Cable for testing oil leakage and testing system thereof

Abstract

The invention relates to the technical field of test cables, in particular to a cable for testing oil leakage and a test system thereof, comprising a detection module, an induction interface module, a positioning module, a data analysis module, a processing module and an alarm module. The detection module is used for detecting impedance of the induction cable; the induction interface module is used for determining induction cable segments with impedance changes; the positioning module is used for positioning the positions of the induction cable segments; the data analysis module is used for judging the leakage degree of the pipeline according to the change trend of cable impedance; evaluating the risk level and reason of leakage, and predicting the response time of the system to quantify the detection capability of the leakage; correcting the number of leakage points according to the comparison condition of adjacent induction cables; the processing module is used for adjusting the valve opening of the oil pipeline; the alarm module is used for sending out alarm signals of different levels according to the leakage levels. According to the invention, accurate detection and positioning of oil leakage are realized by monitoring the impedance change of the cable.

Description

Technical Field

[0001] The invention relates to the technical field of testing cables, and in particular to a cable for testing oil leakage and a testing system thereof. Background Art

[0002] Pipeline transportation is now being used more and more widely because of its economy and safety. With the rapid development of pipeline technology, pipeline transportation has become the fifth largest means of transportation in the world. Since the medium of oil and gas pipelines is flammable and explosive, once a leak occurs, it is very easy to cause accidents such as fire and explosion, causing casualties, property losses and environmental pollution. Therefore, accurate positioning of the leak point of the oil and gas pipeline is a prerequisite for the safe operation of the pipeline. The scientific and technological work of various countries attaches great importance to pipeline leakage detection technology.

[0003] Chinese Patent Publication No.: CN118275047A discloses an oil leakage detection and positioning device and method, the oil leakage detection and positioning device comprises: a plurality of oil leakage detection ropes, a detection connection bar and an oil leakage controller; the input end of the oil leakage detection rope is arranged on the detection connection bar along the length direction of the detection connection bar, and the leaked oil penetrates into the oil leakage detection rope to make the detection line in the oil leakage detection rope conductive to form a loop; the output end of the detection connection bar is connected to the input end of the oil leakage detection rope, and is used to form a current loop between the oil leakage controller and the oil leakage detection rope that conducts current when oil leaks, so that the oil leakage controller detects the current; the oil leakage controller is used to provide voltage, detect current value, determine the actual oil leakage position according to the current value and output it; it can be seen that the oil leakage detection and positioning device and method have the following problems: For oil leaks with high impedance or low conductivity, the method of detecting oil leaks through current is not sensitive enough and cannot accurately detect them; environmental factors, such as temperature, humidity, electromagnetic interference, etc., may affect the electrical performance of the detection rope, resulting in false alarms or missed alarms. Summary of the invention

[0004] To this end, the present invention provides a cable for testing oil leakage and a testing system thereof, so as to overcome the problem in the prior art that the method of detecting oil leakage by current is not sensitive enough and cannot accurately detect oil leakage with high impedance or low conductivity.

[0005] To achieve the above object, the present invention provides a cable for testing oil leakage and a testing system thereof, comprising: A detection module, which is connected to the data analysis module, comprises an oil sensing cable and a plurality of impedance measuring instruments arranged on different sections of the oil sensing cable, wherein the impedance measuring instruments are used to detect the impedance of the sensing cable, and the sensing cable is arranged below the oil pipeline; A sensing interface module, connected to the sensing cable and the positioning module, detects the time when the oil sensing cable undergoes impedance change, determines the sensing cable segment where the impedance change occurs, and transmits the data to the positioning module; A positioning module connected to the data analysis module is used to accurately locate the position of the sensing cable segment on a map according to the determined cable segment where the impedance of the sensing cable changes; A data analysis module, which is connected to the sensing interface module and the alarm module, is used to determine the leakage degree of the oil pipeline according to the change trend and degree of the cable impedance, and send a signal to the alarm module to issue an audible and visual alarm prompt; evaluate the risk level of the oil pipeline leakage and the cause of the oil pipeline leakage, and predict the response time of the system to quantify the detection capability of oil leakage; and correct the number of leakage points of the oil pipeline according to the comparison of the impedance difference and response time difference of adjacent sensing cables; A processing module, connected to the data analysis module, for adjusting the valve opening of the oil pipeline according to the signal of the data analysis module; The alarm module is used to send out alarm signals of different levels according to the leakage level and supports several alarm modes.

