Optical cable capable of being remotely inspected as well as preparation method and application of optical cable

Abstract

The invention discloses an optical cable capable of being remotely inspected and a preparation method and application thereof, and belongs to the technical field of optical cable preparation, the optical cable comprises an optical unit, an electric unit and an outer sheath, the optical unit is arranged in a containing space of the outer sheath, the electric unit is connected with the outer sheath, the arrangement direction of the electric unit is parallel to the axis of the outer sheath, and the optical cable is arranged in the containing space. And the positive excess length of the electrical unit relative to the outer sheath is 0.05%-0.8%. According to the optical cable capable of being remotely inspected, when the optical cable is coated with ice, the electric unit and the outer sheath are synchronously stretched, the electric unit cannot be stretched and thinned due to the existence of the positive excess length, after the stretched length of the outer sheath makes up the excess length of the electric unit, the electric unit is stretched along with the outer sheath, and the increase of wave impedance of the electric unit can be detected through a TDR detection technology; an optical cable maintainer can maintain the optical cable in advance when the wave impedance of the electric unit is increased, the ice on the surface of the optical cable is removed, and the problem of cable breakage caused by continuous accumulation of ice and snow is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical cable preparation, and in particular relates to an optical cable capable of remote inspection and a preparation method and application thereof. Background Art

[0002] Optical cable is a type of communication cable, which is usually composed of a single or multiple optical fibers and is mainly used to transmit optical signals. Optical cable has the characteristics of large capacity, low attenuation, anti-interference and good confidentiality.

[0003] With the continuous change of climate and the continuous destruction of the environment, the current extreme weather is becoming more and more common. Especially in the north, when there is extremely cold weather, a large amount of snow will accumulate on the overhead optical cables. Eventually, the weight of the snow accumulation exceeds the weight of the optical cables, causing the optical cables to break. In severe cases, it may even damage or cause the towers to tilt and collapse, resulting in communication interruption.

[0004] In order to solve the problem that cables are prone to breakage in an ice-covered environment, the existing solutions mainly include setting a rotating structure on the outside of the optical cable. When the ice on the outer periphery of the cable reaches a certain weight, the rotating structure rotates relative to the optical cable to throw the snow off the surface of the optical cable, thereby reducing the snow accumulation on the surface of the optical cable. However, the rotating structure itself will seriously increase the weight of the optical cable itself. In an environment where the cable is overhead for tens of kilometers, the rotating structure itself will cause a large amount of load-bearing on the optical cable and greatly increase the cost of the optical cable per kilometer, which is of low practicality. In addition to changing the external shape of the optical cable, there is also a heating element buried inside the optical cable to melt the snow by heating the inside of the optical cable. However, due to the long distance of the optical cable layout, the use of heating will result in a large waste of energy, and the cable maintenance personnel cannot determine the ice coverage of the cable. If the heating is continued, the maintenance cost of the optical cable will increase significantly. In addition, the conventional wire heating structure will cause a large waste of energy, and the buried heating element will not only increase the difficulty of preparing the optical cable, but also increase the cost of the optical cable. Summary of the invention

[0005] In response to one or more of the above defects or improvement needs in the prior art, the present invention provides an optical cable that can be remotely inspected, which embeds an electric unit in the optical cable and controls the shrinkage excess length ratio of the electric unit and the outer sheath. When the optical cable is covered with ice, the electric unit is stretched together with the outer sheath. When the outer sheath is stretched to make up for the excess length of the electric unit, the electric unit is stretched and thinned together with the outer sheath. The increase in local wave impedance of the electric unit can be quickly detected by TDR detection technology. When the local wave impedance of the electric unit increases, the staff can remove the ice on the surface of the optical cable to avoid the problem of optical fiber breakage inside the cable.

[0006] To achieve the above object, the present invention provides a remotely inspectable optical cable, comprising:

[0007] An optical unit, an electrical unit and an outer sheath, wherein the outer sheath is coated on the outer periphery of the optical unit and the electrical unit;

[0008] The optical unit is arranged in the accommodation space of the outer sheath, the electrical unit is at least partially connected to the outer sheath, and the arrangement direction of the electrical unit is parallel to the axis of the outer sheath;

[0009] The positive excess length of the electrical unit relative to the outer sheath is 0.05% to 0.8%.

