Converter transformer valve side outgoing line device ultrasonic partial discharge measurement and positioning method

Abstract

The application discloses a kind of converter valve side outlet device ultrasonic partial discharge measurement and positioning method, comprising: arranging multidimensional non-coplanar ultrasonic sensor array on the surface of the outer wall of the equipment to be measured, the original ultrasonic waveform signal of each sensor is synchronously collected and processed, and pure local discharge ultrasonic pulse signal is obtained;According to the arrival time of the pure local discharge ultrasonic pulse signal of each channel determined, the relative time delay difference value between each sensor is calculated;According to the time difference relationship established between the local discharge source space coordinates and the propagation distance between each sensor, the theoretical delay difference value of each sensor relative to reference sensor is obtained;According to the relative time delay difference value and the theoretical time delay difference value, construct time delay residual sum of squares objective function;Local discharge source space coordinates and equivalent comprehensive sound speed are taken as common variables to be solved, four-dimensional optimization characteristic space is established, global iterative search is carried out to minimize objective function, and finally local discharge source three-dimensional space coordinates and equivalent comprehensive sound speed correction value are output.

Description

Technical Field

[0001] This invention relates to the field of converter transformer condition monitoring technology, and more specifically, to a method for measuring and locating ultrasonic partial discharge in a converter transformer valve-side outgoing line device. Background Technology

[0002] Converter transformers are core equipment in high-voltage direct current (HVDC) transmission systems, and their safety and stability directly affect the safe operation of the entire power system. Their valve-side outgoing line devices have a complex structure, bearing the combined effects of AC / DC superimposed voltages and steep-front impulse voltages, resulting in an extremely complex insulation electric field distribution. During long-term operation, partial discharge can easily occur inside the valve-side outgoing line device due to insulation aging, manufacturing defects, or mechanical vibration.

[0003] Existing partial discharge detection methods (pulse current method, high frequency method, ultra-high frequency method) suffer from difficulties in deployment and low measurement sensitivity when faced with the complex structure and electromagnetic environment of the converter transformer valve-side outgoing wiring device. In addition, the valve-side outgoing wiring device usually extends into the valve hall or adopts a special shielding structure, making it difficult for conventional fixed-point detection methods to achieve accurate spatial positioning.

[0004] Ultrasonic testing utilizes the mechanical acoustic waves generated by partial discharge, offering the advantage of immunity to strong electromagnetic interference. Currently, however, technical bottlenecks remain in measuring and locating partial discharge in converter transformer valve-side outgoing line devices with unique structures: firstly, the thick insulation and shielding within the outgoing line device cause severe reflection and attenuation of ultrasonic waves, posing a challenge for partial discharge measurement under conditions of strong attenuation and low signal-to-noise ratio; secondly, the arrangement of the sensor array within the outgoing line device to achieve spatial localization of partial discharge. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for measuring and locating ultrasonic partial discharge in a converter valve side outlet device.

[0006] According to one aspect of the present invention, a method for ultrasonic partial discharge measurement and positioning of a converter valve side output device is provided, comprising: A multidimensional non-coplanar ultrasonic sensor array is arranged on the outer surface of the device under test, and the original ultrasonic wave signals of each sensor are collected synchronously. The original ultrasonic wave signal is processed to obtain a clean partial discharge ultrasonic pulse signal; Based on the arrival time of the determined pure partial discharge ultrasonic pulse signal for each channel, the relative time delay difference between each sensor is calculated. Based on the known spatial coordinates of each sensor, a time difference relationship is established according to the spatial coordinates of the partial discharge source and the propagation distance between each sensor, so as to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. Based on the difference between relative and theoretical time delay, construct an objective function for the sum of squared time delay residuals. By treating the spatial coordinates of the partial discharge source and the equivalent composite sound velocity as common variables to be solved, a four-dimensional optimization feature space is established. An improved particle swarm optimization algorithm is used to perform a global iterative search to minimize the objective function, and finally, the corrected values ​​of the three-dimensional spatial coordinates and equivalent composite sound velocity of the partial discharge source are output.

[0007] Optionally, the multidimensional non-coplanar ultrasonic sensor array is arranged as follows: a multidimensional non-coplanar sensor array consisting of multiple high-sensitivity piezoelectric ultrasonic sensors is arranged on the outer wall surface of the converter valve side outlet device.

[0008] Optionally, the outer wall surface includes the cable riser, corner, and sleeve root; the number of ultrasonic sensors shall not be less than 5, and their spatial arrangement must avoid being on the same plane.

[0009] Optionally, the original ultrasonic wave signal is processed to obtain a clean partial discharge ultrasonic pulse signal, including: The original ultrasonic waveform signal is adaptively decomposed into several narrowband eigenmode function components using a variational mode decomposition algorithm. Based on the center frequency, energy ratio, and correlation coefficient with the partial discharge reference template signal of each intrinsic mode function component, a comprehensive judgment is made to remove the intrinsic mode function components corresponding to low-frequency mechanical vibration and stray noise, and retain the partial discharge characteristic components. The retained partial discharge characteristic components are subjected to wavelet packet soft thresholding denoising and signal reconstruction to obtain a clean partial discharge ultrasonic pulse signal with high signal-to-noise ratio.