[0006] Furthermore, the detection module detects the impedance of the sensing cable in real time through an impedance measuring instrument, and the data analysis module draws an impedance change curve according to the impedance of the sensing cable, and calculates the derivative function of the impedance change curve; If the cable impedance in the impedance change curve at any time is greater than or equal to the impedance critical value, the data analysis module determines that oil leakage occurs in the oil pipeline. If the derivative function value corresponding to any moment is greater than zero, the data analysis module determines that the cable impedance is continuously increasing; Among them, if the derivative function value corresponding to any moment is greater than or equal to the standard value, the leakage degree of the oil pipeline is judged to be a sudden leakage; If the derivative function value corresponding to any moment is less than or equal to the standard value, the data analysis module determines that the leakage degree of the oil leakage is a slow leakage.

[0007] Furthermore, when the leakage degree is a sudden leakage, the data analysis module determines that the oil pipeline is ruptured, sends a signal to the processing module to close the valve of the oil pipeline, and sends a signal to the alarm module to issue an emergency alarm signal; When the leakage degree is a slow leakage, the data analysis module determines that the oil pipeline is corroded and perforated, sends a signal to the processing module to reduce the valve opening of the oil pipeline according to the product of the ratio of the impedance critical value to the cable impedance and the derivative function value, and sends a signal to the alarm module to issue a perforation alarm signal.

[0008] Furthermore, when the data analysis module determines that oil leakage occurs in the oil pipeline, If the cable impedance is equal to the impedance critical value at any moment and the corresponding derivative function value is equal to zero, it is judged that the impedance change curve stops changing. The data analysis unit calculates the response time of the system according to the time when the impedance change of the sensing cable in the sensing interface module and the time when the oil pipeline leaks. If the response time is greater than the evaluation value, it is judged that the leakage degree of the oil pipeline is a slight leakage.

[0009] Furthermore, the data analysis module determines that there is a risk of oil leakage in the oil pipeline. If the cable impedance is less than the impedance critical value at any time, and the corresponding derivative function value is greater than zero, the data analysis module determines that the impedance change curve is approaching the impedance critical value; Among them, if the derivative function value is greater than the standard value, the data analysis module determines that the risk of oil leakage is relatively high and the oil pipeline is at the first risk level; If the derivative function value is less than or equal to the standard value, the data analysis module determines that the risk of oil leakage is small and the oil pipeline is at the second risk level.

[0010] Furthermore, when the oil pipeline is at the first risk level, the data analysis module sends a signal to the processing module to use the derivative function value as an adjustment coefficient to reduce the valve opening, and the valve opening is negatively correlated with the derivative function value; When the oil pipeline is at the second risk level, the data analysis module calculates the rising speed of the impedance change curve according to the derivative function value, and predicts the response time of the system according to the rising speed of the impedance change curve and the difference between the impedance critical value and the initial value of the cable impedance.

[0011] Furthermore, when the oil pipeline is at the first risk level, if the corresponding derivative function value after reducing the valve opening is equal to zero, the data analysis module determines that the pipeline stops leaking, and the reason for the leakage of the oil pipeline is that the pipeline is aging and worn, and the oil pressure in the pipeline is too high, resulting in a slight leakage in the pipeline. The data analysis module sends a signal to the alarm module to issue a repair alarm signal.

[0012] When the oil pipeline is at the second risk level, if the response time is longer than the critical time, the data analysis module determines that the system response rate is slow and the sensing cable may be faulty. The impedance critical value is reduced or the inspection and maintenance cycle for detecting, repairing and replacing the sensing cable is reduced. The impedance critical value and the inspection and maintenance cycle are negatively correlated with the ratio of the response time to the critical time.

[0013] Further, the sensing interface module determines the i-th sensing cable whose cable impedance is greater than or equal to the impedance critical value according to the data transmitted by the data analysis module, i=1,2,...,n, and the positioning module determines the location of the pipeline where the oil leakage occurs according to the positioning of the i-th sensing cable; When the impedance of multiple sections of the sensing cable is greater than or equal to the critical impedance value, if the leakage degree of the oil pipeline is slow leakage or slight leakage, the data analysis module determines that there are multiple leakage points in the oil pipeline, and sends a signal to the alarm module to issue a multiple leakage alarm signal; If the oil leakage is sudden, and the impedance of two adjacent sensing cables is greater than or equal to the critical impedance value, the data analysis module determines the number of leakage points.

