Fault location method for high temperature resistant and environmentally friendly electric wires

Abstract

The present application relates to the technical field of wire fault location, and specifically to a fault location method for high temperature resistant and environmentally friendly wires, the method comprising: determining the electromagnetic influence factor of each reflected pulse signal based on the change trend of the peak and valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood; determining a suspected fault signal based on the time interval between the first and last reflected pulse signals, and the electromagnetic influence factors of all reflected pulse signals; determining a fault reflection signal based on the distribution of the peak and valley values ​​of each suspected fault signal and all reflected pulse signals in its neighborhood, and locating the fault of the high temperature resistant and environmentally friendly wire. The present application aims to eliminate the influence of electromagnetic interference and temperature interference on the accuracy of fault location, and improve the accuracy of fault location in high temperature resistant and environmentally friendly wires.

Description

Technical Field

[0001] The present application relates to the technical field of wire fault location, and in particular to a fault location method for high temperature resistant and environment-friendly wires. Background Art

[0002] High-temperature resistant and environmentally friendly wires may work in high-temperature environments for a long time due to their high-temperature resistance. This will cause the wires to be in a high temperature state for a long time, which may easily cause short circuits and open circuits in the wires. When a fault occurs, it is necessary to accurately and quickly locate the fault location for repair to restore the circuit to normal.

[0003] Due to its high temperature resistance, high temperature resistant and environmentally friendly wires usually have low impedance. For low resistance wire faults, the low voltage pulse method is usually used to locate the fault, that is, a low voltage pulse wave is injected into the wire test end, and the pulse wave propagates along the wire to the fault point to generate reflection and then returns to the cable fault tester. According to the time interval between the transmitted pulse wave and the reflected pulse wave, and the propagation speed of the pulse wave in the wire, the distance of the cable fault point can be calculated. Although this method is simple and intuitive to operate, it is easily affected by environmental factors. For example, when the wire is located in a complex electromagnetic environment, the pulse signal may be interfered by electromagnetic waves, causing the reflected pulse signal to be deformed or distorted; when the temperature of the wire changes, the resistivity of the higher temperature part of the wire material will change, resulting in a slight reflection pulse signal at the higher temperature, which interferes with the judgment of the location of the fault pulse signal and reduces the accuracy of fault location of high temperature resistant and environmentally friendly wires. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a fault location method for high temperature resistant and environmentally friendly electric wires to solve the existing problems.

[0005] The fault location method for high temperature resistant and environmentally friendly electric wires of the present application adopts the following technical solutions:

[0006] An embodiment of the present application provides a fault location method for a high temperature resistant and environmentally friendly electric wire, the method comprising the following steps:

[0007] Transmitting a pulse signal to the faulty high temperature resistant environmentally friendly electric wire and acquiring all reflected pulse signals, the time when the pulse signal starts to be transmitted and the time when each reflected pulse signal starts to be received, and the propagation speed of the pulse signal;

[0008] Based on the change trends of the peak values ​​and valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood, the amplitude change sequence of each reflected pulse signal is determined, and based on the discrete degree and average distribution of all elements in the amplitude change sequence, the electromagnetic influence factor of each reflected pulse signal is determined;

[0009] Determine the electromagnetic interference interval based on the time interval between the first and last reflected pulse signals; determine the discrimination threshold based on the electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval; determine the suspected fault signal based on the electromagnetic influence factors of all reflected pulse signals and the discrimination threshold;

[0010] Determine the fault discrimination value of each suspected fault signal based on the distribution of the peak values ​​and valley values ​​of all reflected pulse signals in each suspected fault signal and its neighborhood, so as to determine the fault reflection signal;

[0011] Based on the time interval between transmitting the pulse signal and receiving each fault reflection signal, the fault transmission duration is determined, and combined with the propagation speed, the fault of the high-temperature resistant and environmentally friendly electric wire is located.

[0012] Preferably, the method for determining the amplitude variation sequence of each reflected pulse signal is:

[0013] The absolute values ​​of the valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood are taken, and the first-order difference sequence of the peak and valley absolute values ​​of all reflected pulse signals is arranged in chronological order as the amplitude change sequence of each reflected pulse signal.

[0014] Preferably, the electromagnetic influence factor of each reflected pulse signal is expressed as: ; In the formula, Represents the electromagnetic impact factor of the reflected pulse signal i; Indicates the proportion of positive elements in the amplitude change sequence of the reflected pulse signal i among all elements; , They respectively represent the discreteness and mean value of all elements in the amplitude variation sequence of the reflected pulse signal i; Represents the number of all zero elements in the amplitude change sequence of the reflected pulse signal i.

