Method for evaluating infrasonic wave leakage monitoring system

Abstract

The invention discloses an infrasonic wave leakage monitoring system evaluation method, and relates to the technical field of pipeline defect detection. Comprising the following steps: performing system self-inspection on a monitoring system to obtain self-inspection index parameters; performing a normal operation condition simulation leakage test at the simulation discharge point, and recording normal condition simulation test data; performing an abnormal operation condition simulation leakage test at the simulation discharge point, and recording abnormal condition simulation test data; based on the normal working condition simulation data and the abnormal working condition simulation test data, performing statistics to obtain technical index parameters of the monitoring system; effectiveness testing is carried out on each sensor of the monitoring system, and effectiveness index parameters are obtained; performing a leakage signal simulation test on the monitoring system to obtain a signal index parameter of the monitoring system; and judging whether the performance of the monitoring system is qualified or not based on the self-inspection index parameter, the technical index parameter, the effectiveness index parameter and the signal index parameter. The method can accurately evaluate the effectiveness of the technical indexes of the leakage monitoring system.

Description

Technical Field

[0001] This invention relates to the field of pipeline defect detection technology, and specifically to an evaluation method for an infrasound leakage monitoring system. Background Technology

[0002] Pipelines, as the primary transmission medium for energy, are a crucial part of infrastructure, characterized by their large transport capacity, continuous operation, and rapid operation. The total length of oil and gas pipelines in my country has exceeded 95,000 kilometers. However, in the event of a pipeline leak, only by promptly detecting the leak and accurately locating its point can the economic and environmental losses caused by the leak be minimized.

[0003] Therefore, conducting pipeline leak monitoring through effective technical means can accurately grasp the pipeline's operational status and improve the ability to manage natural gas leak risks. In recent years, in addition to conventional fixed gas detectors and manual inspections, various passive prevention technologies such as infrasound leak monitoring, pipeline sentinel monitoring, laser methane detection, and infrared gas cloud imaging have been introduced for gas leak monitoring. Among them, infrasound leak monitoring systems are often used in long gathering and transmission pipelines due to the slow attenuation of infrasound energy and long propagation distance; pan-tilt-zoom laser leak monitoring systems are mostly installed at dehydration stations, gas gathering stations, and other stations with large gathering and transmission volumes to monitor leaks within the station; pipeline sentinel detection technology is mostly used for fixed monitoring in key areas under complex environments; vehicle-mounted high-precision laser detection technology is mostly used for rapid detection of large areas in pipeline networks; handheld laser methane detectors are used as an auxiliary detection method, generally applied to daily inspections of pipelines, stations, and high-consequence areas; and infrared gas cloud imaging leak monitoring technology is generally used in large chemical plants or large storage tank areas. Infrared leak monitoring systems are mainly used for monitoring leaks in in-service pipelines.

[0004] The accuracy of infrasound leak monitoring systems is primarily affected by two factors: the external environment and the internal system. External environmental factors include site selection and coverage area, while internal system factors include the effectiveness of software and hardware facilities for data acquisition, signal transmission, and analysis and processing. Furthermore, the calibration and testing of infrasound leak monitoring systems lacks the means and methods to verify whether the installed equipment meets design requirements by damaging the pipeline. From installation and commissioning to routine monitoring, there is a lack of corresponding testing methods and means, and currently, all testing is conducted by the manufacturers themselves. This lack of technical oversight before commissioning and guidance for daily operation management, coupled with significant limitations in on-site testing, hinders effective implementation. Summary of the Invention

[0005] To address the technical problem that existing infrasound leak monitoring systems are difficult to effectively test on-site before commissioning in order to accurately assess the effectiveness of their technical indicators, this invention provides an evaluation method for infrasound leak monitoring systems. By simulating system self-testing, normal operating conditions, and abnormal operating conditions, the effectiveness of the leak monitoring system's technical indicators can be accurately assessed, thereby promoting the improvement of pipeline technical security management.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides a method for evaluating an infrasound leakage monitoring system, comprising the following steps:

[0008] Perform a system self-test on the infrasound leakage monitoring system to obtain self-test index parameters;

[0009] After confirming the operating conditions of the infrasound leakage monitoring system, the simulated discharge point was determined;

[0010] Perform a simulated leakage test under normal operating conditions at the simulated discharge point and record the simulated leakage test data under normal operating conditions;

[0011] Perform a simulated leakage test under abnormal operating conditions at the simulated discharge point and record the simulated leakage test data under abnormal operating conditions;

[0012] Based on the normal operating condition simulation data and the abnormal operating condition simulation test data, the technical parameters of the infrasound leakage monitoring system are statistically derived.

