to the magnitude of power grid frequency fluctuations, sets constraints, and uses the particle swarm optimization algorithm to determine the optimal frequency regulation strategy.

[0011] As a further aspect of the present invention, the objective function in step two is:

[0012] K dgree ；

[0013] In the formula F The objective function is... For the normalized system economy; K dgree To determine the system stability after normalization; , These are the weighting coefficients;

[0014] The specific normalization equation is as follows:

[0015] = ;

[0016] K dgree = ；

[0017] In the formula This represents the maximum economic efficiency of the system, expressed in yuan. This represents the minimum economic efficiency of the system, expressed in yuan. This represents the maximum value for system stability. This represents the minimum value for system stability. , Determined through historical data and initial population sampling.

[0018] As a further aspect of the present invention, the dynamic weight adjustment mechanism in step three includes:

[0019] The existing weighting based on the magnitude of frequency fluctuations will be upgraded to a dynamic, real-time weighting adjustment.

[0020] α(t) = | |, β(t) = 1 - α(t);

[0021] Economy and stability with real-time frequency deviation Δ f (t) Dynamically adjusted, the stability weight increases as the frequency deviation increases.

[0022] As a further scheme of the present application, the system economy calculation in the step two comprises investment cost, peak-valley electricity price income, frequency modulation cost and frequency modulation reward income, and the calculation formula is:

[0023] = 投资 + 峰谷 + 调频成本 + 调频奖励；

[0024] The frequency modulation reward income calculation formula is:

[0025] ;

[0026] In the formula, is frequency modulation mileage compensation income, unit is yuan is total transaction cycle number of frequency modulation market; is the frequency modulation mileage provided by the power generation unit in the th transaction cycle, unit is MW; is mileage result calculation price of the th transaction cycle, unit is yuan / MW; is stability index average value of the power generation unit in the th transaction cycle;

[0027] The investment cost calculation formula is:

[0028] 投资= t；

[0029] In the formula, is total investment cost of the system, unit is yuan; n is system life, unit is year; t is use time, unit is s;

[0030] The peak-valley electricity price income refers to that the system purchases electric energy from the power grid for charging at the valley value electricity price and sells electric energy for discharging at the peak value electricity price, and when the SOC of the flywheel energy storage system is greater than 0.6, the charging is stopped, and when the SOC of the lithium battery is greater than 0.55, the charging is stopped; when the SOC of the flywheel energy storage system is less than 0.4, the discharging is stopped, and when the SOC of the lithium battery is less than 0.45, the discharging is stopped.

[0031] As a further scheme of the present application, the frequency modulation cost calculation formula is:

[0032] 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频；

[0033] The cost of frequency modulation of thermal power is derived from the increment of fuel consumption and equipment wear and tear, and the calculation formula is:

[0034] ;

[0035] In the formula, is the output power of thermal power unit for frequency modulation, with the unit of MW; is the cost per kilowatt-hour of thermal power unit, with the unit of yuan / kW·h; is the duration of frequency modulation, with the unit of s; is the mechanical wear and tear cost of power frequency modulation, with the unit of yuan / MW;

[0036] The cost of lithium battery is composed of cycle life loss, energy efficiency loss and power conversion loss:

[0037] ;

[0038] In the formula, is the total throughput energy during frequency modulation, with the unit of MW·h; is the recyclable energy of the whole life cycle of the battery, with the unit of MW·h; is the initial investment cost of the battery, with the unit of yuan; is the charging and discharging efficiency; is the grid price, with the unit of yuan / MW·h;

[0039] The cost of flywheel is the power loss and bearing life:

[0040] ;

[0041] In the formula, 功率损耗 is the cost per kilowatt-hour of flywheel operation, with the unit of yuan / kW·h; N 启停 is the number of start-stop times during frequency modulation; N 寿命 is the maximum number of start-stop times within the design life of flywheel bearing; 轴承 is the bearing replacement cost, with the unit of yuan;

[0042] Coordination frequency modulation cost 协调调频 including the communication of control system, the operation of optimization algorithm and the loss of multi-energy coupling, calculated as 3% of the total cost.

