Liquefied natural gas safety monitoring data processing method

Abstract

The invention relates to the technical field of data monitoring, in particular to a liquefied natural gas safety monitoring data processing method, which comprises the following steps of: determining a suspected interference time period and a normal time period according to an initial interference factor, acquiring the maximum interference of a combined section, and further acquiring a first data interference degree of the combined section; acquiring a combustion sufficient factor sequence and an initial interference factor sequence corresponding to the suspected interference time period of which the duration is greater than a preset duration threshold value to acquire a second data interference degree, and acquiring a final relative interference degree according to a standard combustion sufficient factor and the second data interference degree; and obtaining an interference filtering factor according to the final relative interference degree and the first data interference degree so as to obtain the step length of a filter, and filtering the liquefied natural gas flow data at each moment by adopting the filter and carrying out anomaly detection on the liquefied natural gas flow data. According to the invention, accurate filtering can be realized, so that the anomaly detection of the liquefied natural gas flow data is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of data monitoring, and in particular to a method for processing liquefied natural gas safety monitoring data. Background Art

[0002] As a clean energy, liquefied natural gas (LNG) has shown outstanding advantages in the field of power generation. As a power generation fuel, LNG has been widely used in the power industry due to its high combustion efficiency and low pollution emissions. However, given the low temperature and flammable nature of LNG, its safety monitoring is particularly important.

[0003] In LNG power plants, accurate monitoring of LNG flow from the tank to the vaporizer is key to ensuring stable operation of the power plant and continuous output of stable electricity. This monitoring process not only helps maintain the correct LNG supply rate required by the vaporizer, but also ensures the ideal ratio of air to fuel, which is essential for achieving efficient and environmentally friendly combustion. However, during the flow of LNG, flow instabilities such as eddies and vortices may be encountered, which directly affect the accuracy of flow measurement. In addition, the violent reaction of LNG mixed with air after gasification and combustion may cause vibration of the LNG input pipeline, thereby interfering with the collection of flow data. These interference data will not only reduce the accuracy of flow monitoring, but may also have an adverse effect on the safety monitoring of liquefied natural gas. Therefore, in LNG power plants, effective measures must be taken to ensure accurate monitoring of LNG flow to ensure safe and stable operation of the power plant. Summary of the invention

[0004] In order to solve the technical problem that liquefied natural gas monitoring is not accurate enough, the purpose of the present invention is to provide a liquefied natural gas safety monitoring data processing method, and the technical solution adopted is as follows: Determine an initial interference factor corresponding to each liquefied natural gas flow data according to the liquefied natural gas flow data and the power generation data, and determine a suspected interference period and a normal period, and then obtain a merged section, a maximum interference of the merged section, and a first data interference degree; The combustion sufficiency factor and the initial interference factor corresponding to the liquefied natural gas flow data at each moment in the suspected interference period whose duration is greater than the preset duration threshold are respectively used to form a combustion sufficiency factor sequence and an initial interference factor sequence, thereby obtaining a second data interference degree, and obtaining a final relative interference degree according to the average value of the combustion sufficiency factor corresponding to the liquefied natural gas flow data at each moment in the normal period and the second data interference degree; The interference filtering factor is obtained according to the final relative interference degree and duration and the interference degree and duration of each of the first data and the total duration of the power generation process, and then the step size of the filter is obtained. The filter is used to filter the liquefied natural gas flow data at each moment and then anomaly detection is performed to obtain anomaly values. The liquefied natural gas flow data corresponding to the anomaly value greater than the preset anomaly threshold is abnormal data.

[0005] Furthermore, the process of obtaining the initial interference factor includes: Acquire the power generation data corresponding to the liquefied natural gas flow data at each moment to form a power generation set; Selecting the liquefied natural gas flow data corresponding to the same power generation data in the power generation set to form a liquefied natural gas flow data set; Obtaining the mode of the liquefied natural gas flow data set as standard liquefied natural gas flow data; A normalized value of the absolute value of the difference between each of the liquefied natural gas flow data in the liquefied natural gas flow data set and the standard liquefied natural gas flow data is calculated as the initial interference factor.

[0006] Furthermore, the process of acquiring the suspected interference period and the normal period includes: The time corresponding to when the initial interference factor is greater than the first preset value or less than the second preset value is taken as the suspected interference time; The adjacent suspected interference moments constitute the suspected interference period, and the adjacent non-suspected interference moments constitute the normal period.

[0007] Further, obtaining the maximum interference of the merged segment includes: Obtaining a first minimum value and a first maximum value of the initial interference factor corresponding to the merged segment; Obtain a second minimum value between the first minimum value and a value obtained by subtracting the first maximum value from a third preset value; The value obtained by subtracting the second minimum value from the third preset value is used as the maximum interference of the merged segment.

[0008] Further, obtaining the first data interference degree of the merged segment includes: The number of interference moments in the merged segment is divided by the duration of the merged segment as a duration ratio, wherein the interference moment is a suspected interference moment in the suspected interference time period; Obtaining the sum of time intervals between adjacent suspected interference time periods in the merged segment; The first data interference degree is obtained by multiplying the duration ratio, the maximum interference, and the inverse of the sum of the time intervals in sequence.

[0009] Furthermore, the process of obtaining the combustion sufficiency factor includes: Obtaining first oxygen content data and first carbon monoxide content data in the air before combustion and second oxygen content data and second carbon monoxide content data in the air after combustion corresponding to the liquefied natural gas flow rate data at any time in any of the suspected interference time periods; The oxygen content ratio is obtained by subtracting the second oxygen content data from the first oxygen content data and then dividing the result by the first oxygen content data; The second carbon monoxide content data is subtracted from the first carbon monoxide content data, and then divided by the second carbon monoxide content data to obtain a carbon monoxide content ratio; The value obtained by subtracting the carbon monoxide content ratio from the third preset value is used as the carbon monoxide content change characteristic value, and the oxygen content ratio is used as the oxygen content change characteristic value; The average value of the carbon monoxide content change characteristic value and the oxygen content change characteristic value is calculated as the combustion completeness factor.

[0010] Furthermore, the process of obtaining the second data interference degree includes: The Pearson correlation coefficient between the combustion sufficiency factor sequence and the initial interference factor sequence is calculated and normalized to serve as the second data interference degree of the suspected interference period whose duration is greater than a preset duration threshold.

[0011] Furthermore, the process of obtaining the final relative interference degree includes: Calculating a second maximum value of the absolute value of the difference between the combustion sufficiency factor corresponding to the liquefied natural gas flow rate data and the standard combustion sufficiency factor in any of the suspected interference time periods; The second maximum value is multiplied by the duration of the suspected interference period and then normalized to obtain a normalized value. The normalized value is multiplied by the second data interference degree and then added to obtain the final relative interference degree.

[0012] Furthermore, the process of obtaining the interference filtering factor includes: The first factor is obtained by dividing the total duration of the merging segment by the total duration of the power generation process and then multiplying the result by the average value of the first data interference degree of the merging segment; The second factor is obtained by dividing the total duration of the suspected interference periods whose duration is greater than the preset duration threshold by the total duration of the power generation process and then multiplying the result by the average of the final relative interference levels of the suspected interference periods whose duration is greater than the preset duration threshold; The first factor and the second factor are added to obtain the interference filter factor.

[0013] Further, obtaining the step size of the filter according to the interference filtering factor includes: Normalizing the interference filtering factor to obtain an interference filtering normalized value, and multiplying the interference filtering normalized value by a preset weight to obtain a step size adjustment value; The step size of the filter is obtained by subtracting the step size adjustment value from the preset initial step size.

[0014] The present invention has the following beneficial effects: First, the initial interference factor corresponding to each liquefied natural gas flow data is determined according to the liquefied natural gas flow data and the power generation data, and the suspected interference period and the normal period are determined, and then the merging section, the maximum interference of the merging section and the first data interference degree are obtained. The merging section is the period of normal combustion in the power generation process. The greater the first data interference degree, the more serious the interference impact on the liquefied natural gas flow data corresponding to the merging section.

[0015] Secondly, the combustion sufficiency factor and the initial interference factor corresponding to the liquefied natural gas flow data at each moment in the suspected interference period whose duration is greater than the preset duration threshold are respectively used to form a combustion sufficiency factor sequence and an initial interference factor sequence, thereby obtaining a second data interference degree, and obtaining a final relative interference degree according to the mean value of the combustion sufficiency factor corresponding to the liquefied natural gas flow data at each moment in the normal period and the second data interference degree. The suspected interference period whose duration is greater than the preset duration threshold is a period of abnormal combustion in the power generation process, and the greater the final relative interference degree, the more serious the interference effect on the liquefied natural gas flow data corresponding to the suspected interference period whose duration is greater than the preset duration threshold.

[0016] Finally, according to the final relative interference degree and duration and the interference degree and duration of each of the first data and the total duration of the power generation process, the interference filtering factor is obtained, and then the step length of the filter is obtained, and the filter is used to filter the liquefied natural gas flow data at each moment and then perform abnormal detection to obtain abnormal values. The liquefied natural gas flow data corresponding to the abnormal value greater than the preset abnormal threshold is abnormal data. The interference filtering factor is used to adjust the step length of the filter, perform precise filtering, and perform abnormal detection on the liquefied natural gas flow data, which is an existing technology.