[0013] The effectiveness of each sensor in the infrasound leakage monitoring system was tested to obtain effectiveness index parameters.

[0014] Leakage signal simulation tests were conducted on the infrasound leakage monitoring system to obtain the signal index parameters of the infrasound leakage monitoring system.

[0015] Based on the self-test index parameters, the technical index parameters, the effectiveness index parameters, and the signal index parameters, determine whether the performance of the infrasound leakage monitoring system is qualified.

[0016] The evaluation method for an infrasound leakage monitoring system provided by this invention first performs a system self-test to obtain self-test index parameters. Then, it conducts simulated leakage tests under normal operating conditions at simulated leakage points to obtain normal operating condition simulated test data and simulated leakage tests under abnormal operating conditions to obtain abnormal operating condition simulated test data. Based on the normal operating condition simulated data and the abnormal operating condition simulated test data, the technical index parameters of the infrasound leakage monitoring system are statistically derived. Next, the effectiveness of each sensor in the infrasound leakage monitoring system is tested to obtain effectiveness index parameters, and the leakage signal simulation test is conducted to obtain signal index parameters of the infrasound leakage monitoring system. Finally, based on the self-test index parameters, technical index parameters, effectiveness index parameters, and signal index parameters, the performance of the infrasound leakage monitoring system is determined to be qualified.

[0017] Therefore, the evaluation method for infrasound leakage monitoring systems provided by this invention covers both the software and hardware aspects of the leakage monitoring system, and accurately evaluates the effectiveness of the technical indicators of the leakage monitoring system. It can comprehensively evaluate the effectiveness of the technical indicators of natural gas pipeline leakage monitoring systems, promote the improvement of pipeline technical prevention and management, and facilitate the analysis of weak links in natural gas pipeline leakage monitoring systems, thereby proposing targeted rectification and daily maintenance suggestions, and providing technical guidance and theoretical basis for the daily management and operation of leakage monitoring systems.

[0018] Specifically, when performing a system self-test on the infrasound leak monitoring system, a system self-test is performed on each natural gas pipeline covered by the infrasound leak monitoring system.

[0019] Specifically, performing a system self-test on an infrasound leakage monitoring system includes the following steps:

[0020] Under normal operating conditions, based on the simulated leakage section of the infrasound leakage monitoring system, simulated leakage is carried out in at least two intervals.

[0021] Perform system self-checks under abnormal operating conditions.

[0022] Specifically, the interval between two adjacent simulated discharge operations is greater than 3 minutes.

[0023] Specifically, the abnormal operating conditions are that the infrasound leakage monitoring system is offline and disconnected from the explosion-proof box.

[0024] Specifically, confirming the operating status of the infrasound leakage monitoring system includes the following steps:

[0025] Close all sensors at a safe distance and confirm pipeline operation;

[0026] Establish a cordon and a safety zone;

[0027] Install and inspect temporary relief systems;

[0028] Inspect the high-pressure hose and absorption device.

[0029] Specifically, the steps for installing and inspecting a temporary relief system are as follows:

[0030] Close the ball valve of the local pressure gauge and remove the pressure gauge according to the operating procedures.

[0031] Install a high-pressure ball valve for testing at the original pressure gauge interface;

[0032] Install a simulated leakage test tool at the other end of the pressure gauge ball valve;

[0033] Connect a high-pressure hose to the tail end of the simulated leak test tool and secure the high-pressure hose.

[0034] Close the high-pressure ball valve for testing and open the original pressure gauge ball valve to check for leaks.

[0035] Specifically, the simulated discharge point includes a debugging point and a newly added test point. The newly added test point is located within the monitoring range of the corresponding sensor and is located on the main pipeline.

