Primary frequency modulation control method and comprehensive primary frequency modulation control method for coal-fired heat supply unit

Abstract

The invention provides a primary frequency modulation control method and a comprehensive primary frequency modulation control method for a coal-fired heat supply unit, and the method comprises the following steps: obtaining a primary frequency modulation reference signal, building power grid frequency measurement and coal-fired heat supply unit rotation speed measurement, fitting a power grid frequency signal and a steam turbine rotation speed signal, and obtaining a primary frequency modulation reference signal; responding to primary frequency modulation control by using the reference signal; a steam extraction heat regeneration system is established to participate in primary frequency modulation, and the station service power consumption rate is quickly increased and decreased by changing condensate pump power consumption in a short time, so that the power generator is controlled to quickly increase and decrease work to respond to primary frequency modulation control of a power grid; a heat supply system is established to participate in primary frequency modulation, and the instantaneous power generation power of the steam turbine is increased or decreased by adjusting the opening degree of a heat supply adjusting valve of the heat supply system. The primary frequency modulation capability of the unit is enhanced, the safety of the unit when the primary frequency modulation is put into operation can be improved, and the unit can quickly respond to maintain the stable operation of the power grid and protect the safety of the power grid and user equipment when the frequency of the power grid fluctuates.

Description

Technical Field

[0001] The present invention relates to the technical field of control of coal-fired heating units, and in particular to a primary frequency modulation control method and a comprehensive primary frequency modulation control method for coal-fired heating units. Background Art

[0002] The frequency of my country's power grid is usually stable at 50Hz. Since electricity cannot be stored, when the user's instantaneous power consumption is greater than the power generation, the power grid frequency will decrease. On the contrary, the power grid frequency will increase. Primary frequency regulation means that when the absolute value of the frequency difference (grid frequency - 50HZ) exceeds 0.033Hz, the thermal power plant needs to respond instantly and quickly increase or reduce the instantaneous power generation to maintain the grid frequency at 50Hz.

[0003] With the continuous growth of impact and nonlinear loads, power quality problems such as grid frequency reduction, voltage waveform distortion, voltage fluctuation, flicker and three-phase imbalance are becoming increasingly prominent, directly affecting the quality of electricity. Enhancing the primary frequency regulation capability of the unit can improve the safety of the unit when the primary frequency regulation is put into operation, ensure the quality of power and maintain the safety of the grid. In related technologies, the primary frequency regulation signal of the ultra-high pressure coal-fired heating unit is usually converted from the unit speed to the frequency (3000 divided by 60). When the primary frequency regulation is triggered, the control strategy usually adopts the fast opening or closing of the main steam valve of the steam turbine, and uses the rapid heat storage or release of the steam inside the pipeline to achieve the primary frequency regulation demand. However, in actual applications, on the one hand, due to the difference between the speed signal and the actual frequency acquisition signal of the power grid, the primary frequency regulation response of the ultra-high pressure coal-fired heating unit has a certain lag when it is in action, causing the primary frequency regulation process to fail to meet the two detailed assessment requirements; on the other hand, relying solely on the fast opening or closing of the main steam valve of the steam turbine to achieve primary frequency regulation requires the unit to retain part of the steam work capacity during actual operation, so that the unit is in a large throttling operation state for a long time, and the unit operation efficiency is low. Therefore, improving the accuracy of the frequency benchmark of the primary frequency regulation response of the ultra-high pressure coal-fired heating unit and improving the unit operation efficiency are important directions for the implementation of the new primary frequency regulation control method. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a primary frequency modulation control method and a comprehensive primary frequency modulation control method for a coal-fired heating unit. To achieve the above-mentioned purpose, the present invention adopts the following technical solutions: A primary frequency modulation control method for a coal-fired heating unit comprises the following steps: Obtain the primary frequency modulation reference signal, establish the grid frequency measurement and the coal-fired heating unit speed measurement, fit the grid frequency signal and the turbine speed signal, and respond to the primary frequency modulation control with the reference signal; Establish an extraction steam heat recovery system to participate in the primary frequency regulation, and achieve rapid increase or decrease in the plant power consumption rate by changing the power consumption of the condensing pump in a short time, thereby controlling the rapid increase or decrease in the work done by the generator to respond to the primary frequency regulation control of the power grid; Establish a heating system to participate in primary frequency regulation, and increase or decrease the instantaneous power generation of the steam turbine by adjusting the opening of the heating regulating valve of the heating system; The response time of the primary frequency control method does not exceed 2 seconds to meet the power system's requirement for rapid response.

