CN-121856733-B - Acoustic-electric combined imaging method and system for positioning internal defects of extremely cold lightning arrester

CN121856733BCN 121856733 BCN121856733 BCN 121856733BCN-121856733-B

Abstract

The invention relates to the technical field of positioning of internal defects of a lightning arrester, and particularly discloses a method and a system for positioning the internal defects of an extremely cold lightning arrester by means of combined acoustic and electric imaging, wherein electromagnetic wave front distortion parameters are calculated to evaluate the state of an internal medium by synchronously collecting acoustic and electric combined signals of the lightning arrester, and a standard or self-adaptive anti-interference positioning mode is selected according to a dynamic broadening threshold value; and finally, outputting the three-dimensional coordinates of the internal defect source by utilizing the initial arrival time difference data set and the filtered high-weight acoustic data set through a joint optimization solving algorithm. The invention can effectively solve the problem of uneven medium in the lightning arrester in the extremely cold environment, improves the accuracy and reliability of defect positioning, and provides powerful support for safe and stable operation of the power grid.

Inventors

WANG LEI
MENG PENGFEI
YU WENBO
YIN YUE
WANG XUETING
WANG XUEDONG
LI ZHIBIN
WANG LUXIN
HE XIAOHUI

Assignees

国网黑龙江省电力有限公司电力科学研究院
四川大学

Dates

Publication Date: 20260512
Application Date: 20260319

Claims (10)

