Method for detecting breakpoint position of linear anode

Abstract

The invention relates to a method for detecting a linear anode breakpoint position. An optical communication cable is arranged inside, on the outer surface or on the periphery of the linear anode and is arranged in the length direction of the linear anode, and the length of the optical communication cable is equal to that of the linear anode; the breakpoint position of the optical communication cable is measured with the optical communication cable test end as the starting point through the optical time domain reflection technology, and the measured breakpoint position is the position of the linear anode breakpoint.

Description

Technical Field

[0001] This field relates to the technical field of underground transmission pipeline maintenance, and particularly relates to a method for detecting the break point position of a linear anode. Background Art

[0002] With the completion and commissioning of many large-scale oil and gas storage and transportation projects in China, the maintenance work of storage and transportation facilities has become increasingly onerous. In particular, eliminating the potential safety hazards caused by pipeline and storage tank corrosion and leakage is the top priority of maintenance. The main root cause of the potential safety hazards of pipelines and storage tanks is the damage caused by pipeline corrosion by the environment. The cathodic protection technology can effectively solve the corrosion problem, so it is widely used in the corrosion control of buried pipelines, large storage tanks, ships, offshore oil production platforms, sluices and wharves, and reinforced concrete structures. The impressed current cathodic protection is applicable to large structures and occasions with large current requirements. The cathodic protection systems of long-distance pipelines, large storage tanks, and marine facilities have been widely used at home and abroad. To solve problems such as very high soil resistivity, inapplicability of deep well anode beds to underground structures, intricate buried pipelines in process stations, and interference with the cathodic protection system of long-distance pipelines, the linear anode bed was invented in the impressed current cathodic protection system. The application of the linear anode bed has solved the above technical problems that cannot be overcome by deep well anode beds and shallow buried anode beds.

[0003] A linear anode bed refers to a method of an auxiliary anode bed that lays a linear and easily bendable auxiliary anode along the protected body (such as the outer wall of a buried pipeline or a storage tank bottom plate) at a close distance to provide cathodic protection current. Linear anodes are divided into: conductive polymer linear anodes and mixed metal oxide linear anodes. However, it also has defects. For example, due to the rapid economic development in China, the process stations with dense buried pipelines are frequently renovated and expanded. The linear anodes laid underground along the buried pipelines are easily damaged by third parties during the renovation and expansion process. Because they are buried underground, once the linear anode breaks, it is very difficult to find the specific position of the break point of the linear anode, and it is difficult to repair in time, resulting in the failure of the cathodic protection system in the station area. As a result, the corrosion of the buried pipeline will be in a state where it can neither be controlled nor monitored; there are also instances where geological disasters such as earthquakes damage the linear anodes buried underground and cannot be repaired because the break points are difficult to find. Eventually, the cases of corrosion and leakage of buried pipelines occur frequently.

[0004] In the prior art, there is a solution to place a copper core cable into the linear anode to measure the break point position of the linear anode, such as Patent CN108823574. This solution uses a cable fault measuring instrument as the detection tool for measuring the break point position, but this solution has technical defects.

[0005] When using a cable fault measuring instrument to measure the position of the copper core break point with a pulse signal, there should not be multiple connection joints in the copper core cable itself. Because the measurement principle of commercially available cable fault measuring instruments is the ultrasonic reflection method, that is, a pulse signal is sent to the cable, and the break point or impedance mutation point is located through the reflected wave. And each joint may generate a small reflected signal. When the number of joints is large, the reflected waves will be superimposed, which will cover up the signal of the real break point, resulting in difficult positioning by the measuring instrument; the signal attenuation in the long copper core cable is already obvious, and multiple joints will exacerbate this problem. The contact resistance or impedance mismatch at the joints will attenuate the signal, and the superposition of the two factors reduces the effective detection distance of the measuring instrument; if the joint spacing is small, the measuring instrument may not be able to distinguish the joint reflection from the real break point.

[0006] Even if there are no joints on the copper core cable, if you want to improve the measurement accuracy of the break point position, it is also necessary to calibrate the wave velocity. For different cable models of the cable to be measured for breaks, the appropriate measurement wave velocity value for each cable model by the cable fault measuring instrument is a range value, not a fixed value. For example, for a cable to be measured for breaks with the specification ZA-KYJVP 22 -0.45 / 0.75kV 2×2.5mm 2 as an example, the appropriate wave velocity value range for this cable model for break measurement is between 176 and 183 m / ms; if a 100-meter-long cable of the above specification is found as a standard sample and the length of this cable is measured with a cable fault measuring instrument, the test wave velocity usually given by the instrument is 181 m / ms, and the measurement result is 101.4 m. Since the length of the standard sample is known to be 100 m, the appropriate measurement wave velocity x can be calculated accordingly, that is, 100 / x = 101.4 / 181, and the calculated result is x = 178.5. After setting the measurement wave velocity on the cable fault measuring instrument to 179 m / ms and then measuring the length of the standard sample again, it is 100.2 m. In this way, the measurement wave velocity with the smallest measurement error is determined. This technology is highly professional and the process is relatively complex.