[0010] As a further improvement of the present invention, the outer sheath is an eccentric structure, the outer sheath includes a center and a center of gravity, and the electrical unit is arranged on a side of the center of gravity away from the center.

[0011] As a further improvement of the present invention, the electrical unit is embedded between the inner wall and the outer wall of the outer sheath.

[0012] As a further improvement of the present invention, the shortest distance between the electrical unit and the outer wall of the outer sheath is not less than 0.6 mm; the shortest distance between the electrical unit and the inner wall of the outer sheath is not less than 0.3 mm.

[0013] As a further improvement of the present invention, there are at least two electrical units, and the plurality of electrical units are evenly arranged in an annular direction with the axial center of the outer sheath as the center.

[0014] As a further improvement of the present invention, the electrical unit is partially embedded in the inner wall of the outer sheath, and the remaining portion of the electrical unit is located in the accommodating space of the outer sheath.

[0015] As a further improvement of the present invention, the portion of the electrical unit embedded in the inner wall of the outer sheath is larger than the portion of the electrical unit located in the accommodating space of the outer sheath.

[0016] As a further improvement of the present invention, the tensile modulus of the outer sheath is 100-1500 MPa, and the tensile strength is 7-30 MPa.

[0017] The present application also includes a method for preparing an optical cable capable of remote inspection, comprising the following steps:

[0018] The traction optical unit uses a pay-off device to synchronously pay out the electrical unit;

[0019] Extruding an outer sheath around the optical unit and the electrical unit, and cooling and shaping the outer sheath;

[0020] The prepared cable is wound up using a wire-winding device, wherein the wire-winding speed of the wire-winding device is greater than the wire-winding speed of the wire-winding device, so that the electrical unit forms a positive excess length in the outer sheath.

[0021] As a further improvement of the present invention, the ratio of the wire-releasing rate of the wire-releasing device to the wire-retrieving rate of the wire-retrieving device is: 101-102:100.

[0022] As a further improvement of the present invention, the speed of at least one of the pay-off device or the take-up device is adjustable; the speed adjustment method of the pay-off device or the take-up device includes:

[0023] Real-time detection of the relative excess length between the electrical unit and the outer sheath;

[0024] If the relative excess length between the electrical unit and the outer sheath is less than the preset excess length, the wire-releasing speed of the wire-releasing device is increased or the wire-retracting speed of the wire-retracting device is decreased;

[0025] If the relative excess length between the electrical unit and the outer sheath is greater than the preset excess length, the wire-releasing speed of the wire-releasing device is reduced or the wire-retracting speed of the wire-retracting device is accelerated.

[0026] The present invention also includes an application of an optical cable that can be remotely inspected, which involves burying an electric unit in the outer sheath of the optical cable and controlling the shrinkage excess length ratio of the electric unit to the outer sheath; when the optical cable is covered with ice, the electric unit is stretched together with the outer sheath, and when the outer sheath is stretched to a length that compensates for the excess length of the electric unit, the electric unit is stretched and thinned together with the outer sheath, and the local wave impedance change of the electric unit is detected by TDR detection technology to determine the ice coverage condition of the optical cable surface.

[0027] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0028] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects:

[0029] (1) The remotely inspectable optical cable of the present invention embeds an electric unit structure inside the optical cable structure, arranges the electric unit parallel to the axis of the outer sheath, and controls the excess length of the electric unit and the outer sheath so that the electric unit has a positive excess length relative to the outer sheath. When the remotely inspectable optical cable is covered with ice and subjected to stress, the electric unit and the outer sheath are stretched together. Since the electric unit has a positive excess length relative to the outer sheath, the electric unit will not be stretched and deformed. When the outer sheath is stretched to a certain length, the length of the electric unit is consistent with the length of the outer sheath. The electric unit is stretched and thinned together with the outer sheath, resulting in an increase in the resistance of the electric unit. The increase in the local wave impedance of the electric unit can be quickly sensed through the TDR detection technology. Before the optical fiber inside the optical cable and the outer sheath are damaged, the relevant staff removes snow from the surface of the detection section of the optical cable to avoid the problem of communication interruption caused by the internal optical fiber of the optical cable being broken. The remotely inspectable optical cable in the present application does not require additional structural parts on the outside of the optical cable, nor does it require a heating element to be arranged inside the optical cable. It only requires an electrical unit to be buried inside the cable, and the increase in wave impedance of the electrical unit is sensed by TDR detection technology. The stress condition of the optical cable is warned through the stretched state of the electrical unit in an ice-covered state, so that the optical fiber inside the optical cable can be sensed by the staff before it breaks, thereby avoiding the problem of communication interruption and reducing the maintenance cost of the optical cable.

