Method and system for monitoring and locating surface discharge of catenary insulators

Abstract

The application discloses a kind of monitoring positioning methods and systems of contact network insulator surface discharge, belong to electrical equipment fault detection technical field.The method includes: step 1, microphone sampling module is installed on the connecting pipe of contact network wrist arm insulator shoulder frame;Step 2, three-dimensional coordinate system is constructed with microphone sampling module as center;Step 3, the frequency range of railway insulator surface discharge ultrasonic signal is acquired, and the acquisition frequency range of microphone sampling module is set;Step 4, the ultrasonic signal generated by insulator surface discharge is detected by microphone sampling module, and the sound source space energy summation is carried out using random array delay summation beam forming algorithm, and then the discharge point position coordinate is calculated;Step 5, threshold criterion is generated in combination with set fault alarm.The application realizes millimeter level positioning of insulator surface discharge by fusing acoustics array and adaptive algorithm, with the characteristics of strong anti-electromagnetic interference and fast response speed.

Description

Technical Field

[0001] This invention belongs to the field of insulator pollution monitoring technology, specifically relating to a method and system for monitoring and locating surface discharge of contact wire insulators. Background Technology

[0002] The overhead contact system is an overhead transmission line that supplies power to electric locomotives via friction current extraction. It uses skirted rod insulators to connect supports and structural members, providing both mechanical support and electrical insulation. These insulators are exposed to the elements without protection, making them susceptible to the accumulation of industrial pollutants and airborne particles, forming a contamination layer. In humid weather conditions such as rain or snow, this layer becomes increasingly wet, leading to surface discharge under a strong electric field, potentially causing flashover and even large-scale power outages. In recent years, the frequency of power outages caused by insulator flashover has been increasing. Given the large number of insulators installed along the lines within a single power supply zone, when flashover causes a power outage, maintenance personnel must quickly locate the fault. However, the estimated discharge location by the protection devices often has significant errors, making on-site troubleshooting time-consuming and directly impacting railway safety.

[0003] Currently, railway management departments conduct annual surveys of all pollution sources within a 2-kilometer radius, using methods such as Equivalent Salt Deposit Density (ESDD) to estimate the pollution level of insulators in electrified sections, thereby determining the insulator cleaning cycle under different pollution conditions. This method has a certain degree of scientific validity and operability, but it fails to achieve real-time monitoring of the complex and variable natural and electromagnetic environment of the overhead contact line, resulting in significant safety hazards during the inspection cycle. Summary of the Invention

[0004] In view of this, the present invention provides a method and system for monitoring and locating surface discharge of contact wire insulators, in order to solve the problem that the existing technology cannot achieve real-time monitoring of insulator contamination, and that there are significant safety hazards during the detection period.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for monitoring and locating surface discharge in contact wire insulators includes the following steps:

[0007] Step 1: Install the microphone sampling module on the shoulder connecting pipe in the middle of the base of the contact wire cantilever insulator, so that the plane of the microphone sampling module is parallel to the plane formed by the cantilever support.

[0008] The microphone sampling module includes 128 randomly distributed microphones, which are divided into 16 groups, with 8 microphones in each group randomly arranged among each other.

[0009] Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In the three-dimensional coordinate system, the direction of the center of the microphone sampling module perpendicular to the plane formed by the wrist arm support is the y-axis, and the horizontal and vertical directions perpendicular to the y-axis are the x-axis and z-axis, respectively.

[0010] Step 3: Obtain the frequency range of the ultrasonic signal along the surface discharge of the railway insulator, and set the sampling frequency range of the microphone sampling module according to the obtained frequency range;

[0011] Step 4: Detect the ultrasonic signal generated by surface discharge of the insulator through the microphone sampling module, use the random array delay summation beamforming algorithm to sum the spatial energy of the sound source, determine the angle at which the energy summation is maximum as the incident angle, and then calculate the coordinates of the partial discharge point based on the fixed installation distance of the microphone sampling module.

