Coaxial cable strain monitoring system with redundancy function

Abstract

The utility model discloses a coaxial cable strain monitoring system with a redundancy function. The coaxial cable strain monitoring system comprises a coaxial cable provided with a plurality of strain sensors, and a vector network analyzer, one end of the coaxial cable is connected with a port A of the vector network analyzer, the other end of the coaxial cable is connected with the electronic switch, and the electronic switch is used for switching between the matched resistor and a port B of the vector network analyzer or a port B of another vector network analyzer. When the system works normally, the strain measurement precision of the coaxial cable connected with the matched resistor is high; when any part of the coaxial cable or the strain sensor is damaged, the microwave transmitting port of the other vector network analyzer is switched through the electronic switch, and the sensor can still work and can continue monitoring. The device is simple in structure, convenient to use and good in monitoring effect, can make full use of the damaged coaxial cable and the strain sensor, can judge the damaged position of the coaxial cable according to the feedback strain data, can be overhauled in time, and has very high practicability and wide applicability.

Description

Technical Field

[0001] The present invention relates to a strain monitoring system, specifically to a strain monitoring system for oil and gas pipelines using coaxial cables, belonging to the field of structural health monitoring. Background Art

[0002] Oil and gas pipelines often traverse different geological environments and are affected by natural disasters such as earthquakes and geological landslides. Real-time monitoring of oil and gas pipelines can detect the impacts of these external factors on the pipelines in a timely manner and take corresponding measures promptly. The strain monitoring system can not only improve the safety and reliability of oil and gas pipelines, but also optimize operations, reduce costs, and ensure compliance with regulatory requirements. Therefore, it plays an irreplaceable and important role in the management and maintenance of oil and gas pipelines.

[0003] Vibrating wire strain gauges and distributed optical fibers are widely used in the stress and strain monitoring of oil and gas pipelines. The vibrating wire strain gauge belongs to point-type sensing and is more economical when the number of monitoring points is small; the distributed optical fiber belongs to distributed sensing and can monitor oil and gas pipelines dozens of kilometers long, with hundreds or thousands of monitoring points, having great advantages in long-distance monitoring.

[0004] However, both the monitoring scheme of the vibrating wire strain gauge and the monitoring scheme of the distributed optical fiber have a drawback, that is, the monitored strain range is small. A typical vibrating wire strain gauge can measure ±3000 microstrains, and a specially designed vibrating wire strain gauge for large strain measurement can measure ±6000 microstrains. Limited by the fracture limit of glass optical fibers, the common distributed optical fiber can measure a strain range of ±20000 microstrains.

[0005] In some cases with harsh natural conditions, oil and gas pipelines undergo large deformations that exceed the measurement ranges of vibrating wire strain gauges and distributed optical fibers. At this time, a strain monitoring system using coaxial cables can monitor the large deformations of oil and gas pipelines. Coaxial cables can withstand ±150000 microstrains and are a favorable means for large deformation measurement. However, in the face of extreme natural conditions such as debris flows and landslides, coaxial cables may also be damaged.

[0006] Therefore, it is necessary to provide a coaxial cable strain monitoring system with redundancy to monitor the large deformations of oil and gas pipelines. Summary of the Invention

[0007] To solve the deficiencies of the prior art, the purpose of the present invention is to provide a coaxial cable strain monitoring system with redundancy for monitoring large deformations of oil and gas pipelines.

[0008] To achieve the above objectives, the present invention adopts the following technical solutions:

[0009] A coaxial cable strain monitoring system with redundancy function includes a coaxial cable provided with a number of strain sensors and a vector network analyzer;

[0010] One end of the coaxial cable is connected to the A port of the vector network analyzer,

[0011] The other end of the coaxial cable is connected to an electronic switch, which is used to switch between a matching resistor and the B port of the vector network analyzer or the B port of another vector network analyzer.

[0012] A number of vector network analyzers are connected in series by a number of coaxial cables through an electronic switch in turn.

