Thermal power generating unit primary frequency modulation control method based on economical efficiency and stability optimization

Abstract

The invention discloses a thermal power generating unit primary frequency modulation control method based on economical efficiency and stability optimization, which belongs to the technical field of power system control, and is technically characterized by comprising the following steps: step 1, detecting power grid frequency fluctuation, and when the power grid frequency fluctuation exceeds a set normal range, executing step 2; controlling each device to perform primary frequency modulation according to the magnitude of power grid frequency fluctuation and the SOC state of the energy storage device; 2, carrying out dynamic droop coefficient optimization on the energy storage device, and carrying out system economy calculation and stability calculation to obtain an optimal value of a target function; and step 3, setting a dynamic weight adjustment mechanism which is used for dynamically adjusting the weights of economy and stability according to the magnitude of the power grid frequency fluctuation, setting constraint conditions and determining an optimal frequency modulation strategy by using a particle swarm optimization algorithm, and has the advantages of being capable of adjusting and calculating the weights and response strategies in real time according to the power grid frequency fluctuation and improving the frequency modulation accuracy. And the economical efficiency and the stability of the system are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system control, and in particular to a primary frequency regulation control method for a thermal power unit based on economy and stability optimization. Background Art

[0002] As renewable energy capacity continues to climb, uncertainty in renewable energy output exacerbates the difficulty of balancing supply and demand during critical periods of guaranteed power supply. Thermal power units will assume a more crucial role in providing a safety net and regulating the system as the new power system is implemented, ensuring the high proportion of renewable energy capacity can be accommodated. Currently, the primary frequency regulation capabilities of some thermal power units have significantly decreased during periods of deep peak regulation, failing to meet requirements and posing a serious threat to grid frequency security. Therefore, there is an urgent need to improve the dynamic response performance of the units' primary frequency regulation under deep peak regulation conditions, thereby further enhancing the margin for safe and stable grid operation.

[0003] Chinese patent application 202411415671.4 discloses a coordinated control method and system for deep peak regulation of a thermal power unit with an energy storage device. By determining the speed inequality formula of the thermal power unit, the primary frequency regulation demand of the thermal power unit is obtained; then the current power coefficient of the energy storage device is determined; finally, the primary frequency regulation control strategy and load adjustment control strategy of the thermal power unit are determined based on the primary frequency regulation demand of the thermal power 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 unit.

[0004] However, it only considers the frequency regulation strategy, without considering the system response time, economy and stability, and the output of each device needs to be improved. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the embodiment of the present invention aims to provide a primary frequency regulation control method for a thermal power unit based on economic and stability optimization, so as to solve the problems in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: The primary frequency regulation control method of a thermal power unit based on economic and stability optimization includes the following steps: Step 1: Detect grid frequency fluctuations. When the grid frequency fluctuation exceeds the set normal range, each device is controlled to perform frequency modulation based on the magnitude of the grid frequency fluctuation and the SOC status of the energy storage device. Step 2: Optimize the dynamic droop coefficient of the energy storage device, calculate the system economy and stability, and obtain the optimal value of the objective function; Step 3: Set up a dynamic weight adjustment mechanism, which dynamically adjusts the weights of economy and stability according to the magnitude of grid frequency fluctuations, sets constraints, and uses a particle swarm algorithm to determine the optimal frequency regulation strategy.

[0007] As a further solution of the present invention, the objective function in step 2 is: K dgree ； In the formula F is the objective function; is the normalized system economy; K dgree is the stability of the system after normalization; , is the weight coefficient; The specific normalization equation is: = ; K dgree = ； In the formula is the maximum economic efficiency of the system, in yuan; is the minimum value of system economy, in yuan; is the maximum value of system stability; is the minimum value of system stability; , Determined through historical data and initial population sampling.