[0043] As a further scheme of the present application, the system stability calculation in the step two comprises adjusting the adjusting speed k 1, response time k 2, adjusting accuracy k 3 three factors, and the calculation formula is:

[0044] ;

[0045] ;

[0046] ;

[0047] ;

[0048] In the formula is the adjusting speed index; is the response time index; is the adjusting accuracy index; is the measured adjusting speed of the unit, in MW / s; is the average standard adjusting speed of the AGC power generation unit in the frequency regulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in s; is the adjusting error of the unit.

[0049] As a further scheme of the present application, the constraint condition in the step three comprises power balance constraint, SOC constraint, charging and discharging power constraint, frequency constraint and thermal power unit climbing constraint.

[0050] As a further scheme of the present application, the charging and discharging power constraint condition is for the flywheel energy storage system and the lithium battery energy storage system;

[0051] The flywheel charging and discharging power constraint condition is:

[0052] ;

[0053] In the formula: is the maximum output power of the flywheel, in MW; is the state of charge of the flywheel; is the frequency deviation, in Hz; is the droop coefficient of the flywheel, which is dynamically adjusted according to ;

[0054] The lithium battery charging and discharging power constraint condition is:

[0055] ;

[0056] ;

[0057] wherein is an adaptive droop coefficient; is a reference droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

[0058] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0059] The system economy and stability can be effectively improved, the weight and response strategy can be adjusted in real time according to the grid frequency fluctuation, the characteristics of the flywheel energy storage system and the lithium battery energy storage system can be fully utilized, the energy utilization efficiency is improved, the problem of insufficient frequency modulation capability of the thermal power unit under deep peak regulation is solved, and the service life of the energy storage equipment is prolonged.

[0060] The grid frequency is monitored in real time, the flywheel and the lithium battery simultaneously respond to frequency modulation when the grid frequency produces small fluctuations, and the lithium battery and the thermal power unit simultaneously respond to frequency modulation when the grid frequency produces large fluctuations.

[0061] When the grid frequency produces small fluctuations, the economic priority control strategy is adopted, and when the grid frequency produces large fluctuations, the stability priority control strategy is adopted.

[0062] In order to make the structure characteristics and effects of the present application clearer, the present application will be described in detail below in combination with the drawings and specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is a system overall optimization control strategy diagram;

[0064] Figure 2 is a system economy calculation strategy schematic diagram;

[0065] Figure 3 is a system stability calculation strategy schematic diagram;

[0066] Figure 4 is a system constraint condition strategy schematic diagram;

[0067] Figure 5 is a charge-discharge power system model curve example diagram. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0069] The specific implementation of the present application is described in detail below in combination with specific embodiments.

[0070] In one embodiment, the method for optimizing the primary frequency modulation control of a thermal power generating unit based on economy and stability comprises the following steps: Figures 1-5

[0071] Step one: detecting the frequency fluctuation of the power grid, when the frequency fluctuation of the power grid exceeds the set normal range, controlling each device to perform primary frequency modulation according to the size of the frequency fluctuation of the power grid and the SOC state of the energy storage device;

[0072] Step two: optimizing the dynamic droop coefficient of the energy storage device, calculating the economy and stability of the system, and obtaining the optimal value of the objective function;

[0073] Step three: setting a dynamic weight adjustment mechanism, the adjustment mechanism is to dynamically adjust the weights of economy and stability according to the size of the frequency fluctuation of the power grid, setting the constraint condition, and using the particle swarm algorithm to determine the optimal frequency modulation strategy.

[0074] Further, referring to Figures 1-5 , the objective function in step two is:

[0075] K dgree ；

[0076] In the formula, F is the objective function; is the normalized system economy; K dgree is the normalized system stability; , is the weight coefficient;

[0077] The specific normalization equation is:

[0078] = ;

[0079] K dgree = ；

[0080] In the formula, is the maximum value of the system economy, with the unit of yuan; is the minimum value of the system economy, with the unit of yuan; is the maximum value of the system stability; is the minimum value of the system stability; , ​Determination by historical data and initial population sampling.