[0013] The above vector network analyzer is connected to a data acquisition instrument, and the data acquisition instrument and the electronic switch are connected to a cloud host through a wireless module;

[0014] The vector network analyzer is used to obtain the strain data measured by the strain sensors and send it to the cloud host through the data acquisition instrument.

[0015] Furthermore, the above cloud host controls the electronic switch to switch between the matching resistor and the B port of the vector network analyzer according to the received strain data.

[0016] The characteristic impedance of the above coaxial cable is 50 ohms, and the matching resistor is 50 ohms.

[0017] The above strain sensors are fixed on the oil and gas pipeline, and the coaxial cable is laid beside the oil and gas pipeline.

[0018] The beneficial effects of the present invention are as follows:

[0019] For the coaxial cable strain monitoring system with redundancy function of the present invention, when the system works normally, the strain measurement accuracy of the coaxial cable connected to the matching resistor is relatively high; when any part of the coaxial cable or the strain sensor is damaged, through the electronic switch, the original end of the coaxial cable connected to the matching resistor is switched to the microwave transmitting port of another vector network analyzer, so that microwaves are injected into both ends of the coaxial cable. Although the strain measurement accuracy is reduced, most of the strain sensors can still work and can continue to be monitored. And the coaxial cable strain sensors are fixed on the oil and gas pipeline, and the coaxial cable is laid beside the oil and gas pipeline; since the strain sensors are buried in the soil together with the oil and gas pipeline, they can measure both tensile strain and compressive strain.

[0020] The oil and gas pipeline strain monitoring system using coaxial cable of the present invention has the advantages of simple structure, convenient use, good monitoring effect, high efficiency, can make full use of the damaged coaxial cable and strain sensors, and can determine the damage location of the coaxial cable according to the feedback strain data, which is convenient for timely maintenance, and has strong practicability and wide applicability. Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of a coaxial cable strain monitoring system;

[0022] Figure 2 It is a schematic structural diagram of an electronic switch connected to a matching resistor;

[0023] Figure 3 It is a schematic structural diagram of an electronic switch connected to the microwave transmission Port B.

[0024] The meanings of the marks in the attached drawings are as follows: 1. Vector network analyzer, 2. Coaxial cable, 3. Strain sensor, 4. Data acquisition instrument, 5. Cloud host, 6. Port A, 7. Port B, 8. Electronic switch, 9. Microwave transmission Port A, 10. Microwave transmission Port B, 11. Matching resistor. Specific embodiments

[0025] The present invention will be specifically introduced below in conjunction with the attached drawings and specific embodiments.

[0026] As Figure 1 shown, a coaxial cable strain monitoring system with redundant functions for monitoring oil and gas pipelines includes 3 vector network analyzers 1 and 2 coaxial cables 2. Counting from left to right, the vector network analyzers are the 1st, the 2nd, and the 3rd respectively; the coaxial cables each have 5 strain sensors 3, which are the 1st, the 2nd,..., the 10th respectively.

[0027] The vector network analyzers each have a Port A 6 and a Port B 7 for passing through the microwave transmission ports. The connection method is as follows: The Port A of the 1st vector network analyzer is connected to the head end of the 1st coaxial cable, the tail end of the 1st coaxial cable is connected to the electronic switch 8, and the two switching gears of the electronic switch are respectively connected to the matching resistor 11 and the Port B of the 2nd vector network analyzer. The Port A of the 2nd vector network analyzer is connected to the head end of the 2nd coaxial cable, the tail end of the 2nd coaxial cable is connected to the electronic switch, and the two switching gears of the electronic switch are respectively connected to the matching resistor and the Port B of the 3rd vector network analyzer.

[0028] The 3 vector network analyzers are respectively connected to the data acquisition instrument 4, and the data acquisition instrument is connected to the cloud host 5 through a wireless module.

[0029] In the normal working state, the microwave is emitted from the Port A of the 1st vector network analyzer, passes through the 1st to 5th strain sensors of the coaxial cable, and reaches the Port B of the 2nd vector network analyzer. At this time, as Figure 2 shown, at the Port B of the 2nd network analyzer, an electronic switch is provided at the tail end of the coaxial cable, and the electronic switch is connected to the matching resistor and disconnected from the Port B of the 2nd network analyzer.

