Power distribution network medium voltage power cable and intelligent early warning method thereof

Abstract

This invention relates to the field of cable structure technology, and more particularly to a medium-voltage power cable for power distribution networks and its intelligent early warning method. The cable includes an outer jacket, several cable cores arranged in a ring within the jacket, and several suppression structures. The suppression structures are located between adjacent cable cores and are used to suppress vibrations between adjacent cable cores caused by alternating current. This invention effectively reduces the impact of high-frequency vibrations in the outer jacket caused by alternating electromagnetic forces in traditional medium-voltage power cables. By utilizing suppression structures composed of radial and circumferential suppression parts, and their specific positional distribution, a multiple suppression mechanism for cable core vibration is achieved. Specifically, multiple radial suppression parts can counteract the radial attraction force of multiple cable cores combined, while the induced magnetic field generated by the circumferential suppression parts can exert a repulsive force on the forces between adjacent cable cores, thereby suppressing relative displacement between the cable cores.

Description

Technical Field

[0001] This invention relates to the field of cable structure technology, and in particular to a medium-voltage power cable for power distribution networks and its intelligent early warning method. Background Technology

[0002] Medium-voltage power cables typically refer to power cables with rated voltages between 3kV and 35kV. They are indispensable power transmission equipment in scenarios such as urban power distribution networks, industrial power supply, and new energy grid connection. These cables undertake the important task of transmitting electrical energy from substations to end users, and their operational reliability is directly related to the power supply quality and safety of the entire power distribution network.

[0003] In practical applications of power distribution networks, medium-voltage power cables mainly operate in an alternating current (AC) environment. The cable typically contains multiple cores as current carriers. When AC current passes through, according to electromagnetic field theory, currents in adjacent cores with the same direction will generate an attractive electromagnetic force. Since the instantaneous value of AC current changes periodically with time, as the current gradually increases from zero to its peak value, the attraction between adjacent cores also gradually increases from zero to its maximum value. When the current gradually decreases from its peak value to zero, the attraction weakens and eventually disappears. As the current direction changes, in the next half-wave cycle, adjacent cores generate currents in the same direction again, and the attraction reappears and increases again. This cycle repeats itself, causing the cores to be subjected to a periodic electromagnetic force with a frequency twice the power frequency during operation.

[0004] This high-frequency change in electromagnetic attraction directly causes continuous micro-vibration between the multiple cores inside the cable. Under this vibration state for a long time, repeated friction will occur between the core and the insulation layer, causing the insulation layer to gradually wear down and become thinner, and even generate partial discharge channels. At the same time, the conductor material itself will also develop micro-cracks due to high-frequency fatigue, affecting its conductivity and mechanical strength. Summary of the Invention

[0005] This invention provides a medium-voltage power cable in a power distribution network and its intelligent early warning method, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A medium-voltage power cable for a power distribution network includes an outer jacket, a plurality of cable cores arranged in a ring within the outer jacket, and a plurality of suppression structures. The suppression structures are located between two adjacent cable cores and are used to suppress vibrations between two adjacent cable cores caused by alternating current. The suppression structure includes a radial suppression section and two circumferential suppression sections located on both sides of the radial suppression section. The radial suppression section is disposed between the cable core and the outer sheath axis, and the circumferential suppression section is disposed between two adjacent cable cores.

[0007] Furthermore, the suppression structure is formed by stacking several thin sheets made of highly conductive non-magnetic materials, and a damping buffer layer is filled between adjacent thin sheets.

[0008] Furthermore, the suppression structure also includes a support electrode plate corresponding to the radial suppression portion, and the support electrode plate is located on the side close to the outer sleeve axis, with a piezoelectric layer disposed between the support electrode plate and the radial suppression portion.

[0009] Furthermore, the radial suppression portions are distributed in a polygonal pattern, and the radial suppression portions in the suppression structure are electrically connected to the circumferential suppression portions in the suppression structure adjacent to each other on one side via a conductor.

[0010] Furthermore, a central support sleeve is provided in the middle of the outer jacket, and several positioning partition layers are provided on the central support sleeve. The support plate is provided on the central support sleeve, and the corresponding two-dimensional suppression parts in two adjacent suppression structures are in contact with the positioning partition layers and are respectively provided on both sides of the positioning partition layers.