[0017] In summary, the present invention can accurately adjust the step size of the filter based on the degree of interference to the liquefied natural gas flow data to achieve precise filtering, so that the abnormality detection of the filtered liquefied natural gas flow data is more accurate, and if an abnormality is detected, an alarm can be issued in time and corresponding measures can be taken. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A flowchart of a liquefied natural gas safety monitoring data processing method provided by the first embodiment of the present invention; Figure 2 A flowchart of a process for obtaining an initial interference factor provided by a second embodiment of the present invention; Figure 3 A flowchart for determining a suspected interference period and a normal period according to the initial interference factor provided in the third embodiment of the present invention; Figure 4 A flowchart of a process for obtaining maximum interference provided by a fourth embodiment of the present invention; Figure 5 A flowchart of a process for obtaining a first data interference level provided by a fifth embodiment of the present invention; Figure 6 A flowchart of a combustion sufficiency factor acquisition process provided by a sixth embodiment of the present invention; Figure 7 A flowchart of a process for obtaining a final relative interference degree provided by a seventh embodiment of the present invention; Figure 8 A flowchart of a process for obtaining interference filtering factors provided by an eighth embodiment of the present invention; Fig. 9 This is a flow chart of a process for obtaining the step length of a filter provided by the ninth embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a liquefied natural gas safety monitoring data processing method proposed by the present invention, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0021] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0022] A specific scheme of a liquefied natural gas safety monitoring data processing method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0023] See also Figure 1 , which shows a flow chart of a method for processing liquefied natural gas safety monitoring data provided by the first embodiment of the present invention, the method comprising: S101. Determine an initial interference factor corresponding to each liquefied natural gas flow data according to the liquefied natural gas flow data and the power generation data, and determine a suspected interference period and a normal period, and then obtain a merged section, a maximum interference of the merged section, and a first data interference degree.

[0024] In the power generation process of the LNG power station, the present invention implements a set of precise data acquisition system to track and record key parameters in real time. The system automatically collects data every 5 seconds, including LNG flow data, oxygen content data and carbon monoxide content data before and after the gasified natural gas and air are mixed and burned corresponding to the LNG flow data, and the corresponding power generation data. Specifically, the LNG flow data is monitored by a high-precision flow meter, while the oxygen content data and carbon monoxide content data are measured by an advanced gas analyzer, and the power generation data is directly read by the electric meter.

[0025] To ensure stable combustion efficiency, a fixed pre-combustion air-fuel ratio is used to ensure that the fuel and oxygen are fully mixed. This ratio is pre-set based on the LNG flow data at each moment to ensure that the supply of mixed air is known and appropriate.

[0026] It is worth noting that there is a certain time delay in the series of processes from the change of LNG flow data to the change of oxygen content data and carbon monoxide content data after its gasification and mixing with air for combustion, to the final generation of electricity. These delays have been accurately measured through actual testing and calibration, and integrated into the algorithm of the combustion control system. With this information, operators and technicians can more accurately adjust fuel supply and air flow to maintain ideal combustion efficiency and stable power generation.

[0027] The specific process of power generation is: 1. LNG is transported to the power station by tank trucks and stored in cryogenic tanks.

[0028] 2. The stored liquefied natural gas will be converted into gaseous state through the vaporizer.

[0029] 3. The gasified liquefied natural gas is transported to the gas turbine. In the gas turbine, the liquefied natural gas is mixed with air and burned to produce high-temperature and high-pressure gas, which drives the blades of the gas turbine to rotate, thereby driving the generator connected to it to generate electricity.

[0030] 4. The exhaust gas from the gas turbine still has a relatively high temperature. This heat can be recovered through the waste heat boiler to generate steam.

[0031] 5. The steam generated is then sent to the steam turbine, which drives the blades of the steam turbine to rotate, further driving the generator to generate electricity.

[0032] Under normal conditions, there is a direct correlation between the LNG flow rate data and the power generation data. Specifically, an increase in the LNG flow rate often means that the combustion system of the power station has obtained more fuel supply, which in turn leads to a corresponding increase in power generation. Conversely, when the LNG flow rate decreases, the fuel supply decreases accordingly, resulting in a decrease in power generation.

[0033] In chronological order, merging is performed starting from the first suspected interference period whose duration is less than the preset duration threshold, until encountering the suspected interference period whose duration is not less than the preset duration threshold (the merging does not include the suspected interference period whose duration is not less than the preset duration threshold), then the merging is stopped to obtain a time-continuous merged segment, and then in the subsequent time, this merging operation is repeated to obtain several time-non-repeating merged segments, and the merged segment represents a period of sufficient (normal) combustion.

[0034] The process of obtaining the initial interference factor will be described in detail in the second embodiment and will not be repeated here.

[0035] Determining the suspected interference period and the normal period according to the initial interference factor will be described in detail in the third embodiment and will not be repeated here.

[0036] The process of obtaining the maximum interference will be described in detail in the fourth embodiment and will not be repeated here.

[0037] The process of obtaining the first data interference level will be described in detail in the fifth embodiment and will not be repeated here.

