A fire early warning method and system based on distributed optical fiber temperature sensing

Abstract

The application relates to the technical field of optical cable monitoring, and particularly discloses a fire early warning method and system based on distributed optical fiber temperature sensing, wherein after temperature partitioning in an optical cable monitoring area, temperature history following fluctuation analysis is performed on the temperature boundary of the optical cable monitoring area, the temperature dominant mode of the optical cable cross-zone point is determined, temperature comparison analysis of the optical cable cross-zone point is performed according to the temperature dominant mode of the optical cable cross-zone point, and it is judged whether the temperature early warning is triggered; if the temperature early warning is not triggered, temperature gradient comparison analysis of the optical cable cross-zone point and the temperature partition is performed, it is judged whether the temperature gradient early warning of the optical cable cross-zone point is triggered, if the temperature gradient early warning trigger type is a bilateral area trigger, over-temperature prediction analysis is performed based on the temperature gradient, and the temperature gradient early warning priority of the temperature partition is determined in combination with the temperature gradient comparison analysis result, and finally, the precise identification and efficient early warning processing of the fire risk of the overlapping boundary of the optical cable monitoring area are realized.

Description

Technical Field

[0001] This invention relates to the field of optical cable monitoring technology, specifically to a fire early warning method and system based on distributed optical fiber temperature sensing. Background Technology

[0002] Optical cable crossing points—that is, temperature monitoring points where optical cables cross the boundaries of different temperature zones—are critical weak links in fire early warning because they are located at the overlapping boundaries of two or more temperature zones. Existing technologies have significant limitations in monitoring such points:

[0003] Existing technologies typically classify cross-zone points simply based on geographical boundaries (e.g., applying the threshold of a zone if the point is close to a zone). However, the actual temperature of a cross-zone point is often affected by the combined effects of the environments of both zones (e.g., the combined effect of heat dissipation from workshop equipment and cooling from warehouse air conditioning). If it is forcibly classified into a single zone, it is easy to cause false alarms (e.g., judging normal temperature rise in the workshop based on the low threshold of the warehouse) or false alarms (e.g., ignoring abnormal high temperatures in the warehouse based on the high threshold of the workshop), which cannot accurately reflect the true risk of the cross-zone point.

[0004] Current early warning systems largely rely on whether the absolute temperature value exceeds a threshold. However, fire risks at cross-zone points often manifest as "temperatures not reaching the threshold but with abnormal heating rates" (e.g., smoldering flammable materials on the warehouse side causing rapid temperature increases at the cross-zone point within a short period). Due to the different thermal conduction characteristics of the environments on both sides of a cross-zone point, the normal range of its temperature gradient (temperature increase per unit time) differs from that of a single-sided area. Current technologies lack targeted gradient analysis, making it difficult to identify such hidden fire risks where "absolute values ​​are normal but changes are out of control."

[0005] When a cross-zone point is simultaneously affected by two zones, resulting in abnormal temperature gradients on both sides (such as overheating of workshop equipment and spontaneous combustion of warehouse materials causing temperature rise at the cross-zone point), existing technology cannot distinguish the urgency of the risks on both sides, and simply triggers an overall warning, making it difficult for maintenance personnel to determine the order of handling and delaying the best intervention opportunity in the early stage of a fire.

[0006] Therefore, the present invention provides a fire early warning method and system based on distributed optical fiber temperature sensing. Summary of the Invention

[0007] The purpose of this invention is to provide a fire early warning method and system based on distributed optical fiber temperature sensing to solve the problems mentioned above.

[0008] The objective of this invention can be achieved through the following technical solution: a fire early warning method based on distributed optical fiber temperature sensing, comprising the following steps:

[0009] Step 1: On the temperature boundaries after temperature zoning in the optical cable monitoring area, perform historical temperature fluctuation analysis of the optical cable crossing points to determine the temperature dominance mode of the optical cable crossing points. The temperature dominance mode includes unilateral region dominance and bilateral region dominance.

[0010] Step 2: Based on the temperature-dominant method of the optical cable crossing point, conduct a temperature comparison analysis of the optical cable crossing point to determine whether a temperature warning has been triggered at the optical cable crossing point;

[0011] Step 3: If no temperature warning is triggered, perform a temperature gradient comparison analysis between the optical cable crossing point and the temperature zone to determine whether the optical cable crossing point has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering.

[0012] Step 4: If the temperature gradient warning trigger type is bilateral region trigger, perform over-temperature prediction analysis based on the temperature gradient and determine the temperature gradient warning priority of the temperature zone by combining the temperature gradient comparison analysis results.

[0013] As a further aspect of the present invention: the process of performing temperature history tracking fluctuation analysis at the cross-regional points of the optical cable is as follows:

[0014] The temperature of the optical cable crossing point during the historical monitoring period and the temperature of the two temperature zones corresponding to the optical cable crossing point during the historical monitoring period are obtained.

[0015] The historical monitoring period is divided into several historical sub-periods of equal duration;

[0016] Based on the temperatures of the optical cable crossing point and temperature zone at the beginning and end of the historical sub-cycle, the temperature trends of the optical cable crossing point and temperature zone within the historical sub-cycle are determined respectively.