[0012] Step 4 specifically includes the following steps:

[0013] Step 4.1: Detect the ultrasonic signal generated by surface discharge of the insulator using the microphone sampling module, calculate the time delay of the signal reaching each microphone, and perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal; Step 4.1 specifically includes the following steps:

[0014] Step 4.11: Detect the ultrasonic signal generated by surface discharge of the insulator using the microphone sampling module;

[0015] Step 4.12: Calculate the time delay of the signal arriving at each microphone, as shown in the following formula:

[0016]

[0017] Where, τ m (θ) represents the time delay of the signal reaching the m-th microphone, where θ represents the incident angle of the sound source, p m =[p xm p ym p zm [ ] represents the spatial coordinates of the m-th microphone, c represents the speed of sound, and v represents the velocity of sound. T (θ) represents the transpose of the unit vector of the sound source direction;

[0018] Step 4.13: Obtain the signal observed by the m-th microphone, as shown in the following formula:

[0019] s m (t)=s[t-τ m (θ)]

[0020] Among them, s m(t) represents the signal detected by the m-th microphone at time t;

[0021] Step 4.14: Perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal, as shown in the following equation:

[0022]

[0023] Among them, S m (ω) represents the frequency domain representation of the signal detected by the m-th microphone. Let e ​​represent the integral over time t from negative infinity to positive infinity. -jωτ Let represent a complex exponential function, where j is the imaginary unit and ω is the angular frequency.

[0024] Step 4.2: Represent the signals from each microphone as vectors, determine the angle at which the energy is at its maximum as the angle of incidence, establish a signal model, and perform linear time-invariant filtering and summation on the collected data to obtain the beam output;

[0025] Step 4.2 specifically includes the following steps:

[0026] Step 4.21: Represent the signals from each microphone as vectors, as shown in the following equation:

[0027]

[0028] Among them, X s (ω) The signal S received by each microphone m A column vector composed of (ω);

[0029] Step 4.22: Determine the angle at which the energy is at its maximum as the incident angle θ, and establish the signal model as shown in the following equation:

[0030]

[0031] Step 4.23: Perform linear time-invariant filtering and summation on the acquired data to obtain the beam output, as shown in the following formula:

[0032]

[0033] Among them, Y S (θ) represents the beam output, X S T (ω) represents the signal vector X received by the microphone array. s The transpose of (ω), ε * (θ) denotes the complex conjugate of the phase vector ε(θ).

[0034] Step 4.3: Set the threshold value, filter out noise interference, and determine the discharge position based on the beam output.

[0035] Step 4.3 specifically includes: setting a threshold value Y. M When Y S (θ0)≥Y M At that time, determine the discharge location:

[0036]

[0037] Where s represents the distance from the discharge position to the center of the array coordinates, and α0 and β0 represent the angular parameters of the sound source direction.

[0038] Step 5: Based on the discharge point location coordinates from Step 4 and the set threshold criteria, generate a fault alarm and transmit the fault alarm data to the railway power dispatch center in real time. After comprehensive analysis and judgment, arrange the handling process.

[0039] A monitoring and positioning system for surface discharge of contact wire insulators includes a sampling module, a core board, a power supply module, and a peripheral module. The sampling module includes a microphone sampling module and an image acquisition module. The microphone sampling module includes multiple microphones, which are randomly distributed on the same substrate. Each microphone and the image acquisition module are connected to the core board. The peripheral module and the power supply module are connected to the core board.

[0040] Preferably, the sampling module further includes an FPGA, the 128 microphones are respectively connected to the FPGA, the FPGA is connected to the core board, and the image acquisition module includes a camera, which is connected to the core board via MIPI.

[0041] Preferably, the peripheral module includes a TF card, an RJ45 port, and a USB port, and the TF card, RJ45 port, and USB port are respectively connected to the core board.

[0042] Preferably, the power module includes an input power supply and four step-down circuits, which are a 5V step-down circuit, a 4V step-down circuit, a 3.3V step-down circuit, and a 1.8V step-down circuit, respectively. The input terminals of the four step-down circuits are respectively connected to the input power supply.

[0043] The core board is connected to a display module via a MIPI transmission interface.

[0044] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0045] This invention proposes a method and system for monitoring and locating surface discharge of contact wire insulators. A random array of silicon crystal microphones is used to monitor surface discharge of the insulators. A beamforming algorithm for delay summation of a multi-microphone random array is studied, and supporting positioning software is developed. This invention realizes real-time monitoring and abnormal alarm functions for surface discharge of insulators, and has certain engineering value and practical significance. Attached Figure Description

[0046] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0047] Figure 1 This is a diagram showing the distribution of the microphone and camera on the substrate according to the present invention;

[0048] Figure 2 A schematic diagram showing the installation position and coordinate system of the random microphone array of the present invention;

[0049] Figure 3 This is a schematic diagram of the workflow and processing principle in Embodiment 1 of the present invention;

