CN-122017842-A - Backward projection imaging method, system, equipment and medium for defect detection of external insulation equipment of power system

CN122017842ACN 122017842 ACN122017842 ACN 122017842ACN-122017842-A

Abstract

The invention belongs to the technical field of detection of external insulation equipment, and discloses a backward projection imaging method, a backward projection imaging system, backward projection imaging equipment and a backward projection imaging medium for detecting defects of the external insulation equipment of a power system, so as to solve the problem that the imaging efficiency is low due to the fact that the repeated calculation amount of an electromagnetic wave propagation path is large in an existing backward projection imaging algorithm. According to the method, the axisymmetric structural characteristic of the external insulation equipment is utilized, one reference detection azimuth is selected to calculate the electromagnetic wave propagation path distribution, the reference path distribution is rotated to other detection azimuth to obtain the path distribution to be interpolated, the target pixel point is accurately calculated by adopting an inverse distance weighted interpolation method, and finally the path data of all detection azimuth are obtained for imaging by repeating the steps. The invention obviously reduces the repeated calculation of the electromagnetic wave propagation path in a parameter multiplexing mode, greatly improves the backward projection imaging efficiency on the premise of ensuring the imaging precision, and can meet the requirement of on-site rapid detection of the external insulation equipment of the power system.

Inventors

QIAN DUN
WANG YIFAN
ZENG MINGQUAN
LI WENBO
WANG SHAOFEI
ZHU CHENGRU
CHEN YIHENG
LU KAI

Assignees

国网浙江省电力有限公司电力科学研究院

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. The back projection imaging method for detecting the defects of the external insulation equipment of the power system is characterized by comprising the following steps: S1, selecting any detection azimuth as a reference detection azimuth, and acquiring electromagnetic wave propagation path data of each pixel point in an imaging area under the reference detection azimuth by adopting an electromagnetic wave propagation path calculation method to form reference path distribution; S2, rotating the reference path distribution by a preset angle along the symmetry axis of the tested equipment by utilizing the axisymmetric structural characteristic of the external insulation equipment of the power system to obtain the path distribution to be interpolated corresponding to the target detection azimuth; S3, for each target pixel point under the target detection azimuth, determining a plurality of adjacent reference pixel points in the path distribution to be interpolated; S4, calculating to obtain electromagnetic wave propagation path data of the target pixel point by adopting an inverse distance weighted interpolation method based on the distances between the target pixel point and the plurality of reference pixel points; S5, repeating the steps S2 to S4 until the electromagnetic wave propagation path data of each pixel point under all detection orientations are obtained and are used for backward projection imaging.
2. The back projection imaging method for detecting defects of external insulation equipment of a power system according to claim 1, wherein the method comprises the following steps: The electromagnetic wave propagation path data in step S1 includes an electromagnetic wave propagation path or propagation time.
3. The back projection imaging method for detecting defects of external insulation equipment of a power system according to claim 1, wherein the method comprises the following steps: In step S2, the preset angle is an angle difference between the reference detection azimuth and the target detection azimuth.
4. The back projection imaging method for detecting defects of external insulation equipment of a power system according to claim 1, wherein the method comprises the following steps: In step S2, the area of the imaging area of the reference path distribution is smaller than the area of the imaging area of the path distribution to be interpolated.
5. The method for backward projection imaging for detecting defects of external insulation equipment of a power system according to claim 1, wherein in the step S3, the adjacent plurality of reference pixel points are specifically: in the path distribution to be interpolated, four grid pixel points closest to the target pixel point.
6. The back projection imaging method for detecting defects of external insulation equipment of a power system according to claim 1, wherein in step S4, the calculation formula of the inverse distance weighted interpolation method is as follows: , In the formula, Is electromagnetic wave propagation path data of the target pixel point, For the distance between the target pixel and its adjacent reference pixel, For the propagation path distance of the reference pixel point, Is the inverse distance weight of the reference pixel point.
7. The back projection imaging method for detecting defects of external insulation equipment of a power system according to claim 6, wherein the method comprises the following steps: In step S4, when the target pixel point coincides with a certain reference pixel point in the path distribution to be interpolated, electromagnetic wave propagation path data of the reference pixel point is directly assigned to the target pixel point.
8. A rear projection imaging system for defect detection of an external insulation device of an electrical power system, for implementing a rear projection imaging method according to any of claims 1 to 7.
9. A computer device comprising a memory, a processor and a computer program, wherein the computer program when executed by the processor implements the backprojection imaging method according to any one of claims 1 to 7.
10. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements the backprojection imaging method according to any one of claims 1 to 7.

Description

Backward projection imaging method, system, equipment and medium for defect detection of external insulation equipment of power system Technical Field The invention belongs to the technical field of detection of external insulation equipment, and particularly relates to a backward projection imaging method, a backward projection imaging system, backward projection imaging equipment and a backward projection imaging medium for detecting defects of the external insulation equipment of a power system. Background The Back Projection (BP) algorithm is originally derived from the Projection slice theorem of CT imaging, and has a higher imaging resolution, and the core principle is to obtain the energy intensity of a detection point by Back-tracking an electromagnetic wave according to the propagation time of the electromagnetic wave. In the field of defect detection of external insulation equipment of an electric power system, a BP algorithm is usually used in combination with a synthetic aperture radar method, a radar obtains dielectric distribution characteristics of a target in different detection directions by transmitting detection signals to the detected target and receiving reflection signals, the BP algorithm carries out backward projection imaging on the received signals of all detection directions, and carries out coherent processing on images of all detection directions, so that radar imaging of the external insulation equipment is finally realized. However, the BP algorithm faces a problem of large calculation amount in practical engineering application, which seriously hinders popularization and application thereof. The calculation of the electromagnetic wave propagation path of each detection azimuth is the most time-consuming link, and the process needs to calculate the electromagnetic wave propagation path between the antenna and each detection point in the imaging space when the radar antenna is at different positions. Under the condition that the number of imaging space pixels is fixed, when the number of detection orientations in the synthetic aperture radar can linearly influence imaging, high-precision BP imaging generally requires more detection orientations, which further aggravates the calculation burden and brings challenges to rapid BP imaging. On the other hand, the external insulation device of the power system is generally in an axisymmetric structure, and the structures in all directions are basically the same. The structural characteristics enable electromagnetic waves emitted by the radars with different detection orientations to reach the same structural part of the external insulation equipment under the condition that parameters such as the antenna distance and the synthetic aperture radar track are unchanged relative to the object depression angle and the like, and the subsequent refraction and reflection conditions in all layers of media in the external insulation equipment are basically the same. Therefore, under the condition, the independent solution of the electromagnetic wave propagation paths of each detection azimuth belongs to computational redundancy, and the overall computational efficiency is reduced. In summary, the prior art lacks a back projection imaging method capable of reducing repetitive calculation of electromagnetic wave propagation paths by utilizing the axisymmetric structural characteristics of the external insulation device, so that the imaging efficiency is difficult to meet the engineering application requirements. Disclosure of Invention In view of the foregoing drawbacks and deