Monitoring and positioning method and system for surface discharge of overhead line system insulator

Abstract

The invention discloses a monitoring and positioning method and system for surface discharge of an overhead line system insulator, and belongs to the technical field of electrical equipment fault detection. The method comprises the following steps: step 1, installing a microphone sampling module on a connecting pipe of a cantilever insulator shoulder frame of the overhead line system; 2, constructing a three-dimensional coordinate system by taking the microphone sampling module as a center; step 3, acquiring a frequency range of a railway insulator surface discharge ultrasonic signal, and setting an acquisition frequency range of a microphone acquisition module; 4, ultrasonic signals generated by insulator surface discharge are detected through a microphone sampling module, sound source space energy summation is conducted through a random array delay summation beam forming algorithm, and then the position coordinates of a discharge point are calculated according to the distance; and step 5, generating a fault alarm in combination with a set threshold criterion. According to the method, millimeter-level positioning of insulator surface discharge is realized through fusion of the acoustic array and the adaptive algorithm, and the method has the characteristics of high electromagnetic interference resistance and high response speed.

Description

Technical Field

[0001] The present invention belongs to the technical field of insulator pollution monitoring, and particularly relates to a method and system for monitoring and positioning the surface discharge of catenary insulators. Background Art

[0002] The catenary is an overhead transmission line that provides electrical energy for electric locomotives through the friction current collection method. Rod insulators with skirt structures are used to connect the poles and support devices, playing the roles of mechanical support and electrical insulation. The insulators are in an open-air and unprotected environment, and industrial pollutants and airborne suspended particles in the air are likely to deposit on the surface, forming an insulator pollution layer. If it encounters precipitation and humid weather such as rain or snow, the pollution layer is gradually wetted, and under the action of a strong electric field, surface discharge is formed, which may further trigger flashover, and even cause large-scale power outages. In recent years, the frequency of power supply accidents caused by insulator flashover has been increasing continuously. A large number of insulators are installed along the poles in a single power supply section of the catenary. When a power supply section outage is caused by flashover, maintenance personnel need to quickly locate the fault position. However, the error of the discharge position estimated by the protection device is relatively large, and the on-site troubleshooting process takes a lot of time, directly affecting the train operation safety of the railway.

[0003] Currently, the railway management department conducts investigations on all pollution sources within 2 kilometers around every year, and uses methods such as the equivalent salt deposit density method (ESDD, Equivalent Salt Deposit Density) to estimate the pollution level of insulators in the electrified section, and then determines the insulator cleaning cycle under different pollution conditions. This method has a certain degree of scientificity and operability. However, for the complex and changeable natural and electromagnetic environment where the catenary is located, real-time monitoring cannot be achieved, and there are relatively large potential safety hazards during the detection cycle. Summary of the Invention

[0004] In view of this, the present invention provides a method and system for monitoring and positioning the surface discharge of catenary insulators to solve the problem in the prior art that real-time monitoring of insulator pollution cannot be achieved and there are relatively large potential safety hazards during the detection cycle.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for monitoring and positioning the surface discharge of catenary insulators includes the following steps:

[0007] Step 1: Install the microphone sampling module on the shoulder connection pipe fitting at the middle position of the catenary wrist arm insulator base, so that the plane of the microphone sampling module is parallel to the plane formed by the wrist arm poles.

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

[0009] Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In this three-dimensional coordinate system, the direction perpendicular to the plane formed by the center of the microphone sampling module and 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 of the surface discharge of the railway insulator, and set the acquisition frequency range of the microphone acquisition module according to the obtained frequency range;

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

[0012] The specific steps of Step 4 include the following steps:

[0013] 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 Fourier transform on the signals detected by each microphone to obtain the frequency-domain representation of the signals; The specific steps of Step 4.1 include the following steps:

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

[0015] Step 4.12: Calculate the time delay of the signal reaching 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, θ represents the incident angle of the sound source, p m =[p xm , p ym , p zm is the spatial coordinate of the m-th microphone, c is the speed of sound, and v T (θ) represents the transpose of the unit vector in the direction of the sound source;