[0010] Optionally, based on the determined arrival times of the pure partial discharge ultrasonic pulse signals for each channel, the relative time delay difference between each sensor is calculated, including: The initial trigger wavefront of the pure partial discharge ultrasonic signal in each channel is captured by the waveform leading edge energy integration method, the arrival time of each channel signal is initially determined, and the first time delay deviation is obtained based on the arrival time. Using the earliest triggered sensor channel as the reference channel, the signals of the other channels are subjected to generalized cross-correlation operation with the reference channel signal of the reference channel to obtain the cross-correlation function between each channel signal and the reference channel signal; Based on the time offset corresponding to the maximum peak value of the cross-correlation function, the second time delay difference of each sensor relative to the reference sensor is determined in combination with the sampling rate. When the difference between the first delay difference and the second delay difference is within a preset error range, the second delay difference is taken as the relative delay difference.

[0011] Optionally, the expression for calculating the second time delay difference is: In the formula, For the first The time delay difference between each sensor and the reference sensor. and The first The location of the peak sampling point of the signal corresponding to each sensor and the reference sensor. This represents the ultrasonic signal sampling rate.

[0012] Optionally, theoretical delay difference The calculation expression is: in, In the formula, For the source of the bureau to the first The propagation distance of each sensor The propagation distance from the partial discharge source to the reference sensor, For the equivalent combined speed of sound, Let be the position coordinates of the i-th sensor.

[0013] Optionally, the objective function The expression is: In the formula, For the first i The relative time delay difference between the sensors, For the first i The theoretical time delay difference of each sensor; x , y , z () represents the spatial coordinates of the local emission source. For the equivalent combined speed of sound, N This represents the number of sensors.

[0014] According to another aspect of the present invention, an ultrasonic partial discharge measurement and positioning device for a converter valve side output device is provided, comprising: The acquisition module is used to arrange a multi-dimensional non-coplanar ultrasonic sensor array on the outer surface of the device under test and simultaneously acquire the original ultrasonic wave signals of each sensor. The acquisition module is used to process the original ultrasonic wave signal to obtain a pure partial discharge ultrasonic pulse signal; The calculation module is used to calculate the relative time delay difference between each sensor based on the arrival time of the determined pure partial discharge ultrasonic pulse signal of each channel; A module is established to establish a time difference relationship between the spatial coordinates of each sensor and the propagation distance between the spatial coordinates of the partial discharge source and each sensor, based on the known spatial coordinates of each sensor, and to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. The module is used to construct the objective function of the sum of squared residuals based on the difference between the relative delay and the theoretical delay. The output module is used to establish a four-dimensional optimization feature space by taking the spatial coordinates of the partial discharge source and the equivalent comprehensive sound velocity as common variables to be solved. An improved particle swarm optimization algorithm is used to perform a global iterative search to minimize the objective function, and finally outputs the corrected values ​​of the three-dimensional spatial coordinates and the equivalent comprehensive sound velocity of the partial discharge source.

[0015] According to another aspect of the present invention, a computer-readable storage medium is provided, the storage medium storing a computer program for performing the methods described in any of the above aspects of the present invention.

[0016] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising: a processor; a memory for storing executable instructions of the processor; the processor being configured to read the executable instructions from the memory and execute the instructions to implement the method described in any of the preceding aspects of the present invention.

[0017] Therefore, this invention systematically solves the problems of weak partial discharge signal extraction and large spatial positioning deviation in converter transformer valve-side outgoing devices under extreme operating conditions by constructing a multi-dimensional integrated partial discharge measurement and positioning system of "non-coplanar array layout - adaptive joint noise reduction - sound velocity coordinate decoupling optimization". The multi-dimensional non-coplanar sensor array topology breaks the geometric degradation of the confined space and effectively avoids the ill-conditioned solution and singularity risks caused by traditional planar layout. The variational mode decomposition and wavelet packet joint noise reduction mechanism realizes the accurate reconstruction of narrowband modes, eliminates the spurious peak interference caused by strong mechanical vibration and cooling noise in advance, and ensures the accurate extraction of feature time delay under low signal-to-noise ratio. The four-dimensional global optimization algorithm of equivalent sound velocity and spatial coordinate realizes the adaptive correction of dynamic sound field, eliminates the sound velocity error caused by internal thick insulating heterogeneous interface and temperature rise oil flow circulation, and provides a quantitative evaluation basis for the measurement and accurate spatial positioning of weak signals of partial discharge sources in the oil immersion and AC / DC superimposed voltage environment of valve-side outgoing devices. Attached Figure Description