[0038] S102. The combustion sufficiency factor and the initial interference factor corresponding to the liquefied natural gas flow data at each moment in the suspected interference period whose duration is greater than the preset duration threshold are respectively used to form a combustion sufficiency factor sequence and an initial interference factor sequence, thereby obtaining a second data interference degree, and a final relative interference degree is obtained according to the average value of the combustion sufficiency factor corresponding to the liquefied natural gas flow data at each moment in the normal period and the second data interference degree.

[0039] The process of obtaining the combustion sufficiency factor will be described in detail in the sixth embodiment and will not be repeated here.

[0040] Specifically, the process of obtaining the second data interference degree includes: The Pearson correlation coefficient between the combustion sufficiency factor sequence and the initial interference factor sequence is calculated and normalized to serve as the second data interference degree of the suspected interference period whose duration is greater than a preset duration threshold.

[0041] Among them, the Pearson correlation coefficient is a well-known technology, and its value range is between -1 and 1. The closer it is to -1, the more negatively correlated the two sequences are.

[0042] The second data interference degree can be expressed as: ; Among them, the The Pearson correlation coefficient corresponding to the xth suspected interference period whose duration is greater than the preset duration threshold, The second data interference degree corresponding to the xth suspected interference period whose duration is greater than a preset duration threshold, Represents a normalization function, such as the range normalization function.

[0043] Since the initial interference factor should be negatively correlated with the combustion sufficiency factor when there is no interference and only affected by combustion, The larger the value is, the more serious the interference in the xth suspected interference period is. When the interference degree of the second data is greater, it is more necessary to filter out the interference accurately to reduce the error.

[0044] The process of obtaining the final relative interference degree will be described in detail in the seventh embodiment and will not be repeated here.

[0045] S103. Obtain an interference filtering factor according to the final relative interference degree and duration and the interference degree and duration of each of the first data and the total duration of the power generation process, and then obtain the step size of the filter, and use the filter to filter the liquefied natural gas flow data at each moment and then perform anomaly detection to obtain anomaly values. The liquefied natural gas flow data corresponding to the anomaly value greater than the preset anomaly threshold is abnormal data.

[0046] The process of obtaining the interference filtering factor will be described in detail in the eighth embodiment and will not be repeated here.

[0047] The process of obtaining the step length will be described in detail in the ninth embodiment and will not be repeated here.

[0048] Anomaly detection uses a data anomaly detection algorithm, which is an existing technology, such as the LOF algorithm. Algorithms such as Z-Score, box plot, and KNN may also be used.

[0049] When the data anomaly detection algorithm is the LOF algorithm, the anomaly threshold can be set independently, preferably 2.

[0050] When abnormal LNG flow data appears, an alarm can be issued in time and corresponding processing measures can be taken, such as promptly notifying maintenance personnel to adjust the LNG flow and check related equipment.

[0051] Figure 2 This is a flow chart of a process for obtaining an initial interference factor provided by a second embodiment of the present invention. The process for obtaining an initial interference factor includes: S201. Acquire the power generation data corresponding to the liquefied natural gas flow data at each moment to form a power generation set.

[0052] S202. Select the liquefied natural gas flow data corresponding to the same power generation data in the power generation set to form a liquefied natural gas flow data set.

[0053] It should be noted that there may be multiple liquefied natural gas flow data sets. For example, the same power generation data A may constitute a liquefied natural gas flow data set, and the same power generation data B may also constitute a liquefied natural gas flow data set.

[0054] S203. Obtain the mode of the liquefied natural gas flow data set as standard liquefied natural gas flow data.

[0055] It should be noted that, if there are multiple modes, the average value of the modes is calculated as the standard liquefied natural gas flow data.

[0056] S204. Calculate a normalized value of the absolute value of the difference between each liquefied natural gas flow data in the liquefied natural gas flow data set and the standard liquefied natural gas flow data as the initial interference factor.

[0057] The initial interference factor can be expressed as: ; Among them, the represents the bth liquefied natural gas flow data in the liquefied natural gas flow data set, To represent the standard liquefied natural gas flow data, the Represents a normalization function, such as the range normalization function.

[0058] The greater the absolute value of the difference between the liquefied natural gas flow rate data and the standard liquefied natural gas flow rate data, the more likely the liquefied natural gas flow rate data is interference data.

[0059] When LNG flows steadily from the tank to the gasifier, the change in power generation efficiency is mainly dominated by the combustion efficiency. Efficient combustion ensures that more electricity is produced with the same amount of LNG; conversely, inefficient combustion will lead to lower power generation efficiency even when the LNG flow rate is constant.

[0060] In the operation of LNG power plants, it is crucial to maintain the combustion efficiency at a high level and in a relatively stable range. However, in actual operation, various interference factors may be encountered, such as eddies, vortices or other flow instabilities generated during the flow of LNG, and violent reactions that may be caused when LNG is mixed with air after gasification and combustion. These may cause vibrations in the LNG input pipeline, thereby causing random interference in data collection. In addition, incomplete combustion (for example, efficiency exceeding 0.7 means fuel waste) or abnormally efficient combustion (for example, efficiency below 0.3 may cause overload problems, and the difficulty of fine operation and control increases, while increasing the risk of equipment damage and safety accidents) are also actual manifestations of unstable combustion. These problem data often reflect actual problems in the combustion process.