[0036] Specifically, the simulated leakage test under normal operating conditions includes the following steps:

[0037] Replace the alkaline solution at the station according to the sulfur content at the site;

[0038] Close the ball valve of the corresponding instrument and remove the pressure relief plug of the corresponding instrument, and install a test high-pressure ball valve at the pressure relief opening of the corresponding instrument;

[0039] Install a simulated leak test tool at the other end of the high-pressure ball valve for testing, and connect the outlet of the leak test tool to the corresponding alkaline solution container;

[0040] Close the high-pressure ball valve for testing, activate the pressure flow of the corresponding sensor, and open the ball valve of the corresponding instrument to check for leaks in the ventilation line. If there is a leak, reconnect the line. Check for leaks again after each reconnection of the line.

[0041] Simulate pipeline rupture and leakage, and record simulation test data under normal operating conditions;

[0042] Repeat the simulated pipeline rupture and leakage steps multiple times after a preset time interval;

[0043] Repeat the testing at different test points until all simulated discharge points have been tested.

[0044] Specifically, the abnormal operating condition simulation leak test includes the following steps:

[0045] After removing one sensor, a simulated leak test under normal operating conditions was conducted.

[0046] Specifically, the abnormal operating condition simulation leakage test also includes the following steps:

[0047] Disconnect the server power supply of the infrasound leakage monitoring system or disconnect the network connection of the infrasound leakage monitoring system, and then conduct the simulated leakage test under normal operating conditions.

[0048] Specifically, the effectiveness test of each sensor in the infrasound leakage monitoring system includes testing the capacitance and resistance of each sensor.

[0049] Specifically, the steps for simulating leakage signals in an infrasound leakage monitoring system are as follows:

[0050] Select at least one point at any location along the upstream, midstream, and downstream of the pipeline;

[0051] Connect the infrasound generator to the pipeline inside the pipeline test pile;

[0052] The test was conducted by emitting infrasound waves of various frequencies below 20 Hz using an infrasound generator.

[0053] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0054] The evaluation method for an infrasound leakage monitoring system provided by this invention first performs a system self-test to obtain self-test index parameters. Then, it conducts simulated leakage tests at simulated leakage points under normal operating conditions to obtain normal operating condition simulation test data, and conducts simulated leakage tests under abnormal operating conditions to obtain abnormal operating condition simulation test data. Based on the normal operating condition simulation data and the abnormal operating condition simulation test data, it statistically derives the technical index parameters of the infrasound leakage monitoring system. Finally, it sequentially performs effectiveness tests on each sensor of the infrasound leakage monitoring system to obtain effectiveness index parameters, and conducts leakage signal simulation tests on the infrasound leakage monitoring system. This method obtains the signal index parameters of the infrasound leak monitoring system. Finally, based on the self-test index parameters, technical index parameters, effectiveness index parameters, and signal index parameters, it determines whether the performance of the infrasound leak monitoring system is qualified. It covers both the software and hardware aspects of the leak monitoring system and accurately evaluates the effectiveness of the technical indicators of the leak monitoring system. It can comprehensively evaluate the effectiveness of the technical indicators of the natural gas pipeline leak monitoring system, promote the improvement of pipeline technical prevention and management, and facilitate the analysis of weak links in the natural gas pipeline leak monitoring system. This allows for the proposal of targeted rectification and daily maintenance suggestions, providing technical guidance and theoretical basis for the daily management and operation of the leak monitoring system. Attached Figure Description

[0055] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0056] in:

[0057] Figure 1 This is a flowchart illustrating the evaluation method for an infrasound leakage monitoring system provided in an embodiment of the present invention. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0059] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0060] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Furthermore, numerous specific details are set forth in the following description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to implement the invention. In other embodiments, well-known methods are not specifically described to avoid obscuring the invention.

[0061] Example

[0062] Combination Figure 1 This embodiment provides an evaluation method for an infrasound leakage monitoring system. The present invention provides an evaluation method for an infrasound leakage monitoring system, comprising the following steps:

[0063] S100. Perform a system self-test on the infrasound leakage monitoring system to obtain self-test index parameters.

[0064] Specifically, when performing a system self-test on the infrasound leak monitoring system, a system self-test is performed on each natural gas pipeline covered by the infrasound leak monitoring system.

[0065] Performing a system self-test on an infrasound leakage monitoring system includes the following steps:

[0066] S110. Under normal operating conditions, simulated leakage is carried out in at least two intervals based on the simulated leakage section of the infrasound leakage monitoring system.