[0018] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures: Figure 1 This is a flowchart illustrating the ultrasonic partial discharge measurement and positioning method for a converter valve side output device provided in an exemplary embodiment of the present invention. Figure 2 This is another flowchart illustrating the ultrasonic partial discharge measurement and positioning method for the converter valve side output device provided in an exemplary embodiment of the present invention. Figure 3 This is a schematic diagram of a spatial positioning system based on sound velocity correction in complex media, provided by an exemplary embodiment of the present invention. Figure 4 This is a schematic diagram of the ultrasonic partial discharge measurement and positioning device for the converter valve side output device provided in an exemplary embodiment of the present invention. Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. Detailed Implementation

[0019] Hereinafter, exemplary embodiments according to the present invention will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments of the present invention. It should be understood that the present invention is not limited to the exemplary embodiments described herein.

[0020] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention.

[0021] Those skilled in the art will understand that the terms "first," "second," etc., in the embodiments of the present invention are only used to distinguish different steps, devices, or modules, and do not represent any specific technical meaning, nor do they indicate a necessary logical order between them.

[0022] It should also be understood that in the embodiments of the present invention, "multiple" can refer to two or more, and "at least one" can refer to one, two or more.

[0023] It should also be understood that any component, data or structure mentioned in the embodiments of the present invention can generally be understood as one or more unless explicitly defined or given contrary instructions in the context.

[0024] Furthermore, the term "and / or" in this invention is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this invention generally indicates that the preceding and following related objects have an "or" relationship.

[0025] It should also be understood that the description of the various embodiments in this invention emphasizes the differences between the various embodiments, and the similarities or similarities can be referred to each other. For the sake of brevity, they will not be described in detail.

[0026] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0027] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0028] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0029] 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 discussed further in subsequent figures.

[0030] The embodiments of this invention can be applied to electronic devices such as terminal devices, computer systems, and servers, and can operate together with a wide range of other general-purpose or special-purpose computing system environments or configurations. Well-known examples of terminal devices, computing systems, environments, and / or configurations suitable for use with electronic devices such as terminal devices, computer systems, and servers include, but are not limited to: personal computer systems, server computer systems, thin clients, thick clients, handheld or laptop devices, microprocessor-based systems, set-top boxes, programmable consumer electronics, network PCs, minicomputer systems, mainframe computer systems, and distributed cloud computing environments including any of the above systems, etc.

[0031] Electronic devices such as terminal devices, computer systems, and servers can be described in the general context of computer system executable instructions (such as program modules) executed by a computer system. Typically, program modules can include routines, programs, object programs, components, logic, data structures, etc., which perform specific tasks or implement specific abstract data types. Computer systems / servers can be implemented in distributed cloud computing environments, where tasks are executed by remote processing devices linked through communication networks. In distributed cloud computing environments, program modules can reside on local or remote computing system storage media, including storage devices.

[0032] Exemplary methods Figure 1 This is a schematic flowchart illustrating the ultrasonic partial discharge measurement and positioning method for a converter valve-side output device according to an exemplary embodiment of the present invention. This embodiment can be applied to electronic devices, such as… Figure 1 As shown, the ultrasonic partial discharge measurement and positioning method 100 for the converter valve side output device includes the following steps: Step 101: Arrange a multi-dimensional non-coplanar ultrasonic sensor array on the outer wall surface of the device under test, and synchronously collect the original ultrasonic wave signals of each sensor. Step 102: Process the original ultrasonic wave signal to obtain a clean partial discharge ultrasonic pulse signal; Step 103: Calculate the relative time delay difference between each sensor based on the determined arrival time of the pure partial discharge ultrasonic pulse signal for each channel; Step 104: Based on the known spatial coordinates of each sensor, establish the time difference relationship between the spatial coordinates of the partial discharge source and the propagation distance between each sensor to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. Step 105: Construct the objective function of the sum of squared residuals of time delay based on the difference between relative and theoretical time delays; Step 106: Using the spatial coordinates of the partial discharge source and the equivalent composite sound velocity as common variables to be solved, a four-dimensional optimization feature space is established. An improved particle swarm optimization algorithm is used to perform a global iterative search to minimize the objective function. Finally, the corrected values ​​of the three-dimensional spatial coordinates and equivalent composite sound velocity of the partial discharge source are output.

[0033] Specifically, the present invention aims to solve the problem of partial discharge measurement and positioning of the valve-side outlet device of converter transformer in the prior art, and provides an ultrasonic partial discharge measurement and positioning method for converter transformer valve-side outlet device with strong anti-interference ability, high measurement sensitivity and accurate positioning.

[0034] This invention proposes an ultrasonic partial discharge measurement and positioning method for converter valve side output devices. It aims to solve the problems of the complex structure of converter valve side output devices, the superimposed AC and DC electric fields, and the strong electromagnetic interference caused by frequent phase commutation of the converter valve. These problems lead to the traditional ultrasonic positioning method having weak signals that are difficult to extract, large sound velocity errors, and ill-conditioned solutions to equations in complex heterogeneous media, resulting in insufficient positioning accuracy.