[0030] (2) The remotely inspectable optical cable of the present invention arranges the outer sheath of the optical cable as an eccentric structure, and arranges the electric unit on the side where the center of gravity is away from the center, so that after the remotely inspectable optical cable is placed, the electric unit is located on the lower side of the optical cable under the action of gravity. When the optical cable is bent due to pressure from ice, the bending stretching length of the outer sheath and the electric unit on the lower side is the largest, so that the electric unit is stretched and thinned first, thereby avoiding the situation where the electric unit is not stretched and thinned after the outer sheath of the optical cable breaks, thereby ensuring that the electric unit plays an early warning role.

[0031] (3) The remotely inspectable optical cable of the present invention embeds the electric unit between the outer sheath and the accommodating space so that the embedding of the electric unit will not significantly damage the anti-cracking performance of the outer sheath. At the same time, the embedding structure of the electric unit and the outer sheath allows the electric unit and the outer sheath to be stretched synchronously, ensuring that when the optical cable is covered with ice and bears load, the electric unit is stretched and thinned synchronously, thereby providing a warning of ice coverage on the optical cable.

[0032] (4) The remotely inspectable optical cable of the present invention controls the electrical unit to be embedded in the outer sheath so that the electrical unit will not be easily separated from the outer sheath. At the same time, an outer sheath with a certain modulus is selected so that the outer sheath has a certain binding force on the electrical unit to prevent the electrical unit from being separated from the outer sheath. This ensures that when the optical cable is subjected to force, the electrical unit and the outer sheath are stretched synchronously, thereby providing a warning of the load-bearing condition of the optical cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of an optical cable capable of remote inspection in one embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of the overall structure of another optical cable capable of remote inspection in an embodiment of the present invention;

[0035] Figure 3 2 is a schematic diagram of the structure of a remotely inspectable optical cable preparation device according to an embodiment of the present invention;

[0036] Figure 4 It is a waveform diagram of TDR detection of stretched thinning electrical unit in an embodiment of the present invention.

[0037] In all the drawings, the same reference numerals represent the same technical features, specifically:

[0038] 1. Optical fiber; 2. Sleeve; 3. Strengthening core; 4. Water-blocking layer; 5. Electrical unit; 6. Outer sheath; 7. Pay-off rack; 8. Pay-off device; 9. Extruder; 10. Take-up device. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0042] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] Example:

[0045] See also Figures 1 to 4 The remotely inspectable optical cable in a preferred embodiment of the present invention comprises an optical unit, an electrical unit 5 and an outer sheath 6, wherein the outer sheath 6 covers the outer circumference of the optical unit and the electrical unit 5; wherein the optical unit is arranged in the accommodating space of the outer sheath 6, and the electrical unit 5 is at least partially connected to the outer sheath 6, and the arrangement direction of the electrical unit 5 is parallel to the axis of the outer sheath 6, and the positive excess length of the electrical unit 5 relative to the outer sheath 6 is 0.05% to 0.8%.

[0046] The remotely inspectable optical cable in the present application is provided with an electric unit 5 inside the optical cable structure, and the electric unit 5 is arranged parallel to the axis of the outer sheath 6, so that the electric unit 5 and the outer sheath 6 are stretched synchronously with equal length, and the excess length of the electric unit 5 is controlled so that the electric unit 5 has a positive excess length relative to the outer sheath 6. When the optical cable is covered with ice, the electric unit 5 is stretched synchronously with the outer sheath 6, and the electric unit 5 will not be stretched and thinned due to the existence of the positive excess length. When the outer sheath 6 is stretched to compensate for the excess length of the electric unit 5, the electric unit 5 is stretched together with the outer sheath 6. When the wave impedance of the electric unit 5 increases, it can be detected by TDR detection technology. The optical cable maintenance personnel can perform early maintenance on the optical cable when the wave impedance of the electric unit 5 increases, remove the ice on the surface of the optical cable, and avoid the problem of continuous accumulation of snow and cable breakage.