[0050] Figure 4 This is an overall framework diagram of Embodiment 2 of the present invention;

[0051] Figure 5 This is a circuit diagram of the camera of the present invention;

[0052] Figure 6 This is a schematic diagram of the microphone installation according to the present invention;

[0053] Among them: 1-microphone sound wave collection hole, 2-camera acquisition hole, 3-substrate, 4-shoulder bracket, 5-connecting tube, 6-microphone sampling module. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0055] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0057] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0058] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0060] Example 1

[0061] like Figures 1-6 As shown in the figure, an embodiment of the present invention discloses a method for monitoring and locating surface discharge of contact wire insulators, comprising the following steps:

[0062] Step 1: Install the microphone sampling module 6 on the connecting pipe 5 of the shoulder frame 4 in the middle position of the insulator base of the contact wire cantilever arm, at a distance of 2m, so that the plane of the microphone sampling module is parallel to the plane formed by the cantilever arm support. Figure 2 As shown;

[0063] The microphone sampling module includes 128 randomly distributed microphones, which are divided into 16 groups. Each group contains 8 microphones randomly arranged among themselves. Figure 1 As shown.

[0064] Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In the three-dimensional coordinate system, the direction of the center of the microphone sampling module perpendicular to the plane formed by the wrist arm support is the y-axis, and the horizontal and vertical directions perpendicular to the y-axis are the x-axis and z-axis, respectively.

[0065] Step 3: Obtain the frequency range of the ultrasonic signal along the surface discharge of the railway insulator, and set the sampling frequency range of the microphone sampling module according to the obtained frequency range;

[0066] Step 4: Detect the ultrasonic signal generated by surface discharge of the insulator through the microphone sampling module, use the random array delay summation beamforming algorithm to sum the spatial energy of the sound source, determine the angle at which the energy summation is maximum as the incident angle, and then calculate the coordinates of the partial discharge point based on the fixed installation distance of the microphone sampling module.

[0067] Step 4 specifically includes the following steps:

[0068] Step 4.1: Detect the ultrasonic signal generated by surface discharge of the insulator using the microphone sampling module, calculate the time delay of the signal reaching each microphone, and perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal; Step 4.1 specifically includes the following steps:

[0069] Step 4.11: Detect the ultrasonic signal generated by surface discharge of the insulator using the microphone sampling module;

[0070] Step 4.12: Calculate the time delay of the signal arriving at each microphone, as shown in the following formula:

[0071]

[0072] Where, τ m (θ) represents the time delay of the signal reaching the m-th microphone, where θ represents the incident angle of the sound source, p m =[p xm p ym p zm [ ] represents the spatial coordinates of the m-th microphone, c represents the speed of sound, and v represents the velocity of sound. T (θ) represents the transpose of the unit vector of the sound source direction;

[0073] Step 4.13: Obtain the signal observed by the m-th microphone, as shown in the following formula:

[0074] s m (t)=s[t-τ m (θ)]

[0075] Among them, s m (t) represents the signal detected by the m-th microphone at time t;

[0076] Step 4.14: Perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal, as shown in the following equation:

[0077]

[0078] Among them, S m (ω) represents the frequency domain representation of the signal detected by the m-th microphone. Let e ​​represent the integral over time t from negative infinity to positive infinity.-jωτ Let represent a complex exponential function, where j is the imaginary unit and ω is the angular frequency.

[0079] Step 4.2: Represent the signals from each microphone as vectors, determine the angle at which the energy is at its maximum as the angle of incidence, establish a signal model, and perform linear time-invariant filtering and summation on the collected data to obtain the beam output;

[0080] Step 4.2 specifically includes the following steps:

[0081] Step 4.21: Represent the signals from each microphone as vectors, as shown in the following equation:

[0082]

[0083] Among them, X s (ω) The signal S received by each microphone m A column vector composed of (ω);

[0084] Step 4.22: Determine the angle at which the energy is at its maximum as the incident angle θ, and establish the signal model as shown in the following equation:

[0085]

[0086] Step 4.23: Perform linear time-invariant filtering and summation on the acquired data to obtain the beam output, as shown in the following formula:

[0087]

[0088] Among them, Y S (θ) represents the beam output, X S T (ω) represents the signal vector X received by the microphone array. s The transpose of (ω), ε * (θ) denotes the complex conjugate of the phase vector ε(θ).

[0089] Step 4.3: Set the threshold value, filter out noise interference, and determine the discharge position based on the beam output.