[0017] If the temperature trend of the optical cable crossing point and the temperature zone are the same within the historical sub-period, the historical sub-period is marked as the same trend sub-period, and the temperature fluctuation following value is obtained based on the same trend sub-period.

[0018] If the temperature fluctuation following values ​​between the optical cable crossing point and the corresponding two temperature zones are both greater than or equal to the temperature fluctuation following threshold, then the temperature dominance mode of the optical cable crossing point is bilateral region dominance.

[0019] If the temperature fluctuation following value between the optical cable crossing point and only one temperature zone is greater than or equal to the temperature fluctuation following threshold, then the temperature dominance mode of the optical cable crossing point is unilateral region dominance, and the temperature zone is marked as the comparison temperature zone.

[0020] As a further aspect of the present invention: the method for obtaining the temperature fluctuation tracking value is as follows:

[0021] The trend-following value is obtained by statistically analyzing the proportion of sub-cycles with the same trend in historical sub-cycles.

[0022] The temperatures of the cross-zone points and the temperatures of the temperature zones within the same trend sub-cycle are integrated into cross-zone point temperature sequences and zone temperature sequences according to time sequence.

[0023] Calculate the Pearson correlation coefficient between the cross-regional point temperature series and the regional temperature series;

[0024] If the Pearson correlation coefficient is within the preset range, then sub-cycles with the same trend are marked as related sub-cycles;

[0025] The degree of following is obtained by statistically analyzing the proportion of related sub-cycles in sub-cycles with the same trend.

[0026] The temperature fluctuation tracking value between the optical cable crossing point and the temperature zone is obtained by multiplying the trend tracking value and the degree tracking value.

[0027] As a further aspect of the present invention: the process of performing temperature comparison analysis at the cross-regional points of the optical cable is as follows:

[0028] If the temperature-dominant mode is unilateral region-dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning value of the comparison temperature zone;

[0029] If the temperature at the cross-regional point of the optical cable is greater than or equal to the temperature warning value, a temperature warning will be triggered; otherwise, a temperature warning will not be triggered.

[0030] If the temperature-dominant mode is dual-region dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning values ​​of the corresponding two temperature zones.

[0031] If the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning values ​​of the corresponding two temperature zones, or if the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning value of any temperature zone, then a temperature warning is triggered; otherwise, a temperature warning is not triggered.

[0032] As a further aspect of the present invention: the process of comparing and analyzing the temperature gradients at the optical cable crossing points and temperature zones includes:

[0033] If the temperature dominance mode of the optical cable crossing point is unilateral region dominance, the temperature gradient within the historical sub-cycle is determined based on the temperature at the beginning and end of the historical sub-cycle at the optical cable crossing point.

[0034] If the temperature gradient within a historical sub-cycle exceeds the normal temperature gradient range of the compared temperature partition, the historical sub-cycle will be marked as a temperature gradient super-boundary sub-cycle.

[0035] Based on the temperature gradient super-boundary sub-period processing, the temperature gradient over-frequency value and temperature gradient over-degree value are obtained, and then multiplied to obtain the temperature gradient warning value between the optical cable cross-zone point and the comparison temperature zone.

[0036] If the temperature dominance mode at the optical cable crossing point is bilateral region dominance, then the temperature gradient warning values ​​between the optical cable crossing point and the corresponding two temperature zones are calculated separately.

[0037] As a further aspect of the present invention: the process of determining whether a temperature gradient warning is triggered at the cross-regional point of the optical cable is as follows:

[0038] If the temperature gradient warning value between the optical cable crossing point and the temperature comparison zone is greater than or equal to the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and any temperature zone is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in a single area.

[0039] If the temperature gradient warning value between the cross-zone point of the optical cable and the corresponding two temperature zones is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in both areas.

[0040] If the temperature gradient warning value between the optical cable crossing point and the temperature zone being compared is less than the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and the corresponding two temperature zones is less than the temperature gradient warning threshold, then the temperature gradient warning will not be triggered.

[0041] As a further aspect of the present invention: the process of performing overheat prediction analysis based on temperature gradient is as follows:

[0042] Based on the fiber optic cable crossing point and any temperature zone;

[0043] If the temperature gradient at the cross-regional point of the optical cable exceeds the normal temperature gradient range of the temperature zone within the historical sub-period, the historical sub-period will be marked as a temperature gradient super-boundary sub-period.

[0044] Extract the temperature gradients of all temperature gradient superboundary sub-periods and summarize them into a temperature gradient superboundary sequence;

[0045] Calculate the coefficient of variation of the temperature gradient out-of-bounds sequence;

[0046] If the coefficient of variation is less than the preset coefficient of variation, the temperature gradient out-of-bounds sequence is averaged to obtain the predicted temperature gradient.

[0047] If the coefficient of variation is greater than or equal to the preset coefficient of variation, the maximum value in the temperature gradient superboundary sequence is extracted as the predicted temperature gradient.

[0048] As a further aspect of the present invention: the process of determining the temperature gradient early warning priority of the temperature zone is as follows:

[0049] The temperature deviation between the temperature at the cross-zone point of the optical cable and the temperature warning value of the temperature zone is calculated, and the ratio is calculated with the predicted temperature gradient to obtain the time it takes for the temperature at the cross-zone point of the optical cable to reach the temperature warning value of the temperature zone, which is the predicted temperature warning time.