[0047] Optionally, the optical cable in the present application can also be used in other scenarios with a stretching environment. Correspondingly, the optical cable needs to adjust the excess length of the electrical unit 5 relative to the outer sheath 6 so that the electrical unit 5 becomes thinner or breaks before the optical fiber 1 or the outer sheath 6 is damaged. It is worth noting that when the electrical unit 5 needs to be stretched and broken, the electrical unit 5 needs to be arranged in a negative excess length form to accelerate the stretching and breaking process of the electrical unit 5.

[0048] Further preferably, the outer sheath 6 in the present application is an eccentric structure, the outer sheath 6 includes a center and a center of gravity, and the electrical unit 5 is arranged on the side of the center of gravity away from the center. The conventional optical cable is a circular columnar structure. When the optical cable is covered with ice, the pressure is placed on the upper part of the optical cable, causing the outer sheath 6 of the optical cable below gravity to bend downward to a greater extent than the outer sheath 6 of the ice-covered part. When the electrical unit 5 is located at the upper part of the optical cable, the stretching amplitude of the lower outer sheath 6 is greater than the stretching amplitude of the electrical unit 5, and it is easy for the outer sheath 6 to break while the electrical unit 5 is not broken, resulting in the electrical unit 5 being unable to serve as a warning. Therefore, the present application sets the outer sheath 6 as an eccentric structure, and sets the electrical unit 5 on the side of the center of gravity away from the center. During the optical cable arrangement process, because the outer sheath 6 is an eccentric structure, the center of gravity side of the outer sheath 6 is located at the lower part of the optical cable, so that the electrical unit 5 is also located at the lower part of the optical cable. When the optical cable is bent due to ice, the electrical unit 5 located at the lower part bends more greatly, and the electrical unit 5 breaks before the optical unit and the outer sheath 6. The TDR detection technology is used to determine the break position of the electrical unit 5, and the ice on the outside of the optical cable is cleaned to prevent the optical cable from being crushed, thereby playing a warning role.

[0049] Furthermore, in the present application, the electrical unit 5 is at least partially connected to the outer sheath 6. When the electrical unit 5 is connected to the inner wall of the outer sheath 6, the electrical unit 5 is fixed by squeezing the internal optical unit and the outer sheath 6; when the electrical unit 5 is partially embedded or completely embedded in the outer sheath 6, the electrical unit 5 is constrained and fixed by the outer sheath 6.

[0050] Further, as an optional embodiment of the present invention, the electric unit 5 in the present application is embedded in the outer sheath 6, that is, the electric unit 5 is embedded between the inner wall and the outer wall of the outer sheath 6. The electric unit 5 can be synchronously inserted into the outer sheath 6 when the outer sheath 6 is extruded, forming a structure in which the outer sheath 6 covers the electric unit 5. When the outer sheath 6 is stretched due to ice, the electric unit 5 can be stretched together, and the rupture of the electric unit 5 can be used to warn the pressure condition of the optical cable.

[0051] Further, as an optional embodiment of the present invention, there are at least two electrical units 5 in the present application, and the plurality of electrical units 5 are evenly arranged in the circumferential direction with the axis of the outer sheath 6 as the center. During the preparation of the optical cable, if the optical cable is set to a conventional optical cable structure, it is impossible to determine the position of the electrical unit 5. When the electrical unit 5 is located at the upper part of the optical cable, it is easy to cause the outer sheath 6 at the lower part to break while the electrical unit 5 is not broken, resulting in the problem that the electrical unit 5 cannot be warned. Therefore, the present application sets at least two electrical units 5, and the electrical units 5 are arranged symmetrically, so that during the arrangement of the optical cable, at least one electrical unit 5 can be located at the lower part of the optical cable. During the compression and stretching of the optical cable, the electrical unit 5 is stretched synchronously with the outer sheath 6 at the lower part to avoid the situation where the outer sheath 6 breaks while the electrical unit 5 does not break.

[0052] Preferably, the number of electrical units 5 in the present application is 3 or 4, and the electrical units 5 are evenly distributed in the outer sheath 6 along the circumferential direction. The 3 or 4 electrical units 5 ensure that no matter how the optical cable is arranged, at least one electrical unit 5 is located at the lower side of the optical cable, ensuring that the electrical unit 5 can play a role in pressure warning. Correspondingly, when too many electrical units 5 are arranged in the outer sheath 6, it is easy to cause the overall strength loss of the outer sheath 6, so that the compression and tensile resistance of the optical cable are reduced, so it is necessary to strictly control the number of buried electrical units 5.