[0067] S120. Perform system self-test under abnormal operating conditions, wherein the abnormal operating conditions are that the infrasound leakage monitoring system is offline and disconnected from the explosion-proof box.

[0068] In this embodiment, under normal operating conditions, a system self-check is performed on each natural gas pipeline covered by the system. The built-in simulated release interface is accessed through the operation menu of the infrasound leak monitoring system. Simulated releases are performed in two intervals, with an interval of at least 3 minutes between each simulated release. The system self-check status is then checked and recorded. That is, the interval between two adjacent simulated release operations is greater than 3 minutes.

[0069] Abnormal operating conditions include manually disconnecting the network or disconnecting the explosion-proof box.

[0070] S200. After confirming the operating conditions of the infrasound leakage monitoring system, determine the simulated discharge point.

[0071] It is understandable that a series of preparatory works are required before conducting normal operating condition simulated leakage tests and abnormal operating condition simulated leakage tests. Specifically:

[0072] 1) Personnel allocation

[0073] The testing personnel were divided into an on-site testing group and a monitoring and recording group, located at the simulated leak test site and the infrasound leak monitoring and management system installation site, respectively. The two groups maintained contact via explosion-proof walkie-talkies to confirm the test location, test time, test method, etc., ensuring the accuracy of test information and records.

[0074] 2) Material preparation

[0075] The main tools required for each test point are: two stopwatches; one set of vernier calipers; a 50-meter measuring tape; one set of ball valves and connecting fittings of the same pressure rating as the pipeline; two sets of adjustable wrenches; 100 meters of warning tape; two sulfur gas detectors (four-in-one); positive pressure breathing apparatus, prepared according to the number of personnel at the test site, ensuring one per person; two high-pressure hoses of no less than 20 meters (one for use and one for backup) and their anchoring fasteners; an absorption device of sufficient capacity, with reliable stabilization measures; 20 kg of NaHCO3 solid; one bottle of soapy water; 2mm, 3mm...

[0076] 5mm dedicated venting tool.

[0077] 3) Personnel safety training

[0078] Training on simulated leak testing should be provided to personnel involved in on-site testing. On-site testing personnel should identify risks and familiarize themselves with emergency response plans. Under the guidance of local technical and safety supervisors, on-site operations must be completed by two people, one operating and one supervising. If any abnormality occurs at the test site or in the system, the test should be terminated in a timely manner, and the situation should be investigated and resolved before testing can resume.

[0079] 4) Confirmation of operating conditions

[0080] Confirming the operating status of the infrasound leakage monitoring system includes the following steps:

[0081] S211. Close the safety distance of each sensor (and fully open the ball valve at the sensor connection), confirm the pipeline operation, and ensure that the pipeline parameters are normal and the operating parameters are stable, including confirming that the transmission signals of each substation system are unobstructed, the main station system is operating normally, the wind vane set at the test site is operating normally, and confirming the wind direction at the test site.

[0082] S212. Set up a warning zone and a safety zone.

[0083] S213. Install and inspect the temporary relief system.

[0084] Specifically, the steps for installing and inspecting a temporary relief system are as follows:

[0085] S213a. Close the ball valve of the local pressure gauge and remove the pressure gauge according to the operating procedure.

[0086] S213b installs a high-pressure ball valve for testing at the original pressure gauge interface;

[0087] S213c has a simulated leakage test tool installed at the other end of the pressure gauge ball valve;

[0088] The S213d connects a high-pressure hose to the tail end of the simulated leak test tool and secures the high-pressure hose.

[0089] S213e closes the high-pressure ball valve for testing and opens the original pressure gauge ball valve for leak detection.

[0090] S214. Inspect the high-pressure hose and the absorption device. Check in sequence whether the outlet end of the high-pressure hose is firmly fixed to the absorption device, and whether the hose body is firmly fixed with the fixing stake. Perform a test release to check whether the hose will swing violently when the high-pressure gas is ejected.

[0091] The simulated leakage points include debugging points and newly added test points. The newly added test points are located within the monitoring range of the corresponding sensors and are situated on the main pipeline. In other words, this embodiment selects simulated leakage points using a combination of debugging points and newly added points. Simulated leakage at the newly added leakage points should not trigger the station control interlock system to avoid affecting normal production operations. The newly added points must be within the sensor monitoring range, specifically between the first and last sensors and on the main pipeline. Furthermore, the internal aperture of the point must be a straight-through aperture to minimize impact on instrument orifices.