[0007] During actual testing under the condition that the total range of the cable fault measuring instrument is 4 km, if there are no joints on the copper core cable, the measurement error of the open circuit fault is 0.2% - 1.4%; if there is one joint on the copper core cable to be measured for breaks, the measurement error of the open circuit fault is 2.2% - 8.3%; if there are two joints on the copper core cable to be measured for breaks, the measurement error of the open circuit fault is 4.9% - 16.2%; if there are three joints on the copper core cable to be measured for breaks, the cable fault measuring instrument may display an unclear fault or an impedance mismatch fault and cannot measure the open circuit fault. Table 1 is the measured data table.

[0008] Table 1 Influence of the number and position of cable joints on the measurement accuracy of the break point position

[0009]

[0010]

[0011] In practical applications, it is inevitable to use connectors to connect cables. The main situations are as follows: First, the common lengths of copper core cables on the market are usually 500m / roll or 1000m / roll. Therefore, the maximum length of copper core cable products is 1000m. To reduce costs, when making linear anode test cables, copper core cable products with market specifications are mostly purchased in batches. If the length of the linear anode exceeds 1000m, there will be at least one connector. Therefore, in the cathodic protection system of long-distance pipelines, it is very difficult to use the cable break detection function of the linear anode described in CN108823574. Because the cathodic protection of long-distance pipelines generally requires linear anodes of several kilometers or even more than ten kilometers, there will be more than two connectors for detecting the copper core cable, which will cause its cable break detection function to be unusable; or if you want to use it, you have to set a fault measurement point every 500m or 1000m; or specially customize a copper core cable without connectors that is as long as the linear anode; these are obviously uneconomical. Second, the linear anode made of the built-in copper core test cable described in CN108823574 is essentially disposable. Because if the linear anode laid underground is accidentally broken and the cable fault detector finds the break point of the linear anode, while repairing the linear anode, the broken copper core test cable also needs to be reconnected. This will result in a connector of the test cable. The existence of this connector will reduce the accuracy of the cable fault detector in finding new break points. If the linear anode is broken and repaired again, and the copper core test cable connector appears again, the cable fault detector will not be able to accurately judge the fault point. Therefore, to ensure accurate judgment of the break point of the linear anode, the linear anode with an internal test copper core cable can only be used once, which will greatly increase the cost.

[0012] When using a cable fault detector to detect the break point of a cable, although it is relatively effective in locating the break point, there are still the following main disadvantages: (1) High dependence on the cable: If the type of the cable to be detected is unknown or the insulating layer medium of the cable is uneven (such as aging, many connectors), slight insulation damage or partial deterioration will cause an increase in the positioning error; (2) Sensitive to environmental interference: Surrounding environmental noise (such as traffic, mechanical vibration) may cover or interfere with the conduction of ultrasonic waves, making it difficult for the sensor to capture effective signals, especially in a noisy industrial environment; surrounding high-voltage equipment, radio signals, etc. may interfere with the detection of electromagnetic sensors and reduce the signal-to-noise ratio; (3) Sensitive to environmental media: A humid environment or the soil conditions (clay, backfill soil, sand, sulfate-reducing bacteria, salt content, soil resistivity change) around the buried linear anode may interfere with the signal, resulting in misjudgment or measurement failure; (4) High requirements for equipment and operation: Professional equipment (high-voltage pulse generator, high-sensitivity acoustic magnetic sensor, etc.) and skilled operators are required. The equipment maintenance and operation are complex. If the operator does not have certain professional knowledge (such as waveform analysis ability), the results may be misread, the signals may be misjudged, or the detection may be missed.

[0013] Therefore, inventing a linear anode break point detection method and product with high precision, low cost, simple use, and strong practicability is an urgent problem to be solved in the current maintenance of underground long-distance pipelines and the detection of pipeline stations with complex environmental noise interference sources and many underground pipelines in process stations. Summary of the Invention

[0014] Idea of the Present Invention

[0015] Cathodic protection is an electrochemistry corrosion control technology. By making the protected metal structure (such as buried pipelines, storage tank bottoms, etc.) become the cathode in an electrochemical reaction, the method of slowing down or preventing its corrosion is achieved. Therefore, a technology that can measure the position of the other end of a linear anode from one end of the linear anode does not belong to the field of cathodic protection technology, and this problem can only be solved by crossing technical fields.