1. An interior defect positioning method of an extremely cold lightning arrester based on acoustic-electric combined imaging is characterized by comprising the following steps: S1, synchronously acquiring an acoustic-electric combined signal of a lightning arrester, calculating the broadening quantity of the pulse front edge of an electromagnetic pulse waveform acquired by each ultrahigh frequency sensor, and quantifying the broadening quantity into an electromagnetic wave front distortion parameter representing the dielectric loss degree of a signal propagation path; S2, acquiring current external temperature and historical operating voltage data of the lightning arrester to calculate a dynamic broadening threshold value, comparing electromagnetic wave front distortion parameters with the dynamic broadening threshold value, judging the state of medium inside the lightning arrester according to a comparison result, and selecting a standard positioning processing mode or a self-adaptive anti-interference positioning processing mode; S3, when the self-adaptive anti-interference positioning processing mode is selected, calculating the spatial change rate of electromagnetic wave front distortion parameters corresponding to the ultrahigh frequency sensors at different positions, and generating a suspicious abnormal region spatial mask marked with a high-loss dielectric region according to the spatial change rate; s4, when the self-adaptive anti-interference positioning processing mode is selected, calculating an initial arrival time difference data set between piezoelectric acoustic sensors, analyzing the spatial position relation between an acoustic signal propagation path and a suspicious abnormal region spatial mask, and carrying out weighted screening on the initial arrival time difference data set to generate a filtered high-weight acoustic data set; S5, according to the selected positioning processing mode, a positioning solving algorithm is executed by utilizing the initial arrival time difference data set and the filtered high-weight acoustic data set, and the three-dimensional coordinates of the internal defect source are output.
2. The method for positioning the internal defects of the extremely cold lightning arrester by acoustic-electric combined imaging according to claim 1, wherein the step of synchronously collecting the acoustic-electric combined signals of the lightning arrester comprises the following steps: monitoring an output signal of the ultrahigh frequency sensor by using a voltage comparator, and generating a global synchronous trigger moment when any signal is detected to exceed a preset voltage threshold value; and synchronously starting data acquisition of all the ultrahigh frequency sensors and the piezoelectric acoustic sensors according to the global synchronous triggering moment, and recording broadband full-waveform data in a preset time period after the triggering point.
3. The method for locating an internal defect of an extremely cold lightning arrester by combined acoustic and electric imaging according to claim 2, wherein the step of calculating the stretching amount of the pulse front edge and quantifying the stretching amount into an electromagnetic wave front distortion parameter representing the dielectric loss degree of the signal propagation path comprises the steps of: Analyzing the broadband full-waveform data, and determining a first preset percentage moment and a second preset percentage moment when the pulse leading edge amplitude rises to a final stable peak value; And calculating a time difference value between the second preset percentage moment and the first preset percentage moment, and taking the time difference value as an electromagnetic wave front distortion parameter.
4. The method for locating defects in an extremely cold lightning arrester by combined acoustic and electric imaging according to claim 1, wherein the step of obtaining the current external temperature and the historical operating voltage data of the lightning arrester to calculate the dynamic widening threshold value comprises the steps of: inquiring a preset temperature-base stretching mapping table according to the current external temperature to obtain a base stretching amount; inquiring a preset voltage-loss coefficient relation curve according to the historical operating voltage to obtain a voltage correction coefficient; correcting the basic stretching amount by using a voltage correction coefficient, and superposing a preset statistical margin constant to obtain a dynamic stretching threshold.
5. The method for locating defects in an extremely cold lightning arrester by combined acoustic and electric imaging according to claim 4, wherein the steps of determining the state of the medium in the lightning arrester according to the comparison result and selecting a standard locating processing mode or an adaptive anti-interference locating processing mode comprise: if the electromagnetic wave front distortion parameters corresponding to all the ultrahigh frequency sensors are smaller than the dynamic broadening threshold value, judging that the internal medium is uniform, and selecting a standard positioning processing mode; if the electromagnetic wave front distortion parameter corresponding to any ultrahigh frequency sensor is greater than or equal to the dynamic broadening threshold, judging that medium non-uniformity abnormality exists inside, and selecting a self-adaptive anti-interference positioning processing mode.
6. The method for positioning defects in an extremely cold lightning arrester by acoustic-electric combined imaging according to claim 1, wherein the calculating the spatial change rate of electromagnetic wave front distortion parameters corresponding to the ultrahigh frequency sensors at different positions and generating a suspicious abnormal region spatial mask for marking a high-loss dielectric region according to the spatial change rate comprises the following steps: Acquiring axial position coordinates of each ultrahigh frequency sensor at different positions; calculating the ratio of the difference of electromagnetic wave front distortion parameters between two adjacent ultrahigh frequency sensors to the difference of position coordinates to obtain a spatial distribution gradient; And comparing the spatial distribution gradient with a preset gradient threshold, marking the region of the spatial distribution gradient exceeding the preset gradient threshold as an abnormal region, and generating a binary suspicious abnormal region spatial mask.
7. The method for positioning defects in an extremely cold lightning arrester by combined acoustic and electric imaging according to claim 1, wherein the analyzing the spatial positional relationship between the acoustic signal propagation path and the spatial mask of the suspicious abnormal region comprises: Constructing an acoustic signal linear propagation path corresponding to each group of arrival time difference data according to the three-dimensional coordinates of the piezoelectric acoustic sensor; discretizing the straight propagation path of the acoustic signal into a space point set, and inquiring the corresponding logic value of each space point in the space mask of the suspicious abnormal region; If the space point falling into the mask mark abnormal region exists on the acoustic signal linear propagation path, the acoustic signal linear propagation path and the mask are judged to have space overlapping, otherwise, if the space point falling into the mask mark abnormal region does not exist on the acoustic signal linear propagation path, the acoustic signal linear propagation path and the mask are judged to have no space overlapping.
8. The method for locating defects in an extreme cold lightning arrester in acoustic-electric combined imaging according to claim 7, wherein said weighting and filtering the initial arrival time difference dataset to generate a filtered high-weight acoustic dataset comprises: For the acoustic signal straight line propagation path which is judged to have space overlapping with the space mask of the suspicious abnormal region, the corresponding arrival time difference data is given a preset low weight coefficient or is directly removed; for the acoustic signal straight line propagation path which is judged to have no space overlapping with the space mask of the suspicious abnormal region, the corresponding arrival time difference data is given a preset high weight coefficient; All the retained data and its weight coefficients are collected to form a filtered high weight acoustic dataset.
9. The method for positioning an internal defect of an extremely cold lightning arrester by combined acoustic and electric imaging according to claim 1, wherein the performing a positioning solution algorithm using the initial arrival time difference dataset and the filtered high-weight acoustic dataset, outputting three-dimensional coordinates of an internal defect source, comprises: when the selected positioning processing mode is a self-adaptive anti-interference positioning processing mode, constructing a joint optimization objective function, and setting variables to be solved as three-dimensional coordinates of an internal defect source and equivalent sound velocity in a region marked by a space mask of a suspicious abnormal region; Minimizing a weighted error between the measured arrival time difference and a theoretical arrival time difference predicted based on the current variable by an iterative algorithm using the filtered high-weight acoustic dataset; when the algorithm converges, outputting the three-dimensional coordinates of the optimized internal defect source; When the selected positioning processing mode is a standard positioning processing mode, directly calling an initial arrival time difference data set; and calculating and outputting the three-dimensional coordinates of the internal defect source by solving an arrival time difference equation set by adopting a preset global unified sound velocity model.
10. An interior defect positioning system of an extremely cold lightning arrester of sound-electricity combined imaging is characterized by comprising: The signal acquisition and parameter extraction module synchronously acquires the acoustic-electric combined signal of the lightning arrester, calculates the stretching amount of the pulse front edge of the electromagnetic pulse waveform acquired by each ultrahigh frequency sensor, and quantifies the stretching amount into electromagnetic wave front distortion parameters representing the dielectric loss degree of a signal propagation path; The state judging and mode selecting module is used for acquiring the current external temperature and the historical operating voltage data of the lightning arrester to calculate a dynamic broadening threshold value, comparing the electromagnetic wave front distortion parameter with the dynamic broadening threshold value, judging the state of the medium inside the lightning arrester according to a comparison result, and selecting a standard positioning processing mode or a self-adaptive anti-interference positioning processing mode; the regional space mask generation module is used for calculating the space change rate of electromagnetic wave front distortion parameters corresponding to the ultrahigh frequency sensors at different positions when the adaptive anti-interference positioning processing mode is selected, and generating a suspicious abnormal regional space mask marked with a high-loss dielectric region according to the space change rate; The high-weight acoustic data filtering module is used for calculating an initial arrival time difference data set between the piezoelectric acoustic sensors when the self-adaptive anti-interference positioning processing mode is selected, analyzing the spatial position relation between an acoustic signal propagation path and a suspicious abnormal region spatial mask, and carrying out weighted screening on the initial arrival time difference data set to generate a filtered high-weight acoustic data set; And the positioning processing mode solving module is used for executing a positioning solving algorithm by utilizing the initial arrival time difference data set and the filtered high-weight acoustic data set according to the selected positioning processing mode and outputting the three-dimensional coordinates of the internal defect source.