[0015] Preferably, the method for determining the electromagnetic interference interval is:

[0016] The time interval between the start of receiving the first reflected pulse signal and the start of receiving the last reflected pulse signal is recorded as T. The number of all reflected pulse signals in is recorded as n, and the electromagnetic interference interval is ,in .

[0017] Preferably, the method for determining the discrimination threshold is:

[0018] The electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval are used as the input of the Otsu threshold segmentation algorithm, and the output segmentation threshold is used as the discrimination threshold.

[0019] Preferably, the method for determining the suspected fault signal is:

[0020] Among all reflected pulse signals, the reflected pulse signals whose electromagnetic influence factors are less than or equal to the discrimination threshold are regarded as suspected fault signals.

[0021] Preferably, the expression of the fault discrimination value of each suspected fault signal is: ; In the formula, represents the fault discrimination value of the suspected fault signal j; Indicates the degree of dispersion of the absolute values ​​of the peak and valley values ​​of all reflected pulse signals in the suspected fault signal j and its neighborhood; , They represent the number of peaks and valleys of the suspected fault signal j and all reflected pulse signals in its neighborhood respectively; Indicates a preset constant greater than 0.

[0022] Preferably, the method for determining the fault reflection signal is:

[0023] The fault discrimination values ​​of all suspected fault signals are clustered to obtain multiple clusters, and the suspected fault signals corresponding to all elements in the cluster with the largest average fault discrimination value are taken as fault reflection signals.

[0024] Preferably, the method for determining the fault transmission duration is:

[0025] The first-order difference sequence of the time interval between transmitting the pulse signal and receiving all fault reflection signals is taken as the real time series, and the mode in the real time series is taken as the fault transmission duration.

[0026] Preferably, the fault location of the high temperature resistant and environmentally friendly electric wire includes:

[0027] Fault location of high temperature resistant and environmentally friendly wires The expression is: ; In the formula, v represents the propagation speed of the transmitted pulse signal in the high temperature resistant and environmentally friendly wire; Indicates the fault transmission duration.

[0028] This application has at least the following beneficial effects:

[0029] The present application constructs an electromagnetic influence factor by analyzing the changing trends of the peak and valley values ​​of each reflected pulse signal reflected by the faulty high-temperature resistant and environmentally friendly wire and all reflected pulse signals in its neighborhood. The electromagnetic influence factor helps to accurately identify and eliminate the reflected pulse signal caused by electromagnetic interference, thereby improving the accuracy of fault location. Further, based on the electromagnetic influence factor, the present application eliminates the interference of the reflected pulse signal generated by electromagnetic interference on the reflected pulse signal generated by the fault point, obtains a suspected fault signal, and constructs a fault discrimination value based on the peak value of the suspected fault signal and all reflected pulse signals in its neighborhood and the distribution of its faults. The beneficial effect is that it helps to distinguish the reflected pulse signal caused by the fault and the interference signal caused by temperature change, reduces mislocation, and screens out the most likely fault reflection signal, thereby optimizing the fault location result and improving the accuracy of fault location. The present application eliminates the influence of electromagnetic interference and temperature interference on the accuracy of fault location, and improves the accuracy of fault location in high-temperature resistant and environmentally friendly wires. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A flowchart of the steps of a method for locating a fault of a high temperature resistant and environmentally friendly electric wire provided in one embodiment of the present application;

[0032] Figure 2 A schematic diagram of a suspected fault signal acquisition process provided by an embodiment of the present application;

[0033] Figure 3 A schematic diagram of a process for determining a fault location of a high-temperature resistant and environmentally friendly electric wire provided in one embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of the fault location method for high temperature resistant and environmentally friendly electric wires proposed in the present application, its specific implementation, structure, features and effects in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0035] Unless defined otherwise, 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 application belongs.

[0036] The specific scheme of the fault location method for high temperature resistant and environmentally friendly electric wires provided by the present application is described in detail below with reference to the accompanying drawings.

[0037] An embodiment of the present application provides a method for locating a fault of a high temperature resistant and environmentally friendly electric wire. Specifically, the following method for locating a fault of a high temperature resistant and environmentally friendly electric wire is provided. Figure 1 , the method comprises the following steps:

[0038] Step S1: transmitting a pulse signal to the faulty high temperature resistant and environmentally friendly electric wire, and obtaining all reflected pulse signals, the time of starting to transmit the pulse signal and starting to receive each reflected pulse signal, and the propagation speed of the pulse signal.

