A method and apparatus for testing for damage to the insulation of an aircraft wire

Abstract

The application discloses an aircraft wire insulation layer damage fault test method and device, and belongs to the field of aircraft wire fault detection. The method comprises the following steps: a high-voltage pulse power supply generates a short-time high-voltage incident pulse; the short-time high-voltage incident pulse is injected into a measured wire, a high-voltage pulse breaks a gap in air at an insulation layer damage position to form arc discharge; incident pulse current signals generated by the high-voltage pulse power supply, current signals reflected by the incident pulse at the insulation layer damage position of the aircraft wire, and current signals reflected by a tail end of the measured wire are collected, and the peak value, the rising edge time and the time of occurrence of the current signals are recorded; three-level signal processing is performed on the collected current signals; the transmission speed of the signals in the measured wire is obtained; the incident pulse generated by the high-voltage power supply is taken as a reference signal; the time interval between the fault reflection signal and the reference signal is determined through time domain characteristic parameters; and the distance between the fault point and the reference point is calculated. The application has high detection precision, and improves the wire maintenance efficiency and maintenance support capability.

Description

Technical Field

[0001] This invention belongs to the field of aircraft wire fault detection, specifically relating to a method and apparatus for testing aircraft wire insulation layer damage faults. Background Technology

[0002] In aircraft electrical wiring systems, wires act as bridges connecting various electrical devices and serve as the medium for signal transmission. Aircraft wires are diverse and densely distributed, often laid inside the aircraft structure or in inaccessible areas. Compared to ordinary wires, aviation wires are often thinner with thinner insulation. Coupled with ever-increasing rated power, high vibration, and harsh environments, they are prone to insulation degradation and wear, leading to open circuits, short circuits, or arcing, causing system malfunctions. This often results in power outages, system damage, and even catastrophic accidents such as onboard fires, posing a significant threat to flight safety. Therefore, effective monitoring of insulation damage in aircraft wires is crucial.

[0003] In existing technologies, commonly used wire inspection methods are designed based on the principle of reflection. However, when aircraft wires experience insulation layer faults that differ from short circuits or open circuits, conventional detection methods such as time-domain reflectometry, frequency-domain reflectometry, and time-frequency-domain reflectometry inject low-level signals, causing the reflected information of the fault location to be submerged in the normal signal. This makes it difficult for conventional time-domain reflectometry and other detection methods to detect and locate the fault. While high-voltage testing techniques such as partial discharge or DC breakdown may detect some insulation layer defects in the wire, they are difficult to locate precisely, posing safety hazards and causing adverse damage to the wire.

[0004] To test the working condition of aircraft wire insulation, ensure normal wire operation, accurately locate faults caused by damage to aircraft wire insulation, and improve the maintenance and support capabilities of aircraft electrical wiring interconnection systems, a technical solution for testing faults caused by damage to aircraft wire insulation is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for testing the insulation layer damage of aircraft wires, in order to solve the problems of difficulty in achieving accurate positioning, safety hazards, and adverse damage to wires in the existing technology.

[0006] In a first aspect, this application also provides an aircraft wire insulation layer damage fault testing device, the device including a high voltage pulse power supply, a current sensor, a data acquisition card, and an industrial tablet. The high-voltage pulse power supply is connected to the wire of the aircraft under test, the industrial plate is connected to the data acquisition card, the data acquisition card is connected to the current sensor, and the current sensor is installed outside the insulation layer of the wire of the aircraft under test on the injection side of the high-voltage pulse power supply. The high-voltage pulse power supply is used to generate short-time high-voltage incident pulses; The current sensor is used to collect the incident pulse current signal generated by the high-voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the aircraft wire insulation layer, and the current signal reflected from the tail end of the aircraft wire under test. The data acquisition card is used to implement low-pass filtering and temporarily store digital signals; The industrial flat panel is used to simultaneously display the comparison waveforms of the original signal before denoising and the clean signal after denoising, and to label the extracted time-domain feature parameters.

[0007] Furthermore, the high-voltage pulse power supply includes: an adjustable high-voltage power supply, a high-voltage capacitor, and a ball gap; The adjustable high-voltage power supply is connected in parallel with the high-voltage capacitor. The first end of the high-voltage capacitor is connected to the first end of the ball gap, and the second end of the high-voltage capacitor is grounded. The spherical gap is used to output a pulse signal when the high-voltage capacitor is discharged after charging, and the maximum pulse amplitude of the high-voltage pulse power supply is 32kV.

[0008] Furthermore, the high-voltage pulse power supply also includes: a power control switch, a boost switch, a power air switch, and a power socket; The power socket is connected to an external power source. The output terminal of the power socket is connected in series with the power circuit breaker. The output terminal of the power circuit breaker is connected to the input terminal of the power control switch. The output terminal of the power control switch is connected to the input terminal of the boost switch. The output terminal of the boost switch is connected to the input terminal of the adjustable high-voltage power supply. At the start of the test, turn on the power circuit breaker, turn the power control switch to the start position, rotate the voltage adjustment knob of the boost switch to boost the voltage to the required high voltage, and the ball gap discharge generates a pulse; after the test is completed, switch the power control switch to the stop position and turn off the power circuit breaker.

[0009] Furthermore, the industrial tablet is a 7-inch LCD screen smart industrial tablet, which serves as the human-machine interface window for the testing device. It features a dual-core processor, multi-point capacitive touch and interactive voice recognition technology, supports a PXI bus interface, and has one Ethernet interface and two USB interfaces.

[0010] Furthermore, the data acquisition card adopts a high-speed signal acquisition circuit based on the PXI bus, which includes a hardware filtering circuit to achieve low-pass filtering. The sampling rate is 2GSa / s, the number of sampling channels is 1 to 2, and the storage depth is up to 2GB.

[0011] Secondly, embodiments of this application provide a method for testing damage to the insulation layer of aircraft electrical wires, the method comprising the following steps: S1. A short-time high-voltage incident pulse is generated by a high-voltage pulse power supply; S2. A short-time high-voltage incident pulse is injected into the wire of the aircraft under test. At the point of damage to the insulation layer of the wire under test, the short-time high-voltage pulse breaks down the air gap and forms an arc discharge. S3. Install the current sensor outside the insulation layer of the aircraft wire under test on the high voltage pulse power injection side, collect the incident pulse current signal generated by the high voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the insulation layer of the aircraft wire, and the reflected current signal at the tail end of the aircraft wire under test, record the peak value, rise time and the time when the signal appears. When the current peak value exceeds the preset value, it is automatically marked as a valid signal and stored first. S4. Perform three-stage signal processing on the acquired current signal. The first stage uses a low-pass filter circuit for hardware noise reduction. The second stage converts the filtered current signal into a digital signal. The third stage uses a wavelet transform algorithm to further denoise the digital signal and extract the time-domain feature parameters of the fault reflection signal. S5. Obtain the transmission speed of the signal in the wire of the aircraft under test, take the incident pulse generated by the high voltage power supply at the ball gap as the reference signal, take the reflected current signal at the tail end of the wire of the aircraft under test as the reference signal, determine the time interval between the fault reflected signal and the reference signal through the time domain characteristic parameters, and calculate the distance between the fault point and the reference point.

[0012] Furthermore, in step S1, the rise time of the short-time high-voltage incident pulse is from a few nanoseconds to tens of nanoseconds, and the peak voltage is from several thousand volts to tens of thousands of volts.

[0013] Furthermore, in step S2, the tested aircraft wires include coaxial cables, twisted-pair cables, and twisted-triple cables.

[0014] Furthermore, the specific steps of step S4 are as follows: S41. An RC active low-pass filter circuit is adopted. The cutoff frequency of the filter circuit is set to 50MHz-150MHz. The operational amplifier is selected with a high common-mode rejection ratio ≥80dB. By suppressing high-frequency electromagnetic interference signals above 150MHz, the signal-to-noise ratio of the filtered current signal is increased to more than 20dB. S42. Employs a 16-bit or 24-bit high-precision analog-to-digital converter chip. The conversion sampling rate is synchronized with the 2GSa / s sampling rate of the data acquisition card. During the conversion process, calibration is performed using a reference voltage source. The digital signal is temporarily stored in the high-speed cache of the data acquisition card in binary two's complement form. S43. Using db4 wavelet or sym5 wavelet as the basis function, the digital signal is decomposed into 3-5 levels of wavelet decomposition. Noise components in the high-frequency coefficients after decomposition are removed by default thresholding or adaptive thresholding. The denoised clean signal is then obtained by wavelet reconstruction. At the same time, the time-domain feature parameters of the reflected signal are extracted, including the peak amplitude, peak occurrence time, pulse rise time corresponding to 10%-90% amplitude, pulse fall time corresponding to 90%-10% amplitude, and pulse half-width. During the third-level processing, the industrial flat panel displays the comparison waveforms of the original signal before denoising and the clean signal after denoising, and annotates the extracted time-domain feature parameters.

[0015] Furthermore, in step S5, the formula for calculating the distance between the fault point and the reference point is as follows: D=v×Δt / 2 Where D is the distance between the fault point and the reference point, v is the transmission speed of the signal in the wire of the aircraft under test, and Δt is the time interval between the reference signal and the fault reflection signal.

[0016] As can be seen from the above technical solutions, this application has the following advantages: This application discloses a method and apparatus for testing aircraft electrical wire insulation damage. A short-duration high-voltage incident pulse breaks down the air gap at the damage site, creating an arc discharge. This is combined with a current sensor to collect reflected signals. After three levels of signal processing, time-domain characteristic parameters are extracted, and the distance between the fault point and the measurement point is calculated, achieving precise fault location. This avoids the problems of reflected information obliteration or ambiguous location in conventional methods. The method balances compatibility and safety, adapting to various aircraft wires such as coaxial cables, twisted-pair cables, and twisted-triple cables. The high-voltage pulse power output is controllable, and there is no risk of excessive wire damage during testing. Compared to partial discharge and DC breakdown technologies, this method is safer and more reliable. A 7-inch LCD industrial flat panel supports waveform comparison display, parameter annotation, and voice interaction. A PXI bus interface and multiple interfaces ensure convenient data transmission and device connection, reducing manual troubleshooting time and facilitating rapid fault location. This enhances the maintenance and support capabilities of aircraft electrical wiring interconnection systems, strengthening the defense for flight safety. This application features stable performance, reliable operation, and high detection accuracy, enabling fault location of insulation damage in aircraft coaxial cables, twisted-pair cables, and twisted-triple cables. It can save a significant amount of time and manpower, and improve the efficiency of ground maintenance and repair capabilities for electrical wires. Attached Figure Description

[0017] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the test method for damage to the insulation layer of aircraft wires according to this application.

[0019] Figure 2 This is a schematic diagram of the aircraft wire insulation layer damage fault testing device of this application.

[0020] Figure 3 This is a schematic diagram of the high-voltage pulse power supply structure of this application.

[0021] Figure 4 This is a waveform data diagram of the wire insulation layer damage detection in this application. Detailed Implementation

[0022] The various embodiments of the invention will be described more fully in the detailed steps of the aircraft wire insulation damage fault testing method described below. The invention may have various embodiments, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of the invention to the specific embodiments disclosed herein, but rather the invention should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of the invention.

[0023] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0024] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0025] To make the objectives, features, and advantages of this invention more apparent and understandable, specific embodiments and accompanying drawings will be used to clearly and completely describe the technical solutions protected by this invention. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] Please see Figure 1 The diagram shown is a flowchart of a method for testing damage to the insulation layer of aircraft wires in a specific embodiment. The method includes the following steps: S1. A short-time high-voltage incident pulse is generated by a high-voltage pulse power supply; S2. A short-time high-voltage incident pulse is injected into the wire of the aircraft under test. At the point of damage to the insulation layer of the wire under test, the short-time high-voltage pulse breaks down the air gap and forms an arc discharge. S3. Install the current sensor outside the insulation layer of the aircraft wire under test on the high voltage pulse power injection side, collect the incident pulse current signal generated by the high voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the insulation layer of the aircraft wire, and the reflected current signal at the tail end of the aircraft wire under test, record the peak value, rise time and the time when the signal appears. When the current peak value exceeds the preset value, it is automatically marked as a valid signal and stored first. S4. Perform three-stage signal processing on the acquired current signal. The first stage uses a low-pass filter circuit for hardware noise reduction. The second stage converts the filtered current signal into a digital signal. The third stage uses a wavelet transform algorithm to further denoise the digital signal and extract the time-domain feature parameters of the fault reflection signal. S5. Obtain the transmission speed of the signal in the wire of the aircraft under test, take the incident pulse generated by the high voltage power supply at the ball gap as the reference signal, take the reflected current signal at the tail end of the wire of the aircraft under test as the reference signal, determine the time interval between the fault reflected signal and the reference signal through the time domain characteristic parameters, and calculate the distance between the fault point and the reference point.

[0027] It should be noted that the operator sets the kV level energy step by step using the high voltage pulse power supply raising and lowering button, and releases the pulse high voltage into the tested wire through high voltage and ball gap discharge; according to the principle of arc reflection diagnosis and localization of insulation layer damage fault, when the pulse energy propagates along the tested wire and encounters a soft fault with damaged insulation layer of the aircraft wire, arc discharge is very likely to occur in the air gap around the soft fault. The arc discharge with the characteristics of streamer generates a large number of charged particles locally, which distorts the spatial electric field and accelerates the spatial ionization reaction, promoting the development of arc discharge. Once the streamer channel is formed, it flashes with the surrounding air, and the current signal of the tested cable is collected in real time and stored. Because various electromagnetic interferences are unavoidable in the fault location of the reflection-based wire insulation damage testing system, which can sometimes overwhelm the starting point of the reflected signal, leading to missed or false alarms and increasing the fault location error, this system decomposes and suppresses the reflected signal to achieve filtering and noise reduction. Since the speed of the signal in the tested wire is known, the positions of the initial reference signal and the fault reflection signal are determined using intelligent calculation methods. The time interval between the reference signal and the reflected signal can then be calculated, thereby determining the distance between the fault point and the measurement point. Operators input operating commands via an industrial tablet, which displays the test waveform and location information of the soft fault caused by insulation damage in the tested wire.

[0028] Furthermore, as a refinement and extension of the specific implementation of the above embodiments, in order to fully illustrate the specific implementation process in this embodiment, another method for testing aircraft wire insulation layer damage faults is provided, which includes the following steps: S1. A short-time high-voltage incident pulse is generated by a high-voltage pulse power supply; in step S1, the rise time of the short-time high-voltage incident pulse is from a few nanoseconds to tens of nanoseconds, and the peak voltage is from several kilovolts to tens of thousands of volts.

[0029] It should be noted that when the voltage of the high-voltage capacitor reaches the preset value, the ball gap breaks down under the action of high voltage, releasing electrical energy to form a short-term high-voltage incident pulse. The microcontroller precisely controls the ball gap breakdown timing and the voltage change rate of the boost circuit to ensure that the pulse rise time is stable in the range of a few nanoseconds to tens of nanoseconds. S2. A short-time high-voltage incident pulse is injected into the aircraft wire under test. At the point of damage to the insulation layer of the wire under test, the short-time high-voltage pulse breaks down the air gap to form an arc discharge. In step S2, the aircraft wire under test includes coaxial cable, twisted pair, and twisted three.

[0030] For example, three typical aircraft wires were selected for testing: a coaxial cable of model RG-58 (outer diameter 5mm), an AWG22 twisted pair (conductor diameter 0.64mm), and a twisted three with a cross-sectional area of ​​0.5mm². Before testing, each type of wire was pre-treated by creating standardized damage at a distance of 1.5m from one end of the cable: 1mm of the outer insulation layer was stripped from the coaxial cable to expose the shielding layer; 0.5mm pinholes were created in the insulation layer of a single conductor of the twisted pair; and 0.3mm deep scratches were created at the intersection of the twisted three. Connect the output of the high-voltage pulse power supply to the input of the wire under test through a dedicated high-voltage probe. The probe uses a combination of alligator clips and insulating sleeves to ensure reliable contact with different types of cables. For coaxial cables, the probe connects the inner conductor and the outer shielding layer respectively. For twisted-pair and twisted-triple cables, the probe connects one of the conductors to the grounding terminal. Start the high-voltage pulse power supply and output a short-time high-voltage incident pulse with corresponding parameters according to the cable type: 8kV peak voltage and 12ns rise time for coaxial cable, 5kV peak voltage and 8ns rise time for twisted pair cable, and 6kV peak voltage and 15ns rise time for twisted three cable; when the pulse is injected, an arc discharge is formed at the high-voltage breakdown gap air at the damaged part of the wire insulation layer. S3. Install the current sensor outside the insulation layer of the aircraft wire under test on the high voltage pulse power injection side, collect the incident pulse current signal generated by the high voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the insulation layer of the aircraft wire, and the reflected current signal at the tail end of the aircraft wire under test, record the peak value, rise time and the time when the signal appears. When the current peak value exceeds the preset value, it is automatically marked as a valid signal and stored first. For example, a Rogowski coil current sensor with a bandwidth of 100MHz and a sampling rate of 2GSa / s is selected. Its measurement range is ±100A and its resolution is 1mA. It is connected to the data acquisition module through a BNC coaxial cable. The ring core of the current sensor is placed on the grounding wire at the output end of the wire being measured to ensure that it is arranged coaxially with the cable and reduce electromagnetic interference. The testing system has three preset current peak thresholds: 2.5A for coaxial cable, 1.8A for twisted pair cable, and 2.2A for twisted three cable. The thresholds can be adjusted in real time. When a short-term high-voltage incident pulse is injected, the current sensor starts to continuously collect the reflected current signal, and completes one full sampling cycle in 10ms. The acquired current signal is analyzed in real time: First, the maximum value of the signal is extracted using a peak detection algorithm (accuracy ±0.01A); the rise time (i.e., the time interval from 10% to 90% of the peak value) is calculated using the 50% threshold method; the moment when the signal first appears is recorded synchronously (timestamp accuracy ±1ns); when the current peak value is detected to exceed the preset threshold of the corresponding cable, a marking mechanism is automatically triggered, adding a "valid signal" identifier to the header of the data frame, and this set of data is preferentially written to the high-speed cache (write speed up to 1GB / s), while being backed up to the solid-state drive.

[0031] Experimental data show that when an arc discharge is formed at the point of insulation damage, the peak value of the reflected current signal can reach 3.2A (coaxial cable), 2.1A (twisted pair), and 2.8A (twisted three), all exceeding the preset threshold. The rise time is concentrated in the range of 15-35ns, and the system can complete the identification and storage of the effective signal within 10μs. S4. Perform three-stage signal processing on the acquired current signal. The first stage uses a low-pass filter circuit for hardware noise reduction. The second stage converts the filtered current signal into a digital signal. The third stage further denoises the digital signal using a wavelet transform algorithm and extracts the time-domain feature parameters of the fault reflection signal. The specific steps of step S4 are as follows: S41. An RC active low-pass filter circuit is adopted. The cutoff frequency of the filter circuit is set to 50MHz-150MHz. The operational amplifier is selected with a high common-mode rejection ratio ≥80dB. By suppressing high-frequency electromagnetic interference signals above 150MHz, the signal-to-noise ratio of the filtered current signal is increased to more than 20dB. S42. Employs a 16-bit or 24-bit high-precision analog-to-digital converter chip. The conversion sampling rate is synchronized with the 2GSa / s sampling rate of the data acquisition card. During the conversion process, calibration is performed using a reference voltage source. The digital signal is temporarily stored in the high-speed cache of the data acquisition card in binary two's complement form. S43. Using db4 wavelet or sym5 wavelet as the basis function, the digital signal is decomposed into 3-5 levels of wavelet decomposition. Noise components in the high-frequency coefficients after decomposition are removed by default thresholding or adaptive thresholding. The denoised clean signal is then obtained by wavelet reconstruction. At the same time, the time-domain feature parameters of the reflected signal are extracted, including the peak amplitude, peak occurrence time, pulse rise time corresponding to 10%-90% amplitude, pulse fall time corresponding to 90%-10% amplitude, and pulse half-width. During the third-level processing, the industrial flat panel displays the comparison waveforms of the original signal before denoising and the clean signal after denoising, and annotates the extracted time-domain feature parameters.

[0032] First stage: RC active low-pass filter processing A second-order RC active low-pass filter circuit, consisting of an operational amplifier OP27 (common-mode rejection ratio 86dB), is used. The cutoff frequency is dynamically adjusted according to the type of cable under test: 120MHz for coaxial cable, 80MHz for twisted pair, and 100MHz for twisted triple. The circuit forms an RC network with 10kΩ precision resistors and ceramic capacitors. The operational amplifier operates at ±15V, and the output signal is transmitted to the next stage after 50Ω impedance matching.

[0033] The cutoff frequency of an RC network can be calculated using the following formula:

[0034] In the formula, f c The cutoff frequency is given by R, a precision resistor by C, and a ceramic capacitor whose value is adjusted according to the cutoff frequency. A coaxial cable is also included. f When c=120MHz, C=2π×10⁴×120×10⁶¹≈1.33pF; The common-mode rejection ratio can be calculated using the following formula:

[0035] In the formula, Ad is the differential-mode gain, Ac is the common-mode gain; 86dB represents that the common-mode interference is suppressed by approximately 1086 / 20≈2×104 times. The operational amplifier in the circuit operates at ±15V. The output signal is matched by a 50Ω impedance, with the matching condition being that the output impedance = the load impedance = 50Ω. After matching, the signal is transmitted to the next stage.

