Power plant circulating water pump frequency conversion speed regulation control method and system

Abstract

The invention relates to the technical field of steam turbine power generation, and discloses a power plant circulating water pump frequency conversion speed regulation control method and system, and the method comprises the steps: determining cleaning characteristic parameters according to the overall heat transfer coefficient of a steam turbine condenser; determining the current optimal vacuum degree of the steam turbine condenser according to the current load value of the steam turbine and the cleaning characteristic parameters; determining the rotating speed of the circulating water pump according to the current optimal vacuum degree of the steam turbine condenser, correcting the rotating speed of the circulating water pump according to the current circulating water inlet temperature, and performing variable-frequency speed regulation according to the corrected rotating speed of the circulating water pump; adjusting the rotating speed of the circulating water pump according to the power consumption value in the circulating water pump speed adjusting process to obtain the final rotating speed of the circulating water pump. The optimal vacuum degree of the steam turbine condenser can be accurately evaluated, meanwhile, frequency conversion speed regulation is conducted on the circulating water pump based on the optimal vacuum degree, the steam exhaust pressure of a steam turbine is kept at the most favorable vacuum position as much as possible, and economic operation of a unit is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of steam turbine power generation, and more specifically, to a variable frequency speed regulation control method and system for a circulating water pump in a power plant. Background Art

[0002] According to the social electricity consumption and power supply coal consumption of 333g / (kW·h) in 2010, every 1g / (kW·h) reduction in power supply coal consumption of coal-fired power plants can save 3.4×106t of standard coal each year, which has significant economic benefits.

[0003] Therefore, studying the optimal operation mode of the circulating water system is of great significance for saving power consumption and improving the economic benefits of the power plant. Summary of the invention

[0004] The present invention provides a variable frequency speed regulation control method and system for a circulating water pump in a power plant, which is used to solve the technical problem of low economic efficiency of the circulating water system in the prior art, including:

[0005] obtaining an overall heat transfer coefficient of a steam turbine condenser, and determining a cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser;

[0006] Obtaining the current load value of the steam turbine, and determining the optimal vacuum degree of the current steam turbine condenser according to the current load value of the steam turbine and the cleaning characteristic parameter;

[0007] Determine the speed of the circulating water pump according to the current optimal vacuum degree of the steam turbine condenser, obtain the current circulating water inlet temperature, correct the speed of the circulating water pump according to the current circulating water inlet temperature, and perform frequency conversion speed regulation according to the corrected circulating water pump speed;

[0008] The power consumption value of the circulating water pump during the speed regulation process is obtained, and the speed of the circulating water pump is adjusted according to the power consumption value of the circulating water pump during the speed regulation process to obtain the final speed of the circulating water pump.

[0009] Further, the determining of the cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser comprises:

[0010] Calculate the cleanliness factor of the condenser according to the overall heat transfer coefficient of the steam turbine condenser, and draw a cleanliness factor variation curve according to the change of the cleanliness factor of the condenser over time;

[0011] Obtaining a steam turbine power variation curve, and determining a curve correlation coefficient according to the steam turbine power variation curve and a corresponding cleanliness coefficient variation curve;

[0012] Perform curve fitting on the cleaning coefficient variation curve to obtain the cleaning coefficient prediction curve;

[0013] The average cleaning coefficient of the cleaning coefficient within a preset time period is determined according to the cleaning coefficient prediction curve, and the average cleaning coefficient is multiplied by the curve correlation coefficient to obtain the cleaning characteristic parameter.

[0014] Further, the curve correlation coefficient is determined according to the steam turbine power variation curve and the corresponding cleaning coefficient variation curve, including:

[0015] Calculate the correlation coefficient value of the steam turbine power variation curve based on the Pearson correlation coefficient algorithm to obtain the power correlation coefficient;

[0016] Calculate the correlation coefficient value of the corresponding cleaning coefficient change curve based on the Pearson correlation coefficient algorithm to obtain the cleaning correlation coefficient;

[0017] The power correlation coefficient and the cleaning correlation coefficient are added together, and the curve correlation coefficient is determined according to the sum of the power correlation coefficient and the cleaning correlation coefficient.