[0008] As a further solution of the present invention, the step 3 of setting a dynamic weight adjustment mechanism includes: The existing weighting based on frequency fluctuations is upgraded to dynamic real-time weighting; α(t)=| |, β(t)=1-α(t); Economy and stability vary with real-time frequency deviation Δ f (t) Dynamic adjustment: the higher the frequency deviation, the greater the stability weight.

[0009] As a further solution of the present invention, the system economic calculation in step 2 includes investment cost, peak and valley electricity price income, frequency regulation cost and frequency regulation reward income, and the calculation formula is: = 投资 + 峰谷 + 调频成本 + 调频奖励； The calculation formula for the frequency modulation reward income is: ; Where: Frequency regulation mileage compensation income, in yuan is the total number of trading cycles in the FM market; For the power generation unit Frequency modulation mileage provided in each transaction cycle, in MW; For the The price is calculated based on the mileage result of each transaction cycle, in RMB / MW. For the power generation unit The average value of stability indicators for trading cycles; The investment cost calculation formula is: 投资= t； In the formula is the total investment cost of the system, in yuan; n is the system life in years; t is the usage time, in seconds; The peak-valley electricity price income refers to the system purchasing electricity from the grid for charging when the primary frequency regulation is at the valley electricity price, and selling electricity for discharging at the peak electricity price. 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.

[0010] As a further solution of the present invention, the frequency modulation cost calculation formula is: 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频； The cost of thermal power frequency regulation comes from the increase in fuel consumption and equipment wear and tear, and the calculation formula is: ; In the formula The frequency modulation output power of the thermal power unit, in MW; is the electricity cost of thermal power units, in yuan / kW·h; is the frequency modulation duration, in seconds; is the mechanical wear cost of power frequency regulation, in yuan / MW; The cost of lithium batteries is composed of cycle life loss, energy efficiency loss and power conversion loss: ; In the formula is the total throughput energy of the frequency modulation process, in MW·h; The recyclable energy of the battery over its entire life cycle, in MW·h; is the initial investment cost of the battery, in yuan; is the charge and discharge efficiency; is the grid electricity price, in yuan / MW·h; Flywheel costs are power loss and bearing life: ; In the formula 功率损耗 is the electricity cost of the flywheel operation, in yuan / kW·h; N 启停 is the number of starts and stops during the frequency modulation process; N 寿命 The maximum number of starts and stops within the design life of the flywheel bearing; 轴承 is the bearing replacement cost, in yuan; Coordination frequency regulation costs 协调调频 Including control system communication, optimization algorithm operation and multi-energy coupling losses, calculated at 3% of the total cost.

[0011] As a further solution of the present invention, the system stability calculation in step 2 includes adjusting the rate k 1. Response time k 2. Adjustment accuracy k 3Three factors, the calculation formula is: ; ; ; ; In the formula is the adjustment rate indicator; is the response time indicator; To adjust the accuracy index; is the measured regulation speed of the unit, in MW / s; is the average standard regulation rate of AGC power generation units in the frequency regulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in seconds; is the adjustment error of the unit.

[0012] As a further solution of the present invention, the constraints in step three include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints and thermal power unit climbing constraints.

[0013] As a further solution of the present invention, the charging and discharging power constraint conditions are for flywheel energy storage systems and lithium battery energy storage systems; The flywheel charging and discharging power constraints are: ; Where: is the maximum output power of the flywheel, in MW; is the charge state of the flywheel; is the frequency deviation, in Hz; is the flywheel droop coefficient, Dynamic adjustment; The charging and discharging power constraints of lithium batteries are: ; ; In the formula is the adaptive droop coefficient; is the base droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

[0014] In summary, the embodiments of the present invention have the following beneficial effects compared with the prior art: It can effectively improve the economy and stability of the system, and adjust the calculation weights and response strategies in real time according to the frequency fluctuations of the power grid, give full play to the characteristics of the flywheel energy storage system and the lithium battery energy storage system, improve energy utilization efficiency, solve the problem of insufficient frequency regulation capacity of thermal power units under deep peak regulation, and extend the operating life of the energy storage equipment.