[0039] An intelligent cable integrated detector is used to transmit a pulse signal to the test end of the faulty high-temperature resistant and environmentally friendly wire. The pulse signal will generate a reflected pulse signal at the fault location. The reflected pulse signal will eventually be reflected back to the test end, and then reflected from the test end back to the fault location, and so on, until the amplitude of the pulse signal decays to 0.

[0040] An intelligent integrated detector is used to collect the pulse waveform reflected by the faulty high-temperature resistant and environmentally friendly wire, where the pulse waveform includes multiple reflected pulse signals, and all reflected pulse signals reflected by the faulty high-temperature resistant and environmentally friendly wire are obtained and acquired, the time to start transmitting the pulse signal and the time to start receiving each reflected pulse signal, and the propagation speed of the transmitted pulse signal in the faulty high-temperature resistant and environmentally friendly wire.

[0041] Step S2: Based on the change trends of the peak values ​​and valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood, determine the amplitude change sequence of each reflected pulse signal; based on the discrete degree and average distribution of all elements in the amplitude change sequence, determine the electromagnetic impact factor of each reflected pulse signal.

[0042] Even though the high temperature resistant and environmentally friendly wires have high temperature resistance, if they work in a high temperature environment for a long time, the insulation material will age and the impedance of the wire will increase with the temperature, which is easy to cause short circuit and open circuit faults. Therefore, when using the low-voltage pulse method to locate the fault, due to the uneven impedance in the wire, when the pulse signal is sent, it may not only generate a reflected pulse signal at the fault location, but also at the higher impedance, resulting in inaccurate fault location. In addition, when there are many electrical devices in the working environment of the high temperature resistant and environmentally friendly wires, the AC transmission lines in the electrical equipment will generate power frequency electric fields, power frequency magnetic fields, radio interference, etc. These electromagnetic interferences may interfere with the pulse waveform distortion during fault location.

[0043] When using the low-voltage pulse method to measure faults in wires without interference from environmental factors, if a short circuit occurs in the wire, the short circuit will generate a reflection coefficient at the short circuit point, forming positive and negative alternating pulses, and an open circuit will generate a positive reflection coefficient, forming pulses of the same polarity, which also appear periodically. If the working environment of the wire has uneven temperature or is subject to electromagnetic interference, additional reflected pulse signals will be generated to interfere with the reflected pulse signals generated at the fault point, making it difficult to accurately determine the fault location.

[0044] Therefore, by analyzing the difference between the reflected pulse signal generated at the fault point and the interference signal generated by temperature change or electromagnetic interference, the reflected pulse signal generated at the fault point can be accurately identified, thereby accurately locating the fault location in the high-temperature resistant environmentally friendly wire. Specifically:

[0045] (1) Based on the change trends of the peak and valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood, the amplitude change sequence of each reflected pulse signal is determined.

[0046] In the absence of environmental interference, when using the low-voltage pulse method to measure faults in wires, if a short circuit occurs in the wire, the short circuit will generate a reflection coefficient at the short circuit point, forming positive and negative alternating pulses, and the open circuit will generate a positive reflection coefficient, forming pulses of the same polarity, which also appear periodically. When the working environment of the wire is uneven in temperature, the impedance of the wire at the higher temperature is higher, and the pulse signal will have a reflected pulse signal at the higher temperature and the fault location, making it impossible to determine the specific location of the fault in the final waveform; when the wire is subject to electromagnetic interference, the interference waveform will be superimposed on the original waveform, causing the waveform to be distorted.

[0047] Therefore, by constructing an amplitude change sequence, the amplitude change characteristics of the reflected pulse signal can be more clearly reflected to further identify the reflected pulse signal generated at the fault point. Specifically, all reflected pulse signals are sorted in chronological order. In the sorting result, the absolute value of the valley value of each reflected pulse signal and all reflected pulse signals in its neighborhood is taken, and the first-order difference sequence of the results obtained after the absolute values ​​of the peak values ​​and valley values ​​of all reflected pulse signals are arranged in chronological order is used as the amplitude change sequence of each reflected pulse signal.