[0005] Furthermore, a combination of hard measurement and soft measurement is used to obtain a primary frequency modulation reference signal; The hard measurement method is to use the actual measured grid frequency signal to replace the speed signal as the primary frequency modulation reference signal; The soft measurement method is based on a deep learning method to train the speed signal over a period of time and establish a precise speed-frequency model to provide a more accurate fitting frequency signal when the hard measurement device fails; When the hard measurement device fails or the measurement signal communication is abnormal, the primary frequency modulation reference frequency signal is automatically switched to the soft measurement frequency difference signal.

[0006] Furthermore, the hard measurement method also includes: Add a three-phase voltage high-frequency sampling signal at the generator outlet of the ultra-high voltage coal-fired heating unit, with a sampling frequency of 10,000 times per second, and calculate the grid frequency through fast Fourier transform; The actual communication process quantity adopts the frequency difference signal, that is, the difference between the actual calculated grid frequency value and 50Hz is measured by hard measurement; The validity of the frequency difference signal must satisfy the requirement that the measuring device is fault-free and the measuring signal communication is normal; A real-time monitoring system is established to monitor the status of the hard measurement device and trigger the switching mechanism immediately once a fault or communication abnormality is detected.

[0007] Furthermore, the soft measurement method also includes: The corresponding relationship between the speed signal and the actual grid frequency is established by data-driven method to obtain an accurate speed-frequency model; The model input uses the slip signal, i.e., the difference between the actual measured value of the turbine speed and 3000 revolutions, and the model output is synchronously replaced by the frequency difference signal, i.e., the difference between the frequency and 50 Hz; The training data of the soft sensor model comes from the unit's existing speed measurement and the historical frequency measurement data used for scheduling assessment. The training process includes data cleaning, feature selection, model training, verification and optimization. The soft-sensing model is updated regularly to adapt to changes in grid frequency characteristics and unit operating status.

[0008] Furthermore, the method of establishing the extraction steam heat recovery system to participate in primary frequency regulation includes: Conduct a primary frequency regulation characteristic test on the extraction steam heat recovery system to obtain the frequency regulation characteristics under different unit operating conditions; Establish a primary frequency modulation control strategy for the steam extraction heat recovery system, including establishing the corresponding relationship between the frequency difference and the condensate pump frequency and the recirculation valve opening under different loads, as well as the slow recovery process of the condensate pump frequency and the recirculation valve opening after the frequency modulation action is completed; During the primary frequency modulation process, the PID parameters of the deaerator water level, condenser water level and heater water level are adjusted to reduce the disturbance of the primary frequency modulation to the unit load and maintain the load operation stability of the unit.

[0009] Furthermore, the method of establishing the extraction steam heat recovery system to participate in primary frequency modulation also includes: Adjust the turbine sliding pressure curve and turbine regulating valve flow characteristics when the extraction steam regeneration system participates in frequency modulation; For different load conditions of 100%, 75%, 50%, 30%, and 20%, the frequency modulation characteristic test of the extraction steam heat recovery system was carried out respectively, and the frequency modulation characteristics under each condition were recorded and analyzed.

[0010] Furthermore, the frequency modulation characteristic test of the extraction heat recovery system is as follows: the frequency modulation characteristic test of the extraction heat recovery system of the ultra-high pressure coal-fired heating unit is carried out at 100%, 75%, 50%, 30% and 20% load respectively, and the unit is maintained to operate at 100%, 75%, 50%, 30% and 20% load conditions respectively, and the actual load value of the unit, the turbine regulating valve opening, the condensate flow rate, the condensate pump frequency, the low-pressure heater liquid level and the recirculation valve opening parameter value under the current unit operating condition are recorded, the condensate pump frequency is increased or decreased by 2-10Hz, and the turbine regulating valve opening is maintained unchanged, and the changes in the condensate flow rate and the actual load value of the unit within 1 minute after the condensate pump frequency changes are recorded, and the corresponding condensate flow rate change is calculated according to the frequency modulation characteristic test of the heat recovery system, and the condensate pump frequency or the recirculation valve opening is quickly adjusted in a feedforward manner to achieve rapid changes in the condensate flow rate, and the heat exchange of the heat recovery system is quickly increased or reduced to achieve the goal of rapid changes in the amount of steam doing work in the turbine.