[0015] The grid frequency is monitored in real time. When the grid frequency fluctuates slightly, the flywheel and lithium battery respond simultaneously to adjust the frequency. When the grid frequency fluctuates greatly, the lithium battery and thermal power unit respond simultaneously to adjust the frequency.

[0016] When the grid frequency fluctuates slightly, a control strategy that prioritizes economy is adopted. When the grid frequency fluctuates significantly, a control strategy that prioritizes stability is adopted.

[0017] In order to more clearly illustrate the structural features and effects of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Optimize the control strategy diagram for the entire system; Figure 2 Schematic diagram of system economic calculation strategy; Figure 3 Schematic diagram of system stability calculation strategy; Figure 4 Schematic diagram of system constraint strategy; Figure 5 This is an example diagram of the charging and discharging power system model curve. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to 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 intended to limit the present invention.

[0020] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0021] In one embodiment, a method for controlling primary frequency regulation of a thermal power plant based on economic and stability optimization is described. Figures 1 to 5 , including the following steps: Step 1: Detect grid frequency fluctuations. When the grid frequency fluctuation exceeds the set normal range, each device is controlled to perform frequency modulation based on the magnitude of the grid frequency fluctuation and the SOC status of the energy storage device. Step 2: Optimize the dynamic droop coefficient of the energy storage device, calculate the system economy and stability, and obtain the optimal value of the objective function; Step 3: Set up a dynamic weight adjustment mechanism, which dynamically adjusts the weights of economy and stability according to the magnitude of grid frequency fluctuations, sets constraints, and uses a particle swarm algorithm to determine the optimal frequency regulation strategy.

[0022] For further information, see Figures 1 to 5 , the objective function in step 2 is: K dgree ； In the formula F is the objective function; is the normalized system economy; K dgree is the stability of the system after normalization; , is the weight coefficient; The specific normalization equation is: = ; K dgree = ； In the formula is the maximum economic efficiency of the system, in yuan; is the minimum value of system economy, in yuan; is the maximum value of system stability; is the minimum value of system stability; , Determined through historical data and initial population sampling.

[0023] For further information, see Figures 1 to 5 , the setting of the dynamic weight adjustment mechanism in step 3 includes: The existing weighting based on frequency fluctuations is upgraded to dynamic real-time weighting; α(t)=| |, β(t)=1-α(t); Economy and stability vary with real-time frequency deviation Δ f (t) Dynamic adjustment: the higher the frequency deviation, the greater the stability weight.

[0024] For further information, see Figures 1 to 5 The system economic calculation in step 2 includes investment cost, peak-valley electricity price income, frequency regulation cost and frequency regulation reward income. The calculation formula is: = 投资 + 峰谷 + 调频成本 + 调频奖励； The calculation formula for the frequency modulation reward income is: ; Where: Frequency regulation mileage compensation income, in yuan is the total number of trading cycles in the FM market; For the power generation unit Frequency modulation mileage provided in each transaction cycle, in MW; For the The price is calculated based on the mileage result of each transaction cycle, in RMB / MW. For the power generation unit The average value of stability indicators for trading cycles; The investment cost calculation formula is: 投资= t； In the formula is the total investment cost of the system, in yuan; n is the system life in years; t is the usage time, in seconds; The peak-valley electricity price income refers to the system purchasing electricity from the grid for charging when the primary frequency regulation is at the valley electricity price, and selling electricity for discharging at the peak electricity price. 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.