Description

Acoustic-electric combined imaging method and system for positioning internal defects of extremely cold lightning arrester Technical Field The invention belongs to the technical field of positioning of internal defects of lightning arresters, and relates to a method and a system for positioning the internal defects of an extremely cold lightning arrester by acoustic-electric combined imaging. Background In a high-voltage power system, a lightning arrester is used as a key overvoltage protection device, and the reliability of an internal insulation state of the lightning arrester is directly related to safe and stable operation of the whole power grid. Internal manufacturing defects, material aging, or harsh environmental factors may cause partial discharge to occur, which may continue to develop through breakdown if not timely found and precisely located, causing device failure. Therefore, the accurate positioning of the partial discharge defect source in the lightning arrester is an important technical premise for realizing equipment state evaluation and preventive maintenance. The patent with publication number CN102175721B discloses a visual detection method for internal assembly defects of a metal oxide arrester for electric power, which comprises the steps of adopting electric measurement and waveform observation as main means and X-ray perspective irradiation as auxiliary means to realize rapid diagnosis of internal assembly defects of the metal oxide arrester for electric power, carrying out voltage waveform monitoring on two ends of a discharge counter of the charged arrester through a common oscilloscope, if the voltage waveform contains high frequency and high amplitude clutter, indicating that metallic suspended particle defects exist in the arrester, and adopting X-ray perspective irradiation means to focus on the vicinity of the bottom of a single arrester, so as to realize visual display of internal structural forms of the arrester, and further directly determining the defects existing in the arrester. The prior art has the defects that firstly, complex influence of severe environments such as extremely cold and the like on the medium state inside the lightning arrester is not fully considered, and the adopted fixed criterion is possibly insufficient in adaptability when the medium is uneven. Secondly, the technical means mainly depend on electrical measurement and offline X-ray perspective, and the method has limitations in information dimension and real-time property, so that the depth joint analysis and the online self-adaptive positioning based on electromagnetic wave front distortion and acoustic propagation delay are difficult to realize. Disclosure of Invention In view of this, in order to solve the problems set forth in the background art, a method and a system for locating internal defects of an extremely cold lightning arrester by combined imaging of sound and electricity are provided. The invention provides an extremely cold lightning arrester internal defect positioning method based on acoustic-electric combined imaging, which comprises the following steps of S1, synchronously collecting acoustic-electric combined signals of the lightning arrester, calculating the stretching quantity of the pulse front edge of an electromagnetic pulse waveform collected by each ultrahigh frequency sensor, and quantifying the stretching quantity into electromagnetic wave front distortion parameters representing the dielectric loss degree of a signal propagation path. S2, acquiring current external temperature and historical operating voltage data of the lightning arrester to calculate a dynamic broadening threshold value, comparing electromagnetic wave front distortion parameters with the dynamic broadening threshold value, judging the state of medium inside the lightning arrester according to a comparison result, and selecting a standard positioning processing mode or a self-adaptive anti-interference positioning processing mode. And S3, when the self-adaptive anti-interference positioning processing mode is selected, calculating the spatial change rate of electromagnetic wave front distortion parameters corresponding to the ultrahigh frequency sensors at different positions, and generating a suspicious abnormal region spatial mask marked with the high-loss dielectric region according to the spatial change rate. And S4, when the self-adaptive anti-interference positioning processing mode is selected, calculating an initial arrival time difference data set between the piezoelectric acoustic sensors, analyzing the spatial position relation between the acoustic signal propagation path and the suspicious abnormal region spatial mask, and carrying out weighted screening on the initial arrival time difference data set to generate a filtered high-weight acoustic data set. S5, according to the selected positioning processing mode, a positioning solving algorithm is executed by utilizing the initial arrival