CN-122017409-A - Distribution network cable aging detection device based on broadband impedance spectrum

CN122017409ACN 122017409 ACN122017409 ACN 122017409ACN-122017409-A

Abstract

The invention discloses a broadband impedance spectrum-based distribution network cable aging detection device, which comprises a broadband signal generation module, an anti-frequency coupling interference module, a signal conditioning module, a test fixture, a data acquisition module, a main control module, a local aging positioning module, a temperature compensation module, a service life evaluation module and a display storage module, wherein the test fixture is detachably connected with the device through a shielding cable, the device inhibits field interference through the anti-frequency coupling interference module, avoids impedance spectrum data distortion, and improves detection accuracy; the temperature influence is corrected by the cooperation of the clamp embedded temperature sensor and the compensation module, the consistency of the cross-working condition data is ensured, the life assessment module combines an EAB (event-based adaptive algorithm) association model and a real-time temperature equivalent conversion, and a full-dimension assessment result is output, so that accurate data support is provided for the operation and maintenance of the distribution network.

Inventors

Chen Ganghao
TANG YI
TANG LING
LIU HUABAI
LIU XIANGYU
WANG KAIHONG
LIANG ENSHENG
Tang Endong
ZHOU YIXIANG

Assignees

陈港豪

Dates

Publication Date: 20260512
Application Date: 20260202

Claims (10)

1. The device is characterized by comprising a broadband signal generation module, an anti-frequency coupling interference module, a signal conditioning module, a test fixture, a data acquisition module, a main control module, a local ageing positioning module, a temperature compensation module, a service life assessment module and a display storage module; the detection device is provided with a shell, the main control module is arranged in the center of the interior of the shell, the broadband signal generation module and the anti-frequency coupling interference module are stacked on one side of the main control module up and down, the signal conditioning module is positioned below the anti-frequency coupling interference module, the data acquisition module is arranged on the other side of the main control module, the display storage module is embedded in the front of the shell, and the test fixture is detachably connected with the signal conditioning module through a shielding cable; The signal output port of the main control module is electrically connected with the control input end of the broadband signal generation module, and the signal output end of the broadband signal generation module is electrically connected with the input end of the frequency coupling interference resistant module; The output end of the frequency coupling interference resistant module is electrically connected with the input end of the signal conditioning module, and the output end of the signal conditioning module is electrically connected with the signal transmission end of the test fixture through a shielding cable; the signal feedback end of the test fixture is electrically connected with the input end of the data acquisition module, and the signal end of the temperature sensor of the test fixture is electrically connected with the input end of the temperature compensation module; The output end of the data acquisition module is electrically connected with the data input end of the main control module and the input end of the local aging positioning module respectively, and the output end of the local aging positioning module and the output end of the temperature compensation module are electrically connected with the signal input end of the main control module; the output end of the evaluation signal of the main control module is electrically connected with the input end of the life evaluation module, and the output end of the life evaluation module is electrically connected with the input end of the display storage module; the anti-frequency coupling interference module comprises a broadband signal amplitude-frequency control loop, a series-parallel adjustable isolation transformer and an LC filter circuit, wherein the broadband signal amplitude-frequency control loop is in bidirectional communication with the main control module; The local aging positioning module comprises a phase orthogonal transformation unit and a diagnostic function calculation unit, wherein the diagnostic function calculation unit identifies an aging section mutation peak based on an imaginary component of an impedance phase spectrum; The temperature compensation module is pre-stored with a dielectric parameter temperature correction database, and the life evaluation module is internally provided with an EAB (event-based analysis) association model and a time-temperature equivalent conversion unit.
2. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the broadband signal generation module adopts a programmable signal generator, the frequency range of an output signal is 0.1 Hz-10 MHz, and the adjusting range of the signal amplitude is 0.1V-10V.
3. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the broadband signal amplitude-frequency control loop of the anti-frequency coupling interference module synthesizes broadband disturbance signals, the initial frequency of the broadband disturbance signals is 0.1Hz, the interval frequency is 50Hz, the variable ratio adjustable range of the adjustable isolation transformer is 1:1-1:10, and the adjustable isolation transformer is adaptive to 10kV and 0.4kV distribution network cables.
4. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the test fixture comprises two symmetrically arranged conductive clamping heads, the temperature sensor is embedded into the inner clamping surface of the conductive clamping heads, the measurement range of the temperature sensor is-20-80 ℃, and the measurement accuracy is +/-0.1 ℃.
5. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the data acquisition module comprises a voltage sensor, a current sensor and a phase acquisition unit, the precision level of the voltage sensor and the current sensor is not lower than 0.1 level, and the sampling frequency of the phase acquisition unit is not lower than 1MHz.
6. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the diagnosis function calculation unit of the local aging positioning module is provided with a mode of positioning an aging section by performing orthogonal transformation on an impedance phase spectrum, extracting an imaginary component after transformation to construct a diagnosis function, judging that the aging section starts and ends when a single polarity abrupt peak appears in the diagnosis function, judging that the local aging section is a concentrated defect when a continuous heteropolarity abrupt peak appears, and calculating physical position coordinates corresponding to the abrupt peak by combining a cable wave speed.
7. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the temperature compensation module dielectric parameter temperature correction database comprises a real part correction coefficient and an attenuation constant correction coefficient of relative dielectric constants within a range of-20 ℃ to 80 ℃, and the acquired dielectric parameters are corrected in real time through a linear interpolation algorithm.
8. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the EAB correlation model of the lifetime assessment module is a linear regression model of dielectric loss tangent value-elongation at break, and the time-temperature equivalent conversion unit converts the actual running time into an accelerated aging equivalent time of 70 ℃.
9. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the main control module adopts a combined architecture of an ARM Cortex-A9 embedded processor and an FPGA chip, a phase orthogonal transformation algorithm is built in the FPGA chip, and a reflection coefficient analysis and dielectric loss tangent calculation algorithm is built in the embedded processor.
10. The broadband impedance spectrum-based distribution network cable aging detection device according to claim 1, wherein the display storage module comprises a touch display screen, an SD memory card slot and a communication module, and supports local display, storage and cloud uploading of aging degree, aging position coordinates and residual life data.