[0014] Further, the data analysis module calculates the impedance difference and response time difference of two adjacent sensing cables. If the impedance difference is greater than the impedance evaluation value and the response time difference is greater than the time evaluation value, the data analysis module determines that there is a leakage point at the edge of the connection between the adjacent sensing cables; If the impedance difference is less than or equal to the impedance evaluation value and the response time difference is less than or equal to the time evaluation value, the data analysis module determines that two adjacent sensing cables correspond to two leakage points.

[0015] The present invention also provides a cable for testing oil leakage, characterized in that it comprises: The inner conductor is made of stranded nickel-plated copper material; the dielectric layer is made of expanded extruded PTFE material, which has a unique microporous structure to allow petroleum liquids to penetrate into it while preventing the entry of large molecular water molecules. When petroleum liquids leak and penetrate into the expanded PTFE dielectric layer of the cable, the dielectric constant of the dielectric layer will change, which will lead to a sharp increase in the impedance of the cable; the outer conductor is made of polyamide-imide enameled wire to provide electromagnetic shielding; the sheath is made of expanded extruded foamed PTFE material.

[0016] Compared with the prior art, the beneficial effect of the present invention is that the detection of dripping has always been a difficult point in pipeline leakage detection, especially for some old pipelines. If dripping has occurred, how to use the newly installed pipeline online detection system to detect the leakage has important practical significance. The present invention monitors the change of cable impedance through the impedance change curve, determines the leakage degree of the oil pipeline, improves the sensitivity and accuracy of leakage detection, and reduces the pressure on the leakage point by reducing the valve opening of the oil pipeline, thereby avoiding the situation where the oil pressure in the pipeline aggravates the leakage degree of the pipeline; in the process of analyzing the impedance change curve, for the situation where the curve just rises to the impedance critical value and stops changing due to the characteristics of pipeline dripping and the derivative function value is equal to zero, the leakage degree of the pipeline is evaluated by calculating the response time of the system, further improving the sensitivity and detection rate of leakage detection.

[0017] Furthermore, when it is not determined that the oil pipeline has leaked, analyzing the impedance change trend of the sensing cable is helpful to take preventive measures in a timely manner, reduce the risk of oil leakage and prevent the occurrence of oil leakage, further improve the sensitivity of detecting oil leakage, and evaluate the oil pressure of the oil pipeline by analyzing the leakage of the pipeline after adjusting the valve opening, and judge whether the oil pipeline has aging and wear. If the response time of the system when the cable impedance reaches the critical value is not calculated, the timeliness of taking measures to deal with the pipeline leakage and the efficiency of pipeline transportation are reduced when the sensing cable fails. By evaluating the response time of the system, the detection capability of oil leakage is quantified, and the accuracy of the overall system is increased.

[0018] Furthermore, the detection and positioning of multi-point leakage has always been a difficult point in pipeline leakage detection. The number of pipeline locations where oil leakage occurs is one of the important parameters for detecting pipeline leakage. The present invention compares the impedance difference and response time difference of two adjacent sensing cables. A large impedance difference between the two indicates that the difference in the amount of oil leakage detected by the sensing cables is large, and a large response time difference indicates that the time points at which the pipeline leakage occurs are far apart, thereby correcting the number of pipeline leakage locations and further improving the accuracy of pipeline leakage detection.