[0018] Further, the determining of the optimal vacuum degree of the current steam turbine condenser according to the current load value and the cleaning characteristic parameter of the steam turbine includes:

[0019] Determine the historical load value according to the historical operating condition data of the steam turbine, and draw a historical load-optimal vacuum relationship diagram according to the historical load value of the steam turbine and the corresponding optimal vacuum degree;

[0020] Clustering the data in the historical load-optimal vacuum relationship diagram to obtain several clusters;

[0021] Determine the benchmark working condition data according to the data point closest to the cluster center in each cluster, and obtain the historical cleaning coefficient of the benchmark working condition data;

[0022] Establish a training sample set based on the historical cleaning coefficient and historical load value of the benchmark working condition data and the corresponding optimal vacuum degree, establish an optimal vacuum degree evaluation model, and train the optimal vacuum degree evaluation model based on the training sample set;

[0023] The clean characteristic parameters and load value of the current steam turbine are obtained, and the clean characteristic parameters and load value of the current steam turbine are input into the trained optimal vacuum evaluation model to obtain the optimal vacuum of the current steam turbine condenser.

[0024] Furthermore, the data in the historical load-optimal vacuum degree relationship diagram is clustered to obtain several clusters, including:

[0025] Establish a data set based on the data points in the historical load-optimal vacuum relationship diagram, and randomly select k initial cluster centers of the data set;

[0026] Calculate the Euclidean distance from the data point in the data set to the initial cluster center, and divide each data point into the corresponding cluster according to the Euclidean distance from the data point in the data set to the initial cluster center;

[0027] Calculate the average value of the data points in each cluster, and re-determine the cluster center based on the average value of the data points in each cluster;

[0028] Repeat the above steps until the cluster center no longer changes or the number of iterations reaches the preset iteration threshold, and obtain k final cluster centers and corresponding clusters.

[0029] Further, determining the rotating speed of the circulating water pump according to the optimum vacuum degree of the current steam turbine condenser includes:

[0030] Obtaining the current vacuum degree of the condenser, calculating the difference between the optimal vacuum degree and the current vacuum degree, and determining whether the difference between the optimal vacuum degree and the current vacuum degree is greater than a first preset threshold;

[0031] If the difference between the optimal vacuum degree and the current vacuum degree is greater than a first preset threshold, the first speed is set as the speed of the circulating water pump;

[0032] If the difference between the optimal vacuum degree and the current vacuum degree is less than or equal to the first preset threshold, then determine whether the difference between the optimal vacuum degree and the current vacuum degree is greater than the second preset threshold;

[0033] If the difference between the optimal vacuum degree and the current vacuum degree is greater than a second preset threshold, the second speed is set as the speed of the circulating water pump;

[0034] If the difference between the optimal vacuum degree and the current vacuum degree is less than or equal to the second preset threshold, the third rotational speed is set as the rotational speed of the circulating water pump.

[0035] Furthermore, the circulating water pump speed is corrected according to the current circulating water inlet temperature, including:

[0036] The speed of the circulating water pump is corrected according to the current circulating water inlet temperature based on the speed correction formula. The speed correction formula is specifically:

[0037]

[0038] Among them, V is the corrected circulating water pump speed, V α is the initial circulating water pump speed, t α is the preset temperature standard value, t is the current circulating water inlet temperature, R is the preset constant, and exp is the natural exponential function.

[0039] Further, the adjusting the speed of the circulating water pump according to the power consumption value of the circulating water pump speed regulation process includes:

[0040] According to the change of power consumption value in the speed regulation process of the circulating water pump, a power consumption curve of the circulating water pump is drawn, a sliding time window is obtained, and the power consumption curve of the circulating water pump is divided according to the sliding time window to obtain several sub-power consumption curves;

[0041] Calculate the absolute value of the slope of the sub-power consumption curve, and determine the speed adjustment coefficient according to the absolute value of the slope of the sub-power consumption curve;

[0042] Multiply the speed adjustment coefficient by the corrected circulating water pump speed to obtain the final speed of the circulating water pump.

[0043] Further, the determining of the speed adjustment coefficient according to the absolute value of the slope of the sub-power consumption curve includes:

[0044] Obtain historical operation data of the circulating water pump, and set a slope threshold value according to the historical operation data of the circulating water pump;

[0045] Calculating the difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold, and screening out the sub-power consumption curve whose difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold is less than a third preset threshold;

[0046] The proportion of the number of the screened sub-power consumption curves in all the sub-power consumption curves is obtained, and the ratio of the proportion of the number of the screened sub-power consumption curves in all the sub-power consumption curves to the preset standard proportion is calculated to obtain the speed adjustment coefficient.