[0061] Figure 3 The flowchart of determining the suspected interference period and the normal period according to the initial interference factor provided in the third embodiment of the present invention, the acquisition process of the suspected interference period and the normal period includes: S301. The time corresponding to when the initial interference factor is greater than a first preset value or less than a second preset value is taken as a suspected interference time.

[0062] The first preset value can be set independently, preferably 0.7, and the second preset value can be set independently, preferably 0.3.

[0063] S302. The adjacent suspected interference moments constitute the suspected interference period, and the adjacent non-suspected interference moments constitute the normal period.

[0064] Figure 4 The flowchart of the process of obtaining the maximum interference provided by the fourth embodiment of the present invention, wherein obtaining the maximum interference of the merged segment includes: S401. Obtain a first minimum value and a first maximum value of the initial interference factor corresponding to the merged segment.

[0065] is the first minimum value of the initial interference factor in the j-th merging segment, is the first maximum value of the initial interference factor in the jth merging segment.

[0066] S402. Obtain a second minimum value between the first minimum value and a value obtained by subtracting the first maximum value from the third preset value.

[0067] The second minimum value can be expressed as: ; Among them, the represents a function to find the minimum value, represents a third preset value, and the third preset value is 1.

[0068] S403: Subtract the second minimum value from the third preset value as the maximum interference of the merged segment.

[0069] The maximum interference can be expressed as: ; Among them, the represents the maximum interference of the j-th merging segment.

[0070] when The closer it is to 0, the more serious the incomplete combustion is in the jth merging section. The closer ,Right now The closer it is to 0, the more serious the combustion abnormality is in the jth merge segment. The smaller, The larger it is, the more severe the interference.

[0071] Figure 5 The flowchart of the process of obtaining the first data interference degree provided by the fifth embodiment of the present invention, wherein obtaining the first data interference degree of the merged segment includes: S501. Divide the number of interference moments in the merged segment by the duration of the merged segment as a duration ratio, wherein the interference moment is a suspected interference moment in the suspected interference time period.

[0072] The duration ratio can be expressed as: , wherein the represents the duration of the jth merged segment, It represents the number of interference moments in the jth merged segment, that is, the sum of the durations of the suspected interference time periods in the merged segment.

[0073] S502. Obtain the sum of time intervals between adjacent suspected interference time periods in the merged segment.

[0074] The sum of the time intervals can be expressed as: ; Among them, the is the time interval between the tth and t+1th suspected interference periods in the jth merged segment whose duration is less than the preset duration threshold, and T represents the number of suspected interference periods in the jth merged segment whose duration is less than the preset duration threshold.

[0075] S503. The duration ratio, the maximum interference, and the inverse of the sum of the time intervals are multiplied in sequence to obtain the first data interference degree.

[0076] The first data interference degree can be expressed as: ; Among them, the represents the first data interference degree of the j-th merged segment, the represents the maximum interference of the j-th merging segment, Represents a normalization function, such as the range normalization function.

[0077] Among them, the The larger the value is, the greater the proportion of interference moments in the j-th merging segment (combustion full (normal) period) is, and the more serious the interference is. The smaller, that is The larger the value is, the more concentrated the interference moments are in the j-th merged segment, and the more serious the interference impact is.

[0078] Figure 6 This is a flow chart of a combustion sufficiency factor acquisition process provided by a sixth embodiment of the present invention, wherein the combustion sufficiency factor acquisition process includes: S601. Obtain first oxygen content data and first carbon monoxide content data in the air before combustion and second oxygen content data and second carbon monoxide content data in the air after combustion corresponding to the liquefied natural gas flow data at any time in any of the suspected interference time periods.

[0079] The first oxygen content data in the air before combustion corresponding to the liquefied natural gas flow data at the yth moment in the xth suspected interference period is expressed as: , the first carbon monoxide content data is expressed as And the second oxygen content data in the post-combustion air is expressed as And the second carbon monoxide content data is expressed as .

[0080] S602: After subtracting the second oxygen content data from the first oxygen content data, the resultant data is divided by the first oxygen content data to obtain an oxygen content ratio.

[0081] The oxygen content ratio can be expressed as: ; Ideally, complete combustion will consume all the oxygen in the air, that is, if the oxygen content data before combustion is The second oxygen content data after full combustion is 20%. Should be 0%, so for 1 indicates complete combustion. The remaining 5% (15 / 20) is smaller, indicating incomplete combustion.

[0082] S603: After subtracting the first carbon monoxide content data from the second carbon monoxide content data, the resultant data is divided by the second carbon monoxide content data to obtain a carbon monoxide content ratio.