[0090] Step 4.3 specifically includes: setting a threshold value Y. M When Y S (θ0)≥Y M At that time, determine the discharge location:

[0091] Where s represents the distance from the discharge position to the center of the array coordinates, and α0 and β0 represent the angular parameters of the sound source direction.

[0092] Step 5: Based on the discharge point location coordinates from Step 4 and combined with the set threshold criteria, generate a fault alarm. Transmit the fault alarm data to the railway power dispatch center in real time. After comprehensive analysis and judgment, arrange the handling process. Figure 3 As shown, a surface discharge monitoring and locating device for overhead contact line insulators is installed in heavily polluted areas along the railway line to provide focused monitoring of the insulators. When an abnormal surface discharge is detected, the alarm and location information are promptly transmitted to the power dispatch center via a photoelectric transceiver connected to the railway communication network. The power dispatch center then conducts a comprehensive analysis of the alarm data and issues a response order to the nearest overhead contact line team, directing the overhead contact line workers to the site for handling.

[0093] Example 2

[0094] like Figure 4 As shown, this embodiment proposes a monitoring and positioning system for surface discharge of contact wire insulators, including a sampling module, a core board, a power supply module, and peripheral modules. The sampling module includes a microphone sampling module and an image acquisition module. The microphone sampling module includes multiple microphones, which are randomly arrayed on the same plane. Each microphone and the image acquisition module are connected to the core board.

[0095] The peripheral module and power module are respectively connected to the core board.

[0096] In this embodiment, the microphone can collect the high-frequency sound waves generated by the surface discharge of the insulator, thereby detecting the insulator. In this invention, the microphone is 2m away from the insulator, so the sound waves generated by the surface discharge of the insulator are approximately plane waves. The microphone is a far-field pickup. In addition, the microphones are all MEMS silicon digital microphones, model SPH0641LU4H. The sampling frequency of this microphone is 20Hz-80KHz ultrasonic signals. The microphones are all set on the planar substrate 3 and are randomly distributed in an array. This random distribution can improve the spatial resolution and make the detection more accurate. In this embodiment, the core board is RK3588.

[0097] In another embodiment, the microphone sampling module includes 128 microphones, which are divided into 16 groups. The 16 groups of microphones are evenly distributed on the substrate 3, with 8 microphones in each group randomly arranged among each other. The microphones on the substrate 3 exhibit a random and uniform distribution. The uniform distribution means that the 16 groups of microphones are evenly distributed on the substrate 3. Specifically, 128 microphone sound wave collecting holes 1 are randomly and evenly opened on the substrate 3, and one microphone is set in each microphone sound wave collecting hole 1, so as to avoid the microphones being concentrated in a certain area of ​​the substrate 3, thereby reducing the detection accuracy. The random distribution means that the microphones in each group are randomly distributed, so as to form a uniform random distribution as a whole, resulting in higher detection accuracy.

[0098] In another embodiment, the spacing between two adjacent microphones is 15±1mm, and the 128 microphones are evenly and randomly distributed within a circle with a diameter of 150mm on the substrate 3.

[0099] In another embodiment, the spacing between two adjacent microphones is 15mm. It should be noted that when the distance between the receiving point and the transmitting point is greater than twice the far-field boundary, it can be considered to be in the far-field distance. That is, in this invention, if the wavelength is λ, the microphone spacing is d, and the sound velocity is c, then the distance s from the discharge location to the center of the array coordinates can be roughly estimated using the following formula. It should be noted that this formula is an existing formula:

[0100]

[0101] In this embodiment, to ensure that the 128 microphones are located within a circle with a diameter of 150mm on the substrate and at a far-field distance, a spacing of 15mm is chosen between adjacent microphones. Through extensive field experiments and analysis of the ultrasonic characteristics of surface discharge in railway insulators, it is found that the ultrasonic signal of surface discharge in insulators is mainly distributed in the range of 25kHz±3kHz. Therefore, taking the sound velocity c as 340m / s and d as 15mm, we obtain s = 3.7×10 4 It is much larger than the microphone distance from the insulator of 2000mm, thus ensuring that the microphone distribution area is within a circle with a diameter of 150mm and located at the far field distance.

[0102] In this embodiment, the sampling module further includes an FPGA. The 128 microphones are connected to the FPGA, which is connected to the core board. The DAT and CLK pins of the microphones are connected to the corresponding PDM_DAT and PDM_CLK pins on the FPGA, respectively, and output PDM digital signals and clock signals. A capacitor is connected in parallel between the microphone's VDD and GND for filtering. The L / R pins of two adjacent microphones in the same group are connected to a 3.3V power supply and the negative terminal GND, or the negative terminal GND and the 3.3V power supply, respectively.