[0047] In order to achieve the above object, the present invention also provides a power plant circulating water pump variable frequency speed regulation control system, comprising:

[0048] An acquisition module, used for acquiring an overall heat transfer coefficient of a steam turbine condenser, and determining a cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser;

[0049] An evaluation module, used for obtaining a current load value of the steam turbine, and determining an optimal vacuum degree of a current steam turbine condenser according to the current load value of the steam turbine and a cleaning characteristic parameter;

[0050] The speed control module is used to determine the speed of the circulating water pump according to the current optimal vacuum degree of the steam turbine condenser, obtain the current circulating water inlet temperature, correct the circulating water pump speed according to the current circulating water inlet temperature, and perform frequency conversion speed control according to the corrected circulating water pump speed;

[0051] The adjustment module is used to obtain the power consumption value of the circulating water pump during the speed regulation process, adjust the speed of the circulating water pump according to the power consumption value of the circulating water pump during the speed regulation process, and obtain the final speed of the circulating water pump.

[0052] The beneficial effects of the present invention are:

[0053] By applying the above technical scheme, the present invention evaluates the optimal vacuum in combination with the cleanliness factor of the condenser and the turbine load value, and can obtain a more accurate optimal vacuum degree. At the same time, the speed of the circulating water pump is corrected by the circulating water inlet temperature, and the speed is adjusted based on the power consumption value of the circulating water pump speed regulation process, so that the exhaust pressure of the turbine is maintained at the most favorable vacuum position as much as possible to ensure the economical operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0055] Figure 1 The overall flow chart of a variable frequency speed regulation control method for a circulating water pump in a power plant proposed in an embodiment of the present invention is shown;

[0056] Figure 2 The present invention shows a schematic structural diagram of a power plant circulating water pump variable frequency speed regulation control system proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] The present application embodiment provides a variable frequency speed regulation control method for a circulating water pump in a power plant, such as Figure 1 As shown, including:

[0059] S101, obtaining an overall heat transfer coefficient of a steam turbine condenser, and determining a cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser;

[0060] In some embodiments of the present application, the method of determining the cleaning characteristic parameters based on the overall heat transfer coefficient of the steam turbine condenser includes: calculating the cleaning coefficient of the condenser based on the overall heat transfer coefficient of the steam turbine condenser, and drawing a cleaning coefficient change curve based on the change of the cleaning coefficient of the condenser over time; obtaining the steam turbine power change curve, and determining the curve correlation coefficient based on the steam turbine power change curve and the corresponding cleaning coefficient change curve; performing curve fitting on the cleaning coefficient change curve to obtain a cleaning coefficient prediction curve; determining the average cleaning coefficient of the cleaning coefficient within a preset time period based on the cleaning coefficient prediction curve, and multiplying the average cleaning coefficient by the curve correlation coefficient to obtain the cleaning characteristic parameters.

[0061] In this embodiment, the cleanliness factor of the condenser is obtained by the overall heat transfer coefficient based on the empirical formula of the American Heat Transfer Society. Since the cleanliness factor of the condenser will affect the equipment performance of the turbine, the influence of the cleanliness factor on the turbine power is determined by calculating the turbine power change curve and the corresponding cleanliness factor change curve. The average cleanliness factor of the condenser in the future period is determined by the cleanliness factor prediction curve. The average cleanliness factor is corrected according to the influence of the cleanliness factor, which is convenient for the subsequent evaluation of the optimal vacuum degree.

[0062] In some embodiments of the present application, determining the curve correlation coefficient based on the turbine power change curve and the corresponding cleanliness coefficient change curve includes: calculating the correlation coefficient value of the turbine power change curve based on the Pearson correlation coefficient algorithm to obtain the power correlation coefficient; calculating the correlation coefficient value of the corresponding cleanliness coefficient change curve based on the Pearson correlation coefficient algorithm to obtain the cleanliness correlation coefficient; adding the power correlation coefficient and the cleanliness correlation coefficient, and determining the curve correlation coefficient based on the sum of the power correlation coefficient and the cleanliness correlation coefficient.

