High-voltage cable residual life prediction system, method, and storage medium

Abstract

The application discloses a high-voltage cable residual life prediction system and method and a storage medium, and relates to the field of high-voltage cable residual life prediction.The system comprises a harmonic detection unit, a magnetic field signal of a high-voltage cable is collected, and the ratio of the strength of each harmonic signal to the strength of a fundamental wave signal is obtained, so as to obtain the magnetic field characteristic spectrum of the test cable; an analysis unit is used for analyzing the working environment of the cable generating the high-voltage cable aging signal and the high-voltage cable normal signal, and judging the factors affecting the cable aging; a prediction unit is used for receiving the cable aging environment first-level signal and the cable aging environment second-level signal generated by the analysis unit, and analyzing and predicting the cable life according to the two signals.The high-voltage cable residual life prediction system improves the data detection precision through harmonic detection, and accurately obtains the service life of the cable according to the environmental coefficient, so that the use of the cable has good expected operation.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable technology, and in particular to a system, method, and storage medium for predicting the remaining life of high-voltage cables. Background Technology

[0002] Chinese patent CN112162164A discloses a cable life prediction system based on neural networks, including a controller, an environmental parameter acquisition module for collecting environmental parameters of the cable's environment, a test data acquisition module for collecting test data of aging tests under specific environmental parameters, a first training sample generation module for generating a first training sample based on the collected environmental parameters, a first neural network construction module for constructing a first neural network, and a first neural network training module for training the first neural network based on the first training sample.

[0003] In practical applications, when predicting the lifespan of high-voltage cables, the rubber material on the outer surface of the cable is cut to extract a sample, and then the lifespan of the sample is predicted. This method has problems such as damaging the original cable structure and the prediction operation being relatively complicated. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a high-voltage cable remaining life prediction system, method, and storage medium. The high-voltage cable remaining life prediction system improves data detection accuracy through harmonic detection and accurately obtains the cable's service life based on environmental factors, thereby ensuring that the cable has good expected operation.

[0005] The present invention employs the following technical solution: a high-voltage cable remaining life prediction system, comprising:

[0006] The harmonic detection unit is used to collect the magnetic field signal of the high-voltage cable and obtain the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal, which is the magnetic field characteristic spectrum of the cable under test.

[0007] The analysis unit is used to analyze the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, and to determine the factors affecting cable aging.

[0008] The prediction unit is used to receive the primary and secondary signals of cable aging environment generated by the analysis unit, and to analyze and predict the cable life based on these two signals.

[0009] The method of this invention is implemented using the following technical solution: a method for predicting the remaining life of high-voltage cables, comprising the following steps:

[0010] S1. The magnetic field signal of the high-voltage cable is acquired through the harmonic detection unit, and the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal is obtained as the magnetic field characteristic spectrum of the cable under test; the magnetic field characteristic spectrum K of the high-voltage cable under test is compared with the magnetic field characteristic spectrum threshold of the high-voltage cable under test; the aging signal and normal signal of the high-voltage cable are generated.

[0011] S2. The analysis unit analyzes the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, determines the factors affecting cable aging, and calculates the operating coefficient value Y of the tested high-voltage cable based on the environmental influence coefficient. Then, it compares the value with the average operating coefficient to generate a first-level signal and a second-level signal of cable aging environment.

[0012] S3. The prediction unit receives the primary and secondary signals of cable aging environment generated by the analysis unit, and analyzes and predicts the cable life based on these two signals.

[0013] The present invention also proposes a storage medium on which a computer program is stored, wherein when the computer program is executed by a processor, the steps of the high-voltage cable remaining life prediction method of the present invention are implemented.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0015] 1. This invention achieves non-contact diagnosis by utilizing non-contact sensors, using magnetic field signals as detection signals. It does not require power outages for detection and can perform online detection on equipment operating 24 hours a day. Moreover, the test is not affected by changes in the cable's own load. Furthermore, based on the signals generated by the harmonic detection unit, data is collected and analyzed on the cable's surrounding environment and its own environment to determine the impact of the environment. Finally, based on the environmental impact value, the cable's service life is predicted.

[0016] 2. The high-voltage cable remaining life prediction system of the present invention improves the data detection accuracy through harmonic detection and can accurately obtain the service life of the cable based on the environmental coefficient, thereby ensuring that the cable has good expected operation. Attached Figure Description

[0017] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0019] Example

[0020] like Figure 1 As shown, the high-voltage cable remaining life prediction system of the present invention includes:

[0021] The harmonic detection unit is used to collect the magnetic field signal of the high-voltage cable and obtain the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal, which is the magnetic field characteristic spectrum of the cable under test.

[0022] The analysis unit is used to analyze the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, and to determine the factors affecting cable aging.

[0023] The prediction unit is used to receive the primary and secondary signals of cable aging environment generated by the analysis unit, and to analyze and predict the cable life based on these two signals.

[0024] Specifically, in this embodiment, the operation of the harmonic detection unit is as follows:

[0025] S11. Establish a magnetic field characteristic spectrum database for various types of cables;

[0026] S12. A non-contact sensor is used to collect and quantify the magnetic field signal emitted by the tested high-voltage cable during power-on.

[0027] S13. Through FFT analysis, the acquired magnetic field signal is separated into the fundamental signal and each harmonic signal; the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal is calculated, and this ratio is the magnetic field characteristic spectrum of the tested high-voltage cable, and is labeled as K.

[0028] S14. Compare the obtained magnetic field characteristic spectrum K of the tested high-voltage cable with the magnetic field characteristic spectrum threshold of the tested high-voltage cable.

[0029] If the magnetic field characteristic spectrum K of the tested high-voltage cable is greater than the magnetic field characteristic spectrum threshold of the tested high-voltage cable, then a high-voltage cable aging signal is generated and sent to the analysis unit.

[0030] If the magnetic field characteristic spectrum K of the tested high-voltage cable is less than the magnetic field characteristic spectrum threshold of the tested high-voltage cable, a high-voltage cable normal signal is generated and sent to the analysis unit.

[0031] Specifically, the principle of the harmonic detection system is as follows: During the detection process, the original physical quantity detected is energy (joules). This energy is then calculated with the sampling time to obtain power (watts). Software processing yields the power contrast, expressed as a percentage (%), which is the ratio of higher harmonic components to the fundamental component. The data acquisition range of this method typically includes harmonics from the 2nd to the 40th order. The time-domain signal is then transformed to the frequency domain for analysis using the harmonic spectrum. The purpose of spectrum analysis is to decompose complex time-history waveforms into several individual harmonic components through Fourier transform to obtain the frequency structure of the signal and the information on each harmonic and phase. For example, by determining the frequency components and frequency distribution range in the dynamic signal, the amplitude and energy distribution of each frequency component can be calculated, thereby obtaining the frequency values ​​of the main amplitude and energy distributions.

[0032] For a function f(t), if it is absolutely integrable (i.e., has only discontinuities of the first kind, only a finite number of extrema), and satisfies the Dirichlet conditions, then its Fourier transform can be performed. If a waveform can be decomposed into the sum of multiple sine waves of different frequencies, and a linear combination of these sine waves of different frequencies can recover the original signal, then the Fourier transform of this waveform can be determined. This is the basis for harmonic detection using FFT in this method.

[0033] In mathematics, the Fourier transform (FFT) can be represented as:

[0034] The given f(t) in the above equation is considered to be a waveform that can be decomposed into the sum of multiple sine functions. This is called the Fourier transform of f(t), usually denoted as λ, where F is called the Fourier operator. If we consider λ as the frequency variable and t as the time variable, it is called the spectral function, and its magnitude is called the spectrum. The spectral function represents the proportion of each frequency in the waveform. Therefore, the spectrum of each waveform can be obtained through FFT operations, and the frequency components contained in the signal can be determined based on the waveform's spectrum.

[0035] Specifically, in this embodiment, the working process of the analysis unit is as follows:

[0036] S21. Collect the humidity value and corresponding humidity fluctuation frequency of the surrounding environment at the location of the tested high-voltage cable, and label them as Zs and Zsp respectively, according to the following formula:

[0037]

[0038] The environmental impact coefficient X1 of the tested high-voltage cable was calculated; where a1 is the proportionality coefficient with a value of 0.65 and a2 is the proportionality coefficient with a value of 0.98.

[0039] S22. Collect the average current and corresponding current amplitude of the tested high-voltage cable, and label them as Zl and Zlf, respectively; according to the following formula:

[0040]

[0041] The environmental impact coefficient X2 of the tested high-voltage cable was calculated; where b1 is the proportionality coefficient with a value of 0.21 and b2 is the proportionality coefficient with a value of 0.42.