[0016] In the case where only one end is accessible, the other end is inaccessible or the position is unknown, when measuring the length of a long linear object, there are 6 optional measurement methods in 4 different technical fields:

[0017] (1) Capacitance measurement method based on electrical principles (capacitance or reflection technology). Its principle is to regard the long linear object (which needs to be an electronic conductor) as an electrode of a capacitor, and the other electrode is the surrounding environment (such as air or a grounded object). Capacitance C is proportional to length L. However, in single-end measurement, the measured is the parasitic capacitance of the material to the ground. The measurement error of this method mainly depends on the environment (such as humidity, distance to surrounding objects), generally between 5% and 20%.

[0018] (2) Resistance measurement method based on electrical principles (bridge technology). Its principle is to take a resistor with a known resistance value, connect this known resistor in series with the long linear object (which needs to be an electronic conductor), connect it to a power source (such as a battery or a constant voltage source), use bridge technology to measure the resistance of the long linear object, and then calculate the length of the long linear object using the resistivity law. The measurement error of this method mainly depends on environmental factors, contact resistance, and the transfer error of each data measurement, generally about 5%. Although this error is not large, considering that there are joints on the long linear object, the change in the cross-sectional area at the joint will cause a significant increase in the measurement error again because the resistivity formula requires the cross-sectional area of the object to be a definite data.

[0019] (3) Time domain reflectometry based on optoelectronic technology. Its principle is to send an electrical pulse or an optical pulse to one end of the long linear object and measure the time when the signal reflects back. Then calculate the length of the long linear object. If the propagation speed of the electrical pulse or optical pulse in the long linear object is known, the measurement error can be controlled within 1% - 5%; if the propagation speed needs to be estimated, the measurement error may reach 10%.

[0020] (4) Measuring the length of a long linear object by the (ultra) sound wave reflection method based on the acoustic principle, i.e., the technology adopted in Patent CN108823574, will not be elaborated here.

[0021] (5) The heat conduction method based on thermotics. Its principle is to apply a heat pulse at one end, measure the change of temperature with time, and inversely deduce the length by using the heat diffusion equation. This method is applicable to materials with high thermal conductivity (such as metals) and may also be effective for non-metals. However, the thermal physical properties of the material need to be known, and the error is usually between 10% and 30%, with relatively low accuracy.

[0022] (6) The vibration method based on mechanical principle, which is applicable to rigid materials. Its principle is to regard the long linear object as a cantilever beam fixed at one end and free at the other end, measure its natural vibration frequency, and calculate the length of the object through the relationship between the object length and the vibration frequency. The accuracy of this method depends on the accuracy of the material properties (density and elastic modulus), and the measurement error may be between 5% and 15%.

[0023] Among the above methods, the errors of Method 1, Method 5, and Method 6 are relatively large. Method 2 is not applicable to the case of multiple joints of the measured conductor. Method 5 and Method 6 are not applicable to linear anodes. The present invention is based on Method 3. On the basis of literature research and experimental data, the optical time domain reflectometry technology is considered for selection, and a suitable long linear object is to be found as the measurement carrier to reduce the measurement error, and the number and position of joints are fully considered so as not to increase the measurement error.

[0024] This solution overcomes the shortcomings of the prior art, and the specific technical solution is as follows:

[0025] Linear anode break point detection method

[0026] A break point measurement signal line for testing the break point of the linear anode, hereinafter referred to as the signal line, is arranged inside or on the outer surface or around the linear anode. The signal line is arranged in parallel with the inner copper core or inner cable of the linear anode itself along the length direction of the linear anode and is of the same length as the linear anode.

[0027] The minimum requirement for the effective cross-sectional area of the inner copper core or inner cable of the linear anode itself is 10 mm 2 . If the cross-sectional area of the copper core or cable is 10 mm 2 , then the converted diameter of the copper core or cable is 1.78 mm; if the cross-sectional area of the copper core or cable is 16 mm 2 , then the converted diameter of the copper core or cable is 2.26 mm; if the cross-sectional area of the copper core or cable is 25 mm 2 , then the converted diameter of the copper core or cable is 2.82 mm, which does not include the thickness of the inner copper core insulation layer or the inner cable sheath. Usually, the conventional outer diameter of the linear anode is 38 ± 2 mm.

[0028] The detection signal line uses optical fiber or optical cable, and optical fiber is preferably selected.

[0029] The practical optical fiber is a glass fiber slightly thicker than a human hair. The outer diameter of a general optical fiber is generally 125 - 140μm. 140μm is equivalent to 0.14mm, which is only one-thirteenth of the 1.78mm of the effective inner copper core or inner cable of the linear anode. The tensile strength of the optical fiber is about 700MPa, that is, a tensile force of 5 - 10N can break the optical fiber. The cross-sectional area is 10mm 2 The tensile strength of the copper core cable (only considering the copper core) is about 2500N, and the cross-sectional area is 16mm 2 The tensile strength of the copper core cable (only considering the copper core) is about 4000N, and the cross-sectional area is 25mm 2 The tensile strength of the copper core cable (only considering the copper core) is about 6250N. Once the linear anode is broken due to third-party construction or natural disasters, that is, the inner copper core or inner cable of the linear anode itself is broken, then the optical fiber signal line of the same length as the anode set along with the linear anode, which is much smaller in strength than the inner copper core or cable copper core, will also break at the same position.