[0035] This invention provides a method for measuring and locating ultrasonic partial discharge in a converter valve side outlet device. The method mainly includes optimized layout of the ultrasonic sensor array, adaptive extraction of weak partial discharge signals, accurate calculation of the characteristic time delay (TDOA), and spatial positioning based on sound velocity correction in complex media. The process is attached. Figure 2 As shown.

[0036] The optimized layout of the ultrasonic sensor array mainly involves arranging a multi-dimensional non-coplanar sensor array composed of multiple high-sensitivity piezoelectric ultrasonic sensors on the outer wall surface of the converter valve side outlet device (including the outlet riser, corner, and bushing root). The number of sensors must be no less than five, and their spatial arrangement must avoid being on the same plane to eliminate singularities when solving the positioning equations and ensure the uniqueness of the three-dimensional solution.

[0037] The adaptive extraction of the weak partial discharge signal is used to accurately extract the weak partial discharge ultrasonic pulse signal after it has been severely attenuated by a heterogeneous interface (such as a thick insulating cardboard or a voltage equalization ball shield) in the high mechanical noise, cooling system interference and strong electromagnetic environment of converter operation.

[0038] The adaptive extraction step of the weak partial discharge signal mainly includes: 1) The high dynamic range acquisition system synchronously triggers the acquisition of the original ultrasonic wave signals from each sensor at a sampling rate of not less than 2MS / s.

[0039] 2) The variational mode decomposition (VMD) algorithm is used to adaptively decompose the original signal into several narrowband intrinsic mode function (IMF) components.

[0040] 3) Based on the center frequency, energy ratio and correlation coefficient with the partial discharge reference template signal of each IMF component, a comprehensive judgment is made to remove the IMF components corresponding to low-frequency mechanical vibration and spurious noise, and retain the partial discharge characteristic components. For example, a low-frequency threshold is set, and those below the low-frequency threshold are removed.

[0041] 4) The retained high-frequency partial discharge characteristic components are subjected to wavelet packet (WPT) soft threshold denoising and signal reconstruction to obtain a clean partial discharge ultrasonic pulse signal with high signal-to-noise ratio.

[0042] The purpose of the precise calculation of the characteristic time delay (TDOA) is to accurately obtain the time difference between the arrival of the acoustic signal generated by the same partial discharge source at different sensors.

[0043] The precise calculation steps for the characteristic time delay (TDOA) mainly include: 1) The initial trigger wavefront of the pure partial discharge ultrasonic signal in each channel was captured using the waveform leading edge energy integration method to initially determine the arrival time; 2) Using the earliest triggered sensor channel as the reference channel, perform a generalized cross-correlation operation between the signals of the remaining channels and the reference channel signal to obtain the cross-correlation function between the signals of each channel. For the first... The relative time delay difference between each sensor channel and the reference channel is determined by the time offset corresponding to the maximum peak value of the cross-correlation function, i.e.: In the formula, For the first The time delay difference between each sensor and the reference sensor. and The first The location of the peak sampling point of the signal corresponding to each sensor and the reference sensor. This represents the ultrasonic signal sampling rate.

[0044] 3) Double-verify the arrival time of the initial wavefront determined by the waveform leading-edge energy integration method with the time delay result corresponding to the maximum peak value of the generalized cross-correlation function. When the time delay results obtained by the two methods meet the preset error range, the result is determined as the effective time delay difference value of the corresponding sensor; otherwise, the wavefront determination threshold or related calculation window is readjusted for correction, and finally the time delay difference value of each sensor relative to the reference sensor is obtained. The obtained time delay difference is used as the input parameter for subsequent spatial positioning algorithms to construct a set of nonlinear time difference positioning equations between the spatial coordinates of the partial discharge source and the propagation distance between the sensors.

[0045] The purpose of the spatial positioning based on sound velocity correction in complex media is to eliminate the influence of heterogeneous structures such as transformer oil and insulating paperboard inside the valve-side outlet device, as well as the dynamic non-uniform sound field caused by heat generation during operation, on positioning accuracy.

[0046] The spatial positioning steps based on sound velocity correction in complex media mainly include: 1) Obtain the known spatial coordinates of each sensor in the sensor array. The time delay difference between each sensor and the reference sensor obtained from the aforementioned characteristic time delay calculation steps is then used. As input parameters for spatial positioning calculations.

[0047] 2) Based on the location of the local emission source Establish time difference relationships with the propagation distances between each sensor. For the first... The theoretical time delay difference between each sensor and the reference sensor is expressed as: in, In the formula, For the source of the bureau to the first The propagation distance of each sensor The propagation distance from the partial discharge source to the reference sensor, The equivalent composite sound velocity of the medium inside the output device.