[0011] Furthermore, the method of establishing a heating system to participate in primary frequency regulation includes: Conduct a primary frequency regulation characteristic test of the heating system to obtain the frequency regulation characteristics of the heating system under different unit operating conditions; Establish a primary frequency modulation control strategy for the heating system, including establishing the corresponding relationship between the frequency difference and the heating steam flow, heating steam pressure, and the opening of the heating regulating valve under different loads, as well as the slow recovery process of the opening of the heating regulating valve after the frequency modulation action is completed; During a frequency modulation action, the turbine sliding pressure curve and the flow characteristics of the turbine regulating valve are adjusted under the frequency modulation of the heating system.

[0012] Furthermore, the method of establishing a heating system to participate in primary frequency regulation also includes: For the positive large frequency difference condition, the boiler load of the unit is slightly increased according to the large frequency difference response load; Take transitional measures to set a maximum regulation rate limit.

[0013] A comprehensive primary frequency modulation control method for a coal-fired heating unit combines the above-mentioned method to establish a high-precision frequency signal reference, a steam extraction heat recovery system and a coordinated operation of a heating system.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The primary frequency modulation reference signal is obtained by combining hard measurement and soft measurement. In particular, the hard measurement method directly uses the measured grid frequency signal instead of the speed signal, which can significantly improve the timeliness of the primary frequency modulation response. Compared with the traditional method based on the speed signal, this method reduces the lag caused by the difference between the speed signal and the actual frequency acquisition signal of the power grid, ensuring that the primary frequency modulation action can be completed within 2 seconds, meeting the rapid response requirements of the power system; 2. The power consumption rate of the plant can be increased or decreased rapidly by changing the power consumption of the condensing pump in a short time, thereby controlling the rapid increase or decrease of the work done by the generator. Compared with the traditional method that relies on the fast opening or closing of the main steam valve of the steam turbine, this method does not require the unit to retain some steam work capacity during actual operation, reduces the long-term throttling operation state, and improves the operating efficiency of the unit.

[0015] 3. By improving the primary frequency regulation response speed and accuracy, it can more effectively respond to instantaneous changes in grid frequency and maintain the grid frequency at around 50Hz, thereby improving power quality and reducing power quality problems such as voltage waveform distortion, voltage fluctuation, flicker and three-phase imbalance.

[0016] 4. Enhancing the primary frequency regulation capability of the unit can improve the safety of the unit when the primary frequency regulation is put into operation, ensuring that the unit can respond quickly when the grid frequency fluctuates, maintain the stable operation of the grid, and protect the safety of the grid and user equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 is a structural block diagram of an embodiment of the present invention; Figure 2 A structural block diagram of a high-precision frequency signal reference implementation under all working conditions of an embodiment of the present invention; Figure 3This is a structural block diagram of the steam extraction heat recovery system participating in a primary frequency modulation process according to an embodiment of the present invention. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0019] Please refer to Figure 1 As shown, a primary frequency modulation control method for a coal-fired heating unit comprises the following steps: Obtain a frequency modulation reference signal, establish grid frequency measurement and coal-fired heating unit speed measurement, and With turbine speed signal Fitting is performed to respond to the primary frequency modulation control with the reference signal, where the grid frequency Calculated from the three-phase voltage sampling signal by fast Fourier transform (FFT), the sampling frequency is 10,000 times per second, and the turbine speed With grid frequency The relationship is: ; Establish an extraction steam heat recovery system to participate in the primary frequency regulation, and achieve rapid increase or decrease in the plant power consumption rate by changing the power consumption of the condensing pump in a short time, thereby controlling the rapid increase or decrease in the work done by the generator to respond to the primary frequency regulation control of the power grid; Establish a heating system to participate in primary frequency regulation, and increase or decrease the instantaneous power generation of the steam turbine by adjusting the opening of the heating regulating valve of the heating system; The response time of the primary frequency control method shall not exceed 2 seconds to meet the power system's requirement for rapid response; During the implementation of a frequency modulation process, measures are taken to ensure the safety and stability of the system and to prevent over-regulation or malfunction.

