A positioning system and method based on nanocomposite insulation constant wave velocity cable

Abstract

The application discloses a kind of based on nano composite insulation constant wave velocity cable positioning system and method, it is related to the field of insulating material.System includes cable body (100) and double-end traveling wave detection terminal (200).The cable body (100) is equipped with waveguide channel by composite insulation layer (130) and high-frequency low-loss semiconductive layer (140);Composite insulation layer (130) is with polyvinyl ion as matrix, doped modified titanium-silicon molecular sieve (131) and boron nitride nanosheet (133).Coupling end group and matrix ion cluster form coordination crosslinking network (132), synergistically inhibit charge accumulation, lock relative dielectric constant as constant value.Terminal (200) extracts traveling wave time difference, calls preset wave velocity ranging based on constant dielectric constant calibration.The application replaces algorithm compensation with material bottom layer dielectric stability, significantly suppresses wave velocity distortion, realizes high-precision positioning.

Description

Technical Field

[0001] This invention relates to the field of cable and its insulation materials technology, and in particular to a positioning system and method based on a constant wave speed cable with nanocomposite insulation. Background Technology

[0002] With the rapid development of new power systems and high-voltage direct current (HVDC) transmission technology, the application of long-distance underground cables is becoming increasingly widespread. When a cable experiences a fault under complex operating conditions, quickly and accurately locating the fault point is of paramount engineering significance for shortening power outage time and improving power supply reliability. Currently, the two-end traveling wave ranging method is considered the optimal solution for cable fault location because it is unaffected by system operating modes and transition resistance.

[0003] However, traditional two-end traveling wave positioning systems face insurmountable accuracy bottlenecks in practical engineering applications. The core logic of traveling wave positioning highly depends on the propagation speed (i.e., wave velocity) of transient traveling waves in the cable insulation medium. Traditional high-voltage cables commonly use cross-linked polyethylene (XLPE) as the main insulation material. Under high temperatures (such as when the cable is fully loaded and heating up) and long-term exposure to strong electric fields, XLPE materials are prone to the injection and accumulation of space charge, accompanied by microstructural deformation caused by local thermomechanical stress. These material-level degradations lead to a significant and nonlinear drift in the relative permittivity of XLPE. Since the propagation speed of electromagnetic waves (traveling waves) is inversely proportional to the relative permittivity of the medium, this drift directly results in severe distortion and uncertainty in the traveling wave velocity.

[0004] Currently, the mainstream approaches to solving wave velocity distortion problems in the industry all focus on "algorithm-side compensation," such as using complex adaptive filtering, high-order neural networks, or multiple ranging equations to dynamically estimate wave velocity. However, these purely algorithmic methods not only consume enormous computing power, but also often result in positioning errors of hundreds of meters when faced with real-world water tree aging or local heat island effects due to model mismatch.

[0005] Therefore, there is an urgent need for a completely new system architecture that can break free from the limitations of "algorithm compensation" and directly start from the underlying physical and chemical properties of cable insulation materials to construct an absolutely constant waveguide medium that is unaffected by temperature and electric field fluctuations, thereby fundamentally eliminating wave velocity errors and achieving precise positioning of double-ended traveling waves. Summary of the Invention

[0006] The purpose of this invention is to provide a positioning system and method based on a nanocomposite insulated constant wave speed cable. By performing underlying physicochemical modification on the insulation material and semiconductive shielding layer of the cable body, an electromagnetic waveguide channel with absolutely stable dielectric constant and low transmission loss is constructed, which solves the technical problem of wave speed distortion and large positioning error caused by dielectric constant drift in traditional traveling wave positioning.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A positioning system based on a nanocomposite insulated constant wave speed cable includes a cable body 100 and a double-ended traveling wave detection terminal 200 respectively connected to both ends of the cable body 100. The cable body 100 is coaxially extruded from the inside to the outside with a conductor core 110, an inner semiconductive shielding layer 120, a composite insulation layer 130, a high-frequency low-loss semiconductive layer 140, and an outer sheath 150. The high-frequency, low-loss semiconducting layer 140 is a cross-linked polyethylene layer doped with carbon nanotubes, which together with the conductor core 110 constitutes a broadband coaxial waveguide channel for the propagation of transient traveling wave signals. The composite insulation layer 130 is a multiphase nanocomposite insulation system. Its matrix is ​​made of polyethylene-based ionomer material with a neutralization degree of 25% to 40%, and titanium-silicon molecular sieve 131 with a mass fraction of 1.5wt% to 3.0wt% is uniformly dispersed in the matrix. The titanium-silicon molecular sieve 131 is surface modified with a silane coupling agent, and the end groups of the silane coupling agent form a coordination crosslinking network 132 with the ion clusters in the polyethylene ionosphere material. The dual-end traveling wave detection terminal 200 is used to extract the transient traveling wave signal generated by the fault from the broadband coaxial waveguide channel and to locate it using the dual-end time difference.