[0011] Furthermore, a detection cable for detecting the current intensity and frequency inside the suppression structure is provided inside the central support sleeve.

[0012] Furthermore, the outer casing includes a conductor shielding layer, an insulating shielding layer, and a metal sheath arranged sequentially from the inside out.

[0013] Furthermore, a self-healing layer is provided between the insulating shielding layer and the metal sheath, the self-healing layer including a microcapsule layer located inside the metal sheath and an oleophobic layer located outside the insulating shielding layer; The microcapsules contain a single-component quick-drying adhesive that cures upon contact with air or moisture, or the microcapsules contain a two-component quick-drying adhesive that can come into contact with, mix with, and cure between the capsules. The oleophobic layer has a directional microporous structure for oleophobic purposes.

[0014] Furthermore, the cable also includes a stress balancing layer located on the outer jacket or the cable core. The stress balancing layer comprises stranded wires or corrugated tapes made of shape memory alloy material. The phase transition temperature of the stress balancing layer is within the operating temperature range of the cable, and the stress balancing layer generates directional contraction force when the cable is energized and heated.

[0015] A smart early warning method for medium-voltage power cables in a power distribution network includes the following steps: S1. Real-time monitoring of induced current parameters inside the suppression structure via detection cables; S2. Extract the intensity and frequency characteristic values ​​of the induced current; S3. Compare the extracted feature values ​​with the preset safety threshold range; S4. Determine whether the induced current intensity exceeds the threshold or whether abnormal harmonics appear in the frequency. S5. When the detected value exceeds the limit, the cable core vibration is determined to be abnormal and an early warning signal is issued; S6. Upload the early warning information to the monitoring center and prompt for inspection or maintenance.

[0016] The technical solution of this invention can achieve the following technical effects: This method effectively reduces the impact of high-frequency vibration of the outer jacket caused by AC electromagnetic force in traditional medium-voltage power cables. By utilizing a suppression structure composed of radial and circumferential suppression parts and their specific positional distribution, a multiple suppression mechanism for cable core vibration is achieved. Specifically, multiple radial suppression parts can counteract the radial attraction force of multiple cable cores combined, while the induced magnetic field generated by the circumferential suppression parts can exert a repulsive force on the force between adjacent cable cores, thereby suppressing the relative displacement between the cable cores. This combination of global radial suppression and local circumferential suppression allows the suppression structure to act on the cable core in all directions and dimensions, effectively absorbing and counteracting the dynamic electromagnetic force generated by the periodic changes of AC power, and significantly reducing the amplitude of high-frequency micro-vibrations of the cable core.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of medium-voltage power cables in a power distribution network; Figure 2 for Figure 1 A schematic diagram of the middle inhibition structure; Figure 3 for Figure 1 Schematic diagram of the central support sleeve; Reference numerals: 100, outer jacket; 101, conductor shielding layer; 102, insulating shielding layer; 103, metal sheath; 104, oleophobic layer; 105, microcapsule layer; 106, stress balancing layer; 200. Cable core; 300, Suppression structure; 301, Radial suppression section; 302, Circumferential suppression section; 303, Supporting electrode; 304, Piezoelectric layer; 305, Conductor; 400. Central support sleeve; 401. Positioning partition layer; 500. Test cable; 600, Filler layer. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] like Figure 1 As shown, this application provides a medium-voltage power cable for a power distribution network, including an outer jacket 100, a plurality of cable cores 200 arranged in a ring within the outer jacket 100, and a plurality of suppression structures 300. The suppression structures 300 are located between two adjacent cable cores 200 and are used to suppress vibrations between two adjacent cable cores 200 caused by alternating current. The suppression structure 300 includes a radial suppression part 301 and two circumferential suppression parts 302 located on both sides of the radial suppression part 301. The radial suppression part 301 is disposed between the axis of the cable core 200 and the outer jacket 100, and the circumferential suppression part 302 is disposed between two adjacent cable cores 200.