[0036] Level 2: High-precision analog-to-digital conversion A 24-bit ADS1278 analog-to-digital converter chip is selected to maintain synchronization with the 2GSa / s sampling rate of the data acquisition card. The conversion circuit uses a REF5045 reference voltage source (accuracy ±0.02%) for real-time calibration, completing a zero-point drift correction every 10μs. The converted digital signal is temporarily stored in the acquisition card's 4GB DDR4 high-speed cache in 32-bit binary two's complement format, with a single-channel data storage rate of up to 250MB / s, ensuring no data loss during continuous acquisition. Level 3: Wavelet Transform Denoising and Feature Extraction The digital signal was decomposed into four levels using the db4 wavelet. Based on the Birgé-Massart strategy, an adaptive thresholding method was used to denoise the high-frequency coefficients. After wavelet reconstruction, the root mean square value of the signal noise was reduced. At the same time, five time-domain feature parameters were extracted: peak amplitude of the reflected signal (accuracy ±0.005A), peak occurrence time (timestamp accuracy ±0.5ns), rise time of 10%-90% amplitude, fall time of 90%-10% amplitude (all accurate to 1ns), and pulse half width at half maximum (accuracy ±2ns). The 7-inch industrial flat panel displays a real-time comparison waveform: the upper half of the screen shows the original signal before noise reduction (red), and the lower half of the screen shows the clean signal after noise reduction (green), with the values ​​of various characteristic parameters displayed through yellow highlight boxes; S5. Obtain the transmission speed of the signal in the wire of the aircraft under test, take the incident pulse generated by the high voltage power supply at the ball gap as the reference signal, take the reflected current signal at the tail end of the aircraft under test as the reference signal, determine the time interval between the fault reflection signal and the reference signal through the time domain characteristic parameters, and calculate the distance between the fault point and the reference point. It should be noted that the reflected current signal at the tail end of the aircraft's electrical wire is used as the reference signal. First, find the tail end reflected signal, and then find the fault reflected signal between the reference signal and the tail end reflected signal. In step S5, the formula for calculating the distance between the fault point and the reference point is as follows: D=v×Δt / 2 Where D is the distance between the fault point and the reference point, v is the transmission speed of the signal in the wire of the aircraft under test, and Δt is the time interval between the reference signal and the fault reflection signal.

[0037] For example, such as Figure 4 As shown, the curve represents the change in current value in the test cable. There are four obvious peaks within the sampling interval, with current values ​​represented as I1, I2, I3, and I4. I1 serves as a reference signal, representing the current surge caused by the arc generated by the breakdown at the ball gap switch, resulting in an ionization wave. I2 represents the current surge caused by the arc generated by the breakdown at the soft fault point of the wire insulation, resulting in an ionization wave. I3 and I4 are both reflected waves.

[0038] It should be noted that the above embodiments are for detecting single insulation layer damage faults. In some embodiments, multiple insulation layer damage faults can also be detected. Using the incident pulse generated at the high-voltage power supply ball gap as a reference signal, combined with the extracted high-precision time-domain feature parameters, the time interval Δt between the reference signal and the fault reflection signal can be accurately located, effectively avoiding errors caused by reference ambiguity in traditional positioning. At the same time, by obtaining the signal transmission speed v adapted to different wire types (coaxial cable, twisted pair, twisted three) in advance, and then substituting it into the formula D=v×Δt / 2, the fault location error can be controlled at the millimeter level, compared to... Conventional detection methods significantly improve positioning accuracy, solving the problem of difficulty in accurately locating faults in aircraft electrical wiring due to its concealed laying and diverse types. The calculation logic is simple and clear, requiring no complex algorithm iterations. Data calculation and result output can be completed in real time using an industrial tablet, allowing staff to quickly obtain distance information between the fault point and the measurement point, eliminating the tedious process of repeated troubleshooting and estimation. Especially for the characteristics of densely distributed aircraft electrical wiring and inaccessible areas, fault locations can be accurately located without disassembling the aircraft structure, significantly reducing maintenance time, lowering maintenance costs, and improving the maintenance and support efficiency of aircraft electrical wiring interconnection systems.

[0039] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0040] like Figure 2 As shown, the following are embodiments of the aircraft wire insulation layer damage fault testing device provided in this disclosure. This device and the aircraft wire insulation layer damage fault testing method of the above embodiments belong to the same inventive concept. For details not described in detail in the embodiments of the aircraft wire insulation layer damage fault testing device, please refer to the embodiments of the above aircraft wire insulation layer damage fault testing method.

[0041] The device includes: a high-voltage pulse power supply connected to the wire of the aircraft under test, an industrial flat panel connected to the data acquisition card, the data acquisition card connected to the current sensor, and the current sensor installed outside the insulation layer of the wire of the aircraft under test on the injection side of the high-voltage pulse power supply. The high-voltage pulse power supply is used to generate short-time high-voltage incident pulses; The current sensor is used to collect the incident pulse current signal generated by the high-voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the aircraft wire insulation layer, and the current signal reflected from the tail end of the aircraft wire under test. The data acquisition card is used to implement low-pass filtering and temporarily store digital signals; The industrial flat panel is used to simultaneously display the comparison waveforms of the original signal before denoising and the clean signal after denoising, and to label the extracted time-domain feature parameters.