[0030] Use the optical time domain reflectometry technology to measure the distance from the optical fiber measurement point to the break point. This distance is also the break point distance of the linear anode, and thus the break point position of the linear anode can be accurately determined.

[0031] The connection nodes of the optical fiber signal line have no influence on the measurement accuracy.

[0032] Optical time domain reflectometry is a non-destructive measurement technology used to test the performance and faults of optical fibers in optical fiber communication systems. It is a technology that evaluates the length, loss, joint quality, and break point fault position of optical fibers by sending optical pulses into the optical fiber and analyzing the reflected signals.

[0033] The basic principle of optical time domain reflectometry is as follows:

[0034] (1) Optical pulse emission: The optical pulse emission and reception analysis device emits a short-time high-intensity optical pulse from one end of the optical fiber.

[0035] (2) Reflection and scattering: When light propagates in the optical fiber, echoes are generated due to the following reasons:

[0036] - Rayleigh Scattering: Microscopic inhomogeneities in the optical fiber material cause part of the light to be scattered backward.

[0037] - Fresnel Reflection: Strong specular reflections are generated at the break points, joints, or ends of the optical fiber.

[0038] (3) Signal analysis: The optical pulse emission and reception analysis device generates the loss curve along the optical fiber (called the OTDR trace) by receiving the intensity and time of the reflected signal, and then locates the events in the optical fiber (such as breakpoints, joints, bends, etc.). Optical time domain reflectometry can accurately measure the total length of the optical fiber, and the error is usually at the meter level or even the centimeter level.

[0039] The typical feature of an optical fiber breakpoint is that the signal drops sharply (no subsequent signal) after the Fresnel reflection peak (high-intensity reflection), and this feature is usually significantly different from the loss caused by a joint (low reflection, small attenuation). When the optical pulse emission and reception analysis device measures an optical fiber breakpoint, the breakpoint will generate a strong reflection peak and signal interruption. Different from the loss characteristics of joints, even if there are multiple joints, the breakpoint can still be identified by waveform features; the optical pulse emission and reception analysis device analyzes the optical fiber section by section, and each joint or breakpoint is independently located on the time axis, and the joint will not cover up the existence of subsequent breakpoints. Therefore, when using the optical pulse emission and reception analysis device to measure the breakpoint of the optical fiber, there is no requirement for the number of joints on the optical fiber. Even if there are multiple optical fiber joints, it is still possible to accurately determine the breakpoint position of the linear anode equal in length to the optical fiber by measuring the optical fiber breakpoint. Whether there are optical fiber joints or different forms of optical fiber joints, as long as the light is in a conducting state between the optical fiber measurement point and the breakpoint, the position from the measurement point to the optical fiber breakpoint can be found.

[0040] Therefore, when using the optical pulse emission and reception analysis device to measure the breakpoints of the optical fiber break detection signal lines arranged inside and outside the linear anode, as long as the length of the optical fiber is the same as that of the linear anode, regardless of whether there are knots on the optical fiber and how many knots there are, it does not affect the measurement accuracy of the device; due to repeated breakage and multiple repairs of the linear anode caused by third-party construction and natural geological disasters, there will also be multiple repair nodes on the optical fiber as the break detection signal line, but it does not affect the measurement accuracy of the device.

[0041] Other advantages of the optical fiber signal line:

[0042] The optical pulse emission and reception analysis device uses optical wave conduction and has nothing to do with surrounding interference sources such as electricity, magnetism, and sound; due to the principle of optical time domain reflectometry, the optical pulse emission and reception analysis device has a high degree of integration and automation. A miniaturized and intelligent digital device can be used with simple training for general personnel and does not require experienced professional detection personnel, and the measurement of faults is simple and fast.

[0043] Types of optical communication cables selected for the break detection signal line:

[0044] Optical fiber or optical cable.

[0045] 1. Optical fiber: Also known as optical waveguide fiber or optical fiber, it is a fiber made of glass or plastic and is an optical conduction tool that uses the principle of total internal reflection of light to transmit light in these fibers.

[0046] 2. Optical cable: Also known as fiber optic cable, it is a component similar to a cable but contains one or more optical fibers for transmitting light.

[0047] Any optical fiber or optical cable that meets the above definition can be used as the optical communication cable break detection signal line of the linear anode.

[0048] In actual use, the specifications, lengths, and position settings of the linear anode and the optical communication cable signal line.

[0049] 1. The signal line can be one or more optical fibers or one or more optical cables.

[0050] 2. The signal line can be various permutations and combinations of one or more optical fibers or one or more optical cables, such as optical fibers and / or optical fibers and / or fiber optic cables.

