6kV to 35kV copper conductor crosslinked polyethylene insulated power cable

Abstract

The application discloses a 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable and relates to the technical field of cable sheaths, which comprises a cabling unit and a monitoring unit, the cabling unit comprises a cable core and a sheath arranged on the outer periphery of the cable core, the monitoring unit is arranged between the cable core and the sheath, the monitoring unit comprises a plurality of monitoring strips arranged at intervals around the cable core and a plurality of diaphragms, the monitoring strips extend along the axial direction of the cable core, a plurality of monitoring cavities are formed in the monitoring strips along the extending direction of the monitoring strips, adjacent two monitoring cavities are communicated, the monitoring cavities are filled with contents, the diaphragms and the monitoring cavities are in one-to-one correspondence, and the diaphragms are fixedly connected with the monitoring strips. The application improves the safety factor of the cable.

Description

Technical Field

[0001] This invention relates to the field of cable sheath technology, specifically to 6kV to 35kV copper conductor cross-linked polyethylene insulated power cables. Background Technology

[0002] In actual operation, cracks or damage to the outer sheath of cables caused by mechanical construction damage, external pressure, termite infestation, or long-term bending fatigue are one of the main causes of cable failures.

[0003] If a through-hole defect occurs in the sheath, external moisture and water will seep into the cable through the damaged area, causing electrochemical corrosion of the metal shielding layer and accelerating the deterioration of insulation strength, ultimately leading to a breakdown accident.

[0004] Currently, the detection of cracks and damage to the outer sheath of cables mainly relies on periodic manual inspections. However, manual inspections can only detect mechanical damage that has already expanded significantly on the surface, and can hardly identify hidden cracks. This makes it impossible to detect existing cracks in the cable in the first place, which may lead to safety accidents, thus resulting in a reduction in the safety factor. Summary of the Invention

[0005] The purpose of this invention is to provide 6kV to 35kV copper conductor cross-linked polyethylene insulated power cables to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable, comprising:

[0007] A cabling unit includes a cable core and a sheath disposed around the outer periphery of the cable core; and

[0008] A monitoring unit is disposed between the cable core and the sheath. The monitoring unit includes multiple monitoring strips spaced around the cable core and multiple diaphragms. The monitoring strips extend along the axial direction of the cable core and have multiple monitoring cavities along their extension direction. Adjacent monitoring cavities are connected and filled with contents. The diaphragms correspond one-to-one with the monitoring cavities and are fixedly connected to the monitoring strips.

[0009] Furthermore, the monitoring unit also includes a fixing frame spaced apart along the axial direction of the cable core, the fixing frame having a mounting groove for placing the monitoring strip.

[0010] Furthermore, the inner width of the mounting groove is smaller than the outer width of the mounting groove.

[0011] Furthermore, the unit also includes a pressure ring slidably disposed in the groove and a covering film covering the port of the pressure ring. The pressure ring moves radially along the cable core, and the covering film is fixedly connected to the pressure ring. A storage space is formed between the covering film and the diaphragm. Substance A is disposed in the storage space, and substance A expands when it comes into contact with water.

[0012] Furthermore, the circumference of the groove is provided with a plurality of protrusions at intervals, and the protrusions are fixedly connected to the monitoring strip.

[0013] Furthermore, the inner wall of the slide groove is provided with a clearance groove, and a retaining plate is rotatably connected to the inner wall of the clearance groove. An elastic element is provided at the connection between the retaining plate and the inner wall of the clearance groove. The elastic element has a pre-tightening force that causes the retaining plate to extend out of the clearance groove. The outer wall of the pressure ring is provided with a retaining groove that is adapted to engage with the retaining plate.

[0014] Furthermore, the end of the card plate is provided with a bent portion.

[0015] Furthermore, a through transverse groove is formed on the inner wall of the monitoring cavity;

[0016] An auxiliary unit is provided inside the monitoring cavity;

[0017] The auxiliary unit includes:

[0018] A slidable spike is disposed within the monitoring cavity. The slidable spike moves radially along the cable core. An insertion port is formed on the outer wall of the slidable spike, and a first inclined surface is formed on the inner wall of the insertion port.