[0025] For further information, see Figures 1 to 5 , the frequency modulation cost calculation formula is: 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频； The cost of thermal power frequency regulation comes from the increase in fuel consumption and equipment wear and tear, and the calculation formula is: ; In the formula The frequency modulation output power of the thermal power unit, in MW; is the electricity cost of thermal power units, in yuan / kW·h; is the frequency modulation duration, in seconds; is the mechanical wear cost of power frequency regulation, in yuan / MW; The cost of lithium batteries is composed of cycle life loss, energy efficiency loss and power conversion loss: ; In the formula is the total throughput energy of the frequency modulation process, in MW·h; The recyclable energy of the battery over its entire life cycle, in MW·h; is the initial investment cost of the battery, in yuan; is the charge and discharge efficiency; is the grid electricity price, in yuan / MW·h; Flywheel costs are power loss and bearing life: ; In the formula 功率损耗 is the electricity cost of the flywheel operation, in yuan / kW·h; N 启停 is the number of starts and stops during the frequency modulation process; N 寿命 The maximum number of starts and stops within the design life of the flywheel bearing; 轴承 is the bearing replacement cost, in yuan; Coordination frequency regulation costs 协调调频 Including control system communication, optimization algorithm operation and multi-energy coupling losses, calculated at 3% of the total cost.

[0026] For further information, see Figures 1 to 5 The system stability calculation in step 2 includes adjusting the rate k 1. Response time k 2. Adjustment accuracy k 3Three factors, the calculation formula is: ; ; ; ; In the formula is the adjustment rate indicator; is the response time indicator; To adjust the accuracy index; is the measured regulation speed of the unit, in MW / s; is the average standard regulation rate of AGC power generation units in the frequency regulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in seconds; is the adjustment error of the unit.

[0027] For further information, see Figures 1 to 5 The constraints in step three include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints, and thermal power unit ramp constraints.

[0028] For further information, see Figures 1 to 5 , 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: ; Where: is the maximum output power of the flywheel, in MW; is the charge state of the flywheel; is the frequency deviation, in Hz; is the flywheel droop coefficient, Dynamic adjustment; The charging and discharging power constraints of lithium batteries are: ; ; In the formula is the adaptive droop coefficient; is the base droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

[0029] In this embodiment, the grid frequency is monitored in real time. When the grid frequency fluctuates slightly, the flywheel and the lithium battery respond simultaneously to frequency modulation. When the grid frequency fluctuates greatly, the lithium battery and the thermal power unit respond simultaneously to frequency modulation.

[0030] When the grid frequency fluctuates slightly, a control strategy that prioritizes economy is adopted. When the grid frequency fluctuates significantly, a control strategy that prioritizes stability is adopted.

[0031] Specifically, the control strategy is adjusted by changing the weights of economy and stability in the objective function.

[0032] The objective function of this system is: K dgree ； In the formula F is the objective function; is the normalized system economy; K dgree is the stability of the system after normalization; , is the weight coefficient; The present invention adopts a dynamic weight optimization strategy, which takes an economy priority strategy when the grid frequency fluctuates slightly, and takes a stability priority strategy when the grid frequency fluctuates greatly.

[0033] The target weight is adjusted in real time according to the intensity of the power grid frequency fluctuation. The existing weight divided according to the magnitude of the frequency fluctuation can be further upgraded to a dynamic real-time adjustment weight.

[0034] α(t)= | |, β(t) = 1 - α(t); where α(t) is the stability weight and β(t) is the economic weight, which are dynamically adjusted according to the real-time frequency deviation Δ f (t). The higher the frequency deviation, the greater the stability weight.

[0035] The specific normalization equation is: = ; K dgree = ； In the formula is the maximum value of system economy, with the unit of yuan; is the minimum value of system economy, with the unit of yuan; is the maximum value of system stability; is the minimum value of system stability; , which is determined by historical data or initial population sampling.

[0036] To avoid overcharging and over-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 the lithium battery energy storage system. The specific control is as Figure 3 shown. The control strategy of the flywheel energy storage system is that when 0.7 < SOC < 1, it charges with a low droop coefficient and discharges with the maximum droop coefficient; when 0.3 ≤ SOC ≤ 0.7, it charges and discharges with the maximum droop coefficient; when 0 ≤ SOC ≤ 0.3, it discharges with a low droop coefficient and charges with the maximum droop coefficient. The control strategy of the lithium battery energy storage system is that when 0.8 ≤ SOC < 1, charging stops and it discharges with the maximum droop coefficient; when 0.55 < SOC < 0.8, it charges with a low droop coefficient and discharges with the maximum droop coefficient; when 0.45 ≤ SOC ≤ 0.55, it charges and discharges with the maximum droop coefficient; when 0.2 < SOC < 0.45, it discharges with a low droop coefficient and charges with the maximum droop coefficient; when 0 ≤ SOC < xxxx, it discharges stops and it charges with the maximum droop coefficient.