[0081] Further, referring to Figures 1-5 , the setting of the dynamic weight adjustment mechanism in step three includes:

[0082] The existing weight divided according to the size of frequency fluctuation is promoted to a dynamic real-time adjustment weight;

[0083] α(t) = |f(t) - f(t-1)| / f(t-1)| β(t) = 1 - α(t);

[0084] The economy and stability are dynamically adjusted with real-time frequency deviation Δ f (t), and the higher the frequency deviation, the greater the stability weight.

[0085] Further, referring to Figures 1-5 , the system economy calculation in step two includes investment cost, peak-valley electricity price income, frequency modulation cost and frequency modulation reward income, and the calculation formula is:

[0086] = 投资 + 峰谷 + 调频成本 + 调频奖励；

[0087] The calculation formula of the frequency modulation reward income is:

[0088] ;

[0089] In the formula: is the frequency mileage compensation income, with a unit of yuan is the total number of trading periods in the frequency modulation market; is the frequency mileage provided by the power generation unit in the th trading period, with a unit of MW; is the mileage result calculation price of the th trading period, with a unit of yuan / MW; is the stability index average value of the power generation unit in the th trading period;

[0090] The calculation formula of the investment cost is:

[0091] 投资= t；

[0092] In the formula is the total investment cost of the system, with a unit of yuan;n is the system lifetime, in years; t is the usage time, in seconds;

[0093] The peak-valley electricity price income refers to that the system purchases electricity from the power grid for charging at the valley electricity price and sells electricity for discharging at the peak electricity price in primary frequency modulation, and charging is stopped when the SOC of the flywheel energy storage system is greater than 0.6, and charging is stopped when the SOC of the lithium battery is greater than 0.55; discharging is stopped when the SOC of the flywheel energy storage system is less than 0.4, and discharging is stopped when the SOC of the lithium battery is less than 0.45.

[0094] Further, referring to Figures 1-5 , the frequency modulation cost calculation formula is:

[0095] 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频；

[0096] The thermal power frequency modulation cost is derived from the fuel consumption increment and equipment wear, and the calculation formula is:

[0097] ;

[0098] In the formula, is the thermal power unit frequency modulation output power, in MW; is the degree of electricity cost of the thermal power unit, in yuan / kW·h; is the frequency modulation duration, in seconds; is the mechanical wear cost of unit power frequency modulation, in yuan / MW;

[0099] The lithium battery cost is composed of cycle life loss, energy efficiency loss and power conversion loss:

[0100] ;

[0101] In the formula, is the total throughput energy in the frequency modulation process, in MW·h; is the recyclable energy of the battery in the whole life cycle, in MW·h; is the initial investment cost of the battery, in yuan; is the charging and discharging efficiency; is the grid electricity price, in yuan / MW·h;

[0102] The flywheel cost is the power loss and bearing life:

[0103] ;

[0104] In the formula 功率损耗 is the cost per kilowatt-hour of electricity for flywheel operation, in yuan / kW·h; N 启停 is the number of start-stop times during frequency modulation; N 寿命 is the maximum number of start-stop times within the design life of the flywheel bearing; 轴承 is the bearing replacement cost, in yuan;

[0105] Coordination frequency modulation cost 协调调频 including communication of the control system, operation of the optimization algorithm and multi-energy coupling loss, calculated as 3% of the total cost.

[0106] Further, referring to Figures 1-5 , the system stability calculation in step two includes three factors: adjustment rate k 1, response time k 2, adjustment accuracy k 3, the calculation formula is:

[0107] ;

[0108] ;

[0109] ;

[0110] ;

[0111] In the formula is the adjustment rate index; is the response time index; is the adjustment accuracy index; is the measured adjustment speed of the unit, in MW / s; is the average standard adjustment rate of AGC power generation units in the frequency modulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in s; is the adjustment error of the unit.