[0063] In this embodiment, the correlation coefficient values ​​of the two curves are calculated based on the Pearson correlation coefficient algorithm, and the curve correlation coefficient is obtained by normalizing the sum of the correlation coefficient values ​​of the two curves.

[0064] S102, obtaining a current load value of the steam turbine, and determining an optimal vacuum degree of the current steam turbine condenser according to the current load value of the steam turbine and a cleaning characteristic parameter;

[0065] In some embodiments of the present application, the method of determining the optimal vacuum of the current turbine condenser based on the current load value and cleaning characteristic parameters of the turbine includes: determining the historical load value based on the historical operating condition data of the turbine, and drawing a historical load-optimal vacuum relationship diagram based on the historical load value of the turbine and the corresponding optimal vacuum; clustering the data in the historical load-optimal vacuum relationship diagram to obtain a number of clusters; determining the benchmark operating condition data based on the data point closest to the cluster center in each cluster, and obtaining the historical cleaning coefficient of the benchmark operating condition data; establishing a training sample set based on the historical cleaning coefficient and historical load value of the benchmark operating condition data and the corresponding optimal vacuum, establishing an optimal vacuum evaluation model, and training the optimal vacuum evaluation model based on the training sample set; obtaining the cleaning characteristic parameters and load values ​​of the current turbine, and inputting the cleaning characteristic parameters and load values ​​of the current turbine into the trained optimal vacuum evaluation model to obtain the optimal vacuum of the current turbine condenser.

[0066] In this embodiment, by clustering the data in the historical load-optimal vacuum degree relationship diagram, benchmark project data in the historical operating condition data is obtained, a training sample set is established through the benchmark project data, and the optimal vacuum degree evaluation model is trained, which effectively ensures the accuracy of the evaluation results.

[0067] In some embodiments of the present application, the data in the historical load-optimal vacuum degree relationship diagram are clustered to obtain a number of clusters, including: establishing a data set based on the data points in the historical load-optimal vacuum degree relationship diagram, and randomly selecting k initial cluster centers of the data set; calculating the Euclidean distance from the data points in the data set to the initial cluster center, and dividing each data point into a corresponding cluster according to the Euclidean distance from the data point in the data set to the initial cluster center; calculating the average value of the data points in each cluster, and re-determining the cluster center according to the average value of the data points in each cluster; repeatedly iterating the above steps until the cluster center no longer changes or the number of iterations reaches a preset iteration threshold, to obtain k final cluster centers and corresponding clusters.

[0068] In this embodiment, the data points in the historical load-optimal vacuum degree relationship diagram are clustered based on the k-means clustering algorithm, and the value of k is determined by the number of data points. The more data points there are, the larger the k value is.

[0069] S103, determining the speed of the circulating water pump according to the current optimal vacuum degree of the steam turbine condenser, obtaining the current circulating water inlet temperature, correcting the speed of the circulating water pump according to the current circulating water inlet temperature, and performing frequency conversion speed regulation according to the corrected circulating water pump speed;

[0070] In some embodiments of the present application, determining the circulating water pump speed based on the current optimal vacuum of the turbine condenser includes: obtaining the current vacuum of the condenser, calculating the difference between the optimal vacuum and the current vacuum, and judging whether the difference between the optimal vacuum and the current vacuum is greater than a first preset threshold; if the difference between the optimal vacuum and the current vacuum is greater than the first preset threshold, setting the first speed as the circulating water pump speed; if the difference between the optimal vacuum and the current vacuum is less than or equal to the first preset threshold, judging whether the difference between the optimal vacuum and the current vacuum is greater than a second preset threshold; if the difference between the optimal vacuum and the current vacuum is greater than the second preset threshold, setting the second speed as the circulating water pump speed; if the difference between the optimal vacuum and the current vacuum is less than or equal to the second preset threshold, setting the third speed as the circulating water pump speed.

[0071] In this embodiment, the speed of the circulating water pump is set by the difference between the optimal vacuum degree and the current vacuum degree, the first speed> the second speed> the third speed, and the larger the difference, the higher the corresponding speed.

[0072] In some embodiments of the present application, the correcting the speed of the circulating water pump according to the current circulating water inlet temperature includes: correcting the speed of the circulating water pump according to the current circulating water inlet temperature based on a speed correction formula, wherein the speed correction formula is specifically:

[0073]

[0074] Among them, V is the corrected circulating water pump speed, V α is the initial circulating water pump speed, t α is the preset temperature standard value, t is the current circulating water inlet temperature, R is the preset constant, and exp is the natural exponential function.