[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] where s m(t) represents the signal detected by the m-th microphone at time t;

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

[0022]

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

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

[0025] The specific steps of Step 4.2 include the following steps:

[0026] Step 4.21: Represent the signals of each microphone in vector form, as shown in the following formula:

[0027]

[0028] where X s (ω) is a column vector composed of the signals S m (ω) received by each microphone;

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

[0030]

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

[0032]

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

[0034] Step 4.3: Set a threshold value to 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 , determine the discharge position:

[0036] where s represents the distance of the discharge position from the center of the array coordinates, and α0 and β0 represent the angular parameters of the sound source direction.

[0037] Step 5: Generate a fault alarm based on the discharge point position coordinates in Step 4 and in combination with the set threshold criterion, transmit the fault alarm data to the railway power dispatching center in real time, and arrange a disposal process after comprehensive analysis and judgment.

[0038] A monitoring and positioning system for the surface discharge of catenary 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, and the multiple microphones are randomly distributed on the same substrate. Each microphone and the image sampling module are respectively connected to the core board, and the peripheral module and the power supply module are respectively connected to the core board.

[0039] Preferably, the sampling module further includes an FPGA. 128 microphones are respectively connected to the FPGA, and the FPGA is connected to the core board. The image acquisition module includes a camera, and the camera is connected to the core board through MIPI.

[0040] Preferably, the peripheral module includes a TF card, an RJ45, and a USB. The TF card, the RJ45, and the USB are respectively connected to the core board.

[0041] Preferably, the power supply module includes an input power supply and four buck circuits. The four buck circuits are a 5V buck circuit, a 4V buck circuit, a 3.3V buck circuit, and a 1.8V buck circuit. The input ends of the four buck circuits are respectively connected to the input power supply;

[0042] The core board is connected with a display module through an MIPI transmission interface.

[0043] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are:

[0044] In the present invention, a method and system for monitoring and positioning the surface discharge of catenary insulators are proposed. A random array composed of silicon crystal microphones is used to monitor the surface discharge of insulators. The beamforming algorithm of delay and sum for the multi-microphone random array is studied, and the supporting positioning software is developed, realizing functions such as real-time monitoring and abnormal alarm of the surface discharge of insulators, which has certain engineering value and practical significance. Brief Description of the Drawings

[0045] The present invention will be described by way of examples with reference to the accompanying drawings, where:

[0046] Figure 1 is the distribution diagram of the microphones and cameras of the present invention on the substrate;

[0047] Figure 2 is the schematic diagram of the installation position of the random microphone array of the present invention and the establishment of the coordinate system;

[0048] Figure 3 is the schematic diagram of the working process and disposal principle in Embodiment 1 of the present invention;

[0049] Figure 4 is the overall framework diagram of Embodiment 2 of the present invention;

[0050] Figure 5 is the circuit diagram of the camera of the present invention;

[0051] Figure 6 is the installation schematic diagram of the microphone of the present invention;

[0052] Among them: 1 - microphone acoustic wave collection hole, 2 - camera acquisition hole, 3 - substrate, 4 - shoulder bracket, 5 - connecting pipe, 6 - microphone sampling module. Detailed Embodiments

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0054] Therefore, the detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0055] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0056] It should be noted that like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0057] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0058] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0059] Embodiment 1

[0060] As Figures 1 - 6 shown, a method for monitoring and positioning the surface discharge of a catenary insulator is disclosed in an embodiment of the present invention, including the following steps:

[0061] Step 1: Install the microphone sampling module 6 on the connecting pipe 5 of the shoulder bracket 4 at the middle position of the base of the catenary insulator on the boom, with the distance set to 2 m, so that the plane of the microphone sampling module is parallel to the plane formed by the boom struts, as Figure 2 shown;

[0062] The microphone sampling module includes 128 microphones randomly distributed. The 128 microphones are divided into 16 groups, and the 8 microphones in each group are randomly arranged with respect to each other, as Figure 1 shown.

