Thermal Control Method for Assessment of Generation Plan Curve on Thermal Power Generation Exemption Days

Abstract

A thermal control method for reducing or exempting daily power generation plan curve assessments for thermal power generation includes the following steps: Step 1: Add a clock synchronization plug-in; Step 2: Differentiate the front-end control method for reducing daily power generation plan curve assessment costs for thermal power generation between normal and abnormal grid frequency conditions, employ data analysis to determine whether every 5-minute hourly value will be assessed, and implement preemptive control measures; Step 3: Calculate a power deviation signal and a time deviation signal. The power deviation signal represents the deviation between actual power and the power command, while the time deviation signal represents the difference between the actual time and the next 5-minute hourly value. When both the time deviation and the power deviation signal are activated, the power deviation signal, after being corrected by the time deviation signal and a piecewise function, is applied to the integrated valve position command, actuating the turbine valve. By establishing a front-end control strategy for reducing daily power generation plan curve assessment costs for thermal power generation, the post-analysis-based control strategy is improved to a daily power generation plan curve assessment control strategy that incorporates front-end control, process correction, and post-optimization.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid dispatching, and in particular to a thermal control method for assessing a thermal power generation exemption day power generation plan curve. Background Art

[0002] As we build a new power system dominated by renewable energy, thermal power plays an increasingly important role as a ballast. For example, the Central China Power Grid requires connected entities to strictly adhere to the daily power generation plan curve (including corrections) issued by the power dispatching agency. This curve is evaluated during normal operation and key power supply guarantee periods (January, July, August, December each year, and other important power supply guarantee periods), with double evaluations during these periods. The daily power generation plan curve evaluation range is ±2% of the daily power generation dispatch plan output curve.

[0003] As the proportion of renewable energy grows, deep peak regulation of thermal power plants will become more frequent, leading to lower daily power generation scheduling plans and a narrower tolerance for actual output deviations. This places higher demands on load control. Unlike traditional post-assessment analysis and improvements, there are currently no control strategies specifically designed to address power assessments caused by deviations from the daily power generation plan curve. To address this issue, we have proposed a front-end control strategy for thermal power plants to reduce the cost of daily power generation plan curve assessments. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a thermal control method for thermal power generation exemption from daily power generation plan curve assessment, so as to reduce the deviation of the daily power generation plan curve.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The thermal control method for evaluating the daily power generation plan curve for thermal power generation exemptions includes the following steps:

[0007] Step 1: Add a clock synchronization plug-in to ensure that the DCS clock is consistent with the load signal time of the electrical automation device transmitted to the power dispatching organization. The electrical automation device includes an RTU or PMU device.

[0008] Step 2: Differentiate the front-end control method for thermal power generation to reduce the daily power generation plan curve assessment costs between normal and abnormal grid frequency periods. Use data analysis to determine whether the 5-minute hourly value will be assessed, and implement preemptive control.

[0009] Step 3. Calculate the power deviation signal and time deviation signal. The power deviation signal is the deviation between the actual power and the power command, and the time deviation signal is the difference between the actual time and the next 5-minute hour.

[0010] When the time deviation is activated and the power deviation signal is activated, the power deviation signal is corrected by the time deviation signal and the piecewise function and acts on the comprehensive valve position instruction, which acts on the turbine valve.

[0011] The specific conditions for activating the power deviation in the above Step 3 are power deviation > |power command*2%| or power deviation <-|power command*2%|, that is, the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve.

[0012] The specific condition for activating the time deviation in the above Step 3 is that the time deviation is less than n seconds, where n seconds is the set value.

[0013] In Step 3 above, there are:

[0014] (1) When the frequency is normal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)1 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)1 piecewise function is larger. After the instruction is corrected by PID1, it is converted into a correction instruction for the appropriate integrated valve signal. The larger the correction instruction generated by the F(x)1 piecewise function, the larger the correction instruction generated by the integrated valve position signal. After the load correction limit judgment, it is input into the integrated valve position instruction signal, and finally acts on the regulating valves of each steam turbine.

[0015] (2) When the frequency is abnormal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)2 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)2 piecewise function is larger. After the instruction is corrected by PID2, it is converted into a correction instruction of the integrated valve signal within the set range. The larger the correction instruction generated by the F(x)2 piecewise function, the larger the correction instruction of the integrated valve position signal generated. After the load correction limit judgment, it is input into the integrated valve position instruction signal, and finally acts on each steam turbine valve.

[0016] In the above Step 3, when the grid frequency is normal, if the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve, real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the allowable deviation range.

[0017] In the above Step 3, when the grid frequency is abnormal, if the actual output deviation deviates in the same direction as the frequency change, real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation signal at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the load deviation in the same direction as the frequency change.