[0019] Furthermore, conventional oil leak detectors indirectly infer leaks by analyzing pressure and flow, and this indirectness may lead to false alarms or missed alarms, especially when the leak is small or the leak location is relatively concealed; the oil leak detection rope forms a loop through the leaked oil to generate current to detect oil leaks, but is not sensitive enough to leaks with high impedance or low conductivity, and cannot accurately detect them; the present invention realizes high-sensitivity leak detection by using a method in which oil penetrates the sensing cable and causes the impedance of the cable to increase sharply, and determines the specific location of the leak based on the location of the impedance change, which helps to quickly locate the leak point and improve maintenance efficiency; at the same time, the detection method does not require direct contact with the cable, but instead realizes leak detection by monitoring the impedance change of the cable, which reduces the risk in the detection process and also improves the convenience of detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a unit connection diagram of a cable for testing oil leakage and a testing system thereof in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a cable for testing oil leakage in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structural changes of a cable for testing oil leakage in an embodiment of the present invention when it penetrates into a petroleum liquid; Figure 4 A schematic diagram of a coordinate system of an impedance variation curve of a cable for testing oil leakage in an embodiment of the present invention; Figure 5 It is a front cross-sectional view of a cable for testing oil leakage and an oil pipeline in an embodiment of the present invention; Figure 6 It is a side cross-sectional view of a cable and an oil pipeline for testing oil leakage in an embodiment of the present invention; In the figure: 1-induction cable, 2-oil pipeline, 3-oil liquid, 11-dielectric layer, 12-inner conductor, 13-outer conductor. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0023] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0024] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] See also Figure 1-Figure 6 As shown, Figure 1 This is a unit connection diagram of a cable for testing oil leakage and a testing system thereof in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a cable for testing oil leakage in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structural changes of a cable for testing oil leakage in an embodiment of the present invention when it penetrates into a petroleum liquid; Figure 4 A schematic diagram of a coordinate system of an impedance variation curve of a cable for testing oil leakage in an embodiment of the present invention; Figure 5 It is a front cross-sectional view of a cable for testing oil leakage and an oil pipeline in an embodiment of the present invention; Figure 6It is a side cross-sectional view of a cable and an oil pipeline for testing oil leakage in an embodiment of the present invention.

[0026] The present invention provides a cable for testing oil leakage and a testing system thereof, comprising: A detection module, which is connected to the data analysis module, comprises an oil sensing cable 1 and a plurality of impedance measuring instruments arranged on different sections of the oil sensing cable 1, wherein the impedance measuring instruments are used to detect the impedance of the sensing cable 1, and the sensing cable 1 is arranged closely below the oil pipeline; A sensing interface module, connected to the sensing cable 1 and the positioning module, detects the time when the oil sensing cable 1 undergoes impedance change, determines the sensing cable segment where the impedance change occurs, and transmits the data to the positioning module; A positioning module, which is connected to the data analysis module and is used to accurately locate the position of the sensing cable segment on a map according to the determined cable segment where the impedance change of the sensing cable 1 occurs; A data analysis module, which is connected to the sensing interface module and the alarm module, is used to determine the leakage degree of the oil pipeline 2 according to the change trend and degree of the cable impedance, and send a signal to the alarm module to issue an audible and visual alarm prompt; evaluate the risk level of the oil pipeline 2 leakage and the cause of the oil pipeline 2 leakage, and predict the system's response time to quantify the detection capability of oil leakage; and correct the number of leakage points of the oil pipeline 2 according to the comparison of the impedance difference and response time difference of adjacent sensing cables 1; A processing module, which is connected to the data analysis module and is used to adjust the valve opening of the oil pipeline 2 according to the signal of the data analysis module; The alarm module is used to send out different levels of alarm signals according to the leakage level. It supports multiple alarm modes, such as sound alarm, light alarm, and SMS notification. According to specific needs, you can choose the appropriate alarm mode to ensure that the alarm is received in time.

[0027] It is understandable that the present invention can be applied to places that need to prevent oil leakage, such as gas stations, oil pipelines, oil generators, oil depots, oil chemical plants, terminal containers, generator rooms, etc.

[0028] The detection module detects the impedance of the sensing cable 1 in real time through an impedance measuring instrument, and transmits the data to the data analysis module; The data analysis module draws an impedance change curve according to the impedance of the sensing cable 1, and calculates the derivative function of the impedance change curve. The data analysis module is provided with an impedance critical value of the sensing cable 1. The leakage degree of the oil pipeline 2 is judged according to the change trend and degree of the cable impedance, and the leakage degree of the oil pipeline 2 is divided into slight leakage, slow leakage and sudden leakage. If the cable impedance in the impedance change curve at any time is greater than or equal to the impedance critical value, the data analysis module determines that oil leakage occurs in the oil pipeline 2, and transmits data to the sensing interface module to determine the time when the oil pipeline 2 leaks and the sensing cable segment where the impedance change occurs; If the derivative function value corresponding to any moment is greater than zero, the data analysis module determines that the cable impedance is continuously increasing. The data analysis module analyzes the derivative function value corresponding to any moment, and if the derivative function value is greater than or equal to the standard value, it is determined that the leakage degree of the oil pipeline 2 is a sudden leakage; If the derivative function value is less than or equal to the standard value, the data analysis module determines that the leakage degree of the oil leakage is a slow leakage.