[0020] In this embodiment, if Figure 2 As shown, the establishment of high-precision power grid frequency measurement adopts a combination of hard measurement and soft measurement; The hard measurement method is to replace the speed signal with the measured grid frequency signal as the primary frequency modulation reference signal to improve the response timeliness; The soft measurement method is based on deep learning, which uses a long short-term memory neural network (LSTM) or a convolutional neural network (CNN) and a polynomial modeling method to train the speed signal within a period of time and establish a precise speed-frequency model to provide a more accurate fitting frequency signal when the hard measurement device fails. When the hard measurement device fails or the measurement signal communication is abnormal, the primary frequency modulation reference frequency signal is automatically switched to the soft measurement frequency difference signal.

[0021] The hard measurement method also includes: Add a three-phase voltage high-frequency sampling signal at the generator outlet of the ultra-high voltage coal-fired heating unit, with a sampling frequency of 10,000 times per second, and calculate the grid frequency through fast Fourier transform; The actual communication process quantity adopts the frequency difference signal, that is, the difference between the actual calculated grid frequency value and 50Hz is measured by hard measurement; The validity of the frequency difference signal must satisfy the requirement that the measuring device is fault-free and the measuring signal communication is normal; A real-time monitoring system is established to monitor the status of the hard measurement device and trigger the switching mechanism immediately once a fault or communication abnormality is detected.

[0022] The soft measurement method also includes: The corresponding relationship between the speed signal and the actual grid frequency is established by data-driven method to obtain an accurate speed-frequency model; The model input uses the slip signal, i.e., the difference between the actual measured value of the turbine speed and 3000 revolutions, and the model output is synchronously replaced by the frequency difference signal, i.e., the difference between the frequency and 50 Hz; The training data of the soft sensor model comes from the unit's existing speed measurement and the historical frequency measurement data used for scheduling assessment. The training process includes data cleaning, feature selection, model training, verification and optimization to ensure the accuracy and reliability of the model. The soft-sensing model is updated regularly to adapt to changes in grid frequency characteristics and unit operating status.

[0023] In this embodiment, if Figure 3 As shown in the figure, the method of establishing an extraction steam heat recovery system to participate in primary frequency regulation includes: Conduct a primary frequency regulation characteristic test on the extraction steam heat recovery system to obtain the frequency regulation characteristics under different unit operating conditions; Establish a primary frequency modulation control strategy for the steam extraction heat recovery system, including establishing the corresponding relationship between the frequency difference and the condensate pump frequency and the recirculation valve opening under different loads, as well as the slow recovery process of the condensate pump frequency and the recirculation valve opening after the frequency modulation action is completed; In order to ensure the safety and stability of the system, the PID parameters of the deaerator water level, condenser water level and heater water level are adjusted during the primary frequency modulation action to reduce the disturbance of the primary frequency modulation action on the unit load and maintain the stability of the unit load operation.

[0024] Adjust the turbine sliding pressure curve and turbine regulating valve flow characteristics when the extraction heat recovery system participates in frequency modulation, reduce the sliding pressure curve setting value under 20%-100% load conditions, increase the valve opening of the turbine under corresponding load conditions, reduce the throttling degree of the turbine regulating valve, reduce the work change of the turbine regulating valve participating in primary frequency modulation, and improve the unit operation efficiency; For different load conditions of 100%, 75%, 50%, 30%, and 20%, the frequency modulation characteristic test of the extraction steam heat recovery system was carried out respectively, and the frequency modulation characteristics under each condition were recorded and analyzed to optimize the control strategy.

[0025] Sliding pressure curve setting value and valve opening The adjustment formula is: ; in, and are the initial sliding pressure curve setting value and valve opening, and is the adjustment coefficient, determined according to experimental data.