[0042] like Figure 3 As shown, the high-voltage pulse power supply includes: an adjustable high-voltage power supply, a high-voltage capacitor, and a ball gap; The adjustable high-voltage power supply is connected in parallel with the high-voltage capacitor. The first end of the high-voltage capacitor is connected to the first end of the ball gap, and the second end of the high-voltage capacitor is grounded. The spherical gap is used to output a pulse signal when the high-voltage capacitor is discharged after charging, and the maximum pulse amplitude of the high-voltage pulse power supply is 32kV.

[0043] The high-voltage pulse power supply also includes: a power control switch, a boost switch, a power air switch, and a power socket; The power socket is connected to an external power source. The output terminal of the power socket is connected in series with the power circuit breaker. The output terminal of the power circuit breaker is connected to the input terminal of the power control switch. The output terminal of the power control switch is connected to the input terminal of the boost switch. The output terminal of the boost switch is connected to the input terminal of the adjustable high-voltage power supply. At the start of the test, turn on the power circuit breaker, turn the power control switch to the start position, rotate the voltage adjustment knob of the boost switch to boost the voltage to the required high voltage, and the ball gap discharge generates a pulse; after the test is completed, switch the power control switch to the stop position and turn off the power circuit breaker.

[0044] The industrial tablet is a 7-inch LCD screen smart industrial tablet, which serves as the human-machine interface for the testing device. It features a dual-core processor, multi-point capacitive touch and interactive voice recognition technology, supports a PXI bus interface, and has one Ethernet interface and two USB interfaces.

[0045] It should be noted that the current sensor is fitted onto the wire of the aircraft under test to collect the current value of the wire. The acquisition sensitivity is 1 volt / ampere, the maximum peak current is 100 amperes, the rise trigger time is 2 nanoseconds, and the output interface uses an SMA RF connector. The data acquisition card uses a high-speed signal acquisition circuit based on the PXI bus, which includes a hardware filtering circuit to achieve low-pass filtering. The sampling rate is 2 GSa / s, the number of sampling channels is 1 to 2, and the storage depth can reach up to 2 GB.

[0046] This embodiment utilizes the interactive collaboration of a high-voltage pulse power supply, a current sensor, a data acquisition card, and an industrial tablet to locate faults in the insulation layers of aircraft coaxial cables, twisted-pair cables, and twisted-triple cables. This can save a significant amount of time and manpower, and improve the efficiency of ground maintenance and repair capabilities for electrical wires.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for testing damage to the insulation layer of aircraft electrical wires, characterized in that, The device includes a high-voltage pulse power supply, a current sensor, a data acquisition card, and an industrial tablet. The high-voltage pulse power supply is connected to the wire of the aircraft under test, the industrial plate is connected to the data acquisition card, the data acquisition card is connected to the current sensor, and the current sensor is installed outside the insulation layer of the wire of the aircraft under test on the injection side of the high-voltage pulse power supply. The high-voltage pulse power supply is used to generate short-time high-voltage incident pulses; The current sensor is used to collect the incident pulse current signal generated by the high-voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the aircraft wire insulation layer, and the current signal reflected from the tail end of the aircraft wire under test. The data acquisition card is used to implement low-pass filtering and temporarily store digital signals; The industrial flat panel is used to simultaneously display the comparison waveforms of the original signal before denoising and the clean signal after denoising, and to label the extracted time-domain feature parameters.

2. The aircraft wire insulation layer damage fault testing device according to claim 1, characterized in that, The high-voltage pulse power supply includes: an adjustable high-voltage power supply, a high-voltage capacitor, and a ball gap; The adjustable high-voltage power supply is connected in parallel with the high-voltage capacitor. The first end of the high-voltage capacitor is connected to the first end of the ball gap, and the second end of the high-voltage capacitor is grounded. The spherical gap is used to output a pulse signal when the high-voltage capacitor is discharged after charging, and the maximum pulse amplitude of the high-voltage pulse power supply is 32kV.

3. The aircraft wire insulation layer damage fault testing device according to claim 2, characterized in that, The high-voltage pulse power supply also includes: a power control switch, a boost switch, a power air switch, and a power socket; The power socket is connected to an external power source. The output terminal of the power socket is connected in series with the power circuit breaker. The output terminal of the power circuit breaker is connected to the input terminal of the power control switch. The output terminal of the power control switch is connected to the input terminal of the boost switch. The output terminal of the boost switch is connected to the input terminal of the adjustable high-voltage power supply. At the start of the test, turn on the power circuit breaker, turn the power control switch to the start position, rotate the voltage adjustment knob of the boost switch to boost the voltage to the required high voltage, and the ball gap discharge generates a pulse; after the test is completed, switch the power control switch to the stop position and turn off the power circuit breaker.