[0008] Furthermore, the ion clusters in the polyethylene-based ionosphere material are formed by ion interactions, and the titanium-silicon molecular sieve 131 has a nanoporous crystal structure.

[0009] Furthermore, the carbon nanotubes in the high-frequency low-loss semiconducting layer 140 have a mass fraction of 3 wt% to 5 wt%, and the high-frequency volume resistivity of the high-frequency low-loss semiconducting layer 140 is 10⁻⁶. 2 Ω·m to 10 3 Ω·m.

[0010] Furthermore, the composite insulation layer 130 is also co-doped with two-dimensional layered nanofillers, which are boron nitride nanosheets 133 oriented along the cable axial direction within the matrix of the polyethylene ionomer material.

[0011] Furthermore, the dual-end traveling wave detection terminal 200 includes a wideband Rogowski coil 210, a traveling wave conditioning circuit, and a satellite synchronization clock module 220; the wideband Rogowski coil 210 is sleeved on the end of the cable body 100 after the outer sheath 150 has been stripped.

[0012] The present invention also provides a fault location method for the above-mentioned location system based on a constant wave speed cable with nanocomposite insulation, comprising the following steps: When the cable body 100 fails, the transient traveling wave signal propagates to both ends of the cable in the broadband coaxial waveguide channel where the composite insulation layer 130 is located; The double-ended traveling wave detection terminals 200 located at both ends of the cable extract the initial wavefronts of the transient traveling wave signals at both ends in real time, and record the first time stamp of the arrival of the first initial wavefront and the second time stamp of the arrival of the second initial wavefront respectively. Obtain the relative permittivity of the composite insulating layer 130, and retrieve the corresponding preset traveling wave propagation speed based on the relative permittivity; Calculate the time difference between the first timestamp and the second timestamp, and combine it with the preset traveling wave propagation speed to calculate the location of the cable fault point.

[0013] Furthermore, the preset traveling wave propagation speed is obtained through the formula... Calibration; Where v is the preset traveling wave propagation speed, c is the speed of light in a vacuum, and ε r μ is the relative permittivity of the composite insulating layer 130. r The relative permeability of the composite insulating layer 130.

[0014] Furthermore, the specific formula for calculating the location of the cable fault point is as follows: ; Among them, L x The distance from the fault point to the dual-end traveling wave detection terminal 200 that records the first timestamp is L, the total length of the cable body 100 is L, t1 is the first timestamp, t2 is the second timestamp, and v is the preset traveling wave propagation speed.

[0015] Furthermore, before recording the first timestamp of the arrival of the first initial wavefront and the second timestamp of the arrival of the second initial wavefront, the extracted transient traveling wave signal is denoised using a wavelet modulus maxima algorithm based on an adaptive threshold.

[0016] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0017] The beneficial effects of this invention are: 1. Microscopic coordination and synergy, completely locking the dielectric constant under all operating conditions. This invention overcomes the technical bottleneck of nonlinear drift of dielectric constant in traditional cross-linked polyethylene (XLPE) under high pressure and thermomechanical stress. By using polyethylene-based ionomer as the insulating matrix and introducing titanium-silicon molecular sieves modified with silane coupling agents, a highly efficient coordination cross-linking network of "ion clusters-end groups" is spontaneously formed within the material. This three-dimensional network physically constrains the polarization relaxation of polymer chain segments, while the nanoporous structure of the titanium-silicon molecular sieve chemically acts as a "deep-level electron trap," effectively capturing injected free electrons and blocking water molecule permeation. The synergistic effect of these two factors maximally suppresses the space charge polarization effect, locking the relative dielectric constant of the insulating layer within an extremely narrow, highly stable range (maximum deviation ≤ ±0.01) across the entire temperature range of 20℃ to 90℃ and under high voltage and strong electric fields.