[0092] S300. Perform a normal operating condition simulated leakage test at the simulated discharge point and record the normal operating condition simulated test data.

[0093] Specifically, the simulated leakage test under normal operating conditions includes the following steps:

[0094] S310. Replace the alkali solution at the station according to the sulfur content on site.

[0095] Generally, after the testing tools, equipment, and tonnes (the tonnes are on pickup trucks, and the tonnes contain 10 kg of alkaline solution) arrive at the work area, the alkaline solution is replaced every 1-5 stations, depending on the sulfur content at the site.

[0096] S320. Close the ball valve of the corresponding instrument and remove the pressure relief plug of the corresponding instrument, and install a test high-pressure ball valve at the pressure relief opening of the corresponding instrument.

[0097] Specifically, first close the pressure gauge cock connected to the pressure guide pipe of the DN15 sensor, close the lower ball valves of the DN2 and DN50 sensors, wear breathing apparatus, carry a four-in-one gas detector, remove the pressure relief plug of the pressure gauge cock, remove the pressure relief plugs on the side of the lower flange of the DN25 and DN50 sensors, and install the high-pressure ball valve for testing at the pressure relief port of the pressure gauge cock connected to the pressure guide pipe of the DN15 sensor, and at the pressure relief port on the side of the lower flange of the DN25 and DN50 sensors.

[0098] S330. Install a simulated leak test tool (with a short-circuit orifice of 2mm, 3mm, or 5mm) at the other end of the high-pressure ball valve used for testing; and connect the outlet of the leak test tool to the corresponding alkaline container. That is, install a high-pressure relief hose at the rear end of the special simulated leak test tool, and fix the other end of the hose inside the ton container.

[0099] S340. Close the high-pressure ball valve for testing, connect the pressure flow of the corresponding sensor, and open the ball valve of the corresponding instrument to check for leaks in the ventilation line. If there is a leak, reconnect the line (use a leak tester to check for leaks at the connection). Check for leaks again after each reconnection of the line.

[0100] S350, simulate pipeline rupture and leakage, and record simulation test data under normal operating conditions;

[0101] S360, after a preset time interval, repeat the simulated pipeline rupture and leakage steps multiple times;

[0102] S370, change the test point and continue testing until all simulated discharge points have been tested.

[0103] It should be noted that, in this embodiment, after preparation, the high-pressure ball valve is quickly and fully opened to simulate a pipeline rupture and leak. The valve is opened for approximately 5 seconds, and then the infrasound control unit is checked to see if it triggers an alarm, and whether the alarm time and distance meet the requirements. The test data is recorded on the simulated leak record sheet. At a single sensor test point, the venting process is repeated 2-5 times after a 5-minute interval. After the test, all testing tools are disassembled, and the station / valve chamber equipment is restored to its original state and leak checked. The test data is recorded on the simulated leak record sheet.

[0104] S400. Perform a simulated leakage test under abnormal operating conditions at the simulated discharge point and record the simulated leakage test data under abnormal operating conditions.

[0105] Specifically, the abnormal operating condition simulated leakage test includes the following steps: after removing one sensor, the normal operating condition simulated leakage test is performed. That is, before conducting the field test, one sensor is removed, and then the field test is conducted according to the special test procedure (S300) under normal operating conditions.

[0106] Before conducting on-site testing, the server of the infrasound leakage monitoring system should be powered off or its network connection should be disconnected before service. Then, the on-site test should be conducted according to the special test procedure under normal operating conditions (S300). That is, the abnormal operating condition simulated leakage test also includes the following steps: disconnecting the power supply to the server of the infrasound leakage monitoring system or disconnecting the network connection of the infrasound leakage monitoring system, and then conducting the normal operating condition simulated leakage test.

[0107] S500. Based on the normal operating condition simulation data and the abnormal operating condition simulation test data, the technical parameters of the infrasound leakage monitoring system are statistically derived.

[0108] In this embodiment, after each venting, the testing team confirms the alarm time and location with the monitoring team via walkie-talkie and records the data. The recorded data includes the test aperture, venting time, alarm time, alarm response time, system alarm distance, venting time distance, positioning error, and alarm rate. The data is then summarized to statistically determine the test alarm accuracy, positioning error, minimum detectable leak aperture, and system alarm response time, thereby deriving the technical parameters of the infrasound leak monitoring system.