[0103] The GMAC1 pin on the RK3588 core board is connected to the corresponding FIO pin on the FPGA. Specifically, the GMAC1 pins on the RK3588 core board are connected to the FPGA's FIO pins: GMAC1_TXD0, GMAC1_TXD1, GMAC1_TXD2, GMAC1_TXD3, GMAC1_TXEN, GMAC1_TXCLK, GMAC1_RXD0, GMAC1_RXD1, GMAC1_RXD2, GMAC1_RXD3, GMAC1_RXDV_CRS, GMAC1_RXCLK, and GM. The AC1_MDC, GMAC1_MDIO, and GMAC1_RSTn_L pins are connected to the FPGA's FIO_36, FIO_37, FIO_38, FIO_39, FIO_40, FIO_41, FIO_44, FIO_45, FIO_46, FIO_47, FIO_48, FIO_50, FIO_51, FIO_52, and FIO_54 pins, respectively. In this embodiment, the FPGA acts as an intermediate processing unit, undertaking key tasks such as signal acquisition, real-time processing, and protocol conversion.

[0104] In this embodiment, the image acquisition module includes a camera, and the circuit diagram of the camera is shown below. Figure 5 As shown, the camera is connected to the core board via MIPI low-voltage differential signal. The baseboard 3 has a camera acquisition hole 2 in the center, the camera is located in the camera acquisition hole 2, and the microphones are distributed around the camera. The camera is an OV5695 camera, which is used to acquire image signals. The RK3588 core board is connected to the corresponding interface of the camera via the MIPI_CSI interface.

[0105] In this embodiment, the peripheral module includes a TF card, an RJ45 connector, and a USB port. The TF card, RJ45 connector, and USB port are connected to the core board. The TF card is used for local data storage, the RJ45 connector is used for remote monitoring, and the USB port is used to connect to external devices to export data. The TF card is connected to the SDMMC pin of the RK3588 core board. The RK3588 core board is connected to an external PHY chip via the GMAC pin. The PHY chip is an RTL8211F and is responsible for digital-to-analog conversion. The RJ45 connector is connected to the PHY0 pin of the PHY chip. In this embodiment, there are two USB ports, and the RK3588 core board is connected to the USB ports via the TYPEC0 pin.

[0106] In this embodiment, the power module includes an input power supply and four step-down circuits. The four step-down circuits are a 5V step-down circuit, a 4V step-down circuit, a 3.3V step-down circuit, and a 1.8V step-down circuit. The input terminals of the four step-down circuits are respectively connected to the input power supply, and the output terminals are connected to the components to meet the needs of each component.

[0107] In this embodiment, the core board is connected to a display module via a MIPI transmission interface. The display module is an LCD high-definition touch screen, which enables function settings and display of test data.

[0108] In this embodiment, the peripheral module settings, voltage divider circuit, RK3588 core board, FPGA, OV5695 camera and external display module are all existing technologies. The structure of each module and its circuit connection with the RK3588 core board will not be described in detail here.

[0109] The circuits, electronic components, and modules involved are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon. The scope of protection of this invention does not involve any improvement to the software and methods.