[0083] The carbon monoxide content ratio can be expressed as: ; S604. The value obtained by subtracting the carbon monoxide content ratio from the third preset value is used as the carbon monoxide content change characteristic value, and the oxygen content ratio is used as the oxygen content change characteristic value.

[0084] The carbon monoxide content variation characteristic value can be expressed as: ; Among them, the represents a third preset value, and the third preset value is 1.

[0085] Ideally, complete combustion produces carbon dioxide and water vapor, with almost no carbon monoxide or other incomplete combustion products. The second carbon monoxide content data after full combustion is 5%. Still 5%, so is 0, for , indicating complete combustion. If the second carbon monoxide content data after combustion Increased to 7%, indicating incomplete combustion, at this time (2 / 7) is larger, and The smaller it is, the less fully burned it is.

[0086] S605. Obtain an average value of the carbon monoxide content change characteristic value and the oxygen content change characteristic value as the combustion completeness factor.

[0087] The combustion completeness factor can be expressed as: ; Among them, the The combustion sufficiency factor corresponding to the liquefied natural gas flow data at the yth moment in the xth suspected interference period.

[0088] Ideally, complete combustion means that all the fuel reacts with enough oxygen to produce carbon dioxide and water vapor, with little carbon monoxide or other products of incomplete combustion, that is, the oxygen in the air is consumed and there is no increase in carbon monoxide. The closer it is to 1, the more oxygen is consumed after combustion. Close to 0, indicating that there is no increase in carbon monoxide after combustion, so The larger it is, the more complete the combustion is. In reality, it is impossible for the fuel to burn 100% and it will stabilize at a higher percentage.

[0089] Throughout the LNG power generation process, the power station strives to maintain the combustion efficiency within an optimal range through precise fuel and air ratio control, efficient combustion equipment and advanced monitoring technology.

[0090] Therefore, in the event of incomplete or abnormally sufficient combustion (suspected interference period with a duration greater than or equal to the preset duration threshold), in-depth analysis must be conducted to determine the root cause of the abnormal combustion. When filtering out these interference factors, it is necessary to reduce errors as much as possible. For example, when eddies, vortices or other instabilities generated by liquefied natural gas during the flow process, as well as vibrations in the input pipeline, may cause interference during both normal and abnormal combustion periods, the filtering of interference during periods of incomplete or abnormally sufficient combustion must be particularly precise to ensure the accuracy of the data. To this end, a more detailed further analysis should be conducted on the suspected interference period with a duration greater than or equal to the preset duration threshold.

[0091] Figure 7 This is a flow chart of a process for obtaining a final relative interference degree provided by a seventh embodiment of the present invention. The process for obtaining a final relative interference degree includes: S701. Calculate the second maximum value of the absolute value of the difference between the combustion sufficiency factor corresponding to the liquefied natural gas flow rate data and the standard combustion sufficiency factor in any of the suspected interference time periods.

[0092] The second maximum value can be expressed as: ; Among them, the represents the second maximum value corresponding to the xth suspected interference period, represents the combustion sufficiency factor corresponding to the liquefied natural gas flow data at the yth moment in the xth suspected interference period, represents the standard combustion completeness factor, the represents a function for finding the maximum value, Represents a function that finds the absolute value.

[0093] Said It represents the maximum degree of incomplete combustion or abnormal combustion in the xth suspected interference period (ie, a continuous incomplete combustion process or abnormal complete combustion process).

[0094] S702. Multiply the second maximum value by the duration of the suspected interference period and then perform normalization processing to obtain a normalized value, multiply the normalized value by the second data interference degree, and then add the second data interference degree to obtain the final relative interference degree.

[0095] The final relative interference degree can be expressed as: ; Among them, the represents the second data interference degree corresponding to the xth suspected interference period, represents the duration of the xth suspected interference period, represents a normalization function, such as a range normalization function, Represents the final relative interference level corresponding to the xth suspected interference time period.

[0096] Figure 8 The flowchart of the process of obtaining the interference filtering factor provided by the eighth embodiment of the present invention includes: S801. Divide the total duration of the merged segment by the total duration of the power generation process, and then multiply the result by the average value of the first data interference degree of the merged segment to obtain a first factor.

[0097] The first factor can be expressed as: ; Among them, the represents the total duration of the merged segment, represents the total duration of the power generation process, Indicates the average value of the first data interference degree of the merged segment.

[0098] S802. Divide the total duration of the suspected interference periods whose duration is greater than the preset duration threshold by the total duration of the power generation process, and then multiply by the average of the final relative interference levels of the suspected interference periods whose duration is greater than the preset duration threshold to obtain a second factor.

[0099] The second factor can be expressed as: ; Among them, the Indicates the total duration of the suspected interference period whose duration is greater than the preset duration threshold, represents the total duration of the power generation process, The average value of the final relative interference degree of the suspected interference time periods whose duration is greater than a preset duration threshold.