[0053] Preferably, in the present application, the shortest distance between the electrical unit 5 and the outer wall of the outer sheath 6 is not less than 0.6 mm, and the shortest distance between the electrical unit 5 and the inner wall of the outer sheath 6 is not less than 0.3 mm. The shortest distance between the electrical unit 5 and the inner and outer walls of the outer sheath 6 represents the weakest point of the electrical unit 5 relative to the inner and outer walls of the outer sheath 6. When the electrical unit 5 is too close to the inner and outer walls, it will cause severe cracking of the outer sheath 6 during preparation and use, which is inconvenient for the use of the optical cable.

[0054] Further, as a preferred embodiment of the present invention, the electrical unit 5 in the present application is partially embedded in the inner wall of the outer sheath 6, and the remaining part of the electrical unit 5 is located in the accommodation space of the outer sheath 6. When the electrical unit 5 is buried inside the outer sheath 6, since the electrical unit 5 is usually made of metal and the outer sheath 6 is made of plastic, the compatibility of the two is poor. Therefore, burying the electrical unit 5 in the outer sheath 6 will lose the strength of the outer sheath 6, resulting in a decrease in the overall tensile and compressive resistance of the optical cable. Based on this, the present application arranges the electrical unit 5 in the outer sheath 6 in the form of an open cable, and embeds the electrical unit 5 on the inner wall of the outer sheath 6, so that the electrical unit 5 can be stretched synchronously with the outer sheath 6 without significantly losing the tensile and compressive resistance of the outer sheath 6, so that the electrical unit 5 can warn the pressure-bearing capacity of the optical cable. Here, the accommodation space of the outer sheath 6 refers to the space formed by the inner wall of the outer sheath 6.

[0055] Preferably, in the present application, the portion of the electric unit 5 embedded in the inner wall of the outer sheath 6 is larger than the portion of the electric unit 5 located in the outer sheath 6 accommodation space. When the outer sheath 6 is used to fix the electric unit 5, in order to increase the binding force of the outer sheath 6 on the electric unit 5, the present application embeds most of the structure of the electric unit 5 on the inner wall of the outer sheath 6, so that the opening of the contact portion between the electric unit 5 and the outer sheath 6 is smaller than the diameter of the electric unit 5, and the outer sheath 6 itself can lock the electric unit 5 inside the opening to prevent the electric unit 5 from detaching. When preparing the optical cable, it is only necessary to adjust the relative position of the setting position of the electric unit 5 and the extrusion die of the outer sheath 6 to form a structure in which the portion of the electric unit 5 embedded in the inner wall of the outer sheath 6 is larger than the portion of the electric unit 5 located in the outer sheath 6 accommodation space.

[0056] Further preferably, the tensile modulus of the outer sheath 6 in the present application is 100-1500 MPa, and the tensile strength is 7-30 MPa. The outer sheath 6 under the tensile modulus and tensile strength will not deform arbitrarily under the action of external force, and the electrical unit 5 can be locked inside the outer sheath 6 to achieve the fixation of the electrical unit 5. At the same time, the modulus of the outer sheath 6 should not be too large. The outer sheath 6 with too large a modulus is not conducive to the bending of the optical cable and is not convenient for the laying of the optical cable.

[0057] Preferably, the electrical unit 5 in the present application can be made of one or more of gold, silver, copper or aluminum, and can also be made of alloys of the above metals.

[0058] Preferably, the remotely inspectable optical cable in the present application further includes a reinforcement member, a plurality of optical units, and the plurality of optical units are twisted and arranged on the periphery of the reinforcement member, and a water-blocking layer 4 is arranged on the periphery of the plurality of optical units, and the water-blocking layer 4 can be a water-blocking yarn or a water-blocking tape. Optionally, the remotely inspectable optical cable in the present application can also be a micro-cluster cable, an 8-shaped optical cable, or a butterfly cable, etc.

[0059] The positive excess length of the electrical unit 5 is determined below for the icing requirements of the cable:

[0060] Normally, at -10℃, when the cable is covered with 5mm or more ice, conventional ADSS cables are prone to internal optical fiber 1 breakage. Below, we select ADSS optical cable model ADSS-72B1.3, which has a diameter of 13.3mm; ice and snow form a water droplet-like coating structure on the outside of the cable, and its volume accounts for about 3 / 4 of the cylindrical structure. The weight of ice coating on the outside of the cable per unit length can be calculated, and then TDR detection technology is used to detect the wave impedance change of the electrical unit 5 under the same environment.