[0029] When the leakage degree is a sudden leakage, the data analysis module determines that the oil pipeline 2 is ruptured, sends a signal to the processing module to close the valve of the oil pipeline 2, and sends a signal to the alarm module to issue an emergency alarm signal; When the leakage degree is slow leakage, the data analysis module determines that the oil pipeline 2 is corroded and perforated, sends a signal to the processing module to reduce the valve opening of the oil pipeline 2 according to the product of the ratio of the impedance critical value to the cable impedance and the derivative function value, and sends a signal to the alarm module to issue a perforation alarm signal; If the cable impedance is equal to the impedance critical value at any moment and the corresponding derivative function value is equal to zero, it is judged that the impedance change curve stops changing. The data analysis unit calculates the response time of the system according to the time when the impedance change of the sensing cable 1 in the sensing interface module and the time when the leakage of the oil pipeline 2 occurs. If the response time is greater than the evaluation value, it is judged that the leakage degree of the oil pipeline 2 is a slight leakage.

[0030] The standard value is a preset value set according to historical data when the oil pipeline 2 leaks to different degrees.

[0031] Specifically, the detection of dripping has always been a difficult point in pipeline leakage detection, especially for some old pipelines. If dripping has occurred, how to use the newly installed pipeline online detection system to detect the leak has important practical significance. The present invention monitors the change of cable impedance through the impedance change curve, determines the leakage degree of the oil pipeline 2, improves the sensitivity and accuracy of leakage detection, and reduces the pressure on the leakage point by reducing the valve opening of the oil pipeline 2, thereby avoiding the situation where the oil pressure in the pipeline aggravates the leakage degree of the pipeline; in the process of analyzing the impedance change curve, for the situation where the curve just rises to the impedance critical value and stops changing due to the characteristics of pipeline dripping, and the derivative function value is equal to zero, the leakage degree of the pipeline is evaluated by calculating the response time of the system, further improving the sensitivity and detection rate of leakage detection.

[0032] If the cable impedance is less than the critical impedance value at any time, the data analysis module determines that there is a risk of oil leakage in the oil pipeline 2, predicts the change trend of the cable impedance, and estimates the response time of the system when the cable impedance reaches the critical value; If the derivative function value corresponding to any moment is greater than zero, the data analysis module determines that the impedance change curve is approaching the impedance critical value. The data analysis module analyzes the derivative function value. If the derivative function value is greater than the standard value, the data analysis module determines that the risk of oil leakage is relatively high, the oil pipeline 2 is at the first risk level, and transmits the data to the sensing interface module; If the derivative function value is less than or equal to the standard value, the data analysis module determines that the risk of oil leakage is small, the oil pipeline 2 is at the second risk level, and transmits the data to the sensing interface module.

[0033] When the oil pipeline 2 is at the first risk level, the data analysis module sends a signal to the processing module to use the derivative function value as an adjustment coefficient to reduce the valve opening, and the valve opening is negatively correlated with the derivative function value; Among them, if the corresponding derivative function value is equal to zero after reducing the valve opening, the data analysis module determines that the pipeline stops leaking. The reason for the leakage of oil pipeline 2 is that the pipeline is aging and worn, and the oil pressure in the pipeline is too high, resulting in a slight leakage of the pipeline. The data analysis module sends a signal to the alarm module to issue a repair alarm signal.

[0034] When the oil pipeline 2 is at the second risk level, the data analysis module calculates the rising speed of the impedance change curve according to the derivative function value, and predicts the response time of the system according to the rising speed of the impedance change curve and the difference between the impedance critical value and the initial value of the cable impedance. If the response time is longer than the critical time, the data analysis module determines that the response rate of the system is slow, and the sensing cable 1 may be faulty, and reduces the impedance critical value or reduces the inspection cycle for detecting, repairing and replacing the sensing cable 1. The impedance critical value and the inspection cycle are negatively correlated with the ratio of the response time to the critical time. If the response time is less than or equal to the critical time, it is judged that the detection capability of the system can meet the requirements of detecting oil leaks.