[0050] Calculate the ratio of the predicted temperature warning duration to the total predicted temperature warning duration to obtain the warning duration ratio;

[0051] The ratio of the temperature gradient warning value and the warning duration between the optical cable crossing point and the temperature zone is calculated to obtain the warning priority value of the temperature zone.

[0052] Compare the warning priority values ​​of temperature zones to determine the warning priority of temperature gradients in each temperature zone.

[0053] As a further aspect of the present invention: the total duration of the predicted temperature warning is the sum of the duration for which the temperature at the cross-regional point of the optical cable reaches the temperature warning value of each temperature zone.

[0054] A fire early warning system based on distributed fiber optic temperature sensing includes the following modules:

[0055] Cross-zone temperature dominance analysis module: After dividing the optical cable monitoring area into temperature zones, the module performs historical temperature fluctuation analysis of cross-zone points to determine the temperature dominance mode of the cross-zone points. The temperature dominance mode includes single-sided dominance and double-sided dominance.

[0056] Temperature warning trigger judgment module: Based on the temperature dominance mode of the optical cable crossing point, perform temperature comparison analysis of the optical cable crossing point to determine whether the optical cable crossing point has triggered a temperature warning;

[0057] Cross-zone temperature gradient triggering analysis module: If no temperature warning is triggered, the temperature gradient comparison analysis between the cross-zone point of the optical cable and the temperature zone is performed to determine whether the cross-zone point of the optical cable has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering.

[0058] Cross-zone temperature gradient early warning priority analysis module: If the temperature gradient early warning trigger type is bilateral zone triggering, the over-temperature prediction analysis is performed based on the temperature gradient, and the temperature gradient comparison analysis results are combined to determine the temperature gradient early warning priority of the temperature zone.

[0059] The beneficial effects of this invention are as follows: At the temperature boundaries after temperature zoning in the optical cable monitoring area, historical temperature fluctuation analysis is performed on the cross-zone points of the optical cable to determine the dominant temperature pattern at these points. This dominant pattern includes unilateral and bilateral temperature dominance. Based on the dominant temperature pattern, a temperature comparison analysis is performed on the cross-zone points to determine whether a temperature warning has been triggered. If no temperature warning has been triggered, a temperature gradient comparison analysis is performed between the cross-zone points and the temperature zones to determine whether a temperature gradient warning has been triggered. The temperature gradient warning triggering types include unilateral and bilateral temperature triggering. If a temperature gradient warning has been triggered... The warning triggering type is bilateral region triggering. Based on temperature gradient, over-temperature prediction analysis is performed, and the temperature gradient comparison analysis results are combined to determine the temperature gradient warning priority of temperature zones. This invention analyzes the dominant relationship between cross-zone point temperature and unilateral or bilateral regions, and selects the corresponding temperature zone for temperature warning according to the dominant relationship. This improves the accuracy of fire warning at the overlapping boundary of optical cable monitoring area. Temperature gradient comparison is introduced to capture the hidden fire risk at the overlapping boundary of optical cable monitoring area. For bilateral temperature gradient abnormality scenarios, the warning priority is clarified by combining over-temperature prediction, and finally, the accurate identification and efficient warning processing of fire risk at the overlapping boundary (edge ​​area) of optical cable monitoring area are achieved. Attached Figure Description

[0060] The invention will now be further described with reference to the accompanying drawings.

[0061] Figure 1 This is a flowchart of the steps of a fire early warning method based on distributed optical fiber temperature sensing according to the present invention.

[0062] Figure 2 This is a logic judgment diagram of a fire early warning method based on distributed optical fiber temperature sensing according to the present invention.

[0063] Figure 3 This is a flowchart of a fire early warning system based on distributed optical fiber temperature sensing according to the present invention. Detailed Implementation

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] Example 1: Please refer to Figures 1-2 As shown, this invention is a fire early warning method based on distributed optical fiber temperature sensing, comprising the following steps:

[0066] Step 1: On the temperature boundaries after temperature zoning in the optical cable monitoring area, perform historical temperature fluctuation analysis of the optical cable crossing points to determine the temperature dominance mode of the optical cable crossing points. The temperature dominance mode includes unilateral region dominance and bilateral region dominance.

[0067] In step one, the optical cable monitoring area refers to the physical space where the optical cable is actually laid and needs to be monitored for temperature by distributed optical fiber sensors. Simply put, it is all the places where the optical cable "passes", such as production workshops, warehouses, underground pipe corridors, outdoor cable trays, substations, and pipelines along roads in the park. Because the optical cable is laid in these areas, the changes in the ambient temperature may affect the safety of the optical cable (such as fire caused by high temperature), so they need to be monitored in key areas.

[0068] In step one, the temperature zoning method can be:

[0069] Method 1: According to function and purpose: production workshop (equipment heats up, temperature is high), raw material warehouse (stores flammable materials, sensitive to temperature), underground pipe gallery (enclosed space, poor heat dissipation), outdoor roadside (temperature is greatly affected by weather).

[0070] Method 2: According to risk level: high-risk area (such as chemical warehouse, threshold set at 25℃), medium-risk area (such as ordinary workshop, threshold set at 40℃), low-risk area (such as outdoor open area, threshold set at 50℃).