[0023] Specifically, the number of suppression structures 300 is the same as the number of cable cores 200. Their main function is to provide suppression force for the corresponding cable core 200, preventing high-frequency vibration during normal operation. Since the radial suppression sections 301 are located between the cable core 200 and the outer jacket 100 axis, they can be arranged in a polygonal pattern, so that each radial suppression section 301 corresponds to one cable core 200. When the cable cores 200 are energized, a magnetic field is generated around them, and the magnetic fields between adjacent cable cores 200 are in opposite directions. Therefore, an attractive force is generated between adjacent cable cores 200, and an upward force is generated between the cable cores 200. When the distance between the cable core 200 and the radial suppression part 301 changes, the magnetic field around the radial suppression part 301 changes due to the combined force acting on the outer jacket 100 along the axial direction. At this time, an induced current is generated inside the radial suppression part 301. This induced current generates a reverse magnetic field and hinders the movement of the cable core 200. By utilizing the special setting of the position of the radial suppression part 301, the force exerted by the radial suppression part 301 on the cable core 200 can be directly along the radial direction of the outer jacket 100. Thus, by using several radial suppression parts 301, the combined force generated by several cable cores 200 can be directly provided with an electromagnetic resistance opposite to that of the combined force, thereby suppressing the vibration of the cable core 200.

[0024] Furthermore, since the circumferential suppression part 302 in the suppression structure 300 is located between two adjacent cable cores 200, the two corresponding circumferential suppression parts 302 in the two suppression structures 300 will be located between two adjacent cable cores 200 at the same time. When the two adjacent cable cores 200 approach each other due to magnetic attraction, the distance between the cable core 200 and the circumferential suppression part 302 changes. At this time, an induced magnetic force that suppresses the movement of the cable core 200 will also be generated inside the circumferential suppression part 302, thereby suppressing the vibration of the cable core 200. Moreover, the two circumferential suppression parts 302 provide suppression force to the two cable cores 200 respectively, thereby avoiding mutual interference.

[0025] The technical solution of this invention effectively reduces the impact of high-frequency vibration of the outer jacket 100 caused by AC electromagnetic force in traditional medium-voltage power cables. By utilizing the suppression structure 300 composed of radial suppression parts 301 and circumferential suppression parts 302, and by utilizing its specific positional distribution, a multiple suppression mechanism for the vibration of the cable core 200 is achieved. That is, multiple radial suppression parts 301 can counteract the radial attraction force of multiple cable cores 200 combined. At the same time, the induced magnetic field generated by the circumferential suppression parts 302 can exert a repulsive force on the force between two adjacent cable cores 200, thereby suppressing the relative displacement between the cable cores 200. This combination of radial suppression and circumferential suppression allows the suppression structure to act on the cable core 200 from multiple directions, effectively absorbing and counteracting the dynamic electromagnetic force generated by the periodic changes of AC power, and significantly reducing the high-frequency micro-vibration amplitude of the cable core 200.

[0026] Furthermore, the suppression structure 300 is made of several sheets of highly conductive non-magnetic material stacked together, with a damping buffer layer filling the space between adjacent sheets.

[0027] Highly conductive non-magnetic materials can be copper, aluminum, or copper alloys or aluminum alloys. Their low resistivity ensures that a sufficiently strong induced current can be quickly generated in a changing magnetic field, thereby generating a reverse magnetic field. At the same time, their relative permeability will not cause static magnetic attraction with the magnetic field generated by the cable core. In addition, it can ensure that the material itself does not generate hysteresis loss, resulting in a faster response speed.

[0028] Damping buffer layer materials can be viscoelastic polymer materials, such as silicone rubber, butyl rubber, polyurethane elastomer, acrylate damping adhesive, etc., which have the characteristics of both viscous fluid and elastic solid, and can convert mechanical energy into heat energy under alternating stress.

[0029] The plane direction of the thin sheet can be set to be perpendicular to the sensitive direction of the cable core 200 vibration, that is, perpendicular to the line connecting the centers of adjacent cable cores, or perpendicular to the radial direction of the cable, so as to maximize the area of ​​cutting magnetic field lines; the thickness of a single layer of thin sheet is usually 0.1~0.5mm, and the total number of layers is determined according to the cable cross-sectional size and vibration suppression requirements, generally 5~20 layers.

[0030] When the thin sheet undergoes slight bending or relative displacement due to electromagnetic force, the damping buffer layer sandwiched between the sheets undergoes shear deformation. During the shearing process, the molecular chains of the viscoelastic material undergo relative slippage and rearrangement, doing work to overcome internal friction and converting mechanical energy into heat energy, which is then dissipated to the surrounding environment through heat conduction.