[0109] S600: Perform effectiveness tests on each sensor of the infrasound leakage monitoring system to obtain effectiveness index parameters.

[0110] Understandably, current sensor testing methods involve testing the capacitance and resistance of the sensor's output to determine if the sensor has been flooded and if its internal structure is functioning correctly. The testing methods and steps are as follows:

[0111] Prepare a multimeter with capacitance testing function and a sensor output cable;

[0112] Capacitance test: Set the multimeter to the nF capacitance test range. Connect the red wire to the positive terminal of the sensor output cable and the black wire to the negative terminal (ground) of the sensor output cable. Observe the multimeter capacitance. It is best to place the sensor on an insulated flat surface during testing.

[0113] Resistance test: Set the multimeter to the MΩ resistance test range, connect the red wire to the positive terminal of the sensor output cable, and connect the black wire to the negative terminal (ground) of the sensor output cable. Observe the resistance value measured by the multimeter. It is best to place the sensor on an insulated flat surface during the test.

[0114] That is, the effectiveness test of each sensor in the infrasound leakage monitoring system is carried out, including testing the capacitance and resistance of each sensor.

[0115] The capacitance value of each sensor is determined according to the sensor model and batch. A capacitance value of 4 to 20 nF is within the normal range. A resistance value of less than 1 MΩ is abnormal and the sensor needs to be replaced.

[0116] S700 performs leakage signal simulation tests on the infrasound leakage monitoring system to obtain the signal index parameters of the infrasound leakage monitoring system.

[0117] Specifically, the steps for simulating leakage signals in an infrasound leakage monitoring system are as follows:

[0118] S710. Select at least one point (generally one or two points) at any location upstream, midstream, or downstream of the pipeline.

[0119] S720. Connect the infrasound generator to the pipeline inside the pipeline test pile.

[0120] The S730 uses an infrasound generator to emit multiple infrasound waves of the same frequency band below 20 Hz for testing, and observes and statistically analyzes the alarm status of the infrasound leakage monitoring system, including alarm response time and location error.

[0121] S800. Based on the self-test index parameters, the technical index parameters, the effectiveness index parameters, and the signal index parameters, determine whether the performance of the infrasound leakage monitoring system is qualified.

[0122] This embodiment focuses on an infrasound leakage monitoring system used in natural gas transmission pipelines, and its specific evaluation criteria are as follows:

[0123] a) Software System Evaluation Criteria

[0124] ① The infrasound leakage monitoring system should have a backup power supply so that the system located at the main station can operate normally in the event of a sudden power outage.

[0125] ② The infrasound leakage monitoring system has the function of resuming transmission after network interruption. Under the condition of network communication interruption, the system can cache data and perform leakage judgment and location based on the resumed data after the network is restored, so as to avoid network problems affecting pipeline leakage monitoring.

[0126] ③ The infrasound leakage monitoring system can realize real-time monitoring of pipeline acoustic and video information, waveform-graph function; it can record abnormal acoustic and video information; it has historical data query and export functions; and it supports recording the processing results of alarm information.

[0127] ④ The alarm response time of the infrasound leakage monitoring system should be less than 120 seconds during system self-test.

[0128] ⑤ The main station system software of the infrasound leakage monitoring system should be able to access monitoring data from at least three pipelines.

[0129] b) Specific test indicators, see Table 1

[0130] Table 1 Key Technical Indicators of the System

[0131] Serial Number index control value Remark 1 Minimum detectable leak diameter ≥2mm / 2 Alarm accuracy ≥97％ / 3 Positioning error ≤±50m Based on the simulated leak point 4 System response time ≤100s / 5 False alarm rate No more than 3 false alarms per year Data needs to be tracked and analyzed over a long period of time. 6 Single-section pipeline monitoring distance ≥25km

[0132] Except for the false alarm rate, which needs to be statistically analyzed over a long period of time, all other indicators are considered to be qualified if they all reach the control value. If any one of them fails to meet the technical indicators, the system should be re-adjusted and tested; if any one of them still fails, the test is considered unqualified.