[0071] For example, temperature zoning according to Method 1 and Method 2 can be shown in Table 1 below;

[0072] Table 1: The divided temperature zones and their corresponding functions, temperature warning values, and other data;

[0073]

[0074] It should be noted that, for example, the temperature measurement method can be as follows: there is an optical cable laid between the central office and a certain substation. When temperature measurement is required, a temperature measuring device can be connected to the optical cable. If temperature monitoring needs to be carried out further from the substation, but there is no optical cable laid directly to these directions at the central office, the optical cable can be split into multiple branches by installing optical switches on the substation side or intermediate nodes to continue extending to more distant monitoring points, thereby realizing long-distance, multi-branch temperature monitoring.

[0075] In step one, the temperature boundary refers to the overlapping boundary between adjacent temperature zones, and the optical cable crossing point is the temperature monitoring point on the temperature boundary;

[0076] In step one, the process of performing temperature history tracking fluctuation analysis at the cross-regional points of the optical cable is as follows:

[0077] The temperature of the optical cable crossing point during the historical monitoring period and the temperature of the two temperature zones corresponding to the optical cable crossing point during the historical monitoring period are obtained.

[0078] The historical monitoring period is divided into several historical sub-periods of equal duration;

[0079] Based on any optical cable crossing point and any corresponding temperature zone;

[0080] The temperature of the optical cable crossing point at the beginning and end of the historical sub-cycle is obtained, and the temperature trend of the optical cable crossing point within the historical sub-cycle is determined. The temperature trend includes an upward trend, a downward trend, and a fixed trend.

[0081] The temperature of the temperature zone at the beginning and end of the historical sub-cycle is obtained, and the temperature trend of the temperature zone within the historical sub-cycle is determined. The temperature trend includes an upward trend, a downward trend, and a fixed trend.

[0082] Based on any historical sub-cycle;

[0083] If the temperature trend of the optical cable crossing point is the same as the temperature trend of the temperature zone within the historical sub-period, then the historical sub-period is marked as a sub-period with the same trend.

[0084] If the temperature trend of the optical cable crossing point is different from the temperature trend of the temperature zone within the historical sub-period, then the historical sub-period is marked as a non-same-trend sub-period.

[0085] The trend-following value is obtained by statistically analyzing the proportion of sub-cycles with the same trend in historical sub-cycles.

[0086] Based on any sub-cycle with the same trend;

[0087] The temperatures of cross-regional points of optical cables within the same trend sub-cycle are integrated into a cross-regional point temperature sequence according to time sequence, and the temperatures of temperature zones within the same trend sub-cycle are integrated into a zone temperature sequence according to time sequence.

[0088] Calculate the Pearson correlation coefficient between the cross-regional point temperature series and the regional temperature series;

[0089] If the Pearson correlation coefficient is within the preset range, it indicates that there is a strong correlation between the temperature of the optical cable crossing point and the temperature of the corresponding temperature zone within the same trend sub-period, and the same trend sub-period is marked as a correlated sub-period.

[0090] If the Pearson correlation coefficient is not within the preset range, it indicates that there is a weak correlation between the temperature of the optical cable crossing point and the temperature of the corresponding temperature zone within the same trend sub-period, and the same trend sub-period is marked as an uncorrelated sub-period.

[0091] The degree of following is obtained by statistically analyzing the proportion of related sub-cycles in sub-cycles with the same trend.

[0092] The temperature fluctuation tracking value between the optical cable crossing point and the temperature zone is obtained by multiplying the trend tracking value and the degree tracking value.

[0093] In step one, the process of determining the temperature-dominant mode at the optical cable crossing point is as follows:

[0094] If the temperature fluctuation following values ​​between the optical cable crossing point and the corresponding two temperature zones are both greater than or equal to the temperature fluctuation following threshold, it means that the temperature of the optical cable crossing point is affected by the temperature of the corresponding two temperature zones, and the temperature dominance mode of the optical cable crossing point is bilateral region dominance.

[0095] If, in the temperature fluctuation following values ​​between the optical cable crossing point and the corresponding two temperature zones, the temperature fluctuation following value between the optical cable crossing point and one of the temperature zones is greater than or equal to the temperature fluctuation following threshold, and the temperature fluctuation following value between the optical cable crossing point and the other temperature zone is less than the temperature fluctuation following threshold, it indicates that the temperature of the optical cable crossing point is affected by the temperature of one temperature zone. In this case, the temperature dominance mode of the optical cable crossing point is unilateral region dominance, and the temperature zone with a temperature fluctuation following value greater than or equal to the temperature fluctuation following threshold is marked as the comparison temperature zone.

[0096] It should be noted that if the temperature fluctuation following value between the optical cable crossing point and the corresponding two temperature zones is less than the temperature fluctuation following threshold, and the dominant zone affected by the temperature at the optical cable crossing point cannot be determined, then for the necessity of fire early warning, the temperature dominance mode at the optical cable crossing point is also bilateral area dominance.