[0048] (2) Based on the discreteness and average distribution of all elements in the amplitude change sequence of each reflected pulse signal, the electromagnetic impact factor of each reflected pulse signal is determined.

[0049] When the pulse signal is a reflected pulse signal caused by a fault, the absolute values ​​of the elements in the amplitude change sequence will be close, and due to energy attenuation, the amplitude of the reflected pulse signal will show a trend of gradually decreasing. When the pulse signal is a reflected pulse signal caused by temperature interference, the amplitude of the reflected pulse signal will be close in value, and the amplitude of the reflected pulse signal will gradually decrease, and the overall intensity will be small. When the reflected pulse signal is a reflected pulse signal caused by electromagnetic interference, the amplitude of the reflected pulse signal will be more chaotic, fluctuating or even zero.

[0050] Therefore, by analyzing the discrete degree and average distribution of all elements in the amplitude change sequence of the reflected pulse signal, the electromagnetic influence factor of each pulse signal is determined, so as to identify the reflected pulse signal caused by electromagnetic interference and eliminate it, thereby improving the accuracy of fault location. Specifically:

[0051] Electromagnetic influence factor of reflected pulse signal i The expression is: ; Indicates the proportion of positive elements in the amplitude change sequence of the reflected pulse signal i among all elements; , They respectively represent the discreteness and mean value of all elements in the amplitude variation sequence of the reflected pulse signal i; Represents the number of all zero elements in the amplitude change sequence of the reflected pulse signal i.

[0052] It should be noted that there are many methods for measuring the degree of dispersion of a set of data. In this embodiment, whenever the degree of dispersion is calculated, the variance calculation method is used to measure the degree of dispersion. As other implementation methods, the implementer may also use other methods for measuring the degree of dispersion of data, such as dispersion coefficient or standard deviation. This embodiment does not impose any special restrictions on the selection of methods for measuring the degree of dispersion of data.

[0053] Further, according to the electromagnetic influence factor of each reflected pulse signal, it can be understood that when the proportion of elements greater than 0 in the amplitude change sequence of the reflected pulse signal is higher, it means that in the absolute values ​​of the peak values ​​and valley values ​​of all reflected pulse signals in the reflected pulse signal and its neighborhood, the number of data in which the latter value between adjacent values ​​increases relative to the previous value is larger, which further indicates that the reflected pulse signal is likely to be a reflected pulse signal caused by electromagnetic interference; when the degree of discreteness of all elements in the amplitude change sequence of the reflected pulse signal is greater, it means that the absolute values ​​of the peak values ​​and valley values ​​of the reflected pulse signal and all reflected pulse signals in its neighborhood are sometimes large and sometimes small, showing irregular changes, indicating that the reflected pulse signal is more likely to be a reflected pulse signal caused by electromagnetic interference; when the mean value of all elements in the valley value change sequence of the reflected pulse signal is greater, it means that it is more likely to be a reflected pulse signal caused by electromagnetic interference; and when there are more 0 elements in the amplitude change sequence of the reflected pulse signal, it means that there are many moments when there are no pulse signals in the equal-periodic sequence of the pulse signal, which further indicates that the pulse signal is more likely to be an unfixed reflected pulse signal caused by electromagnetic interference.

[0054] On the contrary, when the proportion of elements greater than 0 in the amplitude change sequence of the reflected pulse signal is lower, the discrete degree of all elements in the amplitude change sequence is smaller, which means that the absolute values ​​of the peak and valley values ​​of the reflected pulse signal and all reflected pulse signals in its neighborhood are relatively concentrated and show regular changes, indicating that the reflected pulse signal is less likely to be a reflected pulse signal caused by electromagnetic interference and more likely to be a signal reflected at the fault location; and when the mean value of all elements in the valley change sequence of the reflected pulse signal is smaller and the number of 0 elements is smaller, it means that the pulse signal is less likely to be an unfixed reflected pulse signal caused by electromagnetic interference.

[0055] Step S3: Determine the electromagnetic interference interval based on the time interval between the first and last reflected pulse signals; determine the discrimination threshold based on the electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval; determine the suspected fault signal based on the electromagnetic influence factors of all reflected pulse signals and the discrimination threshold.