[0112] Further, referring to Figures 1-5 , the constraint conditions in step three include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints, and thermal power unit ramp constraints.

[0113] Further, referring to Figures 1-5 , the charge and discharge power constraints are for flywheel energy storage systems and lithium battery energy storage systems;

[0114] The flywheel charge-discharge power constraint condition is:

[0115] ;

[0116] In the formula: Pmax is the maximum output power of the flywheel, in MW; SOC is the state of charge of the flywheel; f is the frequency deviation, in Hz; K is the droop coefficient of the flywheel, dynamically adjusted;

[0117] The lithium battery charge-discharge power constraint condition is:

[0118] ;

[0119] ;

[0120] In the formula K is the adaptive droop coefficient; K0 is the reference droop coefficient; Pmax is the maximum output power of the lithium battery, in MW; η is the discharge / charge efficiency.

[0121] In the embodiment, the power grid frequency is monitored in real time, when the power grid frequency produces a small fluctuation, the flywheel and the lithium battery simultaneously respond to frequency regulation, when the power grid frequency produces a large fluctuation, the lithium battery and the thermal power unit simultaneously respond to frequency regulation.

[0122] When the power grid frequency produces a small fluctuation, the control strategy of economic priority is adopted, when the power grid frequency produces a large fluctuation, the control strategy of stability priority is adopted.

[0123] Specifically, the control strategy is adjusted by changing the weights of economy and stability in the objective function.

[0124] The objective function of the system is:

[0125] K dgree ；

[0126] In the formula F f is the objective function; f is the normalized system economy; K dgree f is the normalized system stability; , w is the weight coefficient;

[0127] ​The application adopts a dynamic weight optimization strategy, adopts an economic priority strategy when the power grid frequency produces small fluctuations, and adopts a stability priority strategy when the power grid frequency produces large fluctuations.

[0128] The target weight is adjusted in real time according to the strength of the grid frequency fluctuation. Further, the existing weight divided according to the size of the frequency fluctuation can be promoted to a dynamic real-time adjustment weight.

[0129] α(t) =| |, β(t) =1-α(t);

[0130] Wherein, α(t) is the stability weight, β(t) is the economic weight, and with the real-time frequency deviation Δ f (t) dynamic adjustment, the higher the frequency deviation, the greater the stability weight.

[0131] The specific normalization equation is:

[0132] = ;

[0133] K dgree = ；

[0134] In the formula is the maximum value of system economy, unit: yuan; is the minimum value of system economy, unit: yuan; is the maximum value of system stability; is the minimum value of system stability; , Determined by historical data or initial population sampling.

[0135] In order to avoid excessive charging and discharging of energy storage devices and improve the operating life of energy storage devices, dynamic droop control optimization is performed on the flywheel energy storage system and lithium battery energy storage system, and the specific control is as follows Figure 3The control strategy of the flywheel energy storage system is as follows: when 0.7 < SOC < 1, charging with a low droop coefficient and discharging with a maximum droop coefficient; when 0.3 ≤ SOC ≤ 0.7, charging and discharging with a maximum droop coefficient; and when 0 ≤ SOC ≤ 0.3, discharging with a low droop coefficient and charging with a maximum droop coefficient. The control strategy of the lithium battery energy storage system is as follows: when 0.8 ≤ SOC < 1, stopping charging and discharging with a maximum droop coefficient; when 0.55 < SOC < 0.8, charging with a low droop coefficient and discharging with a maximum droop coefficient; when 0.45 ≤ SOC ≤ 0.55, charging and discharging with a maximum droop coefficient; when 0.2 < SOC < 0.45, discharging with a low droop coefficient and charging with a maximum droop coefficient; and when 0 ≤ SOC < 0.2, stopping discharging and charging with a maximum droop coefficient.

[0136] System economy The investment cost, the peak-valley electricity price income, the frequency modulation cost and the frequency modulation reward income are included.