[0051] 3. The length of the optical communication cable used as the break detection signal line is equal to that of the linear anode according to the laying requirements of the linear anode.

[0052] 4. The optical communication cable used as the break detection signal line can be set inside the linear anode, that is, at any position in the coke filler between the copper core or inner cable and the wrapping fabric inside the anode. The distance H between the outer surface of the signal line and the conductive polymer coating or mixed metal oxide coating of the linear anode or the outer surface of the inner cable can be 0 mm; or greater than 0 mm and less than or equal to 0.1 mm; or greater than 0.1 mm and less than or equal to 10 mm; or greater than 10 mm and less than or equal to 21 mm; or greater than 21 mm and less than 100 mm.

[0053] The signal line can also be set between the acid and alkali resistant woven layer and the wear resistant woven layer of the linear anode, that is, the signal line is clamped in any position along the circumference between the acid and alkali resistant woven layer and the wear resistant woven layer in the length direction.

[0054] 5. The optical communication cable used as the break detection signal line can be set on the outer surface of the linear anode, that is, the signal line is fixed or not fixed at any position along the circumference of the wear resistant woven layer of the linear anode.

[0055] 6. The optical communication cable used as the break detection signal line can be laid in parallel in the area around the outer surface of the linear anode when the linear anode is laid. The distance d between the outer surface of the signal line and the outer surface of the wear resistant woven layer of the linear anode is 0 mm; or greater than 0 mm and less than or equal to 0.1 mm; or greater than 0.1 mm and less than or equal to 10 mm; or greater than 10 mm and less than or equal to 100 mm; or greater than 100 mm and less than or equal to 1000 mm.

[0056] In the above 4, 5, and 6, the position area where the optical communication cable is set preferably selects the area of the linear anode facing the ground surface.

[0057] 7. The linear anodes described in the present invention include: conductive polymer linear anodes, MMO / Ti linear anodes, and copper core mixed metal oxide layer linear anodes. The conventional outer diameter of the linear anode is usually 38 ± 2 mm or 40 ± 2 mm, and larger outer diameters of the linear anode can also be customized according to actual needs.

[0058] Beneficial effects

[0059] 1. The linear anode with an optical communication cable as the fault detection signal line can be spliced and used according to the actual required length of the linear anode. Multiple connection nodes do not affect the accuracy of the optical pulse emission and reception analysis device for detecting the break point. When applied to the maintenance of the linear anode of a long transmission pipeline, the measurement of the break point is accurate and the efficiency is high.

[0060] 2. The linear anode with an optical communication cable as the fault detection signal line can be repeatedly broken and repaired. Even if natural disasters or third-party construction cause the linear anode of the intricate buried pipelines in the process field station to be broken multiple times, and even if there are multiple connection joints in the optical communication cable used as the fault detection signal line after repeated repair, the accuracy of detecting the break point position with the optical pulse emission and reception analysis device again is still very high. This improves the number of uses of the linear anode, extends its service life, and reduces costs.

[0061] 3. The linear anode with an optical communication cable as the fault detection signal line is constructed by arranging the optical communication cable inside the linear anode, on the wear-resistant braided skin of the linear anode, or laid parallel along the length direction of the linear anode around it. It is simple and fast. At the same time, there is no problem of mutual interference between the optical fiber break point measurement and the electrical, magnetic, and acoustic signals of the linear anode and its surroundings. It not only achieves the purpose of accurately measuring the break point of the linear anode but also reduces the use cost, with strong practicability.

[0062] 4. For the linear anode with an optical communication cable as the fault detection signal line, only the optical pulse emission and reception analysis device needs to be connected to the detection port of the optical communication cable, and the data result can be read on the device. The detection procedure is simple and fast. Description of the drawings

[0063] Figure 1 Is the cross-sectional structure diagram of the conductive polymer linear anode with the optical communication cable built-in

[0064] Figure 2 Is the cross-sectional structure diagram of the MMO / Ti linear anode

[0065] Figure 3 Is the cross-sectional structure diagram of the copper core mixed metal oxide layer linear anode

[0066] Figure 4 Is the cross-sectional structure diagram of the optical communication cable built-in in the conductive polymer linear anode

[0067] Figure 5 Is the cross-sectional structure diagram of the optical communication cable built-in in the MMO / Ti linear anode

[0068] Figure 6 Cross-sectional structure of a linear anode built into a copper core mixed metal oxide layer for optical communication cables

[0069] Figure 7 Cross-sectional structure diagram of optical communication cables bundled on a conductive polymer linear anode wear-resistant braided mesh

[0070] Figure 8 Cross-sectional structure diagram of optical communication cables bundled on MMO / Ti linear anode wear-resistant braided mesh

[0071] Figure 9 Cross-sectional structure diagram of optical communication cables bundled on a copper core mixed metal oxide layer linear anode wear-resistant braided mesh

[0072] Figure 10 Schematic diagram of the preferred position area of the linear anode facing the ground surface when the optical communication cable is arranged parallel along the length