[0031] Through the above-mentioned composite design of "thin sheet electromagnetic induction + damping layer viscoelastic energy dissipation", the suppression structure 300 can effectively alleviate the harm caused by long-term vibration in the background technology without the need for external energy.

[0032] Furthermore, such as Figure 2 As shown, the suppression structure 300 also includes a support plate 303 corresponding to the radial suppression part 301, and the support plate 303 is located on the side close to the axis of the outer jacket 100. A piezoelectric layer 304 is provided between the support plate 303 and the radial suppression part 301.

[0033] The radial suppression portions 301 and the supporting plates 303 on both sides of the piezoelectric layer 304 can serve as the two electrodes of the battery. When the cable core 200 vibrates, an induced current is generated on the radial suppression portion 301, which hinders the vibration of the cable core 200. At this time, the radial suppression portion 301 will be pushed by the cable core 200. If the radial suppression portion 301 and the circumferential suppression portion 302 have high hardness, they can achieve a rigid support effect by utilizing their own structure. If the radial suppression portion 301 has relatively low hardness, it will undergo a small amount of deformation or displacement when subjected to force. The force exerted by the cable core 200 on the radial suppression part 301 will be transmitted to the piezoelectric layer 304. The piezoelectric layer 304 generates voltage due to its own piezoelectric effect, so that the radial suppression part 301 can generate induced current not only by using the changing magnetic field, but also by the pressure on the piezoelectric layer 304. The induced current generated by these two methods together form a magnetic field and provide suppression force on the cable core 200. At the same time, the charge generated in the piezoelectric layer 304 can convert mechanical energy into electrical energy and lose it through the internal resistance of the material itself.

[0034] Furthermore, several radial suppression portions 301 are distributed in a polygonal pattern, and the radial suppression portions 301 in the suppression structure 300 are electrically connected to the circumferential suppression portions 302 in the adjacent suppression structure 300 on one side through a conductor 305.

[0035] The piezoelectric layer 304 and its radial suppression portions 301 and supporting plates 303 on both sides can form a battery structure. When the piezoelectric layer 304 is squeezed, a voltage will be generated between the radial suppression portions 301 and the supporting plates 303. By connecting several battery structures in series with several conductors 305, several suppression structures 300 can be combined together for use. At the same time, it is convenient to combine several piezoelectric battery structures together to make their suppression effect on the cable core 200 stronger and their response more sensitive, while making the suppression force on several cable cores 200 more balanced.

[0036] Furthermore, such as Figure 3 As shown, a central support sleeve 400 is provided in the middle of the outer sleeve 100. Several positioning partition layers 401 are provided on the central support sleeve 400. The support plate 303 is provided on the central support sleeve 400. The corresponding two-dimensional suppression parts 302 in two adjacent suppression structures 300 are in contact with the positioning partition layer 401 and are respectively provided on both sides of the positioning partition layer 401.

[0037] The support plate 303 on the suppression structure 300 is fixedly installed on the outer wall of the central support sleeve 400, so that each suppression structure 300 can extend radially outward to the vicinity of the corresponding cable core 200. The positioning separation layer 401 provides a clear installation positioning reference for two adjacent circumferential suppression parts 302, ensuring that they maintain a preset spacing and angle on the radial cross section of the cable. On the other hand, as a physical partition, it effectively prevents two adjacent circumferential suppression parts 302 from contacting or colliding with each other during the vibration of the cable core 200, eliminating secondary vibration or noise caused by structural interference, and also avoiding mutual interference between the induced magnetic fields of the two, ensuring that each circumferential suppression part 302 can independently and stably generate a precise electromagnetic vibration suppression force on its corresponding cable core 200.

[0038] Furthermore, a detection cable 500 for detecting the current intensity and frequency inside the suppression structure 300 is provided inside the central support sleeve 400.