[0056] Based on the electromagnetic influence factor obtained in step S2, the reflected pulse signal caused by electromagnetic interference can be identified and eliminated, so as to more accurately identify the reflected pulse signal at the fault location, thereby accurately locating the fault location. Therefore, by analyzing the time interval between the receiving end receiving the first reflected pulse signal and the receiving end receiving the last reflected pulse signal, the electromagnetic interference interval is determined, and based on the electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval, the discrimination threshold is determined; based on the electromagnetic influence factors of all reflected pulse signals and the discrimination threshold, the suspected fault signal is determined, thereby eliminating the interference of the reflected pulse signal generated by electromagnetic interference on the fault point location from all reflected pulse signals, specifically:

[0057] (1) Based on the time interval between the first reflected pulse signal and the last reflected pulse signal, the electromagnetic interference interval is determined to identify the reflected pulse signal generated by the electromagnetic interference, specifically:

[0058] The time interval between the start of receiving the first reflected pulse signal and the start of receiving the last reflected pulse signal is recorded as T. The number of all reflected pulse signals in is recorded as n, and the electromagnetic interference interval is ,in .

[0059] The reason for selecting the electromagnetic interference interval is that after the pulse signal is sent, the first pulse signal is the initial pulse sent directly from the test end, which does not contain any reflection information. Therefore, the analysis starts from the second reflected pulse signal, so the lower limit of the electromagnetic interference interval is 2. When the pulse signal is transmitted on the high-temperature resistant and environmentally friendly wire, the rate of change of the signal is very high, which will generate a strong electromagnetic field around the wire. These electromagnetic fields are easily sensed by the surrounding electronic equipment or wires, thereby generating electromagnetic interference. As the energy of the signal decays during the propagation process, the electromagnetic interference will gradually weaken. Therefore, electromagnetic interference is usually most obvious in the early stage of signal transmission, so it is selected. The reflected pulse signal in the The period may contain most of the electromagnetic interference signals, so by analyzing the previous The first few reflected pulse signals within the range can better capture this irregular interference feature. If the analysis time is too long, the reflected pulse signal at the fault point may be included, avoiding the subsequent exclusion of the reflected pulse signal at the fault point. Therefore, the electromagnetic interference range is , ensure that the reflected pulse signal analyzed is within the time period when electromagnetic interference is more significant.

[0060] (2) Furthermore, in order to eliminate the interference of the reflected pulse signal generated by the electromagnetic interference, the discrimination threshold is determined based on the electromagnetic influence factor of all reflected pulse signals within the electromagnetic interference interval, specifically:

[0061] The electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval are used as the input of the Otsu threshold segmentation algorithm, and the output segmentation threshold is used as the discrimination threshold.

[0062] Among them, the Otsu threshold segmentation algorithm is a well-known technology, and its specific principle will not be repeated here.

[0063] (3) Based on the electromagnetic influence factors of all reflected pulse signals and the discrimination threshold, the suspected fault signal is determined, specifically:

[0064] Among all reflected pulse signals, the reflected pulse signals whose electromagnetic influence factors are less than or equal to the discrimination threshold are regarded as suspected fault signals.

[0065] Preferably, the schematic diagram of the suspected fault signal acquisition process provided in this embodiment is as follows: Figure 2 shown.

[0066] Step S4: Based on the distribution of the peak values ​​and valley values ​​of each suspected fault signal and all reflected pulse signals in its neighborhood, the fault discrimination value of each suspected fault signal is determined to determine the fault reflection signal.

[0067] The pulse signal caused by the fault is distinguished from the pulse signal caused by the temperature interference based on their distinctive features. Since the fault type may be an open circuit or a short circuit, the polarity of the reflected pulse signal caused by the fault may always be the same as the polarity of the transmitted pulse, or the pulse signal may change polarity each time, while the polarity of the reflected pulse signal caused by temperature will always be the same as the polarity of the transmitted pulse. Since the temperature rise causes a slight increase in the resistance of the local wire, the reflectivity of the pulse signal is low, so the intensity of the generated reflected pulse is relatively weak, while a short circuit or open circuit fault will cause the wire to have high impedance, resulting in a strong reflected pulse, so the average amplitude of the reflected pulse signal caused by the fault will be greater than the average amplitude of the reflected pulse signal caused by temperature interference.

[0068] (1) Based on the distribution of the peak and valley values ​​of each suspected fault signal and all reflected pulse signals in its neighborhood, the fault discrimination value of each suspected fault signal is determined.