[0037] System economy includes investment cost, peak-valley electricity price revenue, frequency modulation cost, and frequency modulation reward revenue.

[0038] [[ID=*]] = 投资 + 峰谷 + 调频成本 + It should be noted that there is an unclear "xxxx" in the translation of item . Please check and correct the original text if necessary. 调频奖励； The investment cost is the investment cost obtained by dividing the energy storage investment cost of the flywheel energy storage system and the lithium battery of the system by their lifespan.

[0039] 投资= t； In the formula is the total investment cost of the system, in yuan; n is the system life in years; t It is the usage time, in seconds.

[0040] The peak-valley electricity price revenue refers to the system purchasing electricity from the grid for charging during valley electricity prices. Charging stops when the flywheel energy storage system's SOC is greater than 0.6, and when the lithium battery's SOC is greater than 0.55. During peak electricity prices, the system sells electricity for discharge. Discharging stops when the flywheel energy storage system's SOC is less than 0.4, and when the lithium battery's SOC is less than 0.45.

[0041] The frequency regulation cost is the additional energy consumption cost caused by the frequency regulation action and the loss cost of the energy storage equipment.

[0042] 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频； （1） The cost of thermal power frequency regulation mainly comes from the increase in fuel consumption and equipment wear and tear. The calculation formula is: ; In the formula The frequency modulation output power of the thermal power unit, in MW; The unit of cost per kilowatt-hour for thermal power generation is RMB / kW·h, which is usually obtained by fitting the coal consumption characteristic curve. is the frequency modulation duration, in seconds; is the mechanical wear cost of unit power frequency regulation, in yuan / MW.

[0043] (2) The cost of lithium batteries is composed of cycle life loss, energy efficiency loss and power conversion loss: ; In the formula is the total throughput energy of the frequency modulation process, in MW·h; The recyclable energy of the battery over its entire life cycle, in MW·h; is the initial investment cost of the battery, in yuan; is the charge and discharge efficiency; is the grid electricity price, in Yuan / MW·h.

[0044] (3) Flywheel costs are mainly based on power loss and bearing life: ; In the formula 功率损耗 is the electricity cost of the flywheel operation, in yuan / kW·h; N 启停 is the number of starts and stops during the frequency modulation process; N 寿命 The maximum number of starts and stops within the design life of the flywheel bearing; 轴承 is the bearing replacement cost, in yuan.

[0045] (4) Coordination of frequency regulation costs 协调调频 Including control system communication, optimization algorithm operation and multi-energy coupling losses, it can be estimated at 3% of the total cost.

[0046] The frequency adjustment reward income is the subsidy income for successful system frequency adjustment. The frequency adjustment mileage compensation calculation formula is: ; Where: Frequency regulation mileage compensation income, in yuan is the total number of trading cycles in the FM market; For the power generation unit Frequency modulation mileage provided in each transaction cycle, in MW; For the The price is calculated based on the mileage result of each transaction cycle, in RMB / MW. For the power generation unit The average value of the stability index over the trading cycle.

[0047] System stability includes regulation rate k 1. Response time k 2. Adjustment accuracy k 3Three factors, stability indicators The calculation formula is: ; ; ; ; Where: is the adjustment rate indicator; is the response time indicator; To adjust the accuracy index; is the measured regulation speed of the unit, in MW / s; is the average standard regulation rate of AGC power generation units in the frequency regulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in seconds; is the adjustment error of the unit.