[0042] S23. The high-voltage cable under test is divided into several regions and labeled as i, i = 1, 2, 3...n. The temperature value Ti of each region is obtained and then averaged to obtain Tp. The average temperature Tp of each region over a historical period is then obtained and weighted to obtain the temperature influence coefficient X3 of the high-voltage cable under test.

[0043] S24. Based on the obtained environmental influence coefficient X1, environmental influence coefficient X2, and temperature influence coefficient X3 of the tested high-voltage cable, the following formula is used:

[0044]

[0045] The operating coefficient value Y is calculated; where β is the proportional coefficient, and its value is 2.75.

[0046] S25. Compare the obtained operating coefficient value Y of the tested high-voltage cable with the average operating coefficient.

[0047] If the operating coefficient value Y of the tested high-voltage cable is greater than the average operating coefficient, a first-level signal for cable aging environment will be generated.

[0048] If the operating coefficient value Y of the tested high-voltage cable is less than the average operating coefficient, a secondary signal for cable aging environment will be generated.

[0049] Specifically, a Level 1 cable aging environment signal indicates that the environment in which the cable is used differs significantly from the standard environmental value, which greatly accelerates the aging process of the cable. In contrast, a Level 2 cable aging environment signal indicates that the environment in which the cable is used differs less from the standard environmental value, which has a smaller impact on the aging process of the cable.

[0050] Specifically, in this embodiment, the prediction unit operates as follows:

[0051] S31. When a Level 1 signal indicating cable aging environment is received, use the following formula:

[0052]

[0053] The time T1 when the cable aging level drops to 90% is calculated, where, This is the proportionality coefficient, and its value is 2.36;

[0054] S32. When a secondary signal indicating cable aging environment is received, use the following formula:

[0055]

[0056] The time T2 when the cable aging level drops to 90% is calculated, where δ is a proportionality coefficient with a value of 3.41.

[0057] Specifically, the probability of cable failure due to aging is high after this point. Therefore, preventive tests should be conducted on the cable after this point. Based on the test results, the importance of the line, and the analysis of failure losses, it should be considered whether to decommission the cable.

[0058] Based on the same inventive concept, this invention proposes a method for predicting the remaining life of high-voltage cables, comprising the following steps:

[0059] S1. The magnetic field signal of the high-voltage cable is acquired through the harmonic detection unit, and the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal is obtained as the magnetic field characteristic spectrum of the cable under test; the magnetic field characteristic spectrum K of the high-voltage cable under test is compared with the magnetic field characteristic spectrum threshold of the high-voltage cable under test; the aging signal and normal signal of the high-voltage cable are generated.

[0060] S2. The analysis unit analyzes the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, determines the factors affecting cable aging, and calculates the operating coefficient value Y of the tested high-voltage cable based on the environmental influence coefficient. Then, it compares the value with the average operating coefficient to generate a first-level signal and a second-level signal of cable aging environment.

[0061] S3. The prediction unit receives the primary and secondary signals of cable aging environment generated by the analysis unit, and analyzes and predicts the cable life based on these two signals.

[0062] The working principle of this invention is as follows: This invention utilizes non-contact sensors to achieve non-contact diagnostics, using magnetic field signals as detection signals. It eliminates the need for power outages, enabling online monitoring of equipment operating 24 hours a day, and the testing is unaffected by changes in the cable's own load. Furthermore, based on signals generated by the harmonic detection unit, data is collected and analyzed regarding the cable's surrounding environment and its own environment, assessing the impact of the environment. Finally, based on this environmental impact value, the cable's service life is predicted. Therefore, this high-voltage cable remaining life prediction system improves data detection accuracy through harmonic detection and can accurately determine the cable's service life based on environmental factors, thus ensuring the cable's expected operational performance.

[0063] Furthermore, the present invention also proposes a storage medium storing a computer program, which, when executed by a processor, implements steps S1-S3 of the high-voltage cable remaining life prediction method of the present invention.