[0061] The following is a 200m long ADSS-72B1.3 optical cable for testing. The weight when covered with 5mm of ice is calculated:

[0062] [(13.3+0.5) 2 -13.32 ]*3 / 4*π*200*10 2 *0.917=586KG

[0063] Replace the 586KG weight with 20 15KG weights, hang them equally on the 200m long optical cable, the initial hanging sag of the optical cable is 1.45m, when the sag of the optical cable stabilizes under the tension of the weights, it reaches 3.51m (at this time, the sag of the optical cable is the theoretical design limit value), the elongation of the optical cable is obtained;

[0064] By default, the optical cable is stretched to form a triangular structure, and the elongation of the optical cable is calculated as follows: The elongation is the elongation of 100m optical cable, and the elongation is 0.051%.

[0065] At the same time, a copper wire with a length of 10m was selected for testing. The diameter of the copper wire was 2.2mm. The surface of the copper wire was coated with the same HDPE material as ADSS-72B1.3 as the outer sheath 6. The TDR technology was used to detect the wave impedance change of the electric unit 5 at -10℃. Then a 15KG weight was hung under the copper wire, and the TDR technology was used to detect the wave impedance change of the electric unit 5. Figure 4 shown. Figure 4 In order to input a pulse signal at the end of the electric unit 5, the pulse signal forms a large amplitude at the input end. As the pulse signal is gradually transmitted inside the electric unit 5, the waveform amplitude will be greatly attenuated and then tend to be stable. When the electric unit 5 is stretched and thinned, the electric unit 5 at the bottom of the arc has the greatest force, the degree of stretching and thinning is the greatest at this point, and the resistance is the largest. When the pulse signal passes through this point, a sine wave fluctuation is generated (as shown in the dotted box). At the same time Figure 4 This is a relationship diagram between pulse time and pulse amplitude. The transmission speed of the pulse in the electrical unit 5 can be measured, and the weakest stretching point of the electrical unit 5 can be calculated based on the position where the sinusoidal waveform is generated, which is convenient for staff to determine the position that needs to be cleared of ice.

[0066] This application mainly detects the change in the increase in the wave impedance of the electrical unit 5 when the copper wire is stretched and thinned. It can be seen from the figure that when the copper wire is stretched and thinned, the increase in the wave impedance of the copper wire changes, forming a sinusoidal fluctuation. When a copper wire with a positive residual length is set inside the optical cable, the outer sheath 6 is stretched and lengthened first when covered with ice, and the copper wire is not stretched; when the length of the outer sheath 6 is the same as the length of the copper wire, the copper wire and the outer sheath 6 are stretched and thinned together, and the resistance of the copper wire changes. The TDR detects the increase in the wave impedance of the electrical unit 5 in real time.

[0067] At the same time, in order for the electrical unit 5 to play a warning role, the electrical unit 5 needs to be stretched and thinned before the outer sheath 6 stretches to the limit, that is, the positive excess length of the electrical unit 5 should not be greater than the maximum elongation of the outer sheath 6; and, in order to avoid the stretching of the optical cable due to low ice thickness or strong wind environment, and cause the electrical unit 5 to stretch and thin, the positive excess length of the electrical unit 5 needs to be appropriately limited to avoid false alarms caused by the stretching and thinning of the electrical unit 5. Under normal circumstances, when the ice thickness on the surface of the optical cable reaches 5mm, the optical cable is at risk of tensile breakage. At this time, an early warning fluctuation can be set according to the ice thickness reaching 5mm; when the ice thickness on the surface of the optical cable reaches 10mm, the optical cable is at risk of breaking due to external wind or other factors; when the ice thickness on the surface of the optical cable reaches 20mm, the load of the optical cable reaches the limit value, and the possibility of the optical cable breaking is relatively high. The same test method as above is used to obtain the tensile limit of the optical cable and the elongation of the optical cable. When the ice thickness on the cable surface reaches 10mm, the elongation length of 100m cable is 0.21m, and the elongation rate is 0.21%; when the ice thickness on the cable surface reaches 20mm, the elongation length of 100m cable is 0.8m, and the elongation rate is 0.8%.