[0018] The activation conditions for the correction method in Step 3 above are: 1. The coordinated control function button is enabled, that is, CCS is enabled; 2. The power deviation correction function button is enabled.

[0019] The locking conditions of the correction method in the above Step 3 are: 1. Exit of the coordination mode; 2. Exit of the power deviation correction function; 3. RUNBACK action, that is, rapid load reduction start-up due to auxiliary machine failure; 4. Activation of the pressure control loop; 5. Power deviation exceeds the allowable action range; 6. Primary frequency regulation action; 7. DEH logic internal stress margin locking action, that is, turbine thermal stress margin locking action.

[0020] The present invention provides a thermal control method for reducing or exempting daily power generation plan curve assessment for thermal power generation. By setting a front-end control strategy for reducing the daily power generation plan curve assessment costs of thermal power generation, the post-analysis type is improved to a daily power generation plan curve assessment control strategy that includes front-end control, process correction, and post-optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below with reference to the accompanying drawings and examples:

[0022] Figure 1 This is a thermal logic principle diagram for reducing or exempting the daily power generation plan curve deviation assessment in the present invention. DETAILED DESCRIPTION

[0023] like Figure 1 As shown in , the thermal control method for evaluating the thermal power generation exemption daily power generation plan curve has the following control steps:

[0024] Step 1: Add a clock synchronization plug-in to ensure that the DCS clock is consistent with the load signal time of the electrical automation device transmitted to the power dispatching organization. The electrical automation device includes an RTU or PMU device.

[0025] Step 2: Differentiate the front-end control method for thermal power generation to reduce the daily power generation plan curve assessment costs between normal and abnormal grid frequency periods. Use data analysis to determine whether the 5-minute hourly value will be assessed, and implement preemptive control.

[0026] Step 3. Calculate the power deviation signal and time deviation signal. The power deviation signal is the deviation between the actual power and the power command, and the time deviation signal is the difference between the actual time and the next 5-minute hour.

[0027] When the time deviation is activated and the power deviation signal is activated, the power deviation signal is corrected by the time deviation signal and the piecewise function and acts on the comprehensive valve position instruction, which acts on the turbine valve.

[0028] The specific conditions for activating the power deviation in the above Step 3 are power deviation > |power command*2%| or power deviation <-|power command*2%|, that is, the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve.

[0029] The specific condition for activating the time deviation in the above Step 3 is that the time deviation is less than n seconds, where n seconds is the set value.

[0030] In Step 3 above, there are:

[0031] (1) When the frequency is normal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)1 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)1 piecewise function is larger. After the instruction is corrected by PID1, it is converted into a correction instruction for the appropriate integrated valve signal. The larger the correction instruction generated by the F(x)1 piecewise function, the larger the correction instruction generated by the integrated valve position signal. After the load correction limit judgment, it is input into the integrated valve position instruction signal, and finally acts on the regulating valves of each steam turbine.

[0032] (2) When the frequency is abnormal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)2 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)2 piecewise function is larger. After the instruction is corrected by PID2, it is converted into a correction instruction of the integrated valve signal within the set range. The larger the correction instruction generated by the F(x)2 piecewise function, the larger the correction instruction of the integrated valve position signal generated. After the load correction limit judgment, it is input into the integrated valve position instruction signal, and finally acts on each steam turbine valve.

[0033] In the above Step 3, when the grid frequency is normal, if the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve, real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the allowable deviation range.

[0034] In the above Step 3, when the grid frequency is abnormal, if the actual output deviation deviates in the same direction as the frequency change, real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation signal at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the load deviation in the same direction as the frequency change.

[0035] The activation conditions for the correction method in Step 3 above are: 1. The coordinated control function button is enabled, that is, CCS is enabled; 2. The power deviation correction function button is enabled.

[0036] The locking conditions of the correction method in the above Step 3 are: 1. Exit of the coordination mode; 2. Exit of the power deviation correction function; 3. RUNBACK action, that is, rapid load reduction start-up due to auxiliary machine failure; 4. Activation of the pressure control loop; 5. Power deviation exceeds the allowable action range; 6. Primary frequency regulation action; 7. DEH logic internal stress margin locking action, that is, turbine thermal stress margin locking action.

[0037] In the present invention, the specific discrimination indexes for normal and abnormal grid frequency are:

[0038] (1) Normal frequency judgment index: The frequency is higher than 49.90Hz and lower than 50.10Hz. At this time, the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve, and the assessment is based on twice the deviation power.

[0039] (2) Frequency abnormality judgment index: When the frequency is lower than 49.90Hz or higher than 50.10Hz, the actual output deviates from the planned output curve and no longer sets a 2% dead zone. That is, as long as the actual output deviates in the same direction as the frequency change, it will be assessed as 4 times the deviation power.