[0039] The detection cable 500 can be electrically connected to the radial suppression part 301, the support plate 303, or the piezoelectric layer 304 in the suppression structure 300, thereby monitoring the intensity of the induced current generated inside the suppression structure 300 due to the cutting of magnetic field lines in real time. Its working principle is based on electromagnetic induction reverse monitoring logic: when the cable core 200 generates high-frequency micro-vibration due to the action of alternating electromagnetic force, the conductive sheet in the adjacent suppression structure 300 will inevitably move relative to it, cutting the alternating magnetic field generated by the cable core 200, thereby generating an induced current; the intensity of the induced current is positively correlated with the vibration amplitude of the cable core 200, and its frequency is consistent with the vibration frequency of the cable core 200. Therefore, by continuously collecting and analyzing the characteristic parameters of the induced current in the suppression structure 300 through the detection cable 500, the real-time vibration state of the cable core 200 can be indirectly obtained. Once the detected induced current intensity exceeds the preset threshold, or the current frequency fluctuates abnormally, such as the appearance of high-order harmonic components, it can be determined that the vibration amplitude of the cable core 200 is too large or the vibration mode has changed abnormally, indicating that the cable's operating condition has deteriorated or there is a potential risk of failure.

[0040] Furthermore, the outer jacket 100 includes a conductor shielding layer 101, an insulating shielding layer 102, and a metal sheath 103 arranged sequentially from the inside out.

[0041] The outer jacket 100 adopts a multi-layer composite structure design, which sequentially covers the outer surface of the cable core 200 and the suppression structure 300 from the inside out. Among them, the conductor shielding layer 101 tightly covers the outer peripheral surface of several cable cores 200. Its function is to homogenize the electric field distribution on the surface of the cable core, prevent local electric field concentration caused by unevenness of the conductor surface, and at the same time isolate the cable core 200 from the insulating shielding layer 102 to avoid direct contact between the two and the interface defects. An insulating shielding layer 102 is set outside the conductor shielding layer 101. This layer is usually made of semi-conductive material wrapped or extruded, and together with the metal sheath 103, it forms an equipotential shielding structure. Its function is to confine the electric field inside the insulation layer, and at the same time guide the capacitive current and fault current of the cable during operation to the grounding system.

[0042] The outermost layer is a metal sheath 103, typically made of corrugated aluminum, lead, or copper materials, and has multiple key functions: First, as a radial waterproof layer for the cable, it effectively blocks the intrusion of external moisture and corrosive media, protecting the internal insulation structure from moisture damage; second, as a return path for fault current, it carries the short-circuit current when a short-circuit fault occurs in the cable, ensuring system safety; third, together with the insulation shielding layer 102, it forms a metal shielding layer, making the internal electric field of the cable radially distributed and avoiding the generation of a tangential electric field; in addition, the metal sheath 103 also has a certain mechanical protection function, which can withstand the tension and pressure during the laying process, protecting the internal cable core and the suppression structure from damage.

[0043] Furthermore, a self-healing layer is provided between the insulating shielding layer 102 and the metal sheath 103. The self-healing layer includes a microcapsule layer 105 located inside the metal sheath 103 and an oleophobic layer 104 located outside the insulating shielding layer 102. The capsules within the microcapsule layer 105 encapsulate a quick-drying adhesive system that cures upon contact with air or moisture, or the capsules within the microcapsule layer 105 and between the capsules encapsulate a quick-drying adhesive system that can come into contact, mix, and cure. The oleophobic layer 104 has a directional microporous structure for oleophobic purposes.

[0044] The self-healing layer adopts a double-layer composite structure design, consisting of an oleophobic layer 104 and a microcapsule layer 105 from the inside out. The microcapsule layer 105 is located on the outer side, adjacent to the metal sheath 103; the oleophobic layer 104 is located on the inner side, adjacent to the outer wall of the insulating shielding layer 102. The oleophobic layer 104 is made of a material with oleophobic properties and has a directionally arranged microporous structure inside.

[0045] The microcapsule layer 105 encapsulates a quick-drying repair adhesive. According to the formulation design, this adhesive can be a single-component system that cures upon contact with air or moisture; or it can be a two-component system, where one component is encapsulated inside the microcapsule and the other component is dispersed in the carrier material between the microcapsules, or pre-impregnated in the outer oleophobic layer 104. When the metal sheath 103 is damaged by external force, the mechanical stress at the point of damage is transmitted to the inner microcapsule layer 105, causing localized microcapsule rupture and releasing the internal repair adhesive. At this time, due to the oleophobic properties of the inner oleophobic layer 104, the adhesive... The liquid has a large contact angle on its surface, so it will not be sucked in or adsorbed, but will be repelled instead. The crack in the oleophobic layer 104 is the only pressure release point, and the metal surface is usually oleophilic. Therefore, under the condition of "repulsion on the inside and crack on the outside", the adhesive is forced to flow outward to the crack in the metal sheath 103 under the combined action of pressure and surface tension, ensuring that the adhesive can accurately converge in the damaged area. If a two-component system is used, the first component in the capsule will come into contact with and mix with the second component after release, thereby triggering a curing reaction and realizing the self-healing function of the outer shell 100.