[0019] An extrusion block is slidably disposed in the transverse groove. The extrusion block is adapted to be inserted into the socket. The extrusion block is also provided with a second inclined surface adapted to the first inclined surface.

[0020] When the extrusion block is not inserted into the socket, the lowest point of the second inclined surface is aligned with the highest point of the first inclined surface; when the extrusion block is fully inserted into the socket, the puncture bar abuts against the diaphragm.

[0021] Furthermore, a sealing ring is provided between the extrusion block and the inner wall of the transverse groove.

[0022] Furthermore, a control chamber is also provided on the inner wall of the monitoring chamber. An elastic membrane is provided at the port of the control chamber, and a deformation sensing element is provided on the surface of the elastic membrane. The deformation sensing element is used to monitor the deformation of the elastic membrane. The control chamber is also provided with the contents, and the pressure in the control chamber is the same as the pressure in the monitoring chamber.

[0023] Compared with existing technologies, the beneficial effects of this invention are as follows: the diaphragm, as a pre-designated weak point, has a critical rupture force that can be customized according to the strength of the sheath material. This ensures that once a penetrating crack appears in the sheath, the stress field at the crack tip can reliably trigger diaphragm failure, achieving a deterministic action of "damage equals diaphragm rupture, rupture equals pressure relief." This stress-diaphragm rupture-pressure relief chain mechanism directly transforms the mechanical damage to the sheath into a clear signal of pressure drop. Combined with continuous sampling and automatic alarm from external pressure monitoring equipment, it solves the dilemma of manual inspection failing to identify hidden cracks. This allows maintenance personnel to be aware of cable cracks immediately, reducing the possibility of safety accidents and improving the cable's safety factor. Attached Figure Description

[0024] Figure 1 This is a partial cross-sectional view of the 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable of the present invention;

[0025] Figure 2 This is a partial cross-sectional view of the present invention to illustrate the monitoring unit and the auxiliary unit;

[0026] Figure 3 for Figure 2 A magnified view of part A in the middle;

[0027] Figure 4 This is a schematic diagram illustrating the control cavity and elastic membrane of the present invention.

[0028] In the diagram: 10, cabling unit; 101, cable core; 102, sheath;

[0029] 20. Monitoring unit; 201. Monitoring strip; 2011. Monitoring chamber; 2012. Slide groove; 2013. Protrusion; 2014. Clearance groove; 2015. Clamping plate; 20151. Bending part; 2016. Lateral movement groove; 2017. Control chamber; 2018. Elastic membrane; 202. Diaphragm; 203. Fixing frame; 2031. Mounting groove; 204. Pressure ring; 2041. Clamping groove; 205. Covering membrane;

[0030] 30. Auxiliary unit; 301. Destructive spike; 3011. Insert; 302. Extrusion block. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1-4As shown, the present invention provides a technical solution: a 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable, including a cabling unit 10 and a monitoring unit 20; the cabling unit 10 includes a cable core 101 and a sheath 102 disposed on the outer periphery of the cable core 101; the monitoring unit 20 is disposed between the cable core 101 and the sheath 102, the monitoring unit 20 includes a plurality of monitoring strips 201 spaced around the cable core 101 and a plurality of diaphragms 202, the monitoring strips 201 extend along the axial direction of the cable core 101, the monitoring strips 201 have a plurality of monitoring cavities 2011 opened along their own extension direction, two adjacent monitoring cavities 2011 are connected, the monitoring cavities 2011 are filled with contents, the diaphragms 202 and the monitoring cavities 2011 correspond one-to-one, and the diaphragms 202 are fixedly connected to the monitoring strips 201.

[0033] Optional, the contents are gas.

[0034] It should be noted that after the cable is manufactured and laid, dry and chemically stable gas (such as nitrogen or dry air) is first introduced into all monitoring chambers 2011 through a dedicated inflation valve or reserved interface to reach the preset rated positive pressure value. Then, the interface is connected in a sealed manner to external pressure monitoring equipment (such as a remote pressure transmitter or a precision pressure gauge with data storage function) located in the cable terminal, intermediate joint, or branch box along the line, via a gas pipeline. Simultaneously, the continuous sampling and recording function of this equipment is activated. The external pressure monitoring equipment collects the current pressure value in real time at its set sampling frequency (e.g., once per second or once per hundred milliseconds) and continuously compares it with the pre-stored initial rated value and action threshold value. When the pressure value is detected to be continuously decreasing and falling below the set low-pressure alarm threshold, the equipment immediately sends a timestamped alarm signal to the maintenance center.