[0018] 2. Construct a zero-dispersion waveguide channel to ensure extremely high transient wavefront steepness.

[0019] To address the issues of skin effect and severe attenuation in conventional metallic shielding layers for MHz-level high-frequency transient traveling waves, this invention innovatively introduces a high-frequency, low-loss semiconducting layer doped with a specific mass fraction of carbon nanotubes. This layer, together with the conductor core, forms a broadband coaxial waveguide channel specifically for traveling waves, eliminating high-frequency impedance abrupt changes. Simultaneously, two-dimensional boron nitride nanosheets arranged axially and highly oriented within the insulating layer construct a network with high thermal conductivity and extremely low dielectric loss. This dual macro / micro structural design of "low-impedance shielding + low-loss insulation" significantly extends the scattering path of high-frequency electromagnetic waves, eliminating waveform distortion and dispersion during long-distance propagation, enabling dual-end detection terminals to extract the unattenuated, extremely steep initial physical wavefront.

[0020] 3. The algorithm is extremely simplified and dimensionality reduced, achieving a physical-level leap in ranging accuracy.

[0021] Thanks to the high stability of the relative permittivity of the underlying composite material, the propagation speed of traveling waves in the cable is transformed into an intrinsic parameter with minimal fluctuation. This system effectively replaces the computationally intensive high-order neural networks or complex adaptive filtering algorithms used in existing technologies to compensate for wave velocity errors. The main control processor can directly call the propagation speed formula calibrated based on the intrinsic properties of the material. Spatiotemporal algebra calculations are performed. This cross-domain system architecture, which replaces "complex compensation at the computing power level" with "intrinsic stability at the material level", significantly weakens the error propagation chain of "deterioration of operating environment → sudden change in dielectric constant → wave velocity distortion → location failure", and compresses the error limit of cable fault location to the range of hardware clock accuracy.

[0022] 4. Improve engineering reliability and industrial lifespan under extreme environments

[0023] The ultra-high thermal conductivity of boron nitride nanosheets in the composite insulation layer, reaching up to 600 W / (m·K), can rapidly distribute hot spots generated by partial discharge or overload along the axial direction, completely eliminating insulation thermal breakdown caused by local heat island effect. Combined with the water treeing aging resistance of titanium silicon molecular sieve, this cable system can be directly deployed in harsh underground pipe corridors or cross-sea DC transmission projects with high humidity, high heat and strong electromagnetic interference, giving the system extremely high engineering application value and full life cycle reliability. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall system structure and dual-end detection configuration of an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the microstructure of the cable body and its composite insulation layer according to an embodiment of the present invention; Figure 3 This is a comparison curve of the dielectric stability of the composite insulating layer materials in the embodiments of the present invention; Figure 4 This is a flowchart of the fault location method according to an embodiment of the present invention.

[0025] Explanation of reference numerals in the attached figures: 100-Cable body; 110-Conductor core; 120-Inner semiconductive shielding layer; 130-Composite insulation layer; 131-Titanium silicon molecular sieve; 132-Coordination cross-linking network; 133-Boron nitride nanosheets; 140-High frequency low loss semiconductive layer; 150-Outer sheath; 200-Dual-end traveling wave detection terminal; 210-Broadband Rogowski coil; 220-Satellite synchronization clock module. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] Example 1: Macroscopic cable structure and waveguide channel construction specifically for two-end traveling wave detection

[0028] Traditional traveling wave detection typically obtains signals between the cable's metal shield and the conductor core 110. However, ordinary copper tape or copper wire shields have extremely high inductive reactance to high-frequency transient traveling waves at the MHz level, resulting in severe skin effect attenuation. This makes the wavefront reaching the detection terminal flat and makes it impossible to accurately extract the timestamp.