[0040] Example:

[0041] The above method was implemented in Xiangyang, Yicheng, and Nanchang. Data was collected from the Xiangyang Yicheng Power Plant during August 2023, a period when the plant was not participating in the electricity spot market and not conducting deep peak regulation. This period, spanning 18 days of operation, resulted in a power consumption assessment of 110MWh due to deviations from the daily power generation plan curve, with a daily average of 6MWh. After the implementation of this control strategy, a 6MWh daily power assessment reduction, calculated at 0.5 yuan per kilowatt-hour, resulted in an annual power assessment reduction of 2,190MWh, worth approximately 1.1 million yuan.

[0042] In the future, after participating in electricity spot market transactions or when the frequency of deep peak regulation increases, the daily power generation plan curve deviation assessment power will increase several times. When the control method is put into operation, according to the 5-fold basic assessment calculation, the annual power assessment will be reduced by 10,950MWh, or about 5.5 million yuan.

Claims

1. A thermal control method for evaluating thermal power generation plan curves for reduction or exemption days, characterized in that: The control steps are: Step 1: Add a clock synchronization plug-in to ensure that the DCS clock is consistent with the load signal time of the electrical automation device transmitted to the power dispatching organization. The electrical automation device includes an RTU or PMU device. Step 2: Differentiate the front-end control method for thermal power generation to reduce the daily power generation plan curve assessment costs between normal and abnormal grid frequency periods. Use data analysis to determine whether the 5-minute hourly value will be assessed, and implement preemptive control. Step 3. Calculate the power deviation signal and time deviation signal. The power deviation signal is the deviation between the actual power and the power command, and the time deviation signal is the difference between the actual time and the next 5-minute hour. When the time deviation is activated and the power deviation signal is activated, the power deviation signal is corrected by the time deviation signal and the piecewise function and acts on the comprehensive valve position instruction, which acts on the turbine valve.

2. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 1 is characterized in that: The specific conditions for activating the power deviation in Step 3 are power deviation > |power instruction*2%| or power deviation <-|power instruction*2%|, that is, the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve.

3. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 2 is characterized in that: The specific condition for activating the time deviation in Step 3 is that the time deviation is less than n seconds, where n seconds is a set value.

4. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 3 is characterized in that: In Step 3, there are: (1) When the frequency is normal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)1 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)1 piecewise function is larger. After the instruction is corrected by PID1, it is converted into a correction instruction of a suitable integrated valve position signal. The larger the correction instruction generated by the F(x)1 piecewise function, the larger the correction instruction of the generated integrated valve position signal. After the load correction limit judgment, it is input into the integrated valve position instruction signal and finally acts on each turbine valve. (2) When the frequency is abnormal, when the time deviation is activated and the power deviation signal is activated, the power deviation signal is input into the F(x)2 piecewise function according to the time deviation signal to generate a corrected power deviation correction instruction. When the time deviation is smaller and the power deviation is larger, the correction instruction generated by the F(x)2 piecewise function is larger. After the instruction is corrected by PID2, it is converted into a correction instruction of the integrated valve position signal within the set range. The larger the correction instruction generated by the F(x)2 piecewise function, the larger the correction instruction of the integrated valve position signal generated. After the load correction limit judgment, it is input into the integrated valve position instruction signal, and finally acts on each turbine valve.

5. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 4 is characterized in that: In the aforementioned Step 3, when the grid frequency is normal, if the actual output deviation is greater than ±2% of the daily power generation scheduling plan curve, a real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the allowable deviation range.

6. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 4, characterized in that: In the aforementioned Step 3, when the grid frequency is abnormal, if the actual output deviation deviates in the same direction as the frequency change, a real-time trend analysis is performed based on the data of the time deviation signal and the power deviation signal. When it is determined that the power deviation signal at the hourly value every 5 minutes will be activated, the load instruction is corrected in advance to ensure that the actual load at the hourly value every 5 minutes does not exceed the load deviation in the same direction as the frequency change.

7. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 5, characterized in that: The activation conditions of the correction method in Step 3 are:

1. The coordinated control function button is turned on, that is, CCS is turned on; 2. The power deviation correction function button is turned on; conditions 1 and 2 must be met at the same time.

8. The thermal control method for thermal power generation exemption day power generation plan curve assessment according to claim 6, characterized in that: The locking conditions of the correction method in Step 3 are:

1. Exit of the coordination mode; 2. Exit of the power deviation correction function; 3. RUNBACK action, that is, rapid load reduction start-up due to auxiliary machine failure; 4. Activation of the pressure control loop; 5. Power deviation exceeds the allowable action range; 6. Primary frequency regulation action; 7. DEH logic internal stress margin locking action, that is, turbine thermal stress margin locking action; any one of conditions 1-7 can be met.

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