[0026] Specifically, the frequency modulation characteristic test of the steam extraction heat recovery system of the ultra-high pressure coal-fired heating unit was carried out at 100%, 75%, 50%, 30% and 20% load respectively, and the unit was maintained at 100%, 75%, 50%, 30% and 20% load conditions respectively. The actual load value of the unit, turbine regulating valve opening, condensate flow, condensate pump frequency, low-pressure heater liquid level, and recirculation valve opening parameter value under the current unit operating conditions were recorded, the condensate pump frequency was increased or decreased by 2-10Hz, and the turbine regulating valve opening was maintained unchanged. The changes in condensate flow and the actual load value of the unit within 1 minute after the condensate pump frequency changed were recorded, and the corresponding condensate flow change was calculated according to the heat recovery system frequency modulation characteristic test. The condensate pump frequency or recirculation valve opening was quickly adjusted in a feedforward manner to achieve rapid changes in condensate flow, and the heat exchange of the heat recovery system was quickly increased or reduced to achieve the goal of rapid changes in the amount of working steam in the turbine.

[0027] In this embodiment, the method for establishing a heating system participating in primary frequency modulation includes: Conduct a primary frequency regulation characteristic test of the heating system to obtain the frequency regulation characteristics of the heating system under different unit operating conditions.

[0028] Establish a primary frequency modulation control strategy for the heating system, including establishing the corresponding relationship between the frequency difference and the heating steam flow, heating steam pressure, and heating regulating valve opening under different loads, as well as the slow recovery process of the heating regulating valve opening after the frequency modulation action is completed.

[0029] In this embodiment, the condensate pump regulation mode is taken as an example of variable frequency regulation, and the steps of the primary frequency regulation characteristic test of the heating system are as follows: Step 1: Frequency modulation characteristic test of 100% load heating system of ultra-high pressure coal-fired heating unit. Maintain the unit operation at 100% load condition, and record the actual load value of the unit, turbine regulating valve opening, heating regulating valve opening, heating steam flow, heating steam pressure and other parameter values ​​under the current unit operation condition. Open / close the heating regulating valve opening by 2%-20%, maintain the turbine regulating valve opening unchanged, and record the changes in heating steam pressure, heating steam flow, and actual load value of the unit within 1 minute after the valve opening changes.

[0030] Step 2: Frequency modulation characteristic test of 75% load heating system of ultra-high pressure coal-fired heating unit. Maintain the unit under 75% load condition, and record the actual load value of the unit, turbine regulating valve opening, heating regulating valve opening, heating steam flow, heating steam pressure and other parameter values ​​under the current unit operating condition. Open / close the heating regulating valve opening by 2%-20%, maintain the turbine regulating valve opening unchanged, and record the changes in heating steam pressure, heating steam flow, and actual load value of the unit within 1 minute after the valve opening changes.

[0031] Step 3: Frequency modulation characteristic test of 50% load heating system of ultra-high pressure coal-fired heating unit. Maintain the unit to operate at 50% load, and record the actual load value of the unit, turbine regulating valve opening, heating regulating valve opening, heating steam flow, heating steam pressure and other parameter values ​​under the current unit operating conditions. Open / close the heating regulating valve opening by 2%-20%, maintain the turbine regulating valve opening unchanged, and record the changes in heating steam pressure, heating steam flow, and actual load value of the unit within 1 minute after the valve opening changes.

[0032] Step 4: Frequency modulation characteristic test of 30% load heating system of ultra-high pressure coal-fired heating unit. Maintain the unit to operate at 30% load condition, and record the actual load value of the unit, turbine regulating valve opening, heating regulating valve opening, heating steam flow, heating steam pressure and other parameter values ​​under the current unit operating condition. Open / close the heating regulating valve opening by 2%-15%, maintain the turbine regulating valve opening unchanged, and record the changes in heating steam pressure, heating steam flow, and actual load value of the unit within 1 minute after the valve opening changes.