[0073] Figure 11 Schematic diagram of a method for measuring breakpoints of an optical pulse transmitting, receiving and analyzing device through a linear anode built into an optical communication cable signal line

[0074] Figure 12 Schematic diagram of a method for measuring breakpoints of optical communication cable signal lines bundled on the surface of a linear anode by an optical pulse transmitting and receiving analysis device

[0075] Figure 13 Schematic diagram of a method for measuring breakpoints of an optical communication cable signal line through a linear anode external area by an optical pulse transmitting and receiving analysis device

[0076] Figure 14 Schematic diagram of a method for measuring breakpoints of an optical communication cable signal line by a linear anode clamped between an acid- and alkali-resistant braid layer and a wear-resistant braid layer using an optical pulse transmitting and receiving analysis device

[0077] Figure 15 A cross-sectional diagram of the structure of an optical communication cable sandwiched between an acid- and alkali-resistant braid layer and a wear-resistant braid layer in a conductive polymer linear anode.

[0078] Figure 16 Cross-sectional structure diagram of an optical communication cable sandwiched between an MMO / Ti linear anode acid- and alkali-resistant braid layer and a wear-resistant braid layer

[0079] Figure 17 The cross-sectional structure of an optical communication cable sandwiched between a copper core mixed metal oxide layer linear anode acid- and alkali-resistant braid layer and a wear-resistant braid layer

[0080] Reference numerals: 8, test terminal junction box; 9, optical pulse transmitting, receiving and analyzing device; 10, linear anode; 11a, copper core inside the linear anode; 11b, cable inside the linear anode; 12, optical communication cable; 13, conductive polymer coating layer; 14, coke coating layer; 15, acid and alkali resistant woven layer; 16, wear resistant woven layer; 17, MMO / Ti anode wire; 18, mixed metal oxide coating layer; 19, bundling tape or adhesive tape; 20, preferred setting area of the optical communication cable. Detailed implementation manners

[0081]

Example 1

[0082] S01. In actual use, optical fibers include but are not limited to: step-index optical fibers (also known as abrupt-index optical fibers), or graded-index optical fibers, or single-mode optical fibers (including conventional single-mode optical fibers, dispersion-shifted single-mode optical fibers and non-zero dispersion-shifted optical fibers), or multi-mode optical fibers, or silica-based optical fibers, or multi-component glass optical fibers, or plastic-clad silica-core optical fibers, or all-plastic optical fibers, or fluoride optical fibers, or polarization-maintaining optical fibers, or photonic crystal optical fibers;

[0083] In actual use, optical cables include but are not limited to: single-mode optical cables, or multi-mode optical cables, or stranded optical cables, or skeleton optical cables, or central tube optical cables, or ribbon optical cables, or indoor optical cables, or outdoor optical cables, or submarine optical cables, or special optical cables, or communication optical cables, or sensing optical cables, or medical optical cables, or non-armored optical cables, or steel tape armored optical cables, or steel wire armored optical cables, or metal-reinforced optical cables, or non-metal-reinforced optical cables.

[0084] S02. As Figure 1 , Figure 2 , Figure 3 shown, the types of linear anodes include but are not limited to: conductive polymer linear anodes, MMO / Ti linear anodes, copper core mixed metal oxide layer linear anodes, with a conventional outer diameter of 38±2 mm or 40±2 mm, and larger linear anode outer diameters can be customized according to actual needs.

[0085]

Example 2

[0086] S11. Select any optical communication cable including but not limited to those in S01 of Example 1, and place it inside any linear anode including but not limited to those in S02 of Example 1, as Figure 4 , Figure 5 , Figure 6As shown: 11a copper core inside the linear anode, 11b cable inside the linear anode, 12 optical communication cable, 13 conductive polymer coating layer, 14 coke coating layer, 15 acid and alkali resistant woven layer, 16 wear-resistant woven layer, 17 MM0 / Ti anode wire, 18 mixed metal oxide coating layer. The distance H between the optical communication cable 12 and the conductive polymer coating layer (13) or the mixed metal oxide coating layer (18) or the cable 11b inside the linear anode can be: 0mm, 0 - 0.1mm (inclusive), 0.1 - 10mm (inclusive), 10 - 21mm (inclusive), 21 - 100mm. Setting the optical communication cable within this distance range can ensure its synchronous breakage with the linear anode, guaranteeing the accuracy of measuring the break point;

[0087] S12. As Figure 11 shown, bury the linear anode 10 with the signal wire 12 of the built-in optical communication cable into the ground for cathodic protection of the underground transmission pipeline. When natural disasters such as earthquakes or third-party construction occur, it is necessary to detect whether the linear anode is disconnected. Connect the signal wire 12 of the built-in optical communication cable of the linear anode 10 to the optical pulse transmitting and receiving analysis device 9 through the test terminal junction box 8. The device 9 injects a series of optical surges into the optical communication cable 12, and then the optical communication cable 12 on the same side as the injected surge receives the optical signal. The injected signal will scatter and reflect back when encountering media with different refractive indices; due to the sudden termination of the optical communication cable 12 at the break point, a significant Fresnel reflection is formed, that is, when light encounters an interface with a sudden change in refractive index, strong reflection occurs; at the break point, a sharp peak appears in the signal curve of the optical pulse transmitting and receiving analysis device, and then the signal drops suddenly, that is, a Fresnel reflection peak appears. After the strong reflection peak, the signal disappears, which means breakage. The starting point of the reflection peak corresponds to the break position, and the distance can be accurately read through the device to quickly determine the break point position.