[0035] The critical time is the maximum time required for oil leakage detection on the oil pipeline 2.

[0036] Specifically, when it is not determined that the oil pipeline 2 has leaked, analyzing the impedance change trend of the sensing cable 1 is helpful to take preventive measures in time, reduce the risk of oil leakage and prevent the occurrence of oil leakage, further improve the sensitivity of detecting oil leakage, and analyze the leakage of the pipeline after adjusting the valve opening to evaluate the oil pressure of the oil pipeline 2, and determine whether the oil pipeline 2 has aging and wear. If the response time of the system when the cable impedance reaches the critical value is not calculated, when the sensing cable 1 fails, the timeliness of taking measures to deal with pipeline leakage and the efficiency of pipeline transportation are reduced. By evaluating the response time of the system, the detection capability of oil leakage is quantified, and the accuracy of the overall system is increased.

[0037] Perform tail end modularization processing on the end of the induction cable 1, and divide the induction cable 1 into n sections according to the modular tail end, including a first induction cable 1, a second induction cable 1, ... an nth induction cable 1; The sensing interface module determines the i-th sensing cable whose cable impedance is greater than or equal to the impedance critical value according to the data transmitted by the data analysis module, i=1,2,...,n, and the positioning module determines the location of the pipeline where the oil leakage occurs according to the positioning of the i-th sensing cable; If there are multiple sections of the sensing cable 1 whose impedance is greater than or equal to the critical impedance value, the data analysis module determines the number of pipeline locations where oil leakage occurs according to the leakage degree of the oil pipeline 2. If the leakage degree of the oil pipeline 2 is a slow leakage or a slight leakage, the data analysis module determines that there are multiple leakage points in the oil pipeline 2, and sends a signal to the alarm module to issue a multi-stage leakage alarm signal; If the oil leakage is sudden and the impedance of two adjacent sensing cables 1 is greater than or equal to the impedance critical value, the data analysis module determines that there are two leakage points or one leakage point at the edge of the connection between adjacent sensing cables 1 according to the change of the cable impedance values ​​of the adjacent sensing cables 1.

[0038] The data analysis module calculates the impedance difference and response time difference of two adjacent sensing cables 1. If the impedance difference is greater than the impedance evaluation value and the response time difference is greater than the time evaluation value, the data analysis module determines that there is a leakage point at the edge of the connection between the adjacent sensing cables; If the impedance difference is less than or equal to the impedance evaluation value and the response time difference is less than or equal to the time evaluation value, the data analysis module determines that two adjacent sections of the sensing cable 1 correspond to two leakage points.

[0039] The impedance evaluation value and the time evaluation value are 30% of the sum of the cable impedances of two adjacent sections of the induction cables 1 and 20% of the sum of the response time.

[0040] Specifically, the detection and positioning of multi-point leakage has always been a difficult point in pipeline leakage detection. The number of pipeline locations where oil leakage occurs is one of the important parameters for detecting pipeline leakage. The present invention compares the impedance difference and response time difference of two adjacent sections of sensing cables 1. A large impedance difference between the two indicates that the difference in the amount of oil leakage detected by the sensing cable 1 is large, and a large response time difference indicates that the time points at which the pipeline leakage occurs are far apart, thereby correcting the number of pipeline leakage locations and further improving the accuracy of pipeline leakage detection.

[0041] The data analysis module evaluates the leakage level of the pipeline according to the leakage degree and the number of leakage points of the oil pipeline 2, and sends a signal to the alarm module to issue alarm signals of different levels according to the leakage level.

[0042] It can be understood that the greater the number of leakage points and the higher the leakage degree, the higher the alarm signal level.

[0043] The data analysis module compares the pipeline leakage location located by the positioning module with the location of the corresponding i-th sensing cable, If the pipeline leakage location located by the positioning module does not match the location of the corresponding i-th sensing cable, the data analysis module determines that there is a relative deviation between the located pipeline leakage location and the actual pipeline leakage location, the positioning accuracy of the positioning module is small, and the length of the sensing cable segment is reduced.