[0133] Furthermore, this embodiment also applies the infrasound leakage monitoring system evaluation method described above to the Sichuan gas pipeline, which has a pipe diameter of D406×10, a length of 11km, an operating pressure of 6.4MPa, and a transmission capacity of 368×10⁴ Nm³ / d. Two infrasound sensors are installed at the first gas gathering station and two infrasound sensors are installed at the second gas gathering station.

[0134] Specifically:

[0135] First, a system simulation test was conducted on the main line (first gas gathering station - second gas gathering main station), and the test data is shown in Table 2.

[0136] Table 2

[0137] Serial Number Operation time Alarm time Alarm response time / s 1 14:26:58 14:28:43 105

[0138] It can be seen that the alarm response time of the infrasound leakage monitoring system adapted to this trunk line is 105s, and the self-test alarm response time is less than 120s, indicating that the system can alarm normally.

[0139] Then, a special test was conducted on the main pipeline. Two points were selected for the special test at the first gas gathering station, including two existing venting points. Seventeen on-site venting simulation tests were carried out using three different venting orifice diameters of 2, 3, and 5 mm. The alarm response time, positioning error, and alarm accuracy of the 17 tests all met the test indicators. The test data are shown in Table 3.

[0140] Table 3

[0141]

[0142] For the second gas gathering station, two locations were also selected for specialized testing. Twelve on-site venting simulation tests were conducted using a 2mm venting orifice. The alarm response time, positioning error, and alarm accuracy of the twelve tests all met the test specifications. The test data are shown in Table 4.

[0143] Table 4

[0144]

[0145]

[0146] This shows that the infrasound leakage monitoring system of the main line (first gas gathering station - second gas gathering station) has an alarm accuracy of 100%, the system alarm response time is less than 100 seconds, the system positioning error is less than 50m, and the key technical indicators of the system meet the specifications.

[0147] In summary, the evaluation method for the infrasound leakage monitoring system provided in this embodiment first performs a system self-test to obtain self-test index parameters. Then, it conducts simulated leakage tests under normal operating conditions at simulated leakage points to obtain normal operating condition simulated test data, and conducts simulated leakage tests under abnormal operating conditions to obtain abnormal operating condition simulated test data. Based on the normal operating condition simulated data and the abnormal operating condition simulated test data, it statistically derives the technical index parameters of the infrasound leakage monitoring system. Next, it sequentially conducts effectiveness tests on each sensor of the infrasound leakage monitoring system to obtain effectiveness index parameters, and conducts leakage signal simulation tests on the infrasound leakage monitoring system to obtain signal index parameters. Finally, based on the self-test index parameters, technical index parameters, effectiveness index parameters, and signal index parameters, it determines whether the performance of the infrasound leakage monitoring system is qualified.

[0148] In summary, the evaluation method for infrasound leakage monitoring systems provided in this embodiment covers both the software and hardware aspects of the leakage monitoring system, and accurately evaluates the effectiveness of the technical indicators of the leakage monitoring system. It can comprehensively evaluate the effectiveness of the technical indicators of natural gas pipeline leakage monitoring systems, promote the improvement of pipeline technical security management, and facilitate the analysis of weak links in natural gas pipeline leakage monitoring systems, thereby proposing targeted rectification and daily maintenance suggestions, and providing technical guidance and theoretical basis for the daily management and operation of leakage monitoring systems.

[0149] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for evaluating an infrasound leakage monitoring system, characterized in that, Includes the following steps: Perform a system self-test on the infrasound leakage monitoring system to obtain self-test index parameters; After confirming the operating conditions of the infrasound leakage monitoring system, the simulated discharge point was determined; Perform a simulated leakage test under normal operating conditions at the simulated discharge point and record the simulated leakage test data under normal operating conditions; Perform a simulated leakage test under abnormal operating conditions at the simulated discharge point and record the simulated leakage test data under abnormal operating conditions; Based on the normal operating condition simulation data and the abnormal operating condition simulation test data, the technical parameters of the infrasound leakage monitoring system are statistically derived. The effectiveness of each sensor in the infrasound leakage monitoring system was tested to obtain effectiveness index parameters. Leakage signal simulation tests were conducted on the infrasound leakage monitoring system to obtain the signal index parameters of the infrasound leakage monitoring system. Based on the self-test index parameters, the technical index parameters, the effectiveness index parameters, and the signal index parameters, determine whether the performance of the infrasound leakage monitoring system is qualified.