[0075] In this embodiment, since the circulating water inlet temperature varies with the seasons and the higher the temperature, the worse the cooling effect, the rotation speed is corrected by the circulating water inlet temperature so that the target rotation speed of the circulating water pump reaches the best.

[0076] S104, obtaining the power consumption value of the circulating water pump during the speed regulation process, adjusting the speed of the circulating water pump according to the power consumption value of the circulating water pump during the speed regulation process, and obtaining the final speed of the circulating water pump.

[0077] In some embodiments of the present application, the speed of the circulating water pump is adjusted according to the power consumption value of the circulating water pump speed regulation process, including: drawing a circulating water pump power consumption curve according to the change of the power consumption value of the circulating water pump speed regulation process, obtaining a sliding time window, and dividing the circulating water pump power consumption curve according to the sliding time window to obtain a plurality of sub-power consumption curves; calculating the absolute value of the slope of the sub-power consumption curve, and determining the speed adjustment coefficient according to the absolute value of the slope of the sub-power consumption curve; multiplying the speed adjustment coefficient by the corrected circulating water pump speed to obtain the final speed of the circulating water pump.

[0078] In some embodiments of the present application, determining the speed adjustment coefficient based on the absolute value of the slope of the sub-power consumption curve includes: obtaining historical operating data of the circulating water pump, and setting a slope threshold based on the historical operating data of the circulating water pump; calculating the difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold, and screening out the sub-power consumption curve whose difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold is less than a third preset threshold; obtaining the proportion of the number of screened sub-power consumption curves in all sub-power consumption curves, calculating the ratio of the proportion of the number of screened sub-power consumption curves in all sub-power consumption curves to the preset standard proportion, and obtaining the speed adjustment coefficient.

[0079] In this embodiment, the power consumption curve of the circulating water pump during the most economical period is determined through the historical operation data of the circulating water pump, and the slope threshold is obtained through the slope value of the power consumption curve of the circulating water pump during the most economical period. The proportion of the number of sub-power consumption curves in all sub-power consumption curves is determined by real-time detection of the change in the power consumption value of the circulating water pump during the speed regulation process, thereby obtaining the difference between the power consumption value of the circulating water pump after speed regulation and the most economical power consumption value. The larger the difference, the farther the speed adjustment coefficient is from 1. The speed adjustment coefficient is used to adjust the corrected speed of the circulating water pump so that the circulating water pump reaches the optimal power consumption value, which can keep the exhaust pressure of the steam turbine at the most favorable vacuum position as much as possible to ensure the economical operation of the unit.

[0080] Based on the same technical concept, such as Figure 2 As shown, the present invention also provides a variable frequency speed regulation control system for a circulating water pump in a power plant, comprising:

[0081] An acquisition module is used to acquire the overall heat transfer coefficient of the steam turbine condenser and determine the cleaning characteristic parameters according to the overall heat transfer coefficient of the steam turbine condenser; an evaluation module is used to acquire the current load value of the steam turbine and determine the optimal vacuum degree of the current steam turbine condenser according to the current load value of the steam turbine and the cleaning characteristic parameters; a speed regulation module is used to determine the speed of the circulating water pump according to the optimal vacuum degree of the current steam turbine condenser, acquire the current circulating water inlet temperature, correct the speed of the circulating water pump according to the current circulating water inlet temperature, and perform frequency conversion speed regulation according to the corrected circulating water pump speed; an adjustment module is used to acquire the power consumption value of the circulating water pump speed regulation process, adjust the circulating water pump speed according to the power consumption value of the circulating water pump speed regulation process, and obtain the final speed of the circulating water pump.