[0097] Understandably, the temperature fluctuation tracking value reflects the correlation between temperature changes between the optical cable crossing point and the corresponding temperature zone. The purpose of obtaining the temperature fluctuation tracking value is to:

[0098] Function 1: To obtain temperature fluctuation tracking values, thereby determining the dominant temperature zone when temperature changes occur at various optical cable crossing points on the temperature boundary, which is beneficial for analyzing the root causes of fire disasters during fire early warning.

[0099] Function 2: Obtain temperature fluctuation tracking values ​​to determine the dominant temperature zones that are affected, which facilitates the subsequent determination of the target zones for temperature comparison at the cross-zone points of optical cables. For example, temperature warning comparison can be performed between the cross-zone points of optical cables and the raw material warehouse area, which is conducive to achieving accurate fire warning.

[0100] Step 2: Based on the temperature-dominant method of the optical cable crossing point, conduct a temperature comparison analysis of the optical cable crossing point to determine whether a temperature warning has been triggered at the optical cable crossing point;

[0101] In step two, the process of performing temperature comparison analysis at the cross-regional points of the optical cable is as follows:

[0102] If the temperature-dominant mode is unilateral region-dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning value of the comparison temperature zone;

[0103] If the temperature at the cross-regional point of the optical cable is greater than or equal to the temperature warning value, a temperature warning will be triggered.

[0104] If the temperature at the cross-regional point of the optical cable is lower than the temperature warning value, the temperature warning will not be triggered.

[0105] If the temperature-dominant mode is dual-region dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning values ​​of the corresponding two temperature zones.

[0106] If the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning value of the corresponding two temperature zones, or if the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning value of any temperature zone, then a temperature warning is triggered.

[0107] If the temperature at the cross-zone point of the optical cable is lower than the temperature warning value of the corresponding two temperature zones, then the temperature warning will not be triggered.

[0108] It should be noted that this invention is mainly aimed at fire early warning for optical cable monitoring, that is, temperature rise analysis at optical cable crossing points. Therefore, the temperature early warning value is the highest temperature within the temperature zone early warning threshold range.

[0109] Step 3: If no temperature warning is triggered, perform a temperature gradient comparison analysis between the optical cable crossing point and the temperature zone to determine whether the optical cable crossing point has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering.

[0110] In step three, the temperature gradient comparison and analysis process for the optical cable crossing points and temperature zones is as follows:

[0111] If the temperature dominance at the optical cable crossing point is unilateral, then the temperature gradient at the optical cable crossing point is compared with the temperature gradient of the corresponding comparison temperature zone, specifically:

[0112] Based on the temperature at the beginning and end of the historical sub-cycle at the cross-zone point of the optical cable, determine the temperature gradient within the historical sub-cycle (temperature difference between the beginning and end / duration of the historical sub-cycle), and compare the temperature gradient within the historical sub-cycle with the normal temperature gradient range of the comparison temperature zone (e.g., normal gradient in the workshop ≤ 5℃ / 5 minutes, warehouse ≤ 3℃ / 5 minutes).

[0113] If the temperature gradient within a historical sub-cycle exceeds the normal temperature gradient range of the compared temperature partition, the historical sub-cycle will be marked as a temperature gradient super-boundary sub-cycle.

[0114] If the temperature gradient within the historical sub-cycle does not exceed the normal temperature gradient range of the compared temperature partition, then the historical sub-cycle is marked as a non-temperature gradient super-boundary sub-cycle.

[0115] The proportion of overclocked sub-periods in the historical sub-periods is statistically analyzed to obtain the overclocking value of the temperature gradient;

[0116] Based on the temperature gradient super-boundary sub-period, the deviation ratio between the temperature gradient of each temperature gradient super-boundary sub-period and the maximum value of the normal temperature gradient range of the compared temperature zone is calculated, and the summation is used to obtain the temperature gradient super-boundary value.

[0117] The temperature gradient over-frequency value and the temperature gradient over-degree value are multiplied to obtain the temperature gradient warning value between the optical cable cross-zone point and the comparison temperature zone.

[0118] If the temperature dominance mode of the optical cable crossing point is dual-side region dominance, then the temperature gradient warning value between the optical cable crossing point and the corresponding two temperature zones is calculated separately. The temperature gradient warning value between the optical cable crossing point and each temperature zone is calculated in the same way as the temperature gradient warning value between the optical cable crossing point and the comparison temperature zone.

[0119] Understandably, the temperature gradient warning value reflects the degree of abnormality of the temperature gradient at the cross-regional point of the optical cable compared to the normal temperature gradient range of the temperature zone. The purpose of obtaining the temperature gradient warning value is:

[0120] Function 1: Dangers at cross-zone points are often hidden in "changing trends" (for example, if the temperature does not exceed the threshold, but it soars from 20°C to 35°C within 5 minutes, it may be a precursor to a fire). Activating "gradient early warning" for cross-zone points is more sensitive than threshold judgment and uses "abnormal temperature gradient" to detect "hidden risks" at cross-zone points.

[0121] Function 2: Obtaining temperature gradient warning values ​​can determine the priority of temperature gradient warnings for temperature zones when temperature gradient warnings are triggered on both sides of the optical cable crossing point, and allow for the reasonable setting of warning strategies.