2. The evaluation method for infrasound leakage monitoring system according to claim 1, characterized in that, When performing a system self-test on the infrasound leak monitoring system, a system self-test should be performed on each natural gas pipeline covered by the infrasound leak monitoring system.

3. The evaluation method for infrasound leakage monitoring system according to claim 2, characterized in that, Performing a system self-test on an infrasound leakage monitoring system includes the following steps: Under normal operating conditions, based on the simulated leakage section of the infrasound leakage monitoring system, simulated leakage is carried out in at least two intervals. Perform system self-checks under abnormal operating conditions.

4. The evaluation method for infrasound leakage monitoring system according to claim 3, characterized in that, The interval between two adjacent simulated discharge operations is greater than 3 minutes.

5. The evaluation method for an infrasound leakage monitoring system according to claim 3, characterized in that, The abnormal operating conditions are that the infrasound leakage monitoring system is offline and disconnected from the explosion-proof box.

6. The evaluation method for an infrasound leakage monitoring system according to claim 1, characterized in that, Confirming the operating status of the infrasound leakage monitoring system includes the following steps: Close all sensors at a safe distance and confirm pipeline operation; Establish a cordon and a safety zone; Install and inspect temporary relief systems; Inspect the high-pressure hose and absorption device.

7. The evaluation method for an infrasound leakage monitoring system according to claim 6, characterized in that, The steps for installing and inspecting a temporary relief system are as follows: Close the ball valve of the local pressure gauge and remove the pressure gauge according to the operating procedures. Install a high-pressure ball valve for testing at the original pressure gauge interface; Install a simulated leakage test tool at the other end of the pressure gauge ball valve; Connect a high-pressure hose to the tail end of the simulated leak test tool and secure the high-pressure hose. Close the high-pressure ball valve for testing and open the original pressure gauge ball valve to check for leaks.

8. The evaluation method for an infrasound leakage monitoring system according to any one of claims 1 to 7, characterized in that, The simulated discharge points include debugging points and newly added test points. The newly added test points are located within the monitoring range of the corresponding sensors and are located on the main pipeline.

9. The evaluation method for an infrasound leakage monitoring system according to claim 8, characterized in that, The simulated leakage test under normal operating conditions includes the following steps: Replace the alkaline solution at the station according to the sulfur content at the site; Close the ball valve of the corresponding instrument and remove the pressure relief plug of the corresponding instrument, and install a test high-pressure ball valve at the pressure relief opening of the corresponding instrument; Install a simulated leak test tool at the other end of the high-pressure ball valve for testing, and connect the outlet of the leak test tool to the corresponding alkaline solution container; Close the high-pressure ball valve for testing, activate the pressure flow of the corresponding sensor, and open the ball valve of the corresponding instrument to check for leaks in the ventilation line. If there is a leak, reconnect the line. Check for leaks again after each reconnection of the line. Simulate pipeline rupture and leakage, and record simulation test data under normal operating conditions; Repeat the simulated pipeline rupture and leakage steps multiple times after a preset time interval; Repeat the testing at different test points until all simulated discharge points have been tested.

10. The evaluation method for an infrasound leakage monitoring system according to claim 9, characterized in that, The abnormal operating condition simulation leakage test includes the following steps: After removing one sensor, a simulated leak test under normal operating conditions was conducted.

11. The evaluation method for an infrasound leakage monitoring system according to claim 10, characterized in that, The abnormal operating condition simulation leakage test also includes the following steps: Disconnect the server power supply of the infrasound leakage monitoring system or disconnect the network connection of the infrasound leakage monitoring system, and then conduct the simulated leakage test under normal operating conditions.

12. The evaluation method for an infrasound leakage monitoring system according to claim 8, characterized in that, The effectiveness of each sensor in the infrasound leakage monitoring system is tested, including the capacitance and resistance of each sensor.

13. The evaluation method for an infrasound leakage monitoring system according to claim 8, characterized in that, The steps for simulating leakage signals in an infrasound leakage monitoring system are as follows: Select at least one point at any location along the upstream, midstream, and downstream of the pipeline; Connect the infrasound generator to the pipeline inside the pipeline test pile; The test was conducted by emitting infrasound waves of various frequencies below 20 Hz using an infrasound generator.

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