[0029] like Figure 1 and Figure 2As shown, to meet the requirements of high-precision double-ended traveling wave synchronous detection, the cable body 100 of this invention has undergone structural redesign. A special high-frequency, low-loss semiconducting layer 140 is extruded onto the outside of the composite insulation layer 130. This layer is a cross-linked polyethylene layer doped with carbon nanotubes, wherein the mass fraction of carbon nanotubes is precisely controlled between 3 wt% and 5 wt%, ensuring that the high-frequency volume resistivity of this layer is stable at 10 Ω·cm. 2 Ω·m to 10 3 Between Ω·m.

[0030] The key innovation and beneficial effect of this embodiment lies in the fact that this setting not only maintains the original voltage equalization function of the cable, but more importantly, it is used to eliminate the skin effect attenuation of MHz-level transient traveling wave signals propagating in this broadband coaxial waveguide channel. The uniform three-dimensional conductive network formed by nanoscale carbon nanotubes in the polymer avoids the high-frequency impedance abrupt changes caused by macroscopic metal braided mesh, enabling transient traveling waves to be transmitted losslessly to both ends with an extremely low attenuation rate, providing an extremely steep original physical signal for subsequent time difference calculations.

[0031] Regarding the above structure, in order to prove that the DC / power frequency resistivity is 10... 2 Ω·m to 10 3 The Ω·m high-frequency, low-loss semiconducting layer 140 can overcome the theoretical limitations of traditional metallic outer conductors and satisfy the waveguide boundary conditions for transient traveling wave propagation at the MHz level. This embodiment further discloses its microscopic electromagnetic transmission mechanism and simulation calibration data: In classical electromagnetic theory, if conventional carbon black semiconducting materials are used, their AC and DC resistivity changes little, and their skin depth is extremely large in the 1MHz-10MHz frequency band, leading to leakage of traveling wave signals through radiation. However, in this invention, a three-dimensional percolation network is constructed within a cross-linked polyethylene matrix using a specific mass fraction (3wt%-5wt%) of one-dimensional carbon nanotubes (CNTs). This network exhibits strong frequency dispersion characteristics and microscopic interfacial capacitive coupling effects. 1) Dynamic AC impedance abrupt change: This layer exhibits a 10 ohm change at power frequency (50Hz). 2 Ω·m to 10 3 The high resistivity of Ω·m perfectly satisfies the requirements for equalizing the electric field outside the cable insulation layer; however, when the frequency jumps to the transient traveling wave band of 1MHz~10MHz, the microcapacitance at the interface between the substrate and CNT becomes highly conductive, causing its high-frequency equivalent AC resistivity to drop sharply to 10. -2 Below the Ω·m level.

[0032] 2) Kinetic inductance and total internal reflection of plasma: based on the skin depth formula (Where δ is the skin depth of the high-frequency electromagnetic wave in the semiconductive layer 140, ρ is the high-frequency equivalent AC resistivity of the layer, ω is the angular frequency of the transient traveling wave signal, and μ is the absolute permeability of the layer.) Under this high-frequency dynamic resistivity, the skin depth is effectively compressed to the millimeter scale, which is comparable to the physical thickness of the semiconductive layer. More importantly, carbon nanotubes exhibit intrinsic kinetic inductance and high-frequency negative permittivity effects in the MHz band, constructing an electromagnetic reflector wall similar to a "plasma state" at the physical interface between the composite insulating layer 130 and the semiconductive layer 140, forcing the high-frequency electromagnetic wave to undergo total internal reflection, and transforming the transmission mode into a low-loss surface waveguide mode.

[0033] 3) Attenuation coefficient and surface impedance calibration: Electromagnetic simulation and high-frequency measurement data show that at the center frequency of 5MHz, the surface equivalent impedance Z of the carbon nanotube modified layer is [value missing]. s (where the complex impedance Z) s =R s +jX s R s X is the equivalent surface resistance. s The equivalent surface reactance (where j is the imaginary unit) is reduced from hundreds of ohms in traditional carbon black layers to approximately 3.2 + j1.5 Ω. Under these high-frequency dynamic boundary conditions, the attenuation coefficient α (α characterizes the signal amplitude attenuation rate when the electromagnetic wave propagates along the axis) of this broadband coaxial waveguide channel for a 5MHz transient traveling wave signal is effectively suppressed to below 0.08 dB / km. In contrast, the high-frequency attenuation coefficient of traditional pure metal shielding layers is often greater than 0.5 dB / km due to macroscopic eddy currents and skin effect at high frequencies.