[0110] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0111] 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 method for monitoring and locating surface discharge in contact wire insulators, characterized in that, Includes the following steps: Step 1: Install the microphone sampling module on the connecting tube of the bottom shoulder frame of the contact wire cantilever insulator, and make the plane of the microphone sampling module parallel to the plane formed by the cantilever support. Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In the three-dimensional coordinate system, the direction of the center of the microphone sampling module perpendicular to the plane formed by the wrist arm support is the y-axis, and the horizontal and vertical directions perpendicular to the y-axis are the x-axis and z-axis, respectively. Step 3: Obtain the frequency range of the ultrasonic signal along the surface discharge of the railway insulator, and set the sampling frequency range of the microphone sampling module according to the obtained frequency range; Step 4: Detect the ultrasonic signal generated by surface discharge of the insulator through the microphone sampling module, use the random array delay summation beamforming algorithm to sum the spatial energy of the sound source, determine the angle at which the energy summation is maximum as the incident angle, and then calculate the coordinates of the partial discharge point based on the fixed installation distance of the microphone sampling module. Step 4 specifically includes the following steps: Step 4.1: Detect the ultrasonic signal generated by the surface discharge of the insulator through the microphone sampling module, calculate the time delay of the signal reaching each microphone, and perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal; Step 4.2: Represent the signals from each microphone as vectors, determine the angle at which the energy is at its maximum as the angle of incidence, establish a signal model, and perform linear time-invariant filtering and summation on the collected data to obtain the beam output; Step 4.2 specifically includes the following steps: Step 4.21: Represent the signals from each microphone as vectors, as shown in the following equation: Among them, X s (ω) The signal S received by each microphone m A column vector composed of (ω); Step 4.22: Determine the angle at which the energy is at its maximum as the incident angle θ, and establish the signal model as shown in the following equation: Step 4.23: Perform linear time-invariant filtering and summation on the acquired data to obtain the beam output, as shown in the following formula: Among them, Y S (θ) represents the beam output, X S T (ω) represents the signal vector X received by the microphone array. s The transpose of (ω), ε * (θ) represents the complex conjugate of the phase vector ε(θ), and M represents the number of microphones; Step 4.3: Set the threshold value, filter out noise interference, and determine the discharge position based on the beam output; Step 5: Based on the discharge point location coordinates from Step 4 and the set threshold criteria, generate a fault alarm and transmit the fault alarm data to the railway power dispatch center in real time.

2. The method for monitoring and locating surface discharge of contact wire insulators according to claim 1, characterized in that, The microphone sampling module includes 128 microphones that are randomly and evenly distributed.

3. The method for monitoring and locating surface discharge of contact wire insulators according to claim 1, characterized in that, Step 4.1 specifically includes the following steps: Step 4.11: Detect the ultrasonic signal generated by surface discharge of the insulator using the microphone sampling module; Step 4.12: Calculate the time delay of the signal arriving at each microphone, as shown in the following formula: Where, τ m (θ) represents the time delay of the signal reaching the m-th microphone, where θ represents the incident angle of the sound source, p m =[p xm p ym p zm [ ] represents the spatial coordinates of the m-th microphone, c represents the speed of sound, and v represents the velocity of sound. T (θ) represents the transpose of the unit vector of the sound source direction; Step 4.13: Obtain the signal observed by the m-th microphone, as shown in the following formula: s m (t)=s[t-τ m (i)] Among them, s m (t) represents the signal detected by the m-th microphone at time t; Step 4.14: Perform a Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal, as shown in the following equation: Among them, S m S(ω) represents the frequency domain representation of the signal detected by the m-th microphone, and S(ω) represents the frequency domain representation of the signal detected by the microphone. Let e ​​represent the integral over time t from negative infinity to positive infinity. -jωτ Let represent a complex exponential function, where j is the imaginary unit and ω is the angular frequency.

4. The method for monitoring and locating surface discharge of contact wire insulators according to claim 1, characterized in that, Step 4.3 specifically includes: setting a threshold value Y. M When Y S (θ0)≥Y M At that time, determine the discharge location: Where s represents the distance from the discharge position to the center of the array coordinates, and α0 and β0 represent the angular parameters of the sound source direction.

5. A monitoring and positioning system for surface discharge of contact wire insulators, characterized in that, A method for monitoring and locating surface discharge of contact wire insulators as described in any one of claims 1-4 includes: a sampling module, a core board, a power supply module, and a peripheral module. The sampling module includes a microphone sampling module and an image acquisition module. The microphone sampling module includes multiple microphones, which are randomly distributed on the same substrate. Each microphone and the image acquisition module are connected to the core board, and the peripheral module and the power supply module are connected to the core board.

6. A monitoring and positioning system for surface discharge of contact wire insulators according to claim 5, characterized in that, The sampling module also includes an FPGA, and the 128 microphones are respectively connected to the FPGA. The FPGA is connected to the core board. The image acquisition module includes a camera, and the camera is connected to the core board via MIPI.

7. A monitoring and positioning system for surface discharge of contact wire insulators according to claim 6, characterized in that: The peripheral module includes a TF card, an RJ45 port, and a USB port, which are respectively connected to the core board.

8. A monitoring and positioning system for surface discharge of contact wire insulators according to claim 6, characterized in that: The power module includes an input power supply and four step-down circuits, namely a 5V step-down circuit, a 4V step-down circuit, a 3.3V step-down circuit, and a 1.8V step-down circuit. The input terminals of the four step-down circuits are respectively connected to the input power supply. The core board is connected to a display module via a MIPI transmission interface.

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