[0044] The present invention also provides a cable for testing oil leakage, comprising: The inner conductor 12 is made of stranded nickel-plated copper material and has good electrical conductivity and corrosion resistance; The dielectric layer 11 is made of expanded extruded PTFE material, which has a unique microporous structure, allowing the oil liquid 3 to penetrate into it while preventing the entry of large molecular water molecules; When the oil liquid 3 leaks and penetrates into the expanded PTFE dielectric layer 11 of the cable, it will cause the dielectric constant of the dielectric layer 11 to change, thereby causing the impedance of the cable to increase sharply; The outer conductor 13 is made of polyamide-imide enameled wire to provide electromagnetic shielding and protect signal transmission from external interference; The sheath is made of expanded extruded PTFE material, which not only ensures the flexibility of the cable but also enhances its chemical corrosion resistance.

[0045] Specifically, traditional oil leak detectors indirectly infer leaks by analyzing pressure and flow. This indirectness may lead to false alarms or missed alarms, especially when the leak is small or the leak location is relatively hidden. The oil leak detection rope forms a loop through the leaked oil to generate current to detect oil leaks. It is not sensitive enough to detect leaks with high impedance or low conductivity. The present invention realizes high-sensitivity leak detection by using a method in which the impedance of the cable 1 increases sharply due to oil penetration, and determines the specific location of the leak based on the location of the impedance change, which helps to quickly locate the leak point and improve maintenance efficiency. At the same time, the detection method does not require direct contact with the cable, but instead realizes leak detection by monitoring the impedance change of the cable, which reduces the risk in the detection process and also improves the convenience of detection.

[0046] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cable testing system for testing oil leakage, characterized in that: include: A detection module, which is connected to the data analysis module, comprises an oil sensing cable and a plurality of impedance measuring instruments arranged on different sections of the oil sensing cable, wherein the impedance measuring instruments are used to detect the impedance of the sensing cable, and the sensing cable is arranged below the oil pipeline; A sensing interface module, connected to the sensing cable and the positioning module, detects the time when the oil sensing cable undergoes impedance change, determines the sensing cable segment where the impedance change occurs, and transmits the data to the positioning module; A positioning module connected to the data analysis module, for locating the position of the segment of the sensing cable on a map according to the determined cable segment where the impedance change occurs in the sensing cable; A data analysis module, which is connected to the sensing interface module and the alarm module, is used to determine the leakage degree of the oil pipeline according to the change trend and degree of the cable impedance, and send a signal to the alarm module to issue an audible and visual alarm prompt; evaluate the risk level of the oil pipeline leakage and the cause of the oil pipeline leakage, and predict the response time of the system to quantify the detection capability of oil leakage; and correct the number of leakage points of the oil pipeline according to the comparison of the impedance difference and the response time difference of adjacent sensing cables; A processing module, connected to the data analysis module, for adjusting the valve opening of the oil pipeline according to the signal of the data analysis module; The alarm module is used to send out alarm signals of different levels according to the leakage level and supports several alarm modes.

2. The testing system for testing cables for oil leakage according to claim 1, characterized in that: The detection module detects the impedance of the sensing cable in real time through an impedance measuring instrument, and the data analysis module draws an impedance change curve according to the impedance of the sensing cable, and calculates the derivative function of the impedance change curve; If the cable impedance in the impedance change curve at any time is greater than or equal to the impedance critical value, the data analysis module determines that oil leakage occurs in the oil pipeline. If the derivative function value corresponding to any moment is greater than zero, the data analysis module determines that the cable impedance is continuously increasing; Among them, if the derivative function value corresponding to any moment is greater than or equal to the standard value, the leakage degree of the oil pipeline is judged to be a sudden leakage; If the derivative function value corresponding to any moment is less than or equal to the standard value, the data analysis module determines that the leakage degree of the oil leakage is a slow leakage.

3. The testing system for testing cables for oil leakage according to claim 2, characterized in that: When the leakage degree is a sudden leakage, the data analysis module determines that the oil pipeline is ruptured, sends a signal to the processing module to close the valve of the oil pipeline, and sends a signal to the alarm module to issue an emergency alarm signal; When the leakage degree is slow leakage, the data analysis module determines that the oil pipeline is corroded and perforated, sends a signal to the processing module to reduce the valve opening of the oil pipeline according to the product of the ratio of the impedance critical value to the cable impedance and the derivative function value, and sends a signal to the alarm module to issue a perforation alarm signal.