[0048] 3) The actual measured time delay difference value The difference between the theoretical time delay calculated based on the assumed partial discharge source coordinates and the equivalent synthesized sound velocity By comparison, an objective function for the sum of squared residuals with time delays is established: With objective function Minimize the source space coordinates as the optimization objective. With equivalent combined speed of sound As common variables to be solved, thus establishing Four-dimensional optimization feature space.

[0049] 4) Considering the complex sound propagation path formed by oil, insulating paperboard, and other structural materials inside the converter valve side outlet device, the equivalent comprehensive sound velocity is... The target speed is set within the range of 1350–1500 m / s, and an improved particle swarm optimization algorithm is introduced. A global iterative search is performed within the four-dimensional optimization feature space to optimize the objective function. Gradually decrease.

[0050] 5) When the objective function reaches the preset convergence threshold or the maximum number of iterations, output the optimal parameters that minimize the objective function. ,in The three-dimensional spatial coordinates of the local discharge power source inside the converter transformer valve side output device. This is the equivalent composite sound speed correction value that matches the actual propagation path.

[0051] The structure of the space positioning system based on sound velocity correction in complex media is shown in the appendix. Figure 3 As shown, the device mainly consists of an externally mounted ultrasonic sensor array, signal transmission cables, a multi-channel high-speed synchronous acquisition instrument, and a positioning and diagnostic host.

[0052] In a specific embodiment of the present invention, the test process uses an externally attached piezoelectric ultrasonic sensor array as the measurement and positioning object, and performs ultrasonic partial discharge measurement and spatial positioning on the valve side outlet device at the converter transformer site.

[0053] First, optimize the sensor array layout and confirm baseline performance. (According to the attached...) Figure 3 The spatial structure shown features five high-sensitivity piezoelectric ultrasonic sensors tightly attached to the outer wall surfaces of the converter valve side outlet riser, corner, and bushing root, forming a multi-dimensional non-coplanar sensor array to ensure that no four sensors are on the same plane. Before installation, the wall surfaces are cleaned of oil and coated with coupling agent. The coupling state and basic sensitivity of each sensor are verified to ensure consistent performance of the acquisition channels.

[0054] Next, the multi-channel high-speed synchronous acquisition instrument was activated to synchronously acquire the raw ultrasonic waveform signals from five sensor channels at a sampling rate of 2 MS / s. The acquisition instrument transmitted the high-sampling-rate data to the positioning and diagnostic host for adaptive extraction of weak partial discharge signals under strong interference environments. First, the original signal was adaptively decomposed into multiple narrowband IMF components using a variational mode decomposition algorithm. The center frequency, energy proportion, and correlation coefficient with the partial discharge template of each component were calculated to remove low-frequency mechanical vibrations and stray noise. Subsequently, wavelet packet soft thresholding denoising was performed on the retained high-frequency partial discharge characteristic components, and the signals were reconstructed to extract a clean partial discharge ultrasonic pulse signal with a high signal-to-noise ratio.

[0055] The next step is to accurately calculate the characteristic time delay (TDOA). The diagnostic host uses the waveform leading edge energy integration method to capture the initial trigger wavefront of the pure signal of each channel, and locks the earliest triggered sensor (such as S1) as the reference channel; the reconstructed signals of the other channels (S2~S5) are respectively subjected to generalized cross-correlation operation with the S1 signal, and the waveform leading edge and the peak value of the cross-correlation function are used for double verification to accurately calculate the time delay difference δti (i=2,3,4,5) of the other sensors relative to S1.

[0056] Finally, a spatial localization solution based on sound velocity correction in complex media is performed. The known sensor spatial coordinates and the extracted time difference δt are input into the localization algorithm. The equivalent combined sound velocity v, composed of transformer oil and insulating paperboard inside the valve-side outlet device, is used as an unknown variable. This, along with the partial discharge source spatial coordinates (x, y, z), constructs a four-dimensional optimization feature space of (x, y, z, v), where the optimization range of v is set to 1350 m / s to 1500 m / s. A fitness model is established with the objective function of minimizing the sum of the squared residuals between the measured time difference and the theoretically calculated time difference. An improved particle swarm optimization algorithm is introduced for global decoupling iterative optimization. When the fitness function converges to a set threshold, the optimal solution (x, y, z) and the corrected equivalent sound velocity v are output.

[0057] The above measurement and positioning process is now complete, enabling online detection and precise three-dimensional spatial positioning of partial discharge inside the converter transformer valve side outgoing device. This effectively guides the investigation of potential insulation hazards and maintenance decisions on-site.