[0088] For example: In actual application, when using the optical pulse transmitting and receiving analysis device to test the optical fiber, if the OTDR trace shows that the signal returns to zero after a peak, the calculation of the break point distance is as follows: The refractive index IOR of the optical communication cable 12 is marked as 1.468, C is the speed of light. The round-trip time t of the transmitted and received optical pulses is directly measured by the device and automatically calculated, and the break point distance result D is displayed on the device.

[0089] S13. The optical communication cable 12 is the same length as the linear anode 10, so the break point and the break point of the linear anode 10 are at the same location. Then, dig out the broken head of the linear anode 10 at the determined break point for repair. The optical communication cable 12 is also repaired by connecting the optical fiber joint process or connector at the same time. Then, bury the repaired linear anode 10 with the signal wire 12 for measuring the break of the built-in optical communication cable back into the ground for cathodic protection of the transmission pipeline. Through this method, the break point of the damaged linear anode 10 can be repeatedly searched and repaired. Each time, the accuracy of the break point distance detected by the optical pulse transmitting and receiving analysis device is not affected by the number of connection nodes of the signal wire 12 for measuring the break of the optical communication cable.

[0090] S14. In specific applications, in order to reduce costs, the standard specifications of the optical communication cable 12 suppliers are preferably considered. The general common specifications are: short jumpers are 1 m to 30 m, and standard reels are 1 km to 5 km. When the linear anode 10 is equipped with the optical communication cable break detection signal line 12 according to the actual demand, when protecting a long transmission pipeline, the optical communication cable 12 should be kept the same length as the linear anode 10 of more than ten kilometers. If the general specification optical communication cable 12 is not long enough, it can be connected at the node by means such as fiber fusion splicing, mechanical splicing, cold splicing, fiber optic connectors, and fiber optic adapters to keep the optical communication cable 12 and the linear anode 10 of equal length.

[0091]

Embodiment III

[0092] S21. As Figure 7 , Figure 8 , Figure 9 shown, select any optical communication cable in S01 of Embodiment I, including but not limited to, and bundle or bond it to any linear anode wear-resistant braided net 16 in S02 of Embodiment I. 11a is the copper core inside the linear anode, 11b is the cable inside the linear anode, 12 is the optical communication cable, 13 is the conductive polymer coating layer, 14 is the coke coating layer, 15 is the acid and alkali resistant woven layer, 16 is the wear-resistant braided layer, 17 is the MMO / Ti anode wire, 18 is the mixed metal oxide coating layer, 19 is the bundling tape or bonding tape;

[0093] S22. As Figure 12 shown, fix the optical communication cable signal line 12 to the wear-resistant braided net of the linear anode 10 and bury it underground for cathodic protection of the underground transmission pipeline. The remaining steps for measuring the break point are the same as S12 and S13 in Embodiment II, and will not be elaborated here.

[0094]

Embodiment IV

[0095] S31. As Figure 15 , Figure 16 , Figure 17 shown, select any optical communication cable in S01 of Embodiment I, including but not limited to, and clamp it between the acid and alkali resistant woven layer 15 and the wear-resistant braided net 16 of any linear anode in S02 of Embodiment I. 11a is the copper core inside the linear anode, 11b is the cable inside the linear anode, 12 is the optical communication cable, 13 is the conductive polymer coating layer, 14 is the coke coating layer, 15 is the acid and alkali resistant woven layer, 16 is the wear-resistant braided layer, 17 is the MM0 / Ti anode wire, 18 is the mixed metal oxide coating layer;

[0096] S32. As Figure 14As shown in the figure, the signal line 12 of the optical communication cable is sandwiched between the acid and alkali resistant woven layer 15 and the wear-resistant woven mesh 16 of the linear anode 10 and buried underground to carry out cathodic protection on the underground transmission pipeline. The steps of measuring the remaining breakpoints are the same as those of S12 and S13 in the second embodiment, and will not be elaborated here.