Description

Distribution network cable aging detection device based on broadband impedance spectrum Technical Field The invention relates to the technical field of cable insulation material aging detection, in particular to a distribution network cable aging detection device based on broadband impedance spectroscopy. Background The distribution network cable is used as a core carrier for electric energy distribution of an electric power system, is widely applied to urban underground pipe networks, industrial parks and residential communities, and the running stability of the distribution network cable directly determines the reliability of distribution network power supply. The crosslinked polyethylene (XLPE) cable is the main stream choice in the field of distribution network because of the advantages of excellent insulating property, convenient laying and the like, but is subject to environmental temperature fluctuation, soil humidity erosion, power grid harmonic interference and mechanical stress in the long-term operation process, the cable insulating layer is easy to produce ageing defects such as water tree, electric tree and the like, the conductor is also likely to be oxidized and corroded, so that the insulation strength is reduced, partial discharge is aggravated, insulation breakdown and short circuit fault are caused in severe cases, large-area power failure accidents are caused, and great losses are brought to production and life. In order to check the hidden trouble of the cable aging of the distribution network in advance, various detection technologies such as a partial discharge detection method, a dielectric loss detection method, a broadband impedance spectrum detection method and the like have been developed in the industry. The broadband impedance spectrum detection method has the advantages of non-destructiveness, wide detection range and the like by analyzing the impedance response spectrum reverse aging state under different frequencies based on the characteristic that the equivalent impedance of the cable changes along with the frequency, and the related technology is embodied in a patent CN121231958A, and the preliminary judgment of the aging degree of the cable is realized by broadband impedance spectrum acquisition, reflection coefficient analysis and dielectric loss tangent calculation. However, the existing distribution network cable aging detection device based on broadband impedance spectrum still has a plurality of technical defects in practical application, and is difficult to meet the accurate requirements of distribution network operation and maintenance, firstly, the anti-interference capability is weak, a large number of harmonic signals and grounding current interference exist on the distribution network site, the broadband excitation signals are easy to generate frequency coupling, so that impedance spectrum data are distorted, the aging judgment accuracy is affected, secondly, the local aging positioning function is not available, the cable aging degree can only be judged integrally, the aging section and the concentrated defect position can not be positioned, inconvenience is brought to fault investigation and maintenance, thirdly, the influence of temperature on detection parameters is not considered, the cable dielectric parameters can drift due to environmental temperature change, the detection results under different working conditions are lack of comparability, the detection accuracy is limited, fourthly, the aging degree grade can only be output, the residual service life of the cable can not be estimated, and data support is difficult to be provided for the replacement and operation and maintenance planning of the distribution network cable. Disclosure of Invention Aiming at the technical defects in the background technology, the invention provides a broadband impedance spectrum-based distribution network cable aging detection device, which solves the technical problems and meets the actual requirements, and the specific technical scheme is as follows: A distribution network cable aging detection device based on broadband impedance spectrum comprises a broadband signal generation module, an anti-frequency coupling interference module, a signal conditioning module, a test fixture, a data acquisition module, a main control module, a local aging positioning module, a temperature compensation module, a service life assessment module and a display storage module; the detection device is provided with a shell, the main control module is arranged in the center of the interior of the shell, the broadband signal generation module and the anti-frequency coupling interference module are stacked on one side of the main control module up and down, the signal conditioning module is positioned below the anti-frequency coupling interference module, the data acquisition module is arranged on the other side of the main control module, the display storage module is embedded in the front of