[0069] Based on the difference between the reflected pulse signal generated by the temperature interference and the reflected pulse signal generated at the fault point in the above analysis, the fault discrimination value of each suspected fault signal is determined by analyzing the distribution of the peak and valley values ​​of all reflected pulse signals in the suspected fault signal and its neighborhood, so as to distinguish the reflected pulse signal generated by the temperature interference and the fault point, thereby accurately locating the fault location. Specifically:

[0070] Fault discrimination value of suspected fault signal j The expression is: ; In the formula, Represents the average of the absolute values ​​of the peak and valley values ​​of all reflected pulse signals in the suspected fault signal j and its neighborhood; , They represent the number of peaks and valleys of the suspected fault signal j and all reflected pulse signals in its neighborhood respectively; Indicates a preset constant greater than 0 to prevent the denominator from being 0. The value of is set manually. The value of is 0.01. Under the premise of ensuring that the denominator is not 0 and does not excessively affect the calculation result, the implementer can also set it according to the specific situation. This embodiment does not impose any special restrictions.

[0071] According to the fault discrimination value of each suspected fault signal, it can be understood that when the difference between the peak value number and the valley value number of all reflected pulse signals in the suspected fault signal and its neighborhood is The smaller the value, the more likely it is that the suspected fault signal is a short-circuit fault pulse signal with alternating positive and negative pulses. When it is larger, the fault discrimination value of the suspected fault signal The larger it is, the greater the energy intensity of the suspected pulse signal and all reflected pulse signals in its neighborhood is, indicating that the suspected pulse signal is more likely to be a reflected pulse signal caused by a fault.

[0072] On the contrary, when the difference between the peak value and the valley value of all reflected pulse signals in the suspected fault signal and its neighborhood is When the value is larger, and when the average absolute value of the peak and valley values ​​of all reflected pulse signals in the suspected fault signal and its neighborhood is The smaller the value, the higher the fault discrimination value of the suspected fault signal. The smaller it is, the smaller the energy intensity of the suspected pulse signal and all the reflected pulse signals in its neighborhood is, indicating that the suspected pulse signal is more likely to be a reflected pulse signal caused by temperature interference.

[0073] (2) Based on the fault discrimination values ​​of all suspected fault signals, the fault reflection signal is determined, specifically:

[0074] The fault discrimination values ​​of all suspected fault signals are clustered to obtain multiple clusters, and the suspected fault signals corresponding to all elements in the cluster with the largest average fault discrimination value are taken as fault reflection signals.

[0075] It should be noted that there are many commonly used clustering algorithms. In this embodiment, the k-means clustering algorithm is used to cluster suspected fault signals. The implementer may also use other clustering methods such as the DPC density clustering algorithm. Regarding the selection of clustering algorithms, this embodiment does not make any special restrictions.

[0076] Among them, the k-means clustering algorithm is a well-known technology, and its specific clustering process and clustering principle are not described in detail.

[0077] Step S5: Based on the time interval between transmitting the pulse signal and receiving each fault reflection signal, the fault transmission duration is determined, and the fault of the high temperature resistant and environmentally friendly electric wire is located in combination with the propagation speed.

[0078] If the fault reflection signals obtained are all generated by wire faults, then the time interval between each two adjacent reflection pulses should be the same; if there are false detections or missed detections in the fault reflection signals, that is, there are reflection pulse signals generated by temperature interference or electromagnetic interference, then there will be a small amount of difference in the time interval between each two adjacent reflection pulses.

[0079] Therefore, the first-order difference sequence of the time interval between transmitting the pulse signal and receiving all fault reflection signals is taken as the real time series, and the mode in the real time series is taken as the fault transmission duration.

[0080] Further, based on the fault transmission time and the propagation speed of the transmitted pulse signal in the high temperature resistant and environmentally friendly electric wire, the fault location is determined, specifically:

[0081] Fault location of high temperature resistant and environmentally friendly wires The expression is: ; In the formula, v represents the propagation speed of the transmitted pulse signal in the high temperature resistant and environmentally friendly wire; Indicates the fault transmission duration.

[0082] Preferably, the schematic diagram of the fault location determination process of the high temperature resistant and environmentally friendly electric wire provided in this embodiment is as follows: Figure 3 shown.

[0083] So far, this embodiment has constructed an electromagnetic influence factor based on the characteristics of the interference signal generated by electromagnetic interference, eliminated the interference signal caused by electromagnetic interference in the reflected pulse signal, and eliminated the influence of electromagnetic interference; further, based on the distinctive characteristics of the reflected pulse signal generated by the wire fault and temperature interference, a fault discrimination value was constructed, which eliminated the influence of temperature interference and improved the accuracy of fault location of high-temperature resistant and environmentally friendly wires.