[0068] Based on the above detection data, it can be known that when the excess length of the electrical unit 5 relative to the outer sheath 6 is 0.05% to 0.8%, when the outer sheath 6 is stretched to the theoretical limit value, the electrical unit 5 is stretched and thinned accordingly, and the TDR detection technology can detect the increase in wave impedance, thereby warning the icing condition of the optical cable. Further preferably, the excess length of the electrical unit 5 relative to the outer sheath 6 is 0.05% to 0.21%. When the electrical unit 5 is stretched and thinned within this range, the optical fiber 1 inside the optical cable will not have a fiber break problem, which is convenient for maintenance personnel to clean up the ice in time.

[0069] Optionally, according to the requirements of different optical cable application environments, the electrical unit 5 in the present application can also be set to have a positive excess length relative to the outer sheath 6, that is, when the outer sheath 6 is elongated, the electrical unit 5 is stretched and thinned accordingly, and the corresponding elongation of the optical cable can be sensed by TDR detection technology.

[0070] It is worth noting that the present application requires that after the cable is stretched to a certain length, the electric unit 5 is stretched and thinned together with the outer sheath 6. Therefore, no matter which of gold, silver, copper, and aluminum the electric unit 5 in the present application is made of, as long as the outer sheath 6 is stretched to a certain length to compensate for the positive excess length of the electric unit 5, the electric unit 5 is stretched and thinned together with the outer sheath 6.

[0071] Furthermore, with respect to the above-mentioned remotely inspectable optical cable, the present application also includes a method for preparing the remotely inspectable optical cable, which specifically includes the following steps:

[0072] The traction optical unit uses a pay-off device 8 to synchronously pay out the electrical unit 5;

[0073] Extruding an outer sheath 6 on the periphery of the optical unit and the electrical unit 5, and cooling the outer sheath 6 to set the shape;

[0074] The prepared cable is wound up using a wire-winding device 10 , wherein the wire-winding rate of the wire-winding device 8 is greater than the wire-winding rate of the wire-winding device 10 , so that the electrical unit 5 forms a positive excess length in the outer sheath 6 .

[0075] As a further preferred embodiment of the present invention, in the present application, the ratio of the wire-releasing rate of the wire-releasing device 8 to the wire-retrieving rate of the wire-retrieving device 10 is: 101-102:100.

[0076] Further preferably, the pay-out rate / retracting rate of at least one of the pay-out device 8 or the retracting device 10 in the present application is adjustable. Specifically, an online excess length testing device is used to test the relative excess length between the electric unit 5 and the outer sheath 6. When the relative excess length between the electric unit 5 and the outer sheath 6 is less than a preset excess length, the pay-out rate of the pay-out device 8 is accelerated or the retracting rate of the retracting device 10 is reduced; when the relative excess length between the electric unit 5 and the outer sheath 6 is greater than the preset excess length, the pay-out rate of the pay-out device 8 is reduced or the retracting rate of the retracting device 10 is accelerated.

[0077] Preferably, when achieving the relative excess length between the electrical unit 5 and the outer sheath 6, it is preferred to adjust the pay-off rate of the pay-off device 8. Adjustment of the pay-off rate of the pay-off device 8 will only affect the delivery rate of the electrical unit 5, which is relatively controllable, does not interfere with other preparation processes, and has less impact on the overall molding preparation of the optical cable.

[0078] As a further preferred embodiment of the present invention, the present application further comprises pulling the reinforcing core 3, twisting and pulling a plurality of optical units on the periphery of the reinforcing core 3, and coating the periphery of the plurality of optical units with water-blocking yarn.

[0079] Specifically, a pay-off frame 7 is used to pull and release the optical unit, and then an additional pay-off device 8 is arranged to release the electric unit 5. The released optical unit and the electric unit 5 are pulled into the extrusion die, and the outer sheath 6 is extruded around the optical unit and the electric unit 5 by the extruder 9. The molded outer sheath 6 is cooled and shaped, and then passed through the take-up device 10 for winding and storage.