[0048] System constraints include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints, and thermal power unit ramp constraints.

[0049] The power balance constraint is the balance between the system charging and discharging power and the required power, that is, P fly + P bat + P wheel = P load ; The frequency constraint means that the system frequency after frequency modulation must be controlled within the allowable range: ∣Δ f ( t )∣≤0.2Hz; Where Δ f ( t )for t The moment frequency deviation, in Hz.

[0050] The thermal power unit climbing constraint is to constrain the rate of increase of the thermal power unit output power: ; Where: R up is the maximum ramp rate, in MW / s; R down is the maximum ramp-down rate in MW / s.

[0051] 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.

[0052] ; The charge and discharge power constraint is that the flywheel and the lithium battery cannot output input power infinitely, and there is a maximum charge and discharge power, and the charge and discharge power cannot exceed the maximum charge and discharge power.

[0053] The flywheel charging and discharging power constraints are: ; Where: is the maximum output power of the flywheel, in MW; is the charge state of the flywheel; is the frequency deviation, in Hz; is the flywheel droop coefficient, Dynamic adjustment.

[0054] The charging and discharging power constraints of lithium batteries are: ; ; In the formula is the adaptive droop coefficient; is the base droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

[0055] The particle swarm optimization algorithm is used to solve the calculation and obtain the optimal control strategy. The steps for solving the capacity configuration model using the particle swarm optimization algorithm are as follows: (1) Set the initial population size of the particle swarm algorithm to 50, the maximum number of iterations to 100, the acceleration factors C1 and C2 to 1.5, and the maximum and minimum inertia factors to 1 and 0.5 respectively; (2) Initialize the population, randomly generate particles that meet the constraints, set the initial position and velocity of each particle to calculate the fitness value, and record the individual optimal position and optimal value of the particle and the global optimal position and optimal value of the particle swarm; (3) Start iterative calculation, update the speed and position of the particles, and process the boundary conditions of the particles. If the particles cross the boundary, they will be processed to obtain a new generation of particle populations. The fitness of each particle in the new generation of populations is compared with the current optimal solution, and the individual and global optimal solutions are updated; When the maximum number of iterations is met, the search process ends; the global optimal solution is output and the algorithm ends.

[0056] 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 scope of protection of the present invention.

Claims

1. A primary frequency regulation control method for thermal power units based on economic and stability optimization, characterized in that: The following steps are involved: Step 1: Detect grid frequency fluctuations. When the grid frequency fluctuations exceed the set normal range, each device is controlled to perform frequency modulation based on the magnitude of the grid frequency fluctuation and the SOC status of the energy storage device. Step 2: Optimize the dynamic droop coefficient of the energy storage device, calculate the system economy and stability, and obtain the optimal value of the objective function; Step 3: Set up a dynamic weight adjustment mechanism, which dynamically adjusts the weights of economy and stability according to the magnitude of grid frequency fluctuations, sets constraints, and uses a particle swarm algorithm to determine the optimal frequency regulation strategy.

2. The method for controlling primary frequency regulation of a thermal power unit based on economic performance and stability optimization according to claim 1, characterized in that: The objective function in step 2 is: K dgree ； In the formula F is the objective function; is the normalized system economy; K dgree is the stability of the system after normalization; , is the weight coefficient; The specific normalization equation is: = ； K dgree = ； In the formula is the maximum economic efficiency of the system, in yuan; is the minimum value of system economy, in yuan; is the maximum value of system stability; is the minimum value of system stability; , Determined through historical data and initial population sampling.

3. The primary frequency regulation control method for thermal power units based on economic and stability optimization according to claim 2 is characterized in that: The step 3 of setting up a dynamic weight adjustment mechanism includes: The existing weighting based on frequency fluctuations is upgraded to dynamic real-time weighting; α(t)=| |,β(t)=1-α(t); Economy and stability vary with real-time frequency deviation Δ f (t) Dynamic adjustment: the higher the frequency deviation, the greater the stability weight.