[0137] 投资 峰谷 调频成本 调频奖励；

[0138] The investment cost is the investment cost of the flywheel energy storage system and the lithium battery of the system divided by the service life thereof.

[0139] 投资= t；

[0140] In the formula, is the total investment cost of the system, in yuan; n is the service life of the system, in years; t is the use time, in seconds.

[0141] The peak-valley electricity price income refers to that the system charges by purchasing electric energy from the power grid at the valley value of the electricity price, stops charging when the SOC of the flywheel energy storage system is greater than 0.6, and stops charging when the SOC of the lithium battery is greater than 0.55. The system discharges by selling electric energy at the peak value of the electricity price, stops discharging when the SOC of the flywheel energy storage system is less than 0.4, and stops discharging when the SOC of the lithium battery is less than 0.45.

[0142] The frequency modulation cost is the additional energy consumption cost caused by frequency modulation and the loss cost of the energy storage device.

[0143] 调频成本 =​​​​ 火电调频 + 锂电调频 + 飞轮调频 + 协调调频；

[0144] （1） The cost of thermal frequency modulation mainly comes from the increase of fuel consumption and equipment wear and tear, and the calculation formula is:

[0145] ;

[0146] wherein is the output power of thermal power unit frequency modulation, unit: MW; is the unit power cost of thermal power unit, unit: yuan / kW·h, which is usually obtained by fitting the coal consumption characteristic curve; is the duration of frequency modulation, unit: s; is the mechanical wear and tear cost of unit power frequency modulation, unit: yuan / MW.

[0147] (2) The cost of lithium battery is composed of cycle life loss, energy efficiency loss and power conversion loss:

[0148] ;

[0149] wherein is the total throughput energy in the frequency modulation process, unit: MW·h; is the recyclable energy in the whole life cycle of the battery, unit: MW·h; is the initial investment cost of the battery, unit: yuan; is the charging and discharging efficiency; is the grid price, unit: yuan / MW·h.

[0150] (3) The cost of flywheel is mainly power loss and bearing life:

[0151] ;

[0152] wherein 功率损耗 is the unit power cost of flywheel operation, unit: yuan / kW·h; N 启停 is the number of start-stop times in the frequency modulation process; N 寿命 is the maximum number of start-stop times within the design life of flywheel bearing; 轴承 is the bearing replacement cost, unit: yuan.

[0153] (4) The cost of coordinated frequency modulation 协调调频The communication of the control system, the running of the optimization algorithm and the loss of multi-energy coupling can be estimated at 3% of the total cost.

[0154] The frequency modulation reward income is a subsidy income for successful system frequency modulation, and the frequency modulation mileage compensation calculation formula is:

[0155] ;

[0156] In the formula: is the frequency modulation mileage compensation income, and the unit is yuan is the total number of trading periods in the frequency modulation market; is the frequency modulation mileage provided by the power generation unit in the th trading period, and the unit is MW; is the mileage result calculation price of the th trading period, and the unit is yuan / MW; is the stability index average value of the power generation unit in the th trading period.

[0157] The system stability includes three factors of adjustment rate k 1, response time k 2, and adjustment accuracy k 3, and the calculation formula of the stability index is:

[0158] ;

[0159] ;

[0160] ;

[0161] ;

[0162] In the formula: is the adjustment rate index; is the response time index; is the adjustment accuracy index; is the measured adjustment speed of the unit, and the unit is MW / s; is the average standard adjustment rate of the AGC power generation unit in the frequency modulation resource distribution area, and the unit is MW / s; is the response delay time of the power generation unit, and the unit is s; is the adjustment error of the unit.

[0163] The system constraint conditions include power balance constraints, SOC constraints, charging and discharging power constraints, frequency constraints, and thermal power unit ramping constraints.