[0082] By applying the above technical scheme, the present invention obtains the overall heat transfer coefficient of the steam turbine condenser, determines the cleaning characteristic parameters according to the overall heat transfer coefficient of the steam turbine condenser; obtains the current load value of the steam turbine, determines the optimal vacuum of the current steam turbine condenser according to the current load value of the steam turbine and the cleaning characteristic parameters; determines the speed of the circulating water pump according to the optimal vacuum of the current steam turbine condenser, obtains the current circulating water inlet temperature, corrects the speed of the circulating water pump according to the current circulating water inlet temperature, and performs variable frequency speed regulation according to the corrected circulating water pump speed; obtains the power consumption value of the circulating water pump speed regulation process, adjusts the speed of the circulating water pump according to the power consumption value of the circulating water pump speed regulation process, and obtains the final speed of the circulating water pump. The optimal vacuum of the steam turbine condenser can be accurately evaluated, and the circulating water pump can be variable frequency speed regulated based on the optimal vacuum, so that the exhaust pressure of the steam turbine is maintained at the most favorable vacuum position as much as possible to ensure the economic operation of the unit.

[0083] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present invention can be implemented by hardware, or by means of software plus a necessary general hardware platform. Based on such an understanding, the technical solution of the present invention can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.), including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each implementation scenario of the present invention.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A variable frequency speed control method for a circulating water pump in a power plant, characterized in that: include: obtaining an overall heat transfer coefficient of a steam turbine condenser, and determining a cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser; Obtaining the current load value of the steam turbine, and determining the optimal vacuum degree of the current steam turbine condenser according to the current load value of the steam turbine and the cleaning characteristic parameter; Determine the speed of the circulating water pump according to the current optimal vacuum degree of the steam turbine condenser, obtain the current circulating water inlet temperature, correct the speed of the circulating water pump according to the current circulating water inlet temperature, and perform frequency conversion speed regulation according to the corrected circulating water pump speed; The power consumption value of the circulating water pump during the speed regulation process is obtained, and the speed of the circulating water pump is adjusted according to the power consumption value of the circulating water pump during the speed regulation process to obtain the final speed of the circulating water pump.

2. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 1, characterized in that: The method of determining the cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser comprises: Calculate the cleanliness factor of the condenser according to the overall heat transfer coefficient of the steam turbine condenser, and draw a cleanliness factor variation curve according to the change of the cleanliness factor of the condenser over time; Obtaining a steam turbine power variation curve, and determining a curve correlation coefficient according to the steam turbine power variation curve and a corresponding cleanliness coefficient variation curve; Perform curve fitting on the cleaning coefficient variation curve to obtain the cleaning coefficient prediction curve; The average cleaning coefficient of the cleaning coefficient within a preset time period is determined according to the cleaning coefficient prediction curve, and the average cleaning coefficient is multiplied by the curve correlation coefficient to obtain the cleaning characteristic parameter.

3. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 2, characterized in that: Determining the curve correlation coefficient according to the turbine power variation curve and the corresponding cleaning coefficient variation curve includes: Calculate the correlation coefficient value of the steam turbine power variation curve based on the Pearson correlation coefficient algorithm to obtain the power correlation coefficient; Calculate the correlation coefficient value of the corresponding cleaning coefficient change curve based on the Pearson correlation coefficient algorithm to obtain the cleaning correlation coefficient; The power correlation coefficient and the cleaning correlation coefficient are added together, and the curve correlation coefficient is determined according to the sum of the power correlation coefficient and the cleaning correlation coefficient.

4. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 1, characterized in that: Determining the optimal vacuum degree of the current steam turbine condenser according to the current load value and the cleaning characteristic parameter of the steam turbine includes: Determine the historical load value according to the historical operating condition data of the steam turbine, and draw a historical load-optimal vacuum relationship diagram according to the historical load value of the steam turbine and the corresponding optimal vacuum degree; Clustering the data in the historical load-optimal vacuum relationship diagram to obtain several clusters; Determine the benchmark working condition data according to the data point closest to the cluster center in each cluster, and obtain the historical cleaning coefficient of the benchmark working condition data; Establish a training sample set based on the historical cleaning coefficient and historical load value of the benchmark working condition data and the corresponding optimal vacuum degree, establish an optimal vacuum degree evaluation model, and train the optimal vacuum degree evaluation model based on the training sample set; The clean characteristic parameters and load value of the current steam turbine are obtained, and the clean characteristic parameters and load value of the current steam turbine are input into the trained optimal vacuum evaluation model to obtain the optimal vacuum of the current steam turbine condenser.

5. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 4, characterized in that: The data in the historical load-optimal vacuum relationship diagram is clustered to obtain several clusters, including: Establish a data set based on the data points in the historical load-optimal vacuum relationship diagram, and randomly select k initial cluster centers of the data set; Calculate the Euclidean distance from the data point in the data set to the initial cluster center, and divide each data point into the corresponding cluster according to the Euclidean distance from the data point in the data set to the initial cluster center; Calculate the average value of the data points in each cluster, and re-determine the cluster center based on the average value of the data points in each cluster; Repeat the above steps until the cluster center no longer changes or the number of iterations reaches the preset iteration threshold, and obtain k final cluster centers and corresponding clusters.

6. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 1, characterized in that: Determining the rotating speed of the circulating water pump according to the optimum vacuum degree of the current steam turbine condenser comprises: Obtaining the current vacuum degree of the condenser, calculating the difference between the optimal vacuum degree and the current vacuum degree, and determining whether the difference between the optimal vacuum degree and the current vacuum degree is greater than a first preset threshold; If the difference between the optimal vacuum degree and the current vacuum degree is greater than a first preset threshold, the first speed is set as the speed of the circulating water pump; If the difference between the optimal vacuum degree and the current vacuum degree is less than or equal to the first preset threshold, then determine whether the difference between the optimal vacuum degree and the current vacuum degree is greater than the second preset threshold; If the difference between the optimal vacuum degree and the current vacuum degree is greater than a second preset threshold, the second speed is set as the speed of the circulating water pump; If the difference between the optimal vacuum degree and the current vacuum degree is less than or equal to the second preset threshold, the third rotational speed is set as the rotational speed of the circulating water pump.

7. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 6, characterized in that: The method of correcting the circulating water pump speed according to the current circulating water inlet temperature includes: The speed of the circulating water pump is corrected according to the current circulating water inlet temperature based on the speed correction formula. The speed correction formula is specifically: Among them, V is the corrected circulating water pump speed, V α is the initial circulating water pump speed, t α is the preset temperature standard value, t is the current circulating water inlet temperature, R is the preset constant, and exp is the natural exponential function.

8. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 1, characterized in that: The method of adjusting the speed of the circulating water pump according to the power consumption value of the circulating water pump speed regulation process includes: According to the change of power consumption value in the speed regulation process of the circulating water pump, a power consumption curve of the circulating water pump is drawn, a sliding time window is obtained, and the power consumption curve of the circulating water pump is divided according to the sliding time window to obtain several sub-power consumption curves; Calculate the absolute value of the slope of the sub-power consumption curve, and determine the speed adjustment coefficient according to the absolute value of the slope of the sub-power consumption curve; Multiply the speed adjustment coefficient by the corrected circulating water pump speed to obtain the final speed of the circulating water pump.

9. The variable frequency speed regulation control method for a circulating water pump in a power plant according to claim 8, characterized in that: Determining the speed adjustment coefficient according to the absolute value of the slope of the sub-power consumption curve includes: Obtain historical operation data of the circulating water pump, and set a slope threshold value according to the historical operation data of the circulating water pump; Calculating the difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold, and screening out the sub-power consumption curve whose difference between the absolute value of the slope of the sub-power consumption curve and the slope threshold is less than a third preset threshold; The proportion of the number of the screened sub-power consumption curves in all the sub-power consumption curves is obtained, and the ratio of the proportion of the number of the screened sub-power consumption curves in all the sub-power consumption curves to the preset standard proportion is calculated to obtain the speed adjustment coefficient.

10. A variable frequency speed control system for a circulating water pump in a power plant, characterized in that: include: An acquisition module, used for acquiring an overall heat transfer coefficient of a steam turbine condenser, and determining a cleaning characteristic parameter according to the overall heat transfer coefficient of the steam turbine condenser; An evaluation module, used for obtaining a current load value of the steam turbine, and determining an optimal vacuum degree of a current steam turbine condenser according to the current load value of the steam turbine and a cleaning characteristic parameter; The speed control module is used to determine the speed of the circulating water pump according to the optimal vacuum degree of the current steam turbine condenser, obtain the current circulating water inlet temperature, correct the circulating water pump speed according to the current circulating water inlet temperature, and perform frequency conversion speed control according to the corrected circulating water pump speed; The adjustment module is used to obtain the power consumption value of the circulating water pump during the speed regulation process, adjust the speed of the circulating water pump according to the power consumption value of the circulating water pump during the speed regulation process, and obtain the final speed of the circulating water pump.

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