[0033] Step 5: Frequency modulation characteristic test of 20% load heating system of ultra-high pressure coal-fired heating unit. Maintain the unit under 20% load condition, and record the actual load value of the unit, turbine regulating valve opening, heating regulating valve opening, heating steam flow, heating steam pressure and other parameter values ​​under the current unit operating condition. Open / close the heating regulating valve opening by 2%-15%, maintain the turbine regulating valve opening unchanged, and record the changes in heating steam pressure, heating steam flow, and actual load value of the unit within 1 minute after the valve opening changes.

[0034] In order to ensure the safety and stability of the system, the turbine sliding pressure curve and the flow characteristics of the turbine regulating valve under the frequency modulation of the heating system are adjusted during a frequency modulation action to reduce the throttling degree of the turbine regulating valve and improve the operating efficiency of the unit.

[0035] For the positive large frequency difference working condition, according to the large frequency difference response load, slightly increase the unit boiler load, restore the heating regulating valve opening as soon as possible, and maintain the quality stability of the heating system; In order to ensure the safety and stability of the system, transitional measures are taken to set a maximum adjustment rate limit to avoid system instability caused by rapid adjustment.

[0036] The present invention also provides a comprehensive primary frequency regulation control method for a coal-fired heating unit, which combines the above-mentioned method to establish a high-precision frequency signal reference, a steam extraction heat recovery system and a heating system for coordinated operation to improve the primary frequency regulation response speed and accuracy, while improving the unit's operating efficiency.

[0037] This comprehensive approach ensures fast response (no more than 2 seconds) of primary frequency modulation control, system safety and stability, and high energy efficiency.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A primary frequency modulation control method for a coal-fired heating unit, characterized in that: The following steps are involved: Obtain the primary frequency modulation reference signal, establish the grid frequency measurement and the coal-fired heating unit speed measurement, fit the grid frequency signal and the turbine speed signal, and respond to the primary frequency modulation control with the reference signal; Establish an extraction steam heat recovery system to participate in the primary frequency regulation, and achieve rapid increase or decrease in the plant power consumption rate by changing the power consumption of the condensing pump in a short time, thereby controlling the rapid increase or decrease in the work done by the generator to respond to the primary frequency regulation control of the power grid; Establish a heating system to participate in primary frequency regulation, and increase or decrease the instantaneous power generation of the steam turbine by adjusting the opening of the heating regulating valve of the heating system; The response time of the primary frequency control method does not exceed 2 seconds to meet the power system's requirement for rapid response.

2. A primary frequency modulation control method for a coal-fired heating unit according to claim 1, characterized in that: A combination of hard measurement and soft measurement is used to obtain a primary frequency modulation reference signal; The hard measurement method is to use the actual measured grid frequency signal to replace the speed signal as the primary frequency modulation reference signal; The soft measurement method is based on a deep learning method to train the speed signal over a period of time and establish a precise speed-frequency model to provide a more accurate fitting frequency signal when the hard measurement device fails; When the hard measurement device fails or the measurement signal communication is abnormal, the primary frequency modulation reference frequency signal is automatically switched to the soft measurement frequency difference signal.

3. A primary frequency modulation control method for a coal-fired heating unit according to claim 2, characterized in that: The hard measurement method also includes: Add a three-phase voltage high-frequency sampling signal at the generator outlet of the ultra-high voltage coal-fired heating unit, with a sampling frequency of 10,000 times per second, and calculate the grid frequency through fast Fourier transform; The actual communication process quantity adopts the frequency difference signal, that is, the difference between the actual calculated grid frequency value and 50Hz is measured by hard measurement; The validity of the frequency difference signal must satisfy the requirement that the measuring device is fault-free and the measuring signal communication is normal; A real-time monitoring system is established to monitor the status of the hard measurement device and trigger the switching mechanism immediately once a fault or communication abnormality is detected.

4. A primary frequency modulation control method for a coal-fired heating unit according to claim 2, characterized in that: The soft measurement method also includes: The corresponding relationship between the speed signal and the actual grid frequency is established by data-driven method to obtain an accurate speed-frequency model; The model input uses the slip signal, i.e., the difference between the actual measured value of the turbine speed and 3000 revolutions, and the model output is synchronously replaced by the frequency difference signal, i.e., the difference between the frequency and 50 Hz; The training data of the soft sensor model comes from the unit's existing speed measurement and the historical frequency measurement data used for scheduling assessment. The training process includes data cleaning, feature selection, model training, verification and optimization. The soft-sensing model is updated regularly to adapt to changes in grid frequency characteristics and unit operating status.