[0063] Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In the three-dimensional coordinate system, the direction perpendicular to the plane formed by the boom struts at the center of the microphone sampling module is the y-axis, and the horizontal direction and the vertical direction perpendicular to the y-axis are the x-axis and the z-axis respectively;

[0064] Step 3: Obtain the frequency range of the ultrasonic signal of the surface discharge of the railway insulator, and set the acquisition frequency range of the microphone acquisition module according to the obtained frequency range;

[0065] Step 4: Detect the ultrasonic signal generated by the surface discharge of the insulator through the microphone sampling module, use the random array delay and sum beamforming algorithm to sum the spatial energy of the sound source, determine the angle at which the energy sum is the largest as the incident angle, and then calculate the position coordinates of the partial discharge point based on the fixed installation distance of the microphone sampling module;

[0066] The specific steps of Step 4 are as follows:

[0067] 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 Fourier transform on the signals detected by each microphone to obtain the frequency domain representation of the signals; The specific steps of Step 4.1 are as follows:

[0068] Step 4.11: Detect the ultrasonic signal generated by the surface discharge of the insulator through the microphone sampling module;

[0069] Step 4.12: Calculate the time delay of the signal reaching each microphone, as shown in the following formula:

[0070]

[0071] where τ m (θ) represents the time delay of the signal reaching the mth microphone, θ represents the incident angle of the sound source, p m =[p xm , p ym , p zm is the spatial coordinate of the mth microphone, c is the speed of sound, v T (θ) represents the transpose of the unit vector in the direction of the sound source;

[0072] Step 4.13: Obtain the signal observed by the mth microphone, as shown in the following formula:

[0073] s m (t)=s[t - τ m (θ)]

[0074] where s m (t) represents the signal detected by the mth microphone at time t;

[0075] Step 4.14: Perform Fourier transform on the signals detected by each microphone to obtain the frequency domain representation of the signals, as shown in the following formula:

[0076]

[0077] where S m (ω) represents the representation of the signal detected by the mth microphone in the frequency domain, represents the integral of time t from negative infinity to positive infinity, e-jωτ represents a complex exponential function, where \(j\) is the imaginary unit and \(\omega\) is the angular frequency.

[0078] Step 4.2: Represent the signals of each microphone in vector form, determine the angle at which the sum of energies is maximum as the incident angle, establish a signal model, and perform linear time-invariant filtering and summation on the collected data to obtain the beam output;

[0079] The specific steps of Step 4.2 are as follows:

[0080] Step 4.21: Represent the signals of each microphone in vector form as shown in the following equation:

[0081]

[0082] where \(X\) s (\(\omega\)) is a column vector composed of the signals \(S\) m (\(\omega\)) received by each microphone;

[0083] Step 4.22: Determine the angle at which the sum of energies is maximum as the incident angle \(\theta\), and establish a signal model as shown in the following equation:

[0084]

[0085] Step 4.23: Perform linear time-invariant filtering and summation on the collected data to obtain the beam output as shown in the following equation:

[0086]

[0087] where \(Y\) s (\(\theta\)) represents the beam output, \(X\) s T (\(\omega\)) represents the transpose of the signal vector \(X\) s (\(\omega\)) received by the microphone array, and \(\varepsilon\) * (\(\theta\)) represents the complex conjugate of the phase vector \(\varepsilon(\theta)\).

[0088] Step 4.3: Set a threshold value to filter out noise interference, and determine the discharge position based on the beam output.

[0089] The specific steps of Step 4.3 include: setting a threshold value \(Y\) M , and when \(Y\) s (\(\theta_0\)) \(\geq Y\) M , determine the discharge position:

[0090] where \(s\) represents the distance of the discharge position from the center of the array coordinates, and \(\alpha_0\) and \(\beta_0\) represent the angular parameters of the sound source direction.