4. The aircraft wire insulation layer damage fault testing device according to claim 1, characterized in that, The industrial tablet is a 7-inch LCD screen smart industrial tablet, which serves as the human-machine interface for the testing device. It features a dual-core processor, multi-point capacitive touch and interactive voice recognition technology, supports a PXI bus interface, and has one Ethernet interface and two USB interfaces.

5. The aircraft wire insulation layer damage fault testing device according to claim 1, characterized in that, The data acquisition card uses a high-speed signal acquisition circuit based on the PXI bus, and includes a hardware filtering circuit to achieve low-pass filtering. The sampling rate is 2GSa / s, the number of sampling channels is 1 to 2, and the storage depth is up to 2GB.

6. A method for testing damage to the insulation layer of aircraft electrical wires, characterized in that, The method includes the following steps: S1. A short-time high-voltage incident pulse is generated by a high-voltage pulse power supply; S2. A short-time high-voltage incident pulse is injected into the wire of the aircraft under test. At the point of damage to the insulation layer of the wire under test, the short-time high-voltage pulse breaks down the air gap and forms an arc discharge. S3. Install the current sensor outside the insulation layer of the aircraft wire under test on the high voltage pulse power injection side, collect the incident pulse current signal generated by the high voltage pulse power supply, the current signal reflected by the incident pulse at the damaged part of the insulation layer of the aircraft wire, and the reflected current signal at the tail end of the aircraft wire under test, record the peak value, rise time and the time when the signal appears. When the current peak value exceeds the preset value, it is automatically marked as a valid signal and stored first. S4. Perform three-stage signal processing on the acquired current signal. The first stage uses a low-pass filter circuit for hardware noise reduction. The second stage converts the filtered current signal into a digital signal. The third stage uses a wavelet transform algorithm to further denoise the digital signal and extract the time-domain feature parameters of the fault reflection signal. S5. Obtain the transmission speed of the signal in the wire of the aircraft under test, take the incident pulse generated by the high voltage power supply at the ball gap as the reference signal, take the reflected current signal at the tail end of the wire of the aircraft under test as the reference signal, determine the time interval between the fault reflected signal and the reference signal through the time domain characteristic parameters, and calculate the distance between the fault point and the reference point.

7. The aircraft wire insulation layer damage fault test method according to claim 6, characterized in that, In step S1, the rise time of the short-time high-voltage incident pulse is from a few nanoseconds to tens of nanoseconds, and the peak voltage is from several thousand volts to tens of thousands of volts.

8. The method for testing damage to the insulation layer of aircraft wires according to claim 6, characterized in that, In step S2, the aircraft wires under test include coaxial cables, twisted pairs, and twisted triodes.

9. The method for testing damage to the insulation layer of aircraft wires according to claim 6, characterized in that, The specific steps of step S4 are as follows: S41. An RC active low-pass filter circuit is adopted. The cutoff frequency of the filter circuit is set to 50MHz-150MHz. The operational amplifier is selected with a high common-mode rejection ratio ≥80dB. By suppressing high-frequency electromagnetic interference signals above 150MHz, the signal-to-noise ratio of the filtered current signal is increased to more than 20dB. S42. Employs a 16-bit or 24-bit high-precision analog-to-digital converter chip. The conversion sampling rate is synchronized with the 2GSa / s sampling rate of the data acquisition card. During the conversion process, calibration is performed using a reference voltage source. The digital signal is temporarily stored in the high-speed cache of the data acquisition card in binary two's complement form. S43. Using db4 wavelet or sym5 wavelet as the basis function, the digital signal is decomposed into 3-5 levels of wavelet decomposition. Noise components in the high-frequency coefficients after decomposition are removed by default thresholding or adaptive thresholding. The denoised clean signal is then obtained by wavelet reconstruction. At the same time, the time-domain feature parameters of the reflected signal are extracted, including the peak amplitude, peak occurrence time, pulse rise time corresponding to 10%-90% amplitude, pulse fall time corresponding to 90%-10% amplitude, and pulse half-width. During the third-level processing, the industrial flat panel displays the comparison waveforms of the original signal before denoising and the clean signal after denoising, and annotates the extracted time-domain feature parameters.

10. The method for testing damage to the insulation layer of aircraft wires according to claim 6, characterized in that, In step S5, the formula for calculating the distance between the fault point and the reference point is as follows: D=v×Δt / 2 Where D is the distance between the fault point and the reference point, v is the transmission speed of the signal in the wire of the aircraft under test, and Δt is the time interval between the reference signal and the fault reflection signal.

Images