[0058] Therefore, this invention systematically solves the problems of weak partial discharge signal extraction and large spatial positioning deviation in converter transformer valve-side outgoing devices under extreme operating conditions by constructing a multi-dimensional integrated partial discharge measurement and positioning system of "non-coplanar array layout - adaptive joint noise reduction - sound velocity coordinate decoupling optimization". The multi-dimensional non-coplanar sensor array topology breaks the geometric degradation of the confined space and effectively avoids the ill-conditioned solution and singularity risks caused by traditional planar layout. The variational mode decomposition and wavelet packet joint noise reduction mechanism realizes the accurate reconstruction of narrowband modes, eliminates the spurious peak interference caused by strong mechanical vibration and cooling noise in advance, and ensures the accurate extraction of feature time delay under low signal-to-noise ratio. The four-dimensional global optimization algorithm of equivalent sound velocity and spatial coordinate realizes the adaptive correction of dynamic sound field, eliminates the sound velocity error caused by internal thick insulating heterogeneous interface and temperature rise oil flow circulation, and provides a quantitative evaluation basis for the measurement and accurate spatial positioning of weak signals of partial discharge sources in the oil immersion and AC / DC superimposed voltage environment of valve-side outgoing devices.

[0059] Exemplary device Figure 4 This is a schematic diagram of the ultrasonic partial discharge measurement and positioning device for the converter valve side output device provided in an exemplary embodiment of the present invention. Figure 4As shown, the device 400 includes: The acquisition module 410 is used to arrange a multi-dimensional non-coplanar ultrasonic sensor array on the outer wall surface of the device under test and to synchronously acquire the original ultrasonic wave signals of each sensor. The acquisition module 420 is used to process the original ultrasonic wave signal to obtain a pure partial discharge ultrasonic pulse signal; The calculation module 430 is used to calculate the relative time delay difference between each sensor based on the determined arrival time of the pure partial discharge ultrasonic pulse signal of each channel. Module 440 is established to establish a time difference relationship between the spatial coordinates of each sensor and the propagation distance between the partial discharge source and each sensor based on the known spatial coordinates of each sensor, and to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. Module 450 is used to construct the objective function of the sum of squared residuals based on the difference between the relative delay and the theoretical delay. Output module 460 is used to establish a four-dimensional optimization feature space by taking the spatial coordinates of the partial discharge source and the equivalent comprehensive sound velocity as common variables to be solved, and to use an improved particle swarm optimization algorithm to perform a global iterative search to minimize the objective function. Finally, it outputs the corrected values ​​of the three-dimensional spatial coordinates and the equivalent comprehensive sound velocity of the partial discharge source.

[0060] Optionally, the multidimensional non-coplanar ultrasonic sensor array is arranged as follows: a multidimensional non-coplanar sensor array consisting of multiple high-sensitivity piezoelectric ultrasonic sensors is arranged on the outer wall surface of the converter valve side outlet device.

[0061] Optionally, the outer wall surface includes the cable riser, corner, and sleeve root; the number of ultrasonic sensors shall not be less than 5, and their spatial arrangement must avoid being on the same plane.

[0062] Optionally, the original ultrasonic wave signal is processed to obtain a clean partial discharge ultrasonic pulse signal, including: The original ultrasonic waveform signal is adaptively decomposed into several narrowband eigenmode function components using a variational mode decomposition algorithm. Based on the center frequency, energy ratio, and correlation coefficient with the partial discharge reference template signal of each intrinsic mode function component, a comprehensive judgment is made to remove the intrinsic mode function components corresponding to low-frequency mechanical vibration and stray noise, and retain the partial discharge characteristic components. The retained partial discharge characteristic components are subjected to wavelet packet soft thresholding denoising and signal reconstruction to obtain a clean partial discharge ultrasonic pulse signal with high signal-to-noise ratio.

[0063] Optionally, based on the determined arrival times of the pure partial discharge ultrasonic pulse signals for each channel, the relative time delay difference between each sensor is calculated, including: The initial trigger wavefront of the pure partial discharge ultrasonic signal in each channel is captured by the waveform leading edge energy integration method, the arrival time of each channel signal is initially determined, and the first time delay deviation is obtained based on the arrival time. Using the earliest triggered sensor channel as the reference channel, the signals of the other channels are subjected to generalized cross-correlation operation with the reference channel signal of the reference channel to obtain the cross-correlation function between each channel signal and the reference channel signal; Based on the time offset corresponding to the maximum peak value of the cross-correlation function, the second time delay difference of each sensor relative to the reference sensor is determined in combination with the sampling rate. When the difference between the first delay difference and the second delay difference is within a preset error range, the second delay difference is taken as the relative delay difference.

[0064] Optionally, the expression for calculating the second time delay difference is: In the formula, For the first The time delay difference between each sensor and the reference sensor. and The first The location of the peak sampling point of the signal corresponding to each sensor and the reference sensor. This represents the ultrasonic signal sampling rate.

[0065] Optionally, theoretical delay difference The calculation expression is: in, In the formula, For the source of the bureau to the first The propagation distance of each sensor The propagation distance from the partial discharge source to the reference sensor, For the equivalent combined speed of sound, Let be the position coordinates of the i-th sensor.

[0066] Optionally, the objective function The expression is: In the formula, For the first i The relative time delay difference between the sensors, For the first i The theoretical time delay difference of each sensor; x , y , z () represents the spatial coordinates of the local emission source. For the equivalent combined speed of sound,N This represents the number of sensors.