4. The method for controlling primary frequency regulation of a thermal power unit based on economic performance and stability optimization according to claim 1, characterized in that: The system economic calculation in step 2 includes investment cost, peak-valley electricity price income, frequency regulation cost and frequency regulation reward income. The calculation formula is: = 投资 + 峰谷 + 调频成本 + 调频奖励 ； The calculation formula for the frequency modulation reward income is: ； Where: Frequency regulation mileage compensation income, in yuan is the total number of trading cycles in the FM market; For the power generation unit Frequency modulation mileage provided in each transaction cycle, in MW; For the The price is calculated based on the mileage result of each transaction cycle, in RMB / MW. For the power generation unit The average value of stability indicators for trading cycles; The investment cost calculation formula is: 投资= t ； In the formula is the total investment cost of the system, in yuan; n is the system life in years; t is the usage time, in seconds; The peak-valley electricity price income refers to the system purchasing electricity from the grid for charging when the primary frequency regulation is at the valley electricity price, and selling electricity for discharging at the peak electricity price. 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.

5. The method for controlling primary frequency regulation of a thermal power unit based on economic performance and stability optimization according to claim 4, characterized in that: The frequency modulation cost calculation formula is: 调频成本 = 火电调频 + 锂电调频 + 飞轮调频 + 协调调频 ； The cost of thermal power frequency regulation comes from the increase in fuel consumption and equipment wear and tear, and the calculation formula is: ； In the formula The frequency modulation output power of the thermal power unit, in MW; is the electricity cost of thermal power units, in yuan / kW·h; is the frequency modulation duration, in seconds; is the mechanical wear cost of power frequency regulation, in yuan / MW; The cost of lithium batteries is composed of cycle life loss, energy efficiency loss and power conversion loss: ； In the formula is the total throughput energy of the frequency modulation process, in MW·h; The recyclable energy of the battery over its entire life cycle, in MW·h; is the initial investment cost of the battery, in yuan; is the charge and discharge efficiency; is the grid electricity price, in yuan / MW·h; Flywheel costs are power loss and bearing life: ； In the formula 功率损耗 is the electricity cost of the flywheel operation, in yuan / kW·h; N 启停 is the number of starts and stops during the frequency modulation process; N 寿命 The maximum number of starts and stops within the design life of the flywheel bearing; 轴承 is the bearing replacement cost, in yuan; Coordination frequency regulation costs 协调调频 Including control system communication, optimization algorithm operation and multi-energy coupling losses, calculated at 3% of the total cost.

6. The method for controlling primary frequency regulation of a thermal power unit based on economic performance and stability optimization according to claim 4, characterized in that: The system stability calculation in step 2 includes adjusting the rate k 1. Response time k 2. Adjustment accuracy k 3Three factors, the calculation formula is: ； ； ； ； In the formula is the adjustment rate indicator; is the response time indicator; To adjust the accuracy index; is the measured regulation speed of the unit, in MW / s; is the average standard regulation rate of AGC power generation units in the frequency regulation resource distribution area, in MW / s; is the response delay time of the power generation unit, in seconds; is the adjustment error of the unit.

7. The method for controlling primary frequency regulation of a thermal power plant based on economic performance and stability optimization according to claim 1, characterized in that: The constraints in step three include power balance constraints, SOC constraints, charge and discharge power constraints, frequency constraints, and thermal power unit ramp constraints.

8. The method for controlling primary frequency regulation of a thermal power plant based on economic performance and stability optimization according to claim 7, characterized in that: 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: ； Where: is the maximum output power of the flywheel, in MW; is the charge state of the flywheel; is the frequency deviation, in Hz; is the flywheel droop coefficient, Dynamic adjustment; The charging and discharging power constraints of lithium batteries are: ； ； In the formula is the adaptive droop coefficient; is the base droop coefficient; is the maximum output power of the lithium battery, in MW; is the discharge / charge efficiency.

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