[0091] Step 5: Generate a fault alarm based on the discharge point position coordinates in Step 4 and in combination with the set threshold criterion, and transmit the fault alarm data to the railway power dispatching center in real time. After comprehensive analysis and judgment, arrange the disposal process. As Figure 3 shown, install the monitoring and positioning device for the surface discharge of catenary insulators in key polluted areas along the railway to conduct key monitoring on the insulators. When abnormal surface discharge occurs, timely transmit the abnormal alarm and position information to the power dispatching center through the optical and electrical transceiver connected to the railway communication network. The power dispatching center conducts comprehensive analysis based on the alarm data, issues a disposal order to the nearest catenary team, and commands the catenary workers to go to the site for disposal.

[0092] Embodiment 2

[0093] As Figure 4 shown, this embodiment proposes a monitoring and positioning system for the surface discharge of catenary insulators, including 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, and the multiple microphones are randomly arrayed on the same plane. Each microphone and the image sampling module are respectively connected to the core board.

[0094] The peripheral module and the power supply module are respectively connected to the core board.

[0095] In this embodiment, the microphone can collect the high-frequency sound waves generated by the surface discharge of the insulator, so as to detect the insulator. In the present invention, the microphone is 2 m away from the insulator. Therefore, the sound waves generated by the surface discharge of the insulator are approximately plane waves, and the microphone is for far-field sound pickup. In addition, the microphones are all MEMS silicon digital microphones, model SPH0641LU4H. The sampling frequency of this microphone is an ultrasonic signal of 20 Hz - 80 KHz. The microphones are all arranged on the planar substrate 3 and are randomly arrayed. This random distribution can improve the spatial resolution and make the detection more accurate; in this embodiment, the core board uses RK3588.

[0096] In another embodiment, the microphone sampling module includes 128 microphones. The 128 microphones are divided into 16 groups, and the 16 groups of microphones are evenly distributed on the substrate 3. The 8 microphones in each group are randomly arranged with each other. The microphones show the characteristics of random and uniform distribution on the substrate 3. The uniform distribution means that the 16 groups of microphones are evenly distributed on the substrate 3. Specifically, 128 microphone sound wave collection holes 1 are randomly and evenly opened on the substrate 3, and one microphone is arranged in each microphone sound wave collection hole 1 to prevent the microphones from being concentrated in a certain area of the substrate 3, thereby reducing the detection accuracy; the random distribution means that the microphones within each group are randomly distributed, so as to form a uniform and random distribution as a whole, making the detection accuracy higher.

[0097] In another embodiment, the distance between two adjacent ones of the microphones is 15 ± 1 mm, and the 128 microphones are evenly and randomly distributed within a circle with a diameter of 150 mm on the substrate 3.

[0098] In another embodiment, the distance between two adjacent ones of the microphones is 15 mm. 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 at the far-field distance. That is, in the present invention, if the wavelength is λ, the microphone spacing is d, and the sound velocity is c, then the distance s from the discharge position to the center of the array coordinates is roughly estimated by the following formula. It should be noted that this formula is an existing formula:

[0099]

[0100] In this embodiment, while ensuring that the 128 microphones are within a circle with a diameter of 150 mm on the substrate and at the far-field distance, the distance between two adjacent microphones is selected to be 15 mm. Through a large number of on-site test analyses of the ultrasonic characteristics of the surface discharge of railway insulators, it is obtained that the ultrasonic signals of the surface discharge of the insulators are mainly distributed in the range of 25 kHz ± 3 kHz. Therefore, taking the sound velocity c as 340 m / s and d as 15 mm, s = 3.7×10 4 , which is much larger than the 2000 mm between the microphone and the insulator. Therefore, it is ensured that the distribution area of the microphones is within a circle with a diameter of 150 mm and at the far-field distance.

[0101] In this embodiment, the sampling module further includes an FPGA. The 128 microphones are respectively connected to the FPGA, the FPGA is connected to the core board. The DAT pin and the CLK pin of the microphone are respectively connected to the corresponding PDM_DAT and PDM_CLK pins on the FPGA, and output PDM digital signals and clock signals respectively. A capacitor is connected in parallel between the microphone VDD and GND for filtering. The L / R pins of two adjacent microphones in the same group are respectively connected to the 3.3V power supply and the power supply negative electrode GND or the power supply negative electrode GND and the 3.3V power supply.