[0122] The process for determining whether a temperature gradient warning has been triggered at a cross-regional point of the optical cable is as follows:

[0123] If the temperature gradient warning value between the optical cable crossing point and the temperature comparison zone is greater than or equal to the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and any temperature zone is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in a single area.

[0124] If the temperature gradient warning value between the cross-zone point of the optical cable and the corresponding two temperature zones is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in both areas.

[0125] If the temperature gradient warning value between the optical cable crossing point and the temperature zone being compared is less than the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and the corresponding two temperature zones is less than the temperature gradient warning threshold, then the temperature gradient warning will not be triggered.

[0126] Step 4: If the temperature gradient warning trigger type is bilateral region trigger, perform over-temperature prediction analysis based on the temperature gradient and combine the temperature gradient comparison analysis results to determine the temperature gradient warning priority of the temperature zone.

[0127] In step four, the process of performing overheat prediction analysis based on the temperature gradient is as follows:

[0128] Based on the fiber optic cable crossing point and any temperature zone;

[0129] If the temperature gradient at the cross-regional point of the optical cable exceeds the normal temperature gradient range of the temperature zone within the historical sub-period, the historical sub-period will be marked as a temperature gradient super-boundary sub-period.

[0130] Extract the temperature gradients of all temperature gradient superboundary sub-periods and summarize them into a temperature gradient superboundary sequence;

[0131] Calculate the coefficient of variation of the temperature gradient out-of-bounds sequence;

[0132] If the coefficient of variation is less than the preset coefficient of variation, the temperature gradient out-of-bounds sequence is averaged to obtain the predicted temperature gradient.

[0133] If the coefficient of variation is greater than or equal to the preset coefficient of variation, the maximum value in the temperature gradient over-limit sequence is extracted as the predicted temperature gradient.

[0134] It should be noted that if the coefficient of variation is less than the preset coefficient of variation, it reflects that the temperature gradient out-of-bounds sequence is stable. Therefore, the mean value is used to obtain the predicted temperature gradient. Conversely, if the coefficient of variation is greater than the preset coefficient of variation, the temperature gradient out-of-bounds sequence is unstable. The maximum value is used as the predicted temperature gradient to consider extreme cases and improve the timeliness of fire prevention.

[0135] In step four, the process of determining the temperature gradient early warning priority for temperature zones is as follows:

[0136] The temperature deviation between the temperature at the cross-zone point of the optical cable and the temperature warning value of the temperature zone is calculated, and the ratio is calculated with the predicted temperature gradient to obtain the time it takes for the temperature at the cross-zone point of the optical cable to reach the temperature warning value of the temperature zone, which is the predicted temperature warning time.

[0137] Calculate the ratio of the predicted temperature warning duration to the total predicted temperature warning duration to obtain the warning duration ratio;

[0138] The total predicted temperature warning duration is the sum of the duration for which the temperature at the cross-regional point of the optical cable reaches the temperature warning value of each temperature zone.

[0139] The ratio of the temperature gradient warning value and the warning duration between the optical cable crossing point and the temperature zone is calculated to obtain the warning priority value of the temperature zone.

[0140] Compare the warning priority values ​​of temperature zones to determine the warning priority of temperature gradients in each temperature zone;

[0141] Among them, temperature zones with higher temperature gradient warning priorities correspond to larger warning priority values;

[0142] Understandably, the warning priority value for temperature zones is calculated using the temperature gradient warning value and the warning duration ratio. The temperature gradient warning value reflects the degree of abnormality of the temperature gradient at the cross-zone point of the optical cable compared to the normal temperature gradient range of the temperature zone. The higher the degree of abnormality, the higher the warning level of the temperature zone. The warning duration ratio reflects the remaining time that the temperature at the cross-zone point of the optical cable exceeds the temperature warning value of the temperature zone according to the temperature gradient prediction results. The shorter the remaining time, the higher the warning level of the temperature zone.

[0143] The technical solution of this invention is as follows: On the temperature boundaries after temperature zoning in the optical cable monitoring area, historical temperature fluctuation analysis is performed on the cross-zone points of the optical cable to determine the dominant temperature pattern of the cross-zone points. The dominant temperature pattern includes unilateral region dominance and bilateral region dominance. Based on the dominant temperature pattern of the cross-zone points, a temperature comparison analysis is performed to determine whether a temperature warning has been triggered. If no temperature warning has been triggered, a temperature gradient comparison analysis is performed between the cross-zone points and the temperature zones to determine whether a temperature gradient warning has been triggered. The temperature gradient warning triggering type includes unilateral region triggering and bilateral region triggering. If the temperature gradient... The temperature warning trigger type is bilateral region triggering. Based on the temperature gradient, over-temperature prediction analysis is performed, and the temperature gradient comparison analysis results are combined to determine the temperature gradient warning priority of the temperature zone. This invention analyzes the dominant relationship between the temperature of cross-zone points and the single or double regions, and selects the corresponding temperature zone for temperature warning according to the dominant relationship. This improves the accuracy of fire warning at the overlapping boundary of the optical cable monitoring area. Temperature gradient comparison is introduced to capture the hidden fire risk at the overlapping boundary of the optical cable monitoring area. For the scenario of abnormal bilateral temperature gradient, the warning priority is clarified by combining over-temperature prediction, and finally the accurate identification and efficient warning processing of fire risk at the overlapping boundary (edge ​​area) of the optical cable monitoring area are achieved.