[0067] Exemplary electronic devices Figure 5 This is the structure of an electronic device provided in an exemplary embodiment of the present invention. For example... Figure 5 As shown, the electronic device 50 includes one or more processors 51 and memory 52.

[0068] The processor 51 may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions.

[0069] The memory 52 may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions may be stored on the computer-readable storage medium, and the processor 51 may execute the program instructions to implement the methods of the software programs of the various embodiments of the present invention described above, and / or other desired functions. In one example, the electronic device may also include an input device 53 and an output device 54, these components being interconnected via a bus system and / or other forms of connection mechanisms (not shown).

[0070] In addition, the input device 53 may also include, for example, a keyboard, a mouse, etc.

[0071] The output device 54 can output various information to the outside. The output device 54 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, etc.

[0072] Of course, for the sake of simplicity, Figure 5 Only some of the components of this electronic device relevant to the present invention are shown, omitting components such as buses, input / output interfaces, etc. In addition, the electronic device may include any other suitable components depending on the specific application.

[0073] Exemplary computer program products and computer-readable storage media In addition to the methods and apparatus described above, embodiments of the present invention may also be computer program products, which include computer program instructions that, when executed by a processor, cause the processor to perform the steps in the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0074] The computer program product can be written in any combination of one or more programming languages ​​to perform the operations of the embodiments of the present invention. The programming languages ​​include object-oriented programming languages ​​such as Java and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computing device, partially on the user's computing device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0075] Furthermore, embodiments of the present invention may also be computer-readable storage media storing computer program instructions thereon, which, when executed by a processor, cause the processor to perform the steps of the methods according to various embodiments of the present invention described in the "Exemplary Methods" section above.

[0076] The computer-readable storage medium may be any combination of one or more readable media. A readable medium may be a readable signal medium or a readable storage medium. A readable storage medium may be, for example, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, system, or device, or any combination thereof. More specific examples of readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0077] The basic principles of the present invention have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in the present invention are merely examples and not limitations, and should not be considered as essential features of each embodiment of the present invention. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the present invention to the necessity of employing the aforementioned specific details.

[0078] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system embodiments, since they largely correspond to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0079] The block diagrams of devices, systems, devices, and systems involved in this invention are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, systems, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0080] The methods and systems of the present invention may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of the present invention are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, the present invention may also be implemented as a program recorded on a recording medium, the program comprising machine-readable instructions for implementing the methods according to the present invention. Thus, the present invention also covers recording media storing programs for performing the methods according to the present invention.

[0081] It should also be noted that in the systems, apparatus, and methods of the present invention, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalents of the present invention. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the invention. Therefore, the invention is not intended to be limited to the aspects shown herein, but rather to be carried out within the widest scope consistent with the principles and novel features disclosed herein.

[0082] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of the invention to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for ultrasonic partial discharge measurement and positioning of a converter valve side output device, characterized in that, include: A multidimensional non-coplanar ultrasonic sensor array is arranged on the outer surface of the device under test, and the original ultrasonic wave signals of each sensor are collected synchronously. The original ultrasonic wave signal is processed to obtain a pure partial discharge ultrasonic pulse signal; Based on the arrival time of the pure partial discharge ultrasonic pulse signal in each channel, calculate the relative time delay difference between each sensor; Based on the known spatial coordinates of each sensor, a time difference relationship is established according to the spatial coordinates of the partial discharge source and the propagation distance between each sensor, so as to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. Based on the relative delay difference and the theoretical delay difference, construct the objective function of the sum of squared delay residuals. By taking the spatial coordinates of the partial discharge source and the equivalent composite sound velocity as common variables to be solved, a four-dimensional optimization feature space is established. An improved particle swarm optimization algorithm is used to perform a global iterative search to minimize the objective function, and finally outputs the corrected values ​​of the three-dimensional spatial coordinates and equivalent composite sound velocity of the partial discharge source.

2. The method according to claim 1, characterized in that, The arrangement of the multidimensional non-coplanar ultrasonic sensor array is as follows: a multidimensional non-coplanar sensor array composed of multiple high-sensitivity piezoelectric ultrasonic sensors is arranged on the outer wall surface of the converter valve side outlet device.

3. The method according to claim 2, characterized in that, The outer wall surface includes the cable riser, corner, and sleeve root; the number of ultrasonic sensors is no less than 5, and their spatial arrangement must avoid being on the same plane.

4. The method according to claim 1, characterized in that, The original ultrasonic wave signal is processed to obtain a pure partial discharge ultrasonic pulse signal, including: The original ultrasonic waveform signal is adaptively decomposed into several narrowband intrinsic mode function components using a variational mode decomposition algorithm. Based on the center frequency, energy ratio, and correlation coefficient with the partial discharge reference template signal of each intrinsic mode function component, a comprehensive judgment is made to remove the intrinsic mode function components corresponding to low-frequency mechanical vibration and stray noise, and retain the partial discharge characteristic components. The retained partial discharge characteristic components are subjected to wavelet packet soft thresholding denoising and signal reconstruction to obtain the pure partial discharge ultrasonic pulse signal with high signal-to-noise ratio.