[0034] Therefore, the semiconductive layer 140 of this invention is not a pure resistive shield in the traditional sense, but rather a dynamic waveguide boundary constructed using the high-frequency dispersion characteristics of nanocomposite materials, which is a "power frequency equalization voltage-high frequency reflection" structure. This microscopic mechanism establishes its technical effect of achieving "low-loss broadband transmission" from both theoretical and experimental perspectives.

[0035] Example 2: Material formulation and microscopic coordination crosslinking network of multiphase composite insulation system 132

[0036] This embodiment focuses on illustrating the core mechanism determining the absolute stability of traveling wave propagation speed—the microscopic modification formulation of the composite insulating layer 130. Due to the wave speed... If ε r If the position drifts, the positioning will inevitably fail.

[0037] In this invention, the matrix of the composite insulating layer 130 abandons traditional XLPE and adopts a polyethylene-based ionomer material with a neutralization degree of 25% to 40%. Simultaneously, a titanium-silicon molecular sieve 131 (TS-1) with a mass fraction of 1.5 wt% to 3.0 wt% is uniformly dispersed within the matrix. To address the interface defects caused by simple blending of multiphase materials, the titanium-silicon molecular sieve 131 is pre-modified with a silane coupling agent (such as KH-550) for surface modification. During the extrusion crosslinking process, the active functional groups on the end groups of the silane coupling agent spontaneously form a strong coordination crosslinking network 132 with the microscopic ion clusters formed by ion interactions within the polyethylene-based ionomer material.

[0038] The key innovation and beneficial effect of this embodiment lies in the fact that the micro-coordination cross-linking network 132 and the unique 0.51nm-0.56nm three-dimensional nanoporous crystal structure of the titanium-silicon molecular sieve 131 produce an extreme synergistic effect, locking the relative permittivity of the composite insulating layer 130 within an extremely narrow and highly stable range under the full temperature range of 20℃ to 90℃ and high voltage and strong electric field conditions. The specific mechanism is as follows: the coordination cross-linking network 132 acts like "countless micro-molecular anchors," forcibly constraining the relaxation and polarization drift of polymer chain segments under thermomechanical stress; at the same time, the nanoporous crystal structure of the titanium-silicon molecular sieve 131 acts as a "deep-level electron trap," capturing free electrons injected under a strong electric field and blocking the penetration of external water molecules into the interior of the insulating layer, thus suppressing space charge polarization to the greatest extent.

[0039] like Figure 3 As shown, the relative permittivity (ε) of conventional cross-linked polyethylene (XLPE) in the temperature range of 20°C to 90°C is... r The dielectric constant exhibits a significant temperature dependence, increasing from approximately 2.30 at 20°C to approximately 2.55 at 90°C, with a fluctuation range of 0.3. In contrast, the composite insulating layer 130 of this invention, through the physical anchoring of molecular chain segments by the coordination crosslinking network 132 and the charge trapping effect of the nanopores, strictly limits the relative permittivity within a narrow range of 2.25 to 2.26 in this temperature range, compressing the maximum absolute fluctuation amplitude to within ±0.01, thus achieving the temperature-sensitive stripping of dielectric properties.

[0040] According to the formula for traveling wave propagation speed It is known that changes in the relative permittivity directly lead to distortion in wave velocity calculations. From the above... Figure 3Actual measurement data shows that traditional XLPE materials cause an inherent wave velocity calibration error of about 6% in the system, which translates to a positioning deviation of kilometers in a cable spanning hundreds of kilometers. However, this invention, through the aforementioned microscopic material modification, drastically reduces the wave velocity calibration error to less than 0.2%. This ensures that even under extremely degraded operating conditions, the dielectric response of the insulation material in the traveling wave frequency band remains highly stable (deviation controlled within ±0.01).