[0144] Example 2: Please refer to Figure 3 As shown, the present invention is a fire early warning system based on distributed fiber optic temperature sensing, comprising the following modules:

[0145] Cross-zone temperature dominance analysis module: After dividing the optical cable monitoring area into temperature zones, the module performs historical temperature fluctuation analysis of cross-zone points to determine the temperature dominance mode of the cross-zone points. The temperature dominance mode includes single-sided dominance and double-sided dominance.

[0146] Temperature warning trigger judgment module: Based on the temperature dominance mode of the optical cable crossing point, perform temperature comparison analysis of the optical cable crossing point to determine whether the optical cable crossing point has triggered a temperature warning;

[0147] Cross-zone temperature gradient triggering analysis module: If no temperature warning is triggered, the temperature gradient comparison analysis between the cross-zone point of the optical cable and the temperature zone is performed to determine whether the cross-zone point of the optical cable has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering.

[0148] Cross-zone temperature gradient early warning priority analysis module: If the temperature gradient early warning trigger type is bilateral zone triggering, the over-temperature prediction analysis is performed based on the temperature gradient, and the temperature gradient comparison analysis results are combined to determine the temperature gradient early warning priority of the temperature zone.

[0149] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A fire early warning method based on distributed optical fiber temperature sensing, characterized in that: Includes the following steps: Step 1: On the temperature boundaries after temperature zoning in the optical cable monitoring area, perform historical temperature fluctuation analysis of the optical cable crossing points to determine the temperature dominance mode of the optical cable crossing points. The temperature dominance mode includes unilateral region dominance and bilateral region dominance. Step 2: Based on the temperature-dominant method of the optical cable crossing point, conduct a temperature comparison analysis of the optical cable crossing point to determine whether a temperature warning has been triggered at the optical cable crossing point; Step 3: If no temperature warning is triggered, perform a temperature gradient comparison analysis between the optical cable crossing point and the temperature zone to determine whether the optical cable crossing point has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering. Step 4: If the temperature gradient warning trigger type is bilateral region trigger, perform over-temperature prediction analysis based on the temperature gradient and determine the temperature gradient warning priority of the temperature zone by combining the temperature gradient comparison analysis results.

2. The fire early warning method based on distributed optical fiber temperature sensing according to claim 1, characterized in that: The process of performing temperature history tracking and fluctuation analysis at the cross-regional points of optical cables is as follows: The temperature of the optical cable crossing point during the historical monitoring period and the temperature of the two temperature zones corresponding to the optical cable crossing point during the historical monitoring period are obtained. The historical monitoring period is divided into several historical sub-periods of equal duration; Based on the temperatures of the optical cable crossing point and temperature zone at the beginning and end of the historical sub-cycle, the temperature trends of the optical cable crossing point and temperature zone within the historical sub-cycle are determined respectively. If the temperature trend of the optical cable crossing point and the temperature zone are the same within the historical sub-period, the historical sub-period is marked as the same trend sub-period, and the temperature fluctuation following value is obtained based on the same trend sub-period. If the temperature fluctuation following values ​​between the optical cable crossing point and the corresponding two temperature zones are both greater than or equal to the temperature fluctuation following threshold, then the temperature dominance mode of the optical cable crossing point is bilateral region dominance. If the temperature fluctuation following value between the optical cable crossing point and only one temperature zone is greater than or equal to the temperature fluctuation following threshold, then the temperature dominance mode of the optical cable crossing point is unilateral region dominance, and the temperature zone is marked as the comparison temperature zone.

3. The fire early warning method based on distributed optical fiber temperature sensing according to claim 2, characterized in that: The method for obtaining the temperature fluctuation tracking value is as follows: The trend-following value is obtained by statistically analyzing the proportion of sub-cycles with the same trend in historical sub-cycles. The temperatures of the cross-zone points and the temperatures of the temperature zones within the same trend sub-cycle are integrated into cross-zone point temperature sequences and zone temperature sequences according to time sequence. Calculate the Pearson correlation coefficient between the cross-regional point temperature series and the regional temperature series; If the Pearson correlation coefficient is within the preset range, then sub-cycles with the same trend are marked as related sub-cycles; The degree of following is obtained by statistically analyzing the proportion of related sub-cycles in sub-cycles with the same trend. The temperature fluctuation tracking value between the optical cable crossing point and the temperature zone is obtained by multiplying the trend tracking value and the degree tracking value.

4. A fire early warning method based on distributed optical fiber temperature sensing according to claim 3, characterized in that: The process of performing temperature comparison analysis at the cross-regional points of the optical cable is as follows: If the temperature-dominant mode is unilateral region-dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning value of the comparison temperature zone; If the temperature at the cross-regional point of the optical cable is greater than or equal to the temperature warning value, a temperature warning will be triggered; otherwise, a temperature warning will not be triggered. If the temperature-dominant mode is dual-region dominant, then the temperature at the cross-region point of the optical cable will be compared with the temperature warning values ​​of the corresponding two temperature zones. If the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning values ​​of the corresponding two temperature zones, or if the temperature at the cross-zone point of the optical cable is greater than or equal to the temperature warning value of any temperature zone, then a temperature warning is triggered; otherwise, a temperature warning is not triggered.