[0164] The power balance constraint is that the system charging and discharging power is balanced with the required power​

[0165] P fly + P bat + P wheel = P load ;

[0166] The frequency constraint refers to the system frequency after frequency modulation needs to be controlled within the allowed range:

[0167] | Δ f ( t ) | ≤ 0.2 Hz;

[0168] In the formula, Δ f ( t ) is the frequency deviation at the moment, and the unit is Hz. t

[0169] The climbing constraint of the thermal power generating unit refers to the constraint on the increase rate of the output power of the thermal power generating unit:

[0170] ;

[0171] In the formula: R up is the maximum up-climbing rate, and the unit is MW / s; R down is the maximum down-climbing rate, and the unit is MW / s.

[0172] The SOC constraint is to stop charging when the SOC of the lithium battery is ≥0.8, and to stop discharging when the SOC is ≤0.2.

[0173] ;

[0174] The charge-discharge power constraint is that the flywheel and the lithium battery cannot output infinite input power, and have a maximum charge-discharge power. The charge-discharge power cannot exceed the maximum charge-discharge power.

[0175] The flywheel charge-discharge power constraint condition is:

[0176] ;

[0177] In the formula: is the maximum output power of the flywheel, and the unit is MW; is the state of charge of the flywheel; is the frequency deviation, and the unit is Hz; is the droop coefficient of the flywheel, which is dynamically adjusted with .

[0178] The lithium battery charge-discharge power constraint condition is:​

[0179] ;

[0180] ;

[0181] wherein is an adaptive droop coefficient; is a reference droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

[0182] The particle swarm algorithm is used to solve and calculate to obtain an optimal control strategy. The steps of solving the capacity configuration model by using the particle swarm optimization algorithm are as follows:

[0183] (1) The initial population number of the particle swarm algorithm is set to 50, the maximum iteration number is set to 100, the acceleration factors C1 and C2 are both set to 1.5, and the maximum and minimum inertia factors are respectively set to 1 and 0.5;

[0184] (2) The population is initialized, particles meeting the constraint conditions are randomly generated, the initial position and speed of each particle are set, the fitness value is calculated, and the individual optimal position and optimal value of the particle, the global optimal position and optimal value of the particle swarm are recorded;

[0185] (3) Iterative calculation is started, the speed and position of the particle are updated, and the boundary condition of the particle is processed, if the particle is out of boundary, the particle is processed, a new generation of particle population is obtained, the fitness of each particle in the new generation of population is compared with the current optimal solution, and the individual and global optimal solution are updated;

[0186] The maximum iteration number is met, and the search process is ended; the global optimal solution is output, and the algorithm is ended.

[0187] The above only describes the preferred embodiments of the present application and should not be used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A primary frequency regulation control method for thermal power units based on economic and stability optimization, characterized in that, Includes the following steps: Step 1: Detect grid frequency fluctuations. When the grid frequency fluctuations exceed the set normal range, control each device to perform a frequency adjustment based on the magnitude of the grid frequency fluctuations and the SOC status of the energy storage device. Step 2: Optimize the dynamic droop coefficient of the energy storage device, perform economic and stability calculations on the system, and obtain the optimal value of the objective function; Step 3: Set up a dynamic weight adjustment mechanism. The adjustment mechanism dynamically adjusts the weights of economy and stability according to the magnitude of power grid frequency fluctuations, sets constraints, and uses the particle swarm optimization algorithm to determine the optimal frequency regulation strategy. The objective function in step two is: K dgree ； In the formula, F is the objective function; For the normalized system economy; K dgree To determine the system stability after normalization; , These are the weighting coefficients; The specific normalization equation is as follows: = ； K dgree = ； In the formula This represents the maximum economic efficiency of the system, expressed in yuan. This represents the minimum economic efficiency of the system, expressed in yuan. This represents the maximum value for system stability. This represents the minimum value for system stability. , Determined through historical data and initial population sampling; The dynamic weight adjustment mechanism set in step three includes: The existing weighting based on the magnitude of frequency fluctuations will be upgraded to a dynamic, real-time weighting adjustment. α(t)=| |,β(t)=1-α(t); The economy and stability are dynamically adjusted with the real-time frequency deviation Δf(t), and the stability weight is greater when the frequency deviation is higher. The system economic calculation in step two includes investment cost, peak-valley electricity price revenue, frequency regulation cost, and frequency regulation incentive revenue. The calculation formula is as follows: = 投资 + 峰谷 + 调频成本 + 调频奖励 ； The formula for calculating the frequency modulation reward is as follows: ； In the formula: The revenue from FM mileage compensation is expressed in yuan. This represents the total number of trading cycles in the frequency modulation market. For the power generation unit in the first The frequency regulation mileage provided per trading cycle is in MW; For the first The price is calculated based on the mileage results of each transaction cycle, in yuan / MW; For the power generation unit in the first The average stability index over a trading period; The formula for calculating the investment cost is as follows: 投资= t； In the formula The total investment cost of the system is expressed in yuan; n is the system lifespan in years; and t is the usage time in seconds. The peak-valley electricity price revenue refers to the system purchasing electricity from the grid for charging during off-peak hours and selling electricity for discharging during peak hours. Charging stops when the SOC of the flywheel energy storage system is greater than 0.6 and when the SOC of the lithium battery is greater than 0.55; discharging stops when the SOC of the flywheel energy storage system is less than 0.4 and when the SOC of the lithium battery is less than 0.