[0100] S803. Add the first factor and the second factor to obtain the interference filtering factor.

[0101] The interference filtering factor can be expressed as: ; Wherein, the K represents the interference filtering factor.

[0102] The proportion of normal combustion and abnormal combustion duration in the power generation process and The K value is used as the weight to perform weighted summation on the interference degree. The larger the K value is, the more accurate the interference needs to be filtered out during the power generation process.

[0103] The filter may be a minimum mean square error filter to filter out interference from the liquefied natural gas flow data during the power generation process, or may be a moving average filter, an exponential smoothing filter, or other algorithms to filter out interference. All of the above are well-known technologies.

[0104] When using the minimum mean square error filter, the size of the step size is the main parameter of the minimum mean square error filter, and the step size is usually selected between 0 and 1. A step size that is too small will lead to slow convergence, while a step size that is too large may cause instability. When there are more key data (data when combustion is incomplete or abnormally sufficient) and the data interference is more serious, a smaller step size is required to avoid the filter from overreacting to the interference data, thereby maintaining the stability of the filter, and a smaller step size helps the filter track the desired signal more smoothly. When there are fewer key data and the data interference is not serious, a larger step size needs to be selected so that the filter can converge to the optimal solution faster.

[0105] Fig. 9 The flowchart of the process of obtaining the step length of the filter provided by the ninth embodiment of the present invention, wherein obtaining the step length of the filter according to the interference filtering factor includes: S901. Normalize the interference filtering factor to obtain an interference filtering normalized value, and multiply the interference filtering normalized value by a preset weight to obtain a step size adjustment value.

[0106] The step size adjustment value can be expressed as , wherein K represents the interference filter factor, Represents the preset weight, which can be set independently and is preferably 0.1.

[0107] S902. Subtract the step size adjustment value from the preset initial step size to obtain the step size of the filter.

[0108] The step size can be expressed as: ; Among them, the represents the initial step length, which can be set independently, preferably 0.2, and M represents the step length.

[0109] When the initial step size is 0.2 and the preset weight is 0.1, the step size can be expressed as: .

[0110] The present invention has the following beneficial effects: First, the initial interference factor corresponding to each liquefied natural gas flow data is determined according to the liquefied natural gas flow data and the power generation data, and the suspected interference period and the normal period are determined, and then the merging section, the maximum interference of the merging section and the first data interference degree are obtained. The merging section is the period of normal combustion in the power generation process. The greater the first data interference degree, the more serious the interference impact on the liquefied natural gas flow data corresponding to the merging section.

[0111] Secondly, the combustion sufficiency factor and the initial interference factor corresponding to the liquefied natural gas flow data at each moment in the suspected interference period whose duration is greater than the preset duration threshold are respectively used to form a combustion sufficiency factor sequence and an initial interference factor sequence, thereby obtaining a second data interference degree, and obtaining a final relative interference degree according to the mean value of the combustion sufficiency factor corresponding to the liquefied natural gas flow data at each moment in the normal period and the second data interference degree. The suspected interference period whose duration is greater than the preset duration threshold is a period of abnormal combustion in the power generation process, and the greater the final relative interference degree, the more serious the interference effect on the liquefied natural gas flow data corresponding to the suspected interference period whose duration is greater than the preset duration threshold.

[0112] Finally, according to the final relative interference degree and duration and the interference degree and duration of each of the first data and the total duration of the power generation process, the interference filtering factor is obtained, and then the step length of the filter is obtained, and the filter is used to filter the liquefied natural gas flow data at each moment and then perform abnormal detection to obtain abnormal values. The liquefied natural gas flow data corresponding to the abnormal value greater than the preset abnormal threshold is abnormal data. The interference filtering factor is used to adjust the step length of the filter, perform precise filtering, and perform abnormal detection on the liquefied natural gas flow data, which is an existing technology.

[0113] In summary, the present invention can accurately adjust the step size of the filter based on the degree of interference to the liquefied natural gas flow data to achieve precise filtering, so that the abnormality detection of the filtered liquefied natural gas flow data is more accurate, and if an abnormality is detected, an alarm can be issued in time and corresponding measures can be taken.

[0114] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0115] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for processing liquefied natural gas safety monitoring data, characterized in that: The method comprises: Determine an initial interference factor corresponding to each liquefied natural gas flow data according to the liquefied natural gas flow data and the power generation data, and determine a suspected interference period and a normal period, and then obtain a merged section, a maximum interference of the merged section, and a first data interference degree; The combustion sufficiency factor and the initial interference factor corresponding to the liquefied natural gas flow data at each moment in the suspected interference period whose duration is greater than the preset duration threshold are respectively used to form a combustion sufficiency factor sequence and an initial interference factor sequence, thereby obtaining a second data interference degree, and obtaining a final relative interference degree according to the average value of the combustion sufficiency factor corresponding to the liquefied natural gas flow data at each moment in the normal period and the second data interference degree; The interference filtering factor is obtained according to the final relative interference degree and duration and the interference degree and duration of each of the first data and the total duration of the power generation process, and then the step size of the filter is obtained. The filter is used to filter the liquefied natural gas flow data at each moment and then anomaly detection is performed to obtain anomaly values. The liquefied natural gas flow data corresponding to the anomaly value greater than the preset anomaly threshold is abnormal data.

2. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: The process of obtaining the initial interference factor includes: Acquire the power generation data corresponding to the liquefied natural gas flow data at each moment to form a power generation set; Selecting the liquefied natural gas flow data corresponding to the same power generation data in the power generation set to form a liquefied natural gas flow data set; Obtaining the mode of the liquefied natural gas flow data set as standard liquefied natural gas flow data; A normalized value of the absolute value of the difference between each of the liquefied natural gas flow data in the liquefied natural gas flow data set and the standard liquefied natural gas flow data is calculated as the initial interference factor.

3. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: The process of acquiring the suspected interference period and the normal period includes: The time corresponding to when the initial interference factor is greater than the first preset value or less than the second preset value is taken as the suspected interference time; The adjacent suspected interference moments constitute the suspected interference period, and the adjacent non-suspected interference moments constitute the normal period.

4. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: Obtaining the maximum interference of the merged segment includes: Obtaining a first minimum value and a first maximum value of the initial interference factor corresponding to the merged segment; Obtain a second minimum value between the first minimum value and a value obtained by subtracting the first maximum value from a third preset value; The value obtained by subtracting the second minimum value from the third preset value is used as the maximum interference of the merged segment.

5. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: Acquiring a first data interference degree of the merged segment includes: The number of interference moments in the merged segment is divided by the duration of the merged segment as a duration ratio, wherein the interference moment is a suspected interference moment in the suspected interference time period; Obtaining the sum of time intervals between adjacent suspected interference time periods in the merged segment; The first data interference degree is obtained by multiplying the duration ratio, the maximum interference, and the inverse of the sum of the time intervals in sequence.

6. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: The process of obtaining the combustion sufficiency factor includes: Obtaining first oxygen content data and first carbon monoxide content data in the air before combustion and second oxygen content data and second carbon monoxide content data in the air after combustion corresponding to the liquefied natural gas flow rate data at any time in any of the suspected interference time periods; The oxygen content ratio is obtained by subtracting the second oxygen content data from the first oxygen content data and then dividing the result by the first oxygen content data; The second carbon monoxide content data is subtracted from the first carbon monoxide content data, and then divided by the second carbon monoxide content data to obtain a carbon monoxide content ratio; The value obtained by subtracting the carbon monoxide content ratio from the third preset value is used as the carbon monoxide content change characteristic value, and the oxygen content ratio is used as the oxygen content change characteristic value; The average value of the carbon monoxide content change characteristic value and the oxygen content change characteristic value is calculated as the combustion completeness factor.

7. The liquefied natural gas safety monitoring data processing method according to claim 1, characterized in that: The process of obtaining the second data interference degree includes: The Pearson correlation coefficient between the combustion sufficiency factor sequence and the initial interference factor sequence is calculated and normalized to serve as the second data interference degree of the suspected interference period whose duration is greater than a preset duration threshold.

8. The method for processing liquefied natural gas safety monitoring data according to claim 1, characterized in that: The process of obtaining the final relative interference degree includes: Calculating a second maximum value of the absolute value of the difference between the combustion sufficiency factor corresponding to the liquefied natural gas flow rate data and the standard combustion sufficiency factor in any of the suspected interference time periods; The second maximum value is multiplied by the duration of the suspected interference period and then normalized to obtain a normalized value. The normalized value is multiplied by the second data interference degree and then added to obtain the final relative interference degree.

9. The method for processing liquefied natural gas safety monitoring data according to claim 1, characterized in that: The process of obtaining the interference filtering factor includes: The first factor is obtained by dividing the total duration of the merging segment by the total duration of the power generation process and then multiplying the result by the average value of the first data interference degree of the merging segment; The second factor is obtained by dividing the total duration of the suspected interference periods whose duration is greater than the preset duration threshold by the total duration of the power generation process and then multiplying the result by the average of the final relative interference levels of the suspected interference periods whose duration is greater than the preset duration threshold; The first factor and the second factor are added to obtain the interference filter factor.

10. The method for processing liquefied natural gas safety monitoring data according to claim 1, characterized in that: Obtaining the step size of the filter according to the interference filtering factor includes: Normalizing the interference filtering factor to obtain an interference filtering normalized value, and multiplying the interference filtering normalized value by a preset weight to obtain a step size adjustment value; The step size of the filter is obtained by subtracting the step size adjustment value from the preset initial step size.

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