[0102] The GMAC1 pins on the RK3588 core board are connected to the corresponding FIO pins on the FPGA. Specifically, the 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, GMAC1_MDC, GMAC1_MDIO, and GMAC1_RSTn_L pins of the RK3588 core board are connected to the 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 of the FPGA respectively. In this embodiment, the FPGA serves as an intermediate processing unit, undertaking key tasks such as signal acquisition, real-time processing, and protocol conversion.

[0103] In this embodiment, the image acquisition module includes a camera, and the circuit diagram of the camera is as Figure 5 shown. The camera is connected to the core board through MIPI low-voltage differential signals. There is a camera acquisition hole 2 in the center of the substrate 3. The camera is disposed in the camera acquisition hole 2, and the microphone is distributed around the camera. The camera uses an OV5695 camera, which is used to acquire graphic signals. The RK3588 core board is connected to the corresponding interface of the camera through the MIPI_CSI interface.

[0104] In this embodiment, the peripheral module includes a TF card, an RJ45, and a USB. The TF card, RJ45, and the USB are respectively connected to the core board. The TF card is used for local storage of data, the RJ45 is used for remote monitoring, and the USB is used to connect external devices to export data. The TF card is connected to the corresponding SDMMC pins of the RK3588 core board. The RK3588 core board externally connects a PHY chip through the GMAC pins. The PHY chip uses RTL8211F, and the PHY chip is responsible for digital-to-analog conversion. The RJ45 is connected to the corresponding PHY0 pins of the PHY chip. In this embodiment, there are two USB interfaces, and the RK3588 core board is connected to the USB interface through the TYPEC0 pins.

[0105] In this embodiment, the power supply module includes an input power supply and 4 buck circuits. The 4 buck circuits are a 5V buck circuit, a 4V buck circuit, a 3.3V buck circuit, and a 1.8V buck circuit respectively. The input ends of the 4 buck circuits are respectively connected to the input power supply, and the output ends are connected to components to meet the requirements of each component.

[0106] In this embodiment, the core board is connected to a display module through a MIPI transmission interface. The display module is an LCD high-definition touch screen, which realizes function setting and detection data display.

[0107] In this embodiment, the settings of the peripheral module, the voltage division circuit, the RK3588 core board, the FPGA, the OV5695 camera, and the external display module are all prior arts. The structures of each module and the circuit connection relationships with the RK3588 core board will not be elaborated herein.

[0108] The circuits, electronic components, and modules involved are all prior arts, which can be fully realized by those skilled in the art without further elaboration. The content protected by the present invention does not involve improvements to software and methods either.

[0109] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0110] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for monitoring and positioning the surface discharge of an overhead contact line insulator, characterized in that It includes the following steps: Step 1: Install the microphone sampling module on the connecting pipe of the bottom shoulder bracket of the catenary arm insulator, and make the plane of the microphone sampling module parallel to the plane formed by the arm struts; Step 2: Construct a three-dimensional coordinate system with the microphone sampling module as the center. In the three-dimensional coordinate system, the direction perpendicular to the plane formed by the arm struts at the center of the microphone sampling module 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 of the railway insulator surface discharge, and set the acquisition frequency range of the microphone acquisition module according to the obtained frequency range; Step 4: Detect the ultrasonic signal generated by the insulator surface discharge through the microphone sampling module, use the random array delay and sum beamforming algorithm to sum the spatial energy of the sound source, determine the angle at which the energy sum is the largest as the incident angle, and then calculate the local discharge point position coordinates based on the fixed installation distance of the microphone sampling module; Step 5: Generate a fault alarm based on the discharge point position coordinates in Step 4 and in combination with the set threshold criterion, and transmit the fault alarm data to the railway power dispatching center in real time.

2. The monitoring and positioning method for the surface discharge of a catenary insulator according to claim 1, characterized in that The microphone sampling module includes 128 microphones arranged in a random uniform distribution.