5. A primary frequency modulation control method for a coal-fired heating unit according to claim 1, characterized in that: Methods for establishing an extraction steam heat recovery system to participate in primary frequency regulation include: Conduct a primary frequency regulation characteristic test on the extraction steam heat recovery system to obtain the frequency regulation characteristics under different unit operating conditions; Establish a primary frequency modulation control strategy for the steam extraction heat recovery system, including establishing the corresponding relationship between the frequency difference and the condensate pump frequency and the recirculation valve opening under different loads, as well as the slow recovery process of the condensate pump frequency and the recirculation valve opening after the frequency modulation action is completed; During the primary frequency modulation process, the PID parameters of the deaerator water level, condenser water level and heater water level are adjusted to reduce the disturbance of the primary frequency modulation to the unit load and maintain the load operation stability of the unit.

6. A primary frequency modulation control method for a coal-fired heating unit according to claim 5, characterized in that: The method for establishing an extraction steam heat recovery system to participate in primary frequency regulation also includes: Adjust the turbine sliding pressure curve and turbine regulating valve flow characteristics when the extraction steam regeneration system participates in frequency modulation; For different load conditions of 100%, 75%, 50%, 30%, and 20%, the frequency modulation characteristic test of the extraction steam heat recovery system was carried out respectively, and the frequency modulation characteristics under each condition were recorded and analyzed.

7. A primary frequency modulation control method for a coal-fired heating unit according to claim 5, characterized in that: The frequency modulation characteristic test of the extraction heat recovery system is specifically as follows: the frequency modulation characteristic test of the extraction heat recovery system of the ultra-high pressure coal-fired heating unit is carried out at 100%, 75%, 50%, 30% and 20% load respectively, and the unit is maintained to operate at 100%, 75%, 50%, 30% and 20% load conditions respectively, and the actual load value of the unit, turbine regulating valve opening, condensate flow, condensate pump frequency, low-pressure heater liquid level and recirculation valve opening parameter value under the current unit operating condition are recorded, the condensate pump frequency is increased or decreased by 2-10Hz, and the turbine regulating valve opening is maintained unchanged, and the changes in condensate flow and actual load value of the unit within 1 minute after the condensate pump frequency changes are recorded, and the corresponding condensate flow change is calculated according to the frequency modulation characteristic test of the heat recovery system, and the condensate pump frequency or recirculation valve opening is quickly adjusted in a feedforward manner to achieve rapid changes in condensate flow, and the heat exchange of the heat recovery system is quickly increased or reduced to achieve the goal of rapid changes in the amount of steam doing work in the turbine.

8. A primary frequency modulation control method for a coal-fired heating unit according to claim 1, characterized in that: Methods for establishing heating system participation in primary frequency regulation include: Conduct a primary frequency regulation characteristic test of the heating system to obtain the frequency regulation characteristics of the heating system under different unit operating conditions; Establish a primary frequency modulation control strategy for the heating system, including establishing the corresponding relationship between the frequency difference and the heating steam flow, heating steam pressure, and the opening of the heating regulating valve under different loads, as well as the slow recovery process of the opening of the heating regulating valve after the frequency modulation action is completed; During a frequency modulation action, the turbine sliding pressure curve and the flow characteristics of the turbine regulating valve are adjusted under the frequency modulation of the heating system.

9. A primary frequency modulation control method for a coal-fired heating unit according to claim 8, characterized in that: Methods for establishing a heating system to participate in primary frequency regulation also include: For the positive large frequency difference condition, the boiler load of the unit is slightly increased according to the large frequency difference response load; Take transitional measures to set a maximum regulation rate limit.

10. A comprehensive primary frequency modulation control method for a coal-fired heating unit, characterized in that: In combination with the method according to any one of claims 1 to 9, a high-precision frequency signal reference, a steam extraction heat recovery system and a heating system are established to work in coordination.

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