[0041] Example 3: Two-dimensional nanofiller orientation network and dielectric loss suppression

[0042] Building upon Example 2, which ensured a constant dielectric constant, this example further addresses the issue of high-frequency signal energy loss. During the extrusion process of the composite insulation layer 130, two-dimensional layered nanofillers—boron nitride nanosheets 133 (BNNS)—are also co-doped. By controlling a specific shear rate of the extrusion die, the BNNS are forced to align in a highly oriented manner along the cable axis (traveling wave propagation direction) within the polyethylene ionomer matrix.

[0043] The key innovation and beneficial effect of this embodiment is that the two-dimensional BNNS arranged along the axial direction effectively constructs a high thermal conductivity network and significantly reduces the dielectric loss of high-frequency transient traveling waves.

[0044] The specific mechanism is as follows: On a macroscopic level, the extremely high in-plane thermal conductivity of BNNS can quickly spread the hot spots generated by partial discharge along the axial direction, eliminating the interference of "local heat islands" on the wave velocity; on a microscopic level, this orientation of the "brick and mortar structure" greatly extends the scattering path of high-frequency electromagnetic waves inside the dielectric, minimizing the loss of high-frequency electromagnetic energy converted into heat energy, and further ensuring the integrity of the initial traveling wave front.

[0045] Example 4: Precise Positioning Method Based on Intrinsic Dielectric Stability of Materials

[0046] This embodiment illustrates the system ranging software algorithm implemented based on the aforementioned innovations in physics and materials science. For example... Figure 4 As shown: Unlike existing technologies that require high-order complex algorithms to dynamically fit wave velocity changes, the positioning method of this invention is logically simplified and dimensionally reduced. When the system detects a sudden fault, due to the low-loss waveguide channel constructed in Example 1, the transient traveling wave signal propagates undistorted to both ends. The dual-end traveling wave detection terminal 200 uses a wavelet modulus maxima algorithm based on adaptive thresholds to extract the transient traveling wave signal and records the first timestamp t1 of the arrival of the first initial wavefront and the second timestamp t2 of the arrival of the second initial wavefront, respectively.

[0047] It should be clarified that the "wavelet modulus maxima algorithm based on adaptive threshold" used in this embodiment is a basic preprocessing step in the traveling wave signal acquisition process, which aims to filter out environmental noise and obtain the true physical characteristics of the traveling wave head.

[0048] This invention abandons the "complex wave velocity fitting algorithms" (such as high-order neural networks, multiple ranging iterative algorithms, etc.) used in existing technologies to correct wave velocity distortion caused by dielectric drift of insulating materials. In this invention, due to the use of a nanocomposite insulation system, wave velocity is no longer an unknown variable that changes with the environment, but a physically fixed calibration parameter. Therefore, this positioning method no longer needs to run those complex logic branches responsible for "dynamically estimating wave velocity," thus achieving a minimalist dimensionality reduction in the positioning algorithm at the system architecture level. This transformation from dependence on algorithm complexity to dependence on the intrinsic properties of materials is the core difference between this invention and existing technologies.

[0049] Benefiting from the coordination crosslinking network 132 in Examples 2 and 3, the dielectric constant (ε) r With constant locking, the main control processor does not need to estimate; it directly obtains the relative permittivity of the composite insulating layer 130 material as specified at the factory and retrieves the preset traveling wave propagation speed. Finally, substituting into the formula... The location of the cable fault point is calculated. This invention replaces the mathematical compensation of the upper-level electrical algorithm with a hard-core chemical / physical innovation at the bottom layer of the insulation material, completely severing the transmission chain of "change in operating conditions → wave velocity distortion → positioning failure", and achieving extremely accurate positioning in complex field environments.