3. A method for monitoring and positioning the surface discharge of a catenary insulator according to claim 2, characterized in that, The specific steps of Step 4 are as follows: Step 4.1: Detect the ultrasonic signal generated by the insulator surface discharge through the microphone sampling module, calculate the time delay of the signal reaching each microphone, and perform Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal; Step 4.2: Represent the signals of each microphone in vector form, determine the angle at which the energy sum is the largest as the incident angle, establish a signal model, and perform linear time-invariant filtering and summation on the collected data to obtain the beam output; Step 4.3: Set a threshold value to filter out noise interference, and determine the discharge position according to the beam output.

4. A method for monitoring and positioning the surface discharge of a catenary insulator according to claim 3, characterized in that The specific steps of Step 4.1 are as follows: Step 4.11: Detect the ultrasonic signal generated by the insulator surface discharge through the microphone sampling module; Step 4.12: Calculate the time delay of the signal reaching each microphone, as shown in the following formula: where τ m (θ) represents the time delay of the signal arriving at the m-th microphone, θ represents the incident angle of the sound source, p m = [p xm , p ym , p zm is the spatial coordinate of the m-th microphone, c is the speed of sound, v T (θ) represents the transpose of the unit vector in the direction of the sound source; Step 4.13: Obtain the signal observed by the mth microphone, as shown in the following formula: s m s(t) = s[t - τ m (θ)] where s m (t) represents the signal detected by the m-th microphone at time t; Step 4.14: Perform Fourier transform on the signal detected by each microphone to obtain the frequency domain representation of the signal, as shown in the following formula: Among them, S m ($\omega$) represents the representation of the signal detected by the m-th microphone in the frequency domain, represents the integral of time t from negative infinity to positive infinity, e -jωτ represents the complex exponential function, where j is the imaginary unit and $\omega$ is the angular frequency.

5. The monitoring and positioning method for the surface discharge of a catenary insulator according to claim 4, characterized in that, The specific steps of Step 4.2 are as follows: Step 4.21: Represent the signals of each microphone in vector form, as shown in the following formula: Among them, X s The column vector composed of the signals S m (ω) received by each microphone; Step 4.22: Determine the angle at which the energy sum is the largest as the incident angle θ, and establish a signal model, as shown in the following formula: Step 4.23: Perform linear time-invariant filtering and summation on the collected data to obtain the beam output, as shown in the following formula: Among them, Y s (θ) represents the beam output, represents the transpose of the signal vector X s (ω) received by the microphone array, and ε * (θ) represents the complex conjugate of the phase vector ε(θ).

6. A monitoring and positioning method for the surface discharge of a catenary insulator according to claim 5, characterized in that Step 4.3 specifically includes: setting a threshold value Y M , when Y S (θ0) ≥ Y M , determine the discharge position: where s represents the distance from the discharge position to the center of the array coordinates, and α0 and β0 represent the angle parameters of the sound source direction.

7. A monitoring and positioning system for the surface discharge of catenary insulators, characterized in that, A method for monitoring and positioning the surface discharge of a catenary insulator as described in claims 1-6, comprising: 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 a plurality of microphones randomly distributed on the same substrate. Each microphone and the image sampling module are respectively connected to the core board. The peripheral module and the power supply module are respectively connected to the core board.

8. The monitoring and positioning system for the surface discharge of a catenary insulator according to claim 7, characterized in that, The sampling module further includes an FPGA. 128 microphones are respectively connected to the FPGA, and the FPGA is connected to the core board. The image acquisition module includes a camera, and the camera is connected to the core board through MIPI.

9. The on - surface discharge detection and positioning system for catenary insulators according to claim 7, characterized in that: The peripheral module includes a TF card, an RJ45, and a USB. The TF card, the RJ45, and the USB are respectively connected to the core board.

10. A catenary insulator surface discharge detection and positioning system according to claim 7, characterized in that: The power supply module includes an input power supply and four buck circuits, namely a 5V buck circuit, a 4V buck circuit, a 3.3V buck circuit, and a 1.8V buck circuit. The input ends of the four buck circuits are respectively connected to the input power supply. The core board is connected to a display module through a MIPI transmission interface.

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