[0046] Furthermore, such as Figure 1 As shown, the cable also includes a stress balancing layer 106 located on the outer jacket 100 or the cable core 200. The stress balancing layer 106 includes stranded wires or corrugated tapes made of shape memory alloy material. The phase change temperature of the stress balancing layer 106 is within the operating temperature range of the cable, and the stress balancing layer 106 generates directional contraction force when the cable is energized and heated.

[0047] Depending on the installation location, the stress balancing layer 106 can be integrated into the stranded structure of the cable core 200 and stranded together with the conductor; it can also be embedded in the multi-layer structure of the outer jacket 100, for example, located between the conductor shielding layer 101 and the insulation shielding layer 102, or wrapped inside the metal sheath 103. The shape memory alloy material has specific phase transition temperature characteristics, and its phase transition temperature point is precisely controlled by alloy composition design and heat treatment process, and set within the normal operating temperature range of the cable. When the cable load increases, the temperature of the cable core 200 gradually rises due to the Joule heating effect. When the temperature reaches the phase transition initiation temperature of the shape memory alloy, the crystal structure inside the stress balancing layer 106 undergoes a transformation, such as a transformation from martensite to austenite. This phase transition process is accompanied by the redistribution of internal stress in the material, causing the stress balancing layer 106 to generate directional contraction force along the cable axis. The contractile force acts on the cable core 200 or the entire cable structure, causing the cable as a whole to undergo slight axial contraction and appear "tight". This contraction effect just offsets the axial elongation tendency of the cable core 200 due to thermal expansion.

[0048] When the cable is de-energized and cooled, and the temperature drops below the phase transition temperature, the shape memory alloy in the stress balance layer 106 undergoes a reverse phase transition, restoring to its original microstructure. The directional shrinkage force disappears, and the cable returns to its initial "relaxed" state. Through this reversible thermomechanical response mechanism, the stress balance layer 106 achieves automatic adjustment of the cable length according to the power-on and power-off states, effectively reducing the "tightening" phenomenon caused by thermal shock during the moment of power-on and the relaxation phenomenon caused by cooling and contraction after power-off.

[0049] A filling layer 600 is filled between the outer jacket 100 and the cable core 200, and between the central support sleeve 400 and the detection cable 500.

[0050] The filler layer 600 between the outer sheath 100 and the cable core 200 is usually made of water-blocking filler rope or semi-conductive filler adhesive. During the cable cabling process, it fills the gaps between each cable core 200 and the annular space between the cable core 200 and the outer sheath 100. Its main function is to provide stable mechanical support for the cable core 200 and the suppression structure 300, prevent relative displacement of internal components during cable bending or vibration during operation, ensure that the suppression structure 300 always remains in the preset working position, and form a continuous waterproof barrier in the radial direction of the cable. Even if the outer sheath is damaged, it can effectively prevent moisture from penetrating longitudinally and contacting the insulation layer, thus delaying the occurrence of aging.

[0051] The filling layer 600 between the central support sleeve 400 and the detection cable 500 typically uses a low-modulus buffer potting material, such as silicone gel or polyurethane potting compound, to completely encapsulate the detection cable 500 within the internal cavity of the central support sleeve 400. This allows the buffer material to absorb and attenuate the mechanical vibrations transmitted from the cable body to the detection cable 500, protecting sensitive electronic components from vibration damage. Simultaneously, the potting material has excellent thermal conductivity, conducting the heat generated by the detection cable 500 during operation to the central support sleeve 400, which is then dissipated through the cable structure, ensuring reliable operation of the detection cable 500 within its permissible temperature range. Furthermore, the potting material acts as insulation, preventing electrical breakdown between the detection cable 500 and the central support sleeve 400.

[0052] A smart early warning method for medium-voltage power cables in a power distribution network includes the following steps: S1. The induced current parameters inside the suppression structure 300 are monitored in real time by the detection cable 500. S2. Extract the intensity and frequency characteristic values ​​of the induced current; S3. Compare the extracted feature values ​​with the preset safety threshold range; S4. Determine whether the induced current intensity exceeds the threshold or whether abnormal harmonics appear in the frequency. S5. When the detected value exceeds the limit, the cable core 200 is judged to be vibrating abnormally and an early warning signal is issued; S6. Upload the early warning information to the monitoring center and prompt for inspection or maintenance.