[0050] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the present invention. The objectives of the present invention have been fully and effectively achieved. The functions and structural principles of the present invention have been demonstrated and explained in the embodiments, and any variations or modifications may be made to the implementation of the present invention without departing from the stated principles.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A positioning system based on a nanocomposite insulated constant wave speed cable, characterized in that, It includes a cable body (100) and a double-ended traveling wave detection terminal (200) respectively connected to both ends of the cable body (100). The cable body (100) is coaxially extruded from the inside to the outside with a conductor core (110), an inner semiconductive shielding layer (120), a composite insulation layer (130), a high-frequency low-loss semiconductive layer (140), and an outer sheath (150). The high-frequency low-loss semiconducting layer (140) is a cross-linked polyethylene layer doped with carbon nanotubes, which together with the conductor core (110) constitutes a broadband coaxial waveguide channel for the propagation of transient traveling wave signals. The composite insulation layer (130) is a multiphase nanocomposite insulation system. Its matrix is ​​made of polyethylene-based ionomer material with a neutralization degree of 25% to 40%, and titanium-silicon molecular sieve (131) with a mass fraction of 1.5wt% to 3.0wt% is uniformly dispersed in the matrix. The titanium-silicon molecular sieve (131) is surface modified with a silane coupling agent, and the end group of the silane coupling agent forms a coordination crosslinking network (132) with the ion clusters in the polyethylene ionosphere material. The dual-end traveling wave detection terminal (200) is used to extract the transient traveling wave signal generated by the fault from the broadband coaxial waveguide channel and to locate it using the dual-end time difference.

2. The positioning system according to claim 1, characterized in that, The ion clusters in the polyethylene-based plasma material are formed by ion interactions, and the titanium-silicon molecular sieve (131) has a nanoporous crystal structure.

3. The positioning system according to claim 1, characterized in that, The carbon nanotubes in the high-frequency low-loss semiconducting layer (140) have a mass fraction of 3 wt% to 5 wt%, and the high-frequency volume resistivity of the high-frequency low-loss semiconducting layer (140) is 10. 2 Ω·m to 10 3 Ω·m.

4. The positioning system according to claim 1, characterized in that, The composite insulation layer (130) is also co-doped with two-dimensional layered nanofillers, which are boron nitride nanosheets (133) arranged along the cable axial direction in the matrix of the polyethylene ionosphere material.

5. The positioning system according to claim 1, characterized in that, The dual-end traveling wave detection terminal (200) includes a wideband Rogowski coil (210), a traveling wave conditioning circuit, and a satellite synchronization clock module (220); the wideband Rogowski coil (210) is sleeved on the end of the cable body (100) after the outer sheath (150) has been stripped.

6. A fault location method for a location system based on a nanocomposite insulated constant wave speed cable as described in any one of claims 1 to 5, characterized in that, Includes the following steps: When the cable body (100) fails, the transient traveling wave signal propagates to both ends of the cable in the broadband coaxial waveguide channel where the composite insulation layer (130) is located; The double-ended traveling wave detection terminals (200) located at both ends of the cable extract the initial wavefronts of the transient traveling wave signals at both ends in real time, and record the first time stamp of the arrival of the first initial wavefront and the second time stamp of the arrival of the second initial wavefront respectively. Obtain the relative permittivity of the composite insulating layer (130), and retrieve the corresponding preset traveling wave propagation speed based on the relative permittivity; Calculate the time difference between the first timestamp and the second timestamp, and combine it with the preset traveling wave propagation speed to calculate the location of the cable fault point.

7. The positioning method according to claim 6, characterized in that, The preset traveling wave propagation speed is expressed by the formula Calibration; Where v is the preset traveling wave propagation speed, c is the speed of light in a vacuum, and ε r μ is the relative permittivity of the composite insulating layer (130). r is the relative permeability of the composite insulating layer (130).

8. The positioning method according to claim 6, characterized in that, The specific formula for calculating the location of the cable fault point is as follows: ; Among them, L x The physical distance from the fault point to the dual-end traveling wave detection terminal (200) that recorded the first timestamp is L, the total length of the cable body (100) is L, the first timestamp is t1, the second timestamp is t2, and the preset traveling wave propagation speed is v.

9. The positioning method according to claim 6, characterized in that, Before recording the first timestamp of the arrival of the first initial wavefront and the second timestamp of the arrival of the second initial wavefront, the extracted transient traveling wave signal is denoised using a wavelet modulus maxima algorithm based on an adaptive threshold.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 6 to 9.

Images