[0097]

Embodiment Five

[0098] S41. As Figure 10 shown, select any optical communication cable including but not limited to those in S01 of Embodiment One, and lay it parallel to the underground along the length direction with any linear anode including but not limited to those in S02 of Embodiment One. 10 linear anodes, 12 optical communication cables, 16 wear-resistant woven layers, 20 preferred setting areas for optical communication cables. The distance d between the optical communication cable 12 and the wear-resistant woven layer 16 of the linear anode 10 includes but not limited to: 0mm, 0 - 0.1mm (including), 0.1 - 10mm (including), 10 - 100mm (including), 100 - 1000mm (including). The preferred setting range of the optical communication cable 12 is shown as the dotted part 20 in the figure, which is the area of the linear anode facing the ground;

[0099] S42. As Figure 13 shown, place the signal line 12 of the optical communication cable and the linear anode 10 parallel to each other at the designed distance and bury them underground at the same time to carry out cathodic protection on the underground transmission pipeline. The steps of measuring the remaining breakpoints are the same as those of S12 and S13 in the second embodiment, and will not be elaborated here.

[0100] The above is the specific description and implementation mode of the present invention. The implementation methods disclosed in the specification are only the implementation methods of the features, and can be changed to a certain extent in combination with the prior art within the scope of the claims. Any modifications, equivalent replacements, improvements, etc., made without affecting the beneficial effects of the technology shall be included within the protection scope of the present invention.

Claims

1. A method for detecting the break point position of a linear anode, characterized in that, Comprising: An optical communication cable (12) is disposed inside or on the outer periphery of a linear anode (10); The optical communication cable (12) having the same length as the linear anode (10) is arranged parallel to the copper core (11a) inside the linear anode or the cable (11b) inside the linear anode along the length direction of the linear anode (10); An optical pulse transmitting, receiving and analyzing device (9) is connected to the optical communication cable (12) at a measurement point for measuring whether the optical communication cable (12) is disconnected. If it is disconnected, the copper core (11a) inside the linear anode or the cable (11b) inside the linear anode of the linear anode (10) is also disconnected at the same position. The distance of the disconnection point of the optical communication cable (12) measured by the optical pulse transmitting, receiving and analyzing device (9) is the distance from the disconnection point of the copper core (11a) inside the linear anode or the cable (11b) inside the linear anode of the linear anode (10) to the measurement point of the optical pulse transmitting, receiving and analyzing device (9).

2. The method according to claim 1, characterized in that, The optical communication cable (12) includes: optical fiber or optical fibre or fiber optic cable.

3. The method according to claim 2, characterized in that The radial dimension of the optical fiber or optical fibre or fiber optic cable is smaller than the radial dimension of the copper core (11a) inside the linear anode or the cable (11b) inside the linear anode.

4. The method according to claim 2, wherein The optical communication cable (12) includes: one or more of the optical fibers or optical fibres, or one or more of the fiber optic cables; various permutations and combinations of one or more of the optical fibers or optical fibres and one or more of the fiber optic cables, optical fiber and / or optical fibre and / or fiber optic cable.

5. The method according to claim 2, characterized in that, The optical communication cable (12) matches the length of the linear anode (10) and may or may not have connection nodes.

6. The method according to claim 1, wherein The linear anode (10) includes: conductive polymer linear anode or MMO / Ti linear anode or copper core mixed metal oxide layer linear anode.

7. The method according to claim 1, wherein When the optical communication cable (12) is disposed inside the linear anode (10), in the coke coating layer (14) between the copper core (11a) inside the linear anode or the cable (11b) inside the linear anode and the acid and alkali resistant coating (15), the distance between the optical communication cable (12) and the conductive polymer coating layer (13) or the mixed metal oxide coating layer (18) or the cable (11b) inside the linear anode is H, and H is greater than or equal to 0 mm and less than 100 mm.

8. The method according to claim 7, wherein The H is equal to 0 mm; or greater than 0 mm and less than or equal to 0.1 mm; or greater than 0.1 mm and less than or equal to 10 mm; or greater than 10 mm and less than or equal to 21 mm; or greater than 21 mm and less than 100 mm.

9. The method according to claim 1, wherein When the optical communication cable (12) is disposed inside the linear anode (10), it is sandwiched between the acid and alkali resistant woven layer (15) and the wear resistant woven layer (16) of the linear anode.

10. The method according to claim 1, wherein When the optical communication cable (12) is disposed on the outer periphery of the linear anode (10), the distance between the optical communication cable (12) and the wear resistant woven layer (16) is d, and d is greater than or equal to 0 mm and less than or equal to 1000 mm.

11. The method according to claim 10, wherein The d is equal to 0 mm; or greater than 0 mm and less than or equal to 0.1 mm; or greater than 0.1 mm and less than or equal to 10 mm; or greater than 10 mm and less than or equal to 100 mm; or greater than 100 mm and less than or equal to 1000 mm.

12. The method according to claim 11, wherein When the d is equal to 0 mm, the optical communication cable (12) may or may not be fixed to the wear-resistant braided layer (16) on the outer surface of the linear anode (10).

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