[0080] Furthermore, when the remotely inspectable optical cable in the present application is used in an ice-covered environment, an electrical unit is embedded in the outer sheath of the optical cable during preparation, and the ratio of the contraction excess length of the electrical unit to the outer sheath is controlled. When the optical cable is iced, the electrical unit and the outer sheath are stretched synchronously. When the outer sheath is stretched to a length that compensates for the excess length of the electrical unit, the electrical unit and the outer sheath are stretched and thinned together. At this time, the TDR detection technology can detect that the local wave impedance of the electrical unit becomes larger, proving that the stretched length of the outer sheath has compensated for the excess length of the electrical unit. The optical cable is stretched to the set length of the optical cable, and there is a risk of the optical cable being stretched and broken. The staff is required to clean the ice on the surface of the optical cable in time to prevent the continuous accumulation of ice from causing the optical cable to break.

[0081] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A remotely inspectable optical cable, characterized in that: include: An optical unit, an electrical unit and an outer sheath, wherein the outer sheath is coated on the outer periphery of the optical unit and the electrical unit; The optical unit is arranged in the accommodation space of the outer sheath, the electrical unit is at least partially connected to the outer sheath, and the arrangement direction of the electrical unit is parallel to the axis of the outer sheath; The positive excess length of the electrical unit relative to the outer sheath is 0.05% to 0.8%.

2. The remotely inspectable optical cable according to claim 1, characterized in that: The outer sheath is an eccentric structure, the outer sheath includes a center and a gravity center, and the electrical unit is arranged on a side of the gravity center away from the center.

3. The remotely inspectable optical cable according to claim 1, characterized in that: The electrical unit is embedded between the inner wall and the outer wall of the outer sheath.

4. The remotely inspectable optical cable according to claim 3, characterized in that: The shortest distance between the electrical unit and the outer wall of the outer sheath is not less than 0.6 mm; the shortest distance between the electrical unit and the inner wall of the outer sheath is not less than 0.3 mm.

5. The remotely inspectable optical cable according to claim 1, characterized in that: There are at least two electrical units, and the plurality of electrical units are evenly arranged in a circumferential direction with the axis of the outer sheath as the center.

6. The remotely inspectable optical cable according to claim 1, characterized in that: The electric unit is partially embedded in the inner wall of the outer sheath, and the remaining part of the electric unit is located in the accommodating space of the outer sheath.

7. The remotely inspectable optical cable according to claim 6, characterized in that: The portion of the electric unit embedded in the inner wall of the outer sheath is larger than the portion of the electric unit located in the accommodating space of the outer sheath.

8. The remotely inspectable optical cable according to claim 6, characterized in that: The tensile modulus of the outer sheath is 100-1500 MPa, and the tensile strength is 7-30 MPa.

9. A method for preparing an optical cable capable of remote inspection, characterized in that: The steps include: The traction optical unit uses a pay-off device to synchronously pay out the electrical unit; Extruding an outer sheath around the optical unit and the electrical unit, and cooling and shaping the outer sheath; The prepared cable is wound up using a wire-winding device, wherein the wire-winding speed of the wire-winding device is greater than the wire-winding speed of the wire-winding device, so that the electrical unit forms a positive excess length in the outer sheath.

10. The method for preparing a remotely inspectable optical cable according to claim 9, characterized in that: The ratio of the wire-releasing speed of the wire-releasing device to the wire-retrieving speed of the wire-retrieving device is 101-102:

100.

11. The method for preparing a remotely inspectable optical cable according to claim 10, characterized in that: The speed of at least one of the pay-off device or the take-up device is adjustable; the speed adjustment method of the pay-off device or the take-up device includes: Real-time detection of the relative excess length between the electrical unit and the outer sheath; If the relative excess length between the electrical unit and the outer sheath is less than the preset excess length, the wire-releasing speed of the wire-releasing device is increased or the wire-retracting speed of the wire-retracting device is decreased; If the relative excess length between the electrical unit and the outer sheath is greater than the preset excess length, the wire-releasing speed of the wire-releasing device is reduced or the wire-retracting speed of the wire-retracting device is accelerated.

12. An application of remote inspection of optical cables, which embeds an electric unit in the outer sheath of the optical cable and controls the ratio of the contraction excess length of the electric unit to the outer sheath; when the optical cable is covered with ice, the electric unit and the outer sheath are stretched together, and when the outer sheath is stretched to compensate for the excess length of the electric unit, the electric unit and the outer sheath are stretched and thinned together, and the local wave impedance change of the electric unit is detected by TDR detection technology to determine the ice coverage condition of the optical cable surface.

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