[0084] It should be noted that the above sequence of the embodiments of the present application is for description only and does not represent the advantages and disadvantages of the embodiments. The above is a description of a specific embodiment of this specification. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0085] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0086] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Modifications to the technical solutions recorded in the aforementioned embodiments, or equivalent replacement of some of the technical features therein, do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for locating a fault of a high temperature resistant and environmentally friendly electric wire, characterized in that: The method comprises the following steps: Transmitting a pulse signal to the faulty high temperature resistant environmentally friendly electric wire and acquiring all reflected pulse signals, the time when the pulse signal starts to be transmitted and the time when each reflected pulse signal starts to be received, and the propagation speed of the pulse signal; Based on the change trends of the peak values ​​and valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood, the amplitude change sequence of each reflected pulse signal is determined, and based on the discrete degree and average distribution of all elements in the amplitude change sequence, the electromagnetic influence factor of each reflected pulse signal is determined; Determine the electromagnetic interference interval based on the time interval between the first and last reflected pulse signals; determine the discrimination threshold based on the electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval; determine the suspected fault signal based on the electromagnetic influence factors of all reflected pulse signals and the discrimination threshold; Determine the fault discrimination value of each suspected fault signal based on the distribution of the peak values ​​and valley values ​​of all reflected pulse signals in each suspected fault signal and its neighborhood, so as to determine the fault reflection signal; Based on the time interval between transmitting the pulse signal and receiving each fault reflection signal, the fault transmission duration is determined, and combined with the propagation speed, the fault of the high-temperature resistant and environmentally friendly electric wire is located.

2. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the amplitude variation sequence of each reflected pulse signal is as follows: The absolute values ​​of the valley values ​​of each reflected pulse signal and all reflected pulse signals in its neighborhood are taken, and the first-order difference sequence of the peak and valley absolute values ​​of all reflected pulse signals is arranged in chronological order as the amplitude change sequence of each reflected pulse signal.

3. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The expression of the electromagnetic influence factor of each reflected pulse signal is: ; In the formula, Represents the electromagnetic impact factor of the reflected pulse signal i; Indicates the proportion of positive elements in the amplitude change sequence of the reflected pulse signal i among all elements; , They respectively represent the discreteness and mean value of all elements in the amplitude variation sequence of the reflected pulse signal i; Represents the number of all zero elements in the amplitude change sequence of the reflected pulse signal i.

4. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the electromagnetic interference interval is: The time interval between the start of receiving the first reflected pulse signal and the start of receiving the last reflected pulse signal is recorded as T. The number of all reflected pulse signals in is recorded as n, and the electromagnetic interference interval is ,in .

5. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the discrimination threshold is: The electromagnetic influence factors of all reflected pulse signals in the electromagnetic interference interval are used as the input of the Otsu threshold segmentation algorithm, and the output segmentation threshold is used as the discrimination threshold.

6. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the suspected fault signal is: Among all reflected pulse signals, the reflected pulse signals whose electromagnetic influence factors are less than or equal to the discrimination threshold are regarded as suspected fault signals.

7. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The expression of the fault discrimination value of each suspected fault signal is: ; In the formula, represents the fault discrimination value of the suspected fault signal j; Indicates the degree of dispersion of the absolute values ​​of the peak and valley values ​​of all reflected pulse signals in the suspected fault signal j and its neighborhood; , They represent the number of peaks and valleys of the suspected fault signal j and all reflected pulse signals in its neighborhood respectively; Indicates a preset constant greater than 0.

8. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the fault reflection signal is: The fault discrimination values ​​of all suspected fault signals are clustered to obtain multiple clusters, and the suspected fault signals corresponding to all elements in the cluster with the largest average fault discrimination value are taken as fault reflection signals.

9. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method for determining the fault transmission duration is: The first-order difference sequence of the time interval between transmitting the pulse signal and receiving all fault reflection signals is taken as the real time series, and the mode in the real time series is taken as the fault transmission duration.

10. The fault location method for high temperature resistant and environmentally friendly electric wire according to claim 1, characterized in that: The method of locating the fault of the high temperature resistant and environmentally friendly electric wire comprises: Fault location of high temperature resistant and environmentally friendly wires The expression is: ; In the formula, v represents the propagation speed of the transmitted pulse signal in the high temperature resistant and environmentally friendly wire; Indicates the fault transmission duration.

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