5. A fire early warning method based on distributed optical fiber temperature sensing according to claim 1, characterized in that: The process of comparing and analyzing the temperature gradient at the cross-regional points and temperature zones of the optical cable includes: If the temperature dominance mode of the optical cable crossing point is unilateral region dominance, the temperature gradient within the historical sub-cycle is determined based on the temperature at the beginning and end of the historical sub-cycle at the optical cable crossing point. If the temperature gradient within a historical sub-cycle exceeds the normal temperature gradient range of the compared temperature partition, the historical sub-cycle will be marked as a temperature gradient super-boundary sub-cycle. Based on the temperature gradient super-boundary sub-period processing, the temperature gradient over-frequency value and temperature gradient over-degree value are obtained, and then multiplied to obtain the temperature gradient warning value between the optical cable cross-zone point and the comparison temperature zone. If the temperature dominance mode at the optical cable crossing point is bilateral region dominance, then the temperature gradient warning values ​​between the optical cable crossing point and the corresponding two temperature zones are calculated separately.

6. A fire early warning method based on distributed optical fiber temperature sensing according to claim 5, characterized in that: The process for determining whether a temperature gradient warning is triggered at the cross-regional point of the optical cable is as follows: If the temperature gradient warning value between the optical cable crossing point and the temperature comparison zone is greater than or equal to the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and any temperature zone is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in a single area. If the temperature gradient warning value between the cross-zone point of the optical cable and the corresponding two temperature zones is greater than or equal to the temperature gradient warning threshold, it indicates that a temperature gradient warning has been triggered in both areas. If the temperature gradient warning value between the optical cable crossing point and the temperature zone being compared is less than the temperature gradient warning threshold, or if the temperature gradient warning value between the optical cable crossing point and the corresponding two temperature zones is less than the temperature gradient warning threshold, then the temperature gradient warning will not be triggered.

7. A fire early warning method based on distributed optical fiber temperature sensing according to claim 6, characterized in that: The process of performing overheat prediction analysis based on temperature gradient is as follows: Based on the fiber optic cable crossing point and any temperature zone; If the temperature gradient at the cross-regional point of the optical cable exceeds the normal temperature gradient range of the temperature zone within the historical sub-period, the historical sub-period will be marked as a temperature gradient super-boundary sub-period. Extract the temperature gradients of all temperature gradient superboundary sub-periods and summarize them into a temperature gradient superboundary sequence; Calculate the coefficient of variation of the temperature gradient out-of-bounds sequence; If the coefficient of variation is less than the preset coefficient of variation, the temperature gradient out-of-bounds sequence is averaged to obtain the predicted temperature gradient. If the coefficient of variation is greater than or equal to the preset coefficient of variation, the maximum value in the temperature gradient superboundary sequence is extracted as the predicted temperature gradient.

8. A fire early warning method based on distributed optical fiber temperature sensing according to claim 7, characterized in that: The process for determining the temperature gradient early warning priority of temperature zones is as follows: The temperature deviation between the temperature at the cross-zone point of the optical cable and the temperature warning value of the temperature zone is calculated, and the ratio is calculated with the predicted temperature gradient to obtain the time it takes for the temperature at the cross-zone point of the optical cable to reach the temperature warning value of the temperature zone, which is the predicted temperature warning time. Calculate the ratio of the predicted temperature warning duration to the total predicted temperature warning duration to obtain the warning duration ratio; The ratio of the temperature gradient warning value and the warning duration between the optical cable crossing point and the temperature zone is calculated to obtain the warning priority value of the temperature zone. Compare the warning priority values ​​of temperature zones to determine the warning priority of temperature gradients in each temperature zone.

9. A fire early warning method based on distributed optical fiber temperature sensing according to claim 8, characterized in that: The total predicted temperature warning duration is the sum of the duration for which the temperature at the cross-regional point of the optical cable reaches the temperature warning value of each temperature zone.

10. A fire early warning system based on distributed optical fiber temperature sensing, characterized in that: Includes the following modules: Cross-zone temperature dominance analysis module: After dividing the optical cable monitoring area into temperature zones, the module performs historical temperature fluctuation analysis of cross-zone points to determine the temperature dominance mode of the cross-zone points. The temperature dominance mode includes single-sided dominance and double-sided dominance. Temperature warning trigger judgment module: Based on the temperature dominance mode of the optical cable crossing point, perform temperature comparison analysis of the optical cable crossing point to determine whether the optical cable crossing point has triggered a temperature warning; Cross-zone temperature gradient triggering analysis module: If no temperature warning is triggered, the temperature gradient comparison analysis between the cross-zone point of the optical cable and the temperature zone is performed to determine whether the cross-zone point of the optical cable has triggered a temperature gradient warning. The temperature gradient warning triggering types include single-sided area triggering and double-sided area triggering. Cross-zone temperature gradient early warning priority analysis module: If the temperature gradient early warning trigger type is bilateral zone triggering, the over-temperature prediction analysis is performed based on the temperature gradient, and the temperature gradient comparison analysis results are combined to determine the temperature gradient early warning priority of the temperature zone.

Images