[0064] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A high-voltage cable remaining life prediction system, characterized in that, include: The harmonic detection unit is used to collect the magnetic field signal of the high-voltage cable and obtain the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal, which is the magnetic field characteristic spectrum of the cable under test. The analysis unit is used to analyze the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, and to determine the factors affecting cable aging. The prediction unit is used to receive the primary and secondary signals of cable aging environment generated by the analysis unit, and to analyze and predict the cable life based on these two signals. The working process of the analysis unit is as follows: S21. Collect the humidity value and corresponding humidity fluctuation frequency of the surrounding environment at the location of the tested high-voltage cable, and label them as Zs and Zsp respectively, according to the following formula: The environmental impact coefficient X1 of the tested high-voltage cable was calculated; where a1 and a2 are proportionality coefficients. S22. Collect the mean current and corresponding current amplitude of the tested high-voltage cable, and label them as Zl and Zlf, respectively; according to the following formula: The environmental impact coefficient X2 of the tested high-voltage cable was calculated; where b1 and b2 are proportionality coefficients. S23. The high-voltage cable under test is divided into several regions and labeled as i, i=1,2,3...n. The temperature value Ti of each region is obtained and then averaged to obtain Tp. The average temperature Tp of each region over a historical period is then obtained and weighted to obtain the temperature influence coefficient X3 of the high-voltage cable under test. S24. Based on the obtained environmental influence coefficient X1, environmental influence coefficient X2, and temperature influence coefficient X3 of the tested high-voltage cable, the following formula is used: The operating coefficient value Y is calculated; where, This is the proportionality coefficient; S25. Compare the obtained operating coefficient value Y of the tested high-voltage cable with the average operating coefficient.

2. The high-voltage cable remaining life prediction system according to claim 1, characterized in that, The working process of the harmonic detection unit is as follows: S11. Establish a magnetic field characteristic spectrum database for various types of cables; S12. A non-contact sensor is used to collect and quantify the magnetic field signal emitted by the tested high-voltage cable during power-on. S13. Through FFT analysis, the acquired magnetic field signal is separated into the fundamental signal and each harmonic signal; the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal is calculated, and this ratio is the magnetic field characteristic spectrum of the tested high-voltage cable, and is labeled as K. S14. Compare the obtained magnetic field characteristic spectrum K of the tested high-voltage cable with the magnetic field characteristic spectrum threshold of the tested high-voltage cable.

3. The high-voltage cable remaining life prediction system according to claim 2, characterized in that, If the magnetic field characteristic spectrum K of the tested high-voltage cable is greater than the magnetic field characteristic spectrum threshold of the tested high-voltage cable, then a high-voltage cable aging signal is generated and sent to the analysis unit.

4. The high-voltage cable remaining life prediction system according to claim 2, characterized in that, If the magnetic field characteristic spectrum K of the tested high-voltage cable is less than the magnetic field characteristic spectrum threshold of the tested high-voltage cable, a high-voltage cable normal signal is generated and sent to the analysis unit.

5. The high-voltage cable remaining life prediction system according to claim 1, characterized in that, If the operating coefficient value Y of the tested high-voltage cable is greater than the average operating coefficient, a first-level signal for cable aging environment will be generated.

6. The high-voltage cable remaining life prediction system according to claim 1, characterized in that, If the operating coefficient value Y of the tested high-voltage cable is less than the average operating coefficient, a secondary signal for cable aging environment will be generated.

7. The high-voltage cable remaining life prediction system according to claim 1, characterized in that, The prediction unit works as follows: S31. When a Level 1 signal indicating cable aging environment is received, use the following formula: The time T1 when the cable aging level drops to 90% is calculated, where, This is the proportionality coefficient; S32. When a secondary signal indicating cable aging environment is received, use the following formula: The time T2 when the cable aging level drops to 90% is calculated, where, This is the proportionality coefficient.

8. A method for predicting the remaining life of a high-voltage cable based on the high-voltage cable remaining life prediction system according to claim 1, characterized in that, Includes the following steps: S1. Acquire the magnetic field signal of the high-voltage cable through the harmonic detection unit, and obtain the ratio of the intensity of each harmonic signal to the intensity of the fundamental signal, which is the magnetic field characteristic spectrum of the cable under test; compare the obtained magnetic field characteristic spectrum K of the high-voltage cable under test with the magnetic field characteristic spectrum threshold of the high-voltage cable under test; generate the high-voltage cable aging signal and generate the high-voltage cable normal signal. S2. The analysis unit analyzes the working environment of the cable that generates the high-voltage cable aging signal and the high-voltage cable normal signal, judges the factors affecting cable aging, and calculates the operating coefficient value Y of the tested high-voltage cable based on the environmental influence coefficient. Then, it compares the value with the average operating coefficient to generate the first-level signal and the second-level signal of the cable aging environment. S3. The prediction unit receives the primary and secondary signals of cable aging environment generated by the analysis unit, and analyzes and predicts the cable life based on these two signals.

9. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the high-voltage cable remaining life prediction method as described in claim 8.

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