5. The method according to claim 1, characterized in that, Based on the arrival times of the pure partial discharge ultrasonic pulse signals in each channel, the relative time delay difference between each sensor is calculated, including: The initial trigger wavefront of the pure partial discharge ultrasonic signal in each channel is captured by the waveform leading edge energy integration method, the arrival time of each channel signal is initially locked, and the first time delay deviation is obtained based on the arrival time. Using the earliest triggered sensor channel as the reference channel, the signals of the other channels are subjected to a generalized cross-correlation operation with the reference channel signal of the reference channel to obtain the cross-correlation function between each channel signal and the reference channel signal; Based on the time offset corresponding to the maximum peak value of the cross-correlation function, the second time delay difference of each sensor relative to the reference sensor is determined in combination with the sampling rate. When the difference between the first delay difference and the second delay difference is within a preset error range, the second delay difference is used as the relative delay difference.

6. The method according to claim 5, characterized in that, The expression for calculating the second time delay difference is: In the formula, For the first The time delay difference between each sensor and the reference sensor. and The first The location of the peak sampling point of the signal corresponding to each sensor and the reference sensor. This represents the ultrasonic signal sampling rate.

7. The method according to claim 1, characterized in that, The theoretical time delay difference The calculation expression is: in, In the formula, For the source of the bureau to the first The propagation distance of each sensor The propagation distance from the partial discharge source to the reference sensor, For the equivalent combined speed of sound, Let be the position coordinates of the i-th sensor.

8. The method according to claim 1, characterized in that, The objective function The expression is: In the formula, For the first i The relative time delay difference between the sensors, For the first i The theoretical time delay difference of each sensor; x , y , z () represents the spatial coordinates of the local emission source. For the equivalent combined speed of sound, N This represents the number of sensors.

9. An ultrasonic partial discharge measurement and positioning device for a converter valve side output device, characterized in that, include: The acquisition module is used to arrange a multi-dimensional non-coplanar ultrasonic sensor array on the outer surface of the device under test and simultaneously acquire the original ultrasonic wave signals of each sensor. The acquisition module is used to process the original ultrasonic wave signal to obtain a pure partial discharge ultrasonic pulse signal; The calculation module is used to calculate the relative time delay difference between each sensor based on the arrival time of the determined pure partial discharge ultrasonic pulse signal of each channel; A module is established to establish a time difference relationship between the spatial coordinates of each sensor and the propagation distance between the spatial coordinates of the partial discharge source and each sensor, based on the known spatial coordinates of each sensor, and to obtain the theoretical time delay difference value of each sensor relative to the reference sensor. The construction module is used to construct a target function for the sum of squared residuals based on the relative delay difference and the theoretical delay difference; The output module is used to establish a four-dimensional optimization feature space by taking the spatial coordinates of the partial discharge source and the equivalent comprehensive sound velocity as common variables to be solved, and to perform a global iterative search using an improved particle swarm optimization algorithm to minimize the objective function. Finally, it outputs the corrected values ​​of the three-dimensional spatial coordinates and the equivalent comprehensive sound velocity of the partial discharge source.

10. The apparatus according to claim 9, characterized in that, The arrangement of the multidimensional non-coplanar ultrasonic sensor array is as follows: a multidimensional non-coplanar sensor array composed of multiple high-sensitivity piezoelectric ultrasonic sensors is arranged on the outer wall surface of the converter valve side outlet device.

11. The apparatus according to claim 10, characterized in that, The outer wall surface includes the cable riser, corner, and sleeve root; the number of ultrasonic sensors is no less than 5, and their spatial arrangement must avoid being on the same plane.

12. The apparatus according to claim 9, characterized in that, The acquisition module includes: The original ultrasonic waveform signal is adaptively decomposed into several narrowband intrinsic mode function components using a variational mode decomposition algorithm. Based on the center frequency, energy ratio, and correlation coefficient with the partial discharge reference template signal of each intrinsic mode function component, a comprehensive judgment is made to remove the intrinsic mode function components corresponding to low-frequency mechanical vibration and stray noise, and retain the partial discharge characteristic components. The retained partial discharge characteristic components are subjected to wavelet packet soft thresholding denoising and signal reconstruction to obtain the pure partial discharge ultrasonic pulse signal with high signal-to-noise ratio.

13. A computer-readable storage medium, characterized in that, The storage medium stores a computer program for performing the method described in any one of claims 1-8.

14. An electronic device, characterized in that, The electronic device includes: processor; Memory used to store the processor's executable instructions; The processor is configured to read the executable instructions from the memory and execute the instructions to implement the method described in any one of claims 1-8.

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