4. The testing system for testing cables for oil leakage according to claim 2, characterized in that: When the data analysis module determines that oil leakage occurs in the oil pipeline, If the cable impedance is equal to the impedance critical value at any moment and the corresponding derivative function value is equal to zero, it is judged that the impedance change curve stops changing. The data analysis unit calculates the response time of the system according to the time when the impedance change of the sensing cable in the sensing interface module and the time when the oil pipeline leaks. If the response time is greater than the evaluation value, it is judged that the leakage degree of the oil pipeline is a slight leakage.

5. The testing system for testing cables for oil leakage according to claim 1, characterized in that: The data analysis module determines that there is a risk of oil leakage in the oil pipeline. If the cable impedance is less than the impedance critical value at any time, and the corresponding derivative function value is greater than zero, the data analysis module determines that the impedance change curve is approaching the impedance critical value; Among them, if the derivative function value is greater than the standard value, the data analysis module determines that the risk of oil leakage is relatively high and the oil pipeline is at the first risk level; If the derivative function value is less than or equal to the standard value, the data analysis module determines that the risk of oil leakage is small and the oil pipeline is at the second risk level.

6. The testing system for testing cables for oil leakage according to claim 5, characterized in that: When the oil pipeline is at the first risk level, the data analysis module sends a signal to the processing module to use the derivative function value as an adjustment coefficient to reduce the valve opening, and the valve opening is negatively correlated with the derivative function value; When the oil pipeline is at the second risk level, the data analysis module calculates the rising speed of the impedance change curve according to the derivative function value, and predicts the response time of the system according to the rising speed of the impedance change curve and the difference between the impedance critical value and the initial value of the cable impedance.

7. The testing system for testing cables for oil leakage according to claim 6, characterized in that: When the oil pipeline is at the first risk level, if the corresponding derivative value after reducing the valve opening is equal to zero, the data analysis module determines that the pipeline stops leaking. The cause of the oil pipeline leakage is aging and wear of the pipeline, and the excessive oil pressure in the pipeline causes a slight leakage in the pipeline. The data analysis module sends a signal to the alarm module to issue a repair alarm signal. When the oil pipeline is at the second risk level, if the response time is longer than the critical time, the data analysis module determines that the system response rate is slow and the sensing cable may be faulty. The impedance critical value is reduced or the inspection and maintenance cycle for detecting, repairing and replacing the sensing cable is reduced. The impedance critical value and the inspection and maintenance cycle are negatively correlated with the ratio of the response time to the critical time.

8. The testing system for testing cables for oil leakage according to claim 1, characterized in that: The sensing interface module determines the i-th sensing cable whose cable impedance is greater than or equal to the impedance critical value according to the data transmitted by the data analysis module, i=1,2,...,n, and the positioning module determines the location of the pipeline where the oil leakage occurs according to the positioning of the i-th sensing cable; When the impedance of multiple sections of the sensing cable is greater than or equal to the critical impedance value, if the leakage degree of the oil pipeline is slow leakage or slight leakage, the data analysis module determines that there are multiple leakage points in the oil pipeline, and sends a signal to the alarm module to issue a multiple leakage alarm signal; If the oil leakage is sudden, and the impedance of two adjacent sensing cables is greater than or equal to the critical impedance value, the data analysis module determines the number of leakage points.

9. The testing system for testing cables for oil leakage according to claim 8, characterized in that: The data analysis module calculates the impedance difference and response time difference of two adjacent sensing cables. If the impedance difference is greater than the impedance evaluation value and the response time difference is greater than the time evaluation value, the data analysis module determines that there is a leakage point at the edge of the connection between the adjacent sensing cables. If the impedance difference is less than or equal to the impedance evaluation value and the response time difference is less than or equal to the time evaluation value, the data analysis module determines that two adjacent sensing cables correspond to two leakage points.

10. A cable for testing oil leakage, applicable to a testing system for a cable for testing oil leakage as claimed in any one of claims 1 to 9, characterized in that: include: Inner conductor, made of stranded nickel-plated copper material; The dielectric layer is made of expanded extruded PTFE material and has a unique microporous structure, which is used to allow oil liquids to penetrate into it while preventing the entry of large molecular water molecules. When oil liquids leak and penetrate into the expanded PTFE dielectric layer of the cable, the dielectric constant of the dielectric layer will change, thereby causing the impedance of the cable to increase sharply; the outer conductor is made of polyamide-imide enameled wire to provide electromagnetic shielding; the sheath is made of expanded extruded foamed PTFE material.

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