[0053] By adopting the above-mentioned intelligent early warning method, cables can be monitored online, in real time, and non-invasively. This method directly uses the induced current generated by the suppression structure 300 when the cable core 200 vibrates as the monitoring signal source, without the need for additional sensors. This simplifies the system structure and achieves a deep integration of monitoring and vibration suppression functions.

[0054] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A medium-voltage power cable for a power distribution network, characterized in that, It includes an outer jacket, a plurality of cable cores arranged in a ring within the outer jacket, and a plurality of suppression structures, wherein the suppression structures are located between two adjacent cable cores and are used to suppress vibrations between two adjacent cable cores caused by alternating current; The suppression structure includes a radial suppression section and two circumferential suppression sections located on both sides of the radial suppression section. The radial suppression section is disposed between the cable core and the outer sheath axis, and the circumferential suppression section is disposed between two adjacent cable cores.

2. The medium-voltage power cable for a power distribution network according to claim 1, characterized in that, The suppression structure is formed by stacking several thin sheets made of highly conductive non-magnetic materials, with a damping buffer layer filling the space between adjacent sheets.

3. A medium-voltage power cable for a power distribution network according to claim 1, characterized in that, The suppression structure further includes a support electrode plate corresponding to the radial suppression portion, and the support electrode plate is located on the side close to the outer sleeve axis. A piezoelectric layer is provided between the support electrode plate and the radial suppression portion.

4. A medium-voltage power cable for a power distribution network according to claim 3, characterized in that, The radial suppression portions are distributed in a polygonal pattern, and the radial suppression portions in the suppression structure are electrically connected to the circumferential suppression portions in the suppression structure adjacent to each other on one side via a conductor.

5. A medium-voltage power cable for a power distribution network according to claim 3, characterized in that, A central support sleeve is provided in the middle of the outer jacket, and a plurality of positioning partition layers are provided on the central support sleeve. The support plate is provided on the central support sleeve, and the corresponding two-dimensional suppression parts in two adjacent suppression structures are in contact with the positioning partition layers and are respectively provided on both sides of the positioning partition layers.

6. A medium-voltage power cable for a power distribution network according to claim 5, characterized in that, A detection cable for detecting the current intensity and frequency inside the suppression structure is installed inside the central support sleeve.

7. A medium-voltage power cable for a power distribution network according to claim 1, characterized in that, The outer casing includes a conductor shielding layer, an insulating shielding layer, and a metal sheath arranged sequentially from the inside out.

8. A medium-voltage power cable for a power distribution network according to claim 7, characterized in that, A self-healing layer is provided between the insulating shielding layer and the metal sheath. The self-healing layer includes a microcapsule layer located inside the metal sheath and an oleophobic layer located outside the insulating shielding layer. The microcapsules contain a single-component quick-drying adhesive that cures upon contact with air or moisture, or the microcapsules contain a two-component quick-drying adhesive that can come into contact with, mix with, and cure between the capsules. The oleophobic layer has a directional microporous structure for oleophobic purposes.

9. A medium-voltage power cable for a power distribution network according to claim 7, characterized in that, The cable also includes a stress balancing layer located on the outer jacket or the cable core. The stress balancing layer comprises stranded wires or corrugated tapes made of shape memory alloy material. The phase transition temperature of the stress balancing layer is within the operating temperature range of the cable, and the stress balancing layer generates directional contraction force when the cable is energized and heated.

10. A method for intelligent early warning of medium-voltage power cables in a power distribution network, employing a medium-voltage power cable as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Real-time monitoring of induced current parameters inside the suppression structure via detection cables; S2. Extract the intensity and frequency characteristic values ​​of the induced current; S3. Compare the extracted feature values ​​with the preset safety threshold range; S4. Determine whether the induced current intensity exceeds the threshold or whether abnormal harmonics appear in the frequency; S5. When the detected value exceeds the limit, the cable core vibration is determined to be abnormal and an early warning signal is issued; S6. Upload the early warning information to the monitoring center and prompt for inspection or maintenance.

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