[0035] The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable provided in this application embodiment, under normal operating conditions, has an intact and undamaged sheath 102, and the diaphragm 202 inside the monitoring chamber 2011 is in a completely sealed state, isolating the monitoring chamber 2011 from the outside atmosphere, with no leakage path for internal gas, and the overall air pressure is stable at the initial inflation pressure. The external air pressure monitoring equipment continuously displays a constant reading and transmits the normal pressure value back to the remote monitoring platform.

[0036] When the cable outer sheath 102 develops a through crack due to termite infestation, mechanical damage, or long-term bending fatigue, the sheath 102 material near the crack area undergoes local deformation or opening due to stress concentration. This mechanical stress is transmitted to the adjacent monitoring strip 201 and its fixed diaphragm 202. Since the diaphragm 202 is a pre-designed weak interface, its tensile strength is lower than the tearing force generated by the sheath 102 material when the crack propagates. Therefore, the expansion displacement at the crack tip or on both sides of the crack will directly act on the diaphragm 202, causing the diaphragm 202 to be torn, thereby forming a through venting channel between the monitoring cavity 2011 and the external environment.

[0037] After the diaphragm 202 ruptures, the high-pressure gas in the monitoring chamber 2011 leaks rapidly into the atmosphere along the vent, causing a sharp decrease in the number of gas molecules in the chamber and a rapid drop in static pressure. Since adjacent monitoring chambers 2011 within the same monitoring strip 201 are connected to each other, the pressure attenuation will be rapidly transmitted axially to the entire monitoring strip 201 and will eventually be reflected at the sensor end of the external air pressure monitoring equipment.

[0038] The equipment reads the current pressure at a fixed sampling frequency (e.g., multiple times per second). When the value continues to decrease and falls below the preset low-pressure alarm threshold, it sends an alarm signal containing a timestamp and pressure drop rate to the operation and maintenance center, thereby completing the full-process monitoring from crack initiation, stress rupture, gas depressurization, and equipment alarm.

[0039] Compared to existing technologies, the diaphragm 202, as a pre-designed weak point, has a critical rupture force that can be customized based on the material strength of the sheath 102. This ensures that once a penetrating crack appears in the sheath 102, the stress field at the crack tip can reliably trigger the failure of the diaphragm 202, achieving a deterministic action of "damage equals diaphragm rupture, rupture equals pressure relief." This stress-diaphragm rupture-pressure relief chain mechanism directly transforms the mechanical damage to the sheath 102 into a clear signal of pressure drop. Combined with continuous sampling and automatic alarms from external pressure monitoring equipment, it solves the problem of manual inspections being unable to identify hidden cracks. This allows maintenance personnel to be aware of cable cracks immediately, reducing the possibility of safety accidents and improving the cable's safety factor.

[0040] In some embodiments, see Figure 1 and Figure 2 The monitoring unit 20 also includes a fixing frame 203 spaced along the axial direction of the cable core 101, and the fixing frame 203 is provided with a mounting groove 2031 for placing the monitoring strip 201.

[0041] In the cable manufacturing process, the sheath 102 is usually made of molten material extruded under high temperature and high pressure to cover the outer periphery of the cable core 101. During this process, the flow impact force of the molten material can easily cause the uncured monitoring strip 201 to shift, twist or bend, thereby destroying its straight axial extension posture and the predetermined radial distance between it and the cable core 101, ultimately affecting the accuracy of the position of the monitoring cavity 2011.

[0042] The fixing frame 203 provides discrete but sufficiently dense support constraints for the monitoring strip 201 by arranging multiple points at intervals along the axial direction. The mounting groove 2031 restricts the monitoring strip 201 within the designed track in an embedded fit, effectively resisting the scouring force and thermal shrinkage stress of the molten material during co-extrusion. This ensures that the monitoring strip 201 maintains a relatively static geometric relationship with the cable core 101 throughout the entire process of sheath 102 forming, ultimately enabling the monitoring cavity 2011 to be evenly distributed on the outer periphery of the cable core 101.

[0043] In some embodiments, see Figure 2 The inner width of the mounting groove 2031 is smaller than the outer width of the mounting groove 2031.

[0044] When the cable is in the co-extrusion molding stage, the molten sheath 102 material pushes the monitoring strip 201 into the mounting groove 2031 under the extrusion pressure. Since the outer opening of the mounting groove 2031 is wider and the inner bottom is narrower, the monitoring strip 201 is subjected to radial compression of the gradually narrowing contour of the groove wall during the embedding process, which forces its body to undergo elastic contraction deformation, thereby driving the multiple monitoring cavities 2011 opened inside to be compressed simultaneously.

[0045] After the monitoring cavity 2011 is compressed, the diaphragm 202 fixed to the monitoring strip 201 is in a bulging tension state. This bulging state puts the diaphragm 202 in a pre-stretch condition close to its elastic limit. The molecular chains inside the material have been oriented along the direction of force, and the tear resistance is significantly reduced.

[0046] When a cable develops a through-crack due to mechanical damage, termite infestation, or bending fatigue during subsequent operation, the stress concentration at the crack tip does not need to overcome the complete initial elastic modulus of the diaphragm 202. Only a tearing force much smaller than that required for a conventional flat diaphragm 202 is needed to induce rapid fracture along the stress concentration point of the protruding part.

[0047] In some embodiments, see Figure 2The monitoring strip 201 has an annular groove 2012 on the outer periphery of the monitoring cavity 2011; the monitoring unit 20 also includes a pressure ring 204 slidably disposed in the groove 2012 and a covering film 205 covering the port of the pressure ring 204. The pressure ring 204 moves radially along the cable core 101. The covering film 205 is fixedly connected to the pressure ring 204. A storage space is formed between the covering film 205 and the diaphragm 202. Substance A is disposed in the storage space. Substance A expands when it comes into contact with water.

[0048] Optionally, substance A is water-swellable rubber (hydrophilic polyurethane prepolymer).

[0049] Optionally, substance A is a superabsorbent polymer (SAP, such as sodium polyacrylate cross-linked polymer).

[0050] When the cable is in the high temperature and high pressure co-extrusion molding stage, the molten sheath 102 material is radially extruded into the monitoring strip 201. This extrusion force is simultaneously applied to the exposed end face of the pressure ring 204, forcing the pressure ring 204 to slide along the groove 2012. During the movement of the pressure ring 204, the membrane 205 fixed at its port moves forward with it. When the pressure ring 204 reaches the end of its stroke, the membrane 205 ruptures, exposing material A. At the same time, material A adheres to and remains on the surface of the diaphragm 202.

[0051] This process relies entirely on the extrusion pressure of the co-extrusion process itself as the power source, without the need for additional independent pressing or film breaking processes. This simplifies the manufacturing process and avoids inconsistencies caused by manual operation. The released substance A remains chemically inert because it has not yet come into contact with water, and is stably distributed on the surface of the diaphragm 202, forming a chemically responsive layer in a "standby" state.

[0052] When a through-crack appears in the sheath 102 of the cable during service, outside air seeps in along the damaged area. This air contains water, which then comes into contact with substance A. At this point, on one hand, the mechanical stress generated at the crack tip acts directly on the diaphragm 202, subjecting it to tearing tensile stress; on the other hand, the water comes into contact with substance A adhering to the surface of the diaphragm 202, causing substance A to rapidly expand in volume, generating additional pushing force on the surface of the diaphragm 202. These two forces—the mechanical tearing force from crack propagation and the expansion force from the chemical reaction of substance A—work synergistically to form a combined stress field far exceeding that of a single mechanism, allowing the diaphragm 202 to be rapidly ruptured.

[0053] Compared to solutions that rely solely on mechanical stress, this design significantly reduces the triggering requirements for crack width and stress concentration. Even if the sheath 102 only develops micron-level microcracks, as long as air can penetrate, moisture can be carried into contact with material A, and the expansion effect of material A can still be effectively exerted, thereby ensuring that the monitoring unit 20 has a high sensitivity response capability to various types of hidden damage.

[0054] In some embodiments, see Figure 2 The circumference of the chute 2012 is provided with a plurality of protrusions 2013 at intervals, and the protrusions 2013 are fixedly connected to the monitoring strip 201.

[0055] When the pressure ring 204 is pushed into the groove 2012 by the radial extrusion force of the molten sheath 102 material during the co-extrusion process of the sheath 102, the coating 205 covering the port of the pressure ring 204 moves together with the pressure ring 204 until the coating 205 contacts the protrusion 2013. At this time, the coating 205 continues to move under the drive of the pressure ring 204, so that the protrusion 2013 forms multiple through tears or holes on the surface of the coating 205.

[0056] If the sheath 102 cracks after the membrane 205 is punctured, air carrying water can come into contact with the material A through the tear or hole. Furthermore, the spikes 2013 and the monitoring strip 201 are integrally connected without additional assembly, ensuring they will not loosen, fall off, or shift during cable manufacturing and long-term operation, thus providing protection against membrane 205 rupture in the simplest mechanical way.

[0057] In some embodiments, see Figure 2 and Figure 3 The inner wall of the slide groove 2012 is provided with a relief groove 2014. A retaining plate 2015 is rotatably connected to the inner wall of the relief groove 2014. An elastic element is provided at the connection between the retaining plate 2015 and the inner wall of the relief groove 2014. The elastic element has a pre-tightening force that causes the retaining plate 2015 to extend out of the relief groove 2014. The elastic element is a torsion spring. The outer wall of the pressure ring 204 is provided with a retaining groove 2041 that is adapted to engage with the retaining plate 2015.

[0058] When the cable is in the co-extrusion molding stage, the molten sheath 102 material is radially squeezed inward to the exposed end face of the pressure ring 204, forcing the pressure ring 204 to slide continuously in the sliding groove 2012.

[0059] During the process of the pressure ring 204 entering the slide groove 2012, the pressure ring 204 first contacts the end of the clamping plate 2015 extending out of the relief groove 2014. Since the pushing force of the pressure ring 204 is greater than the pre-tightening torque of the elastic element on the clamping plate 2015, the pressure ring 204 gradually presses the clamping plate 2015 into the relief groove 2014, so that the clamping plate 2015 temporarily retracts to make way for the travel channel of the pressure ring 204. At this time, the elastic element is further compressed or twisted due to the rotation of the clamping plate 2015, storing elastic potential energy.

[0060] When the pressure ring 204 is fully inserted into the slide groove 2012, the locking groove 2041 and the relief groove 2014 are aligned. The squeezing constraint from the pressure ring 204 on the locking plate 2015 is suddenly released. The previously compressed elastic element quickly releases the stored elastic potential energy, driving the locking plate 2015 to rotate in the opposite direction around its rotation connection point and extend out of the relief groove 2014 again. The end of the locking plate 2015 is embedded in the locking groove 2041 on the outer wall of the pressure ring 204, forming a stable fit.

[0061] During co-extrusion, the locking mechanism automatically completes the entire sequence of actions: "extrusion-retraction-springback-locking". While the molten sheath 102 material is still warm and solidified, the pressure ring 204 and the slide groove 2012 will not experience relative displacement. If the pressure ring 204 and the slide groove 2012 shift, the pressure ring 204 will compress the molten sheath 102 material, causing deformation. After cooling, a gap will exist between the sheath 102 and the pressure ring 204.

[0062] In some embodiments, see Figure 3 The end of the card plate 2015 is provided with a bent part 20151.

[0063] When the pressure ring 204 is pushed forward to the moment when the slot 2041 is aligned with the port of the clearance slot 2014, the elastic element drives the plate 2015 to rotate in the opposite direction. The bent part 20151, as the first part to enter the slot 2041, has a curved profile that complements the shape of the inner wall of the slot 2041. This not only increases the contact area between the plate 2015 and the slot 2041, but also allows the end of the bent part 20151 to hook onto the bottom or side wall of the slot 2041, forming a mechanical interlocking effect similar to a barb. This makes the fitting depth and pull-out resistance of the plate 2015 in the slot 2041 significantly better than the straight end structure without the bent part 20151.

[0064] In some embodiments, see Figure 2 The inner wall of the monitoring cavity 2011 is provided with a through transverse groove 2016.

[0065] An auxiliary unit 30 is provided inside the monitoring cavity 2011; the auxiliary unit 30 includes a puncture spike 301 and an extrusion block 302; the puncture spike 301 is slidably disposed inside the monitoring cavity 2011 and moves radially along the cable core 101; the outer wall of the puncture spike 301 has an insertion port 3011 and the inner wall of the insertion port 3011 has a first inclined surface; the extrusion block 302 is slidably disposed inside the transverse sliding groove 2016 and is plugged into the insertion port 3011; the extrusion block 302 also has a second inclined surface that is adapted to the first inclined surface.

[0066] When the extrusion block 302 is not inserted into the socket 3011, the lowest point of the second inclined surface is aligned with the highest point of the first inclined surface. When the extrusion block 302 is fully inserted into the socket 3011, the puncture bar 301 abuts against the diaphragm 202.

[0067] When the cable is in the co-extrusion molding stage, the radial extrusion force of the molten sheath 102 material pushes the pressure ring 204 into the slide groove 2012. During its movement, the pressure ring 204 not only punctures the coating 205 and exposes material A, but also squeezes the extrusion block 302 set in the transverse groove 2016. The pressure ring 204 gradually pushes the extrusion block 302 outward from the transverse groove 2016 and extends it into the monitoring cavity 2011. During the process of the extrusion block 302 extending into the monitoring cavity 2011, the second inclined surface at its end and the insertion port 301 of the puncture 301... The first inclined surface on the inner wall forms a wedge-shaped fit. Since the second inclined surface and the first inclined surface have complementary inclination angles, the linear feed of the extrusion block 302 is converted into the radial advancing motion of the piercing spike 301 along the cable core 101 through the relative sliding between the inclined surfaces, until the tip of the piercing spike 301 just abuts against the surface of the diaphragm 202. However, at this stage, the diaphragm 202 is not pierced, but the diaphragm 202 forms a continuous local tension or slightly convex contact state at the tip of the piercing spike 301, which is equivalent to performing a mechanical pretreatment of "pre-positioning" and "pre-compression" on the diaphragm 202.

[0068] The pre-contact state between the tip of the puncture bar 301 and the surface of the diaphragm 202 makes the diaphragm 202 a local stress concentration point immediately after co-extrusion, which is equivalent to pre-creating a weak area on the surface of the diaphragm 202, significantly reducing the rupture trigger threshold of the diaphragm 202.

[0069] In some embodiments, a sealing ring is provided between the extrusion block 302 and the inner wall of the transverse groove 2016.

[0070] When the extrusion block 302 is in the static ready-to-trigger position, it provides a reliable static sealing effect, isolating the monitoring cavity 2011 from the outside. When the extrusion block 302 slides into the monitoring cavity 2011 along the transverse groove 2016 due to the pushing action of the pressure ring 204, the sealing ring can still continuously adhere to the two side walls during the sliding process, thus playing a dynamic sealing function.

[0071] In some embodiments, see Figure 4 The monitoring chamber 2011 also has a control chamber 2017 on its inner wall. An elastic membrane 2018 is provided at the port of the control chamber 2017. A deformation sensing element is provided on the surface of the elastic membrane 2018. The deformation sensing element is used to monitor the deformation of the elastic membrane 2018. The control chamber 2017 also contains the above-mentioned contents. The pressure in the control chamber 2017 is the same as the pressure in the monitoring chamber 2011.

[0072] When the cable outer sheath 102 develops a through crack at a certain location due to termite infestation, mechanical damage, or long-term bending fatigue, the diaphragm 202 ruptures, causing a significant drop in air pressure within the corresponding monitoring chamber 2011 in a short period of time. Meanwhile, the control chamber 2017, paired with the monitoring chamber 2011, is completely isolated from the outside due to its independent and sealed structural design, with no leakage path for the internal gas, and always maintains a constant initial inflation pressure. As a result, a clear and continuously increasing air pressure difference is generated between the two.

[0073] The pressure difference is transmitted through the inner wall of the monitoring chamber 2011 to both sides of the elastic membrane 2018 at the port of the control chamber 2017. The side of the elastic membrane 2018 facing the monitoring chamber 2011 bears the reduced pressure of the monitoring chamber 2011, while the side facing away from the monitoring chamber 2011 bears the constant reference pressure of the control chamber 2017. The pressure imbalance on both sides forces the elastic membrane 2018 to deform away from its initial equilibrium position (convex towards the low-pressure side or concave towards the high-pressure side).

[0074] Deformation sensing elements (such as piezoresistive strain gauges, fiber optic gratings, or capacitive displacement sensors) attached to the surface of the elastic membrane 2018 convert the deformation into a continuous electrical or optical signal output. Since each monitoring cavity 2011 is equipped with a reference cavity 2017 and a deformation sensing element corresponding to its axial position, the signal change output by each sensing element essentially characterizes the air pressure holding state of the monitoring cavity 2011 at its corresponding axial position. If the signal deviates significantly from the initial reference value, it indicates that the monitoring cavity 2011 at that location has leaked due to the rupture of the diaphragm 202, and thus it can be directly determined that the axial position is the area where the sheath 102 crack is located. If the signal remains consistent with the reference, it indicates that the diaphragm 202 is intact and the sheath 102 is undamaged.

[0075] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended embodiments and their equivalents.

Claims

1. A 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable, characterized in that, include: A cabling unit includes a cable core and a sheath disposed on the outer periphery of the cable core; as well as A monitoring unit is disposed between the cable core and the sheath. The monitoring unit includes multiple monitoring strips spaced around the cable core and multiple diaphragms. The monitoring strips extend along the axial direction of the cable core and have multiple monitoring cavities along their extension direction. Adjacent monitoring cavities are connected and filled with contents. The diaphragms correspond one-to-one with the monitoring cavities and are fixedly connected to the monitoring strips.

2. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 1, characterized in that, The monitoring unit also includes a fixing frame spaced apart along the axial direction of the cable core, and the fixing frame is provided with a mounting groove for placing the monitoring strip.

3. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 2, characterized in that, The inner width of the mounting groove is smaller than the outer width of the mounting groove.

4. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 1, characterized in that, The monitoring strip has an annular groove on the outer periphery of the monitoring cavity; The monitoring unit also includes a pressure ring slidably disposed in the groove and a covering film covering the port of the pressure ring. The pressure ring moves radially along the cable core, and the covering film is fixedly connected to the pressure ring. A storage space is formed between the covering film and the diaphragm. Substance A is disposed in the storage space. Substance A expands when it comes into contact with water.

5. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 4, characterized in that, The groove is provided with a plurality of protrusions at intervals on its periphery, and the protrusions are fixedly connected to the monitoring strip.

6. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 4, characterized in that, The inner wall of the slide groove is provided with a clearance groove, and a retaining plate is rotatably connected to the inner wall of the clearance groove. An elastic element is provided at the connection between the retaining plate and the inner wall of the clearance groove. The elastic element has a pre-tightening force that causes the retaining plate to extend out of the clearance groove. The outer wall of the pressure ring is provided with a retaining groove that is adapted to engage with the retaining plate.

7. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 6, characterized in that, The end of the card plate is provided with a bent portion.

8. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 4, characterized in that, The monitoring cavity has a through transverse groove on its inner wall; An auxiliary unit is provided inside the monitoring cavity; The auxiliary unit includes: A slidable spike is disposed within the monitoring cavity. The slidable spike moves radially along the cable core. An insertion port is formed on the outer wall of the slidable spike, and a first inclined surface is formed on the inner wall of the insertion port. An extrusion block is slidably disposed in the transverse groove. The extrusion block is adapted to be inserted into the socket. The extrusion block is also provided with a second inclined surface adapted to the first inclined surface. When the extrusion block is not inserted into the socket, the lowest point of the second inclined surface is aligned with the highest point of the first inclined surface; when the extrusion block is fully inserted into the socket, the puncture bar abuts against the diaphragm.

9. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 8, characterized in that, A sealing ring is provided between the extrusion block and the inner wall of the transverse groove.

10. The 6kV to 35kV copper conductor cross-linked polyethylene insulated power cable according to claim 1, characterized in that, The monitoring chamber also has a control chamber on its inner wall. An elastic membrane is provided at the port of the control chamber, and a deformation sensing element is provided on the surface of the elastic membrane. The deformation sensing element is used to monitor the deformation of the elastic membrane. The control chamber also contains the contents, and the pressure in the control chamber is the same as the pressure in the monitoring chamber.

Images