45. The formula for calculating the frequency modulation cost is as follows: 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频 ； The cost of frequency regulation in thermal power plants comes from the increase in fuel consumption and equipment wear and tear, and the calculation formula is as follows: ； In the formula This refers to the frequency-regulated output power of thermal power units, measured in MW. The cost per kilowatt-hour of thermal power units is expressed in yuan / kW·h. Frequency modulation duration, in seconds; The mechanical wear cost is expressed in yuan / MW, with the unit being power frequency modulation. The cost of lithium batteries consists of cycle life loss, energy efficiency loss, and power conversion loss: ； In the formula The total throughput energy during the frequency modulation process is expressed in MW·h. The cyclic energy of a battery over its entire life cycle is expressed in MW·h. The initial investment cost for the battery is expressed in yuan. For charge and discharge efficiency; This refers to the grid electricity price, expressed in yuan / MW·h. The cost of a flywheel consists of power loss and bearing life. ； In the formula 功率损耗 The cost per kilowatt-hour of the flywheel, expressed in yuan / kW·h; N 启停 N represents the number of starts and stops during the frequency modulation process. 寿命 The maximum number of start-stop cycles within the design life of the flywheel bearing; 轴承 Bearing replacement cost, in yuan; Coordinating frequency modulation costs 协调调频 This includes communication in the control system, optimization algorithm operation, and multi-energy coupling losses, calculated at 3% of the total cost; The constraints in step three include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints, and thermal power unit ramping constraints. The charging and discharging power constraints are for flywheel energy storage systems and lithium battery energy storage systems. The flywheel charging and discharging power constraints are as follows: ； In the formula: This represents the maximum output power of the flywheel, measured in MW. The flywheel is in a charged state; This represents the frequency deviation, measured in Hz. The flywheel sag coefficient is... Dynamic adjustment; The power constraints for lithium battery charging and discharging are as follows: ； ； In the formula An adaptive droop coefficient; The baseline droop coefficient; This represents the maximum output power of the lithium battery, measured in MW. This refers to the discharge / charge efficiency.

2. The primary frequency regulation control method for thermal power units based on economic and stability optimization according to claim 1, characterized in that, The system stability calculation in step two includes three factors: adjustment rate k1, response time k2, and adjustment accuracy k3. The calculation formula is as follows: ； ； ； ； In the formula For adjusting the rate index; For response time metrics; To adjust the accuracy indicators; The measured regulating speed of the unit is expressed in MW / s; The average standard regulation rate of AGC power generation units within the frequency regulation resource distribution area is expressed in MW / s. The response delay time of the power generation unit is expressed in seconds. This refers to the unit's adjustment error.

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