[0030] The A port of the second vector network analyzer is connected to the second coaxial cable. That is, microwave rays are emitted from the A port of the second vector network analyzer, pass through the 6th to 10th strain sensors of the coaxial cable, and reach the B port of the third vector network analyzer.

[0031] In the normal working state, all three vector network analyzers operate in Figure 2 state, that is, at the B port, the electronic switch selects and connects to the matching resistor.

[0032] The vector network analyzer obtains the strain data at the position of the strain sensor by demodulating the microwave reflection signal on the strain sensor. The vector network analyzer is connected to the data acquisition instrument through the control and data lines. The data acquisition instrument transmits the collected strain data to the cloud host through wireless signals and receives instructions from the cloud host.

[0033] Suppose the third strain sensor is damaged during operation.

[0034] When the third coaxial cable strain sensor is damaged, the cloud host determines that the strain data measured by the first vector network analyzer is abnormal based on the feedback strain data. The cloud host controls the electronic switch of the second vector network analyzer through the data acquisition instrument, control, and data lines, so that the electronic switch disconnects from the matching resistor and connects to the B port of the second vector network analyzer, as Figure 3 shown.

[0035] At this time, microwave rays are emitted from the A port of the first vector network analyzer and from the B port of the second vector network analyzer respectively, and the strain data of the 1st, 2nd, 4th, and 5th strain sensors can still be measured. That is, at this time, the first and third vector network analyzers operate in Figure 2 state, and the second vector network analyzer operates in Figure 3 state.

[0036] Similarly, when the 7th strain sensor is damaged, the cloud host determines that the strain data measured by the second vector network analyzer is abnormal. The cloud host controls the electronic switch of the third vector network analyzer through the data acquisition instrument, control, and data lines, so that the electronic switch disconnects from the matching resistor and connects to the B port of the third vector network analyzer, as Figure 3 shown.

[0037] At this time, microwave rays are emitted from the A port of the second vector network analyzer and from the B port of the third vector network analyzer respectively, and the strain data of the 6th, 8th, 9th, and 10th strain sensors can still be measured. That is, at this time, the first and second vector network analyzers operate in Figure 2 state, and the third vector network analyzer operates in Figure 3 state.

[0038] When any one of the coaxial cable or the strain sensor is damaged, the measured strain accuracy decreases because no matching resistor is used. Moreover, in order to prevent more damages from occurring, the damaged part should be repaired as soon as possible to restore the system to its normal working state.

[0039] During actual use,

[0040] the electronic switch and the matching resistor can be set or integrated inside the vector network analyzer, that is, placed between port B and microwave transmitting port B10 for easy operation; port A is directly connected to microwave transmitting port A9; as Figure 2 and 3 shown.

[0041] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

Claims

1. A coaxial cable strain monitoring system with redundancy function, characterized in that: It includes a coaxial cable provided with a plurality of strain sensors, and a vector network analyzer; One end of the coaxial cable is connected to the A port of the vector network analyzer. The other end of the coaxial cable is connected to an electronic switch, and the electronic switch is used to switch between the matching resistor and the B port of the vector network analyzer or the B port of another vector network analyzer.

2. The strain monitoring system according to claim 1, characterized in that: A plurality of vector network analyzers are connected in series in sequence by a plurality of coaxial cables through an electronic switch.

3. The strain monitoring system according to claim 1, characterized in that: The vector network analyzer is connected to the data acquisition instrument, and the data acquisition instrument and the electronic switch are connected to the cloud host through a wireless module; The vector network analyzer is used to obtain strain data measured by the strain sensor and send the data to the cloud host through the data acquisition instrument.

4. The strain monitoring system according to claim 3, characterized in that: The cloud host controls the electronic switch to switch between the matching resistor and the B port of the vector network analyzer according to the received strain data.

5. The strain monitoring system according to claim 1, characterized in that: The strain sensor is fixed on the oil and gas pipeline, and the coaxial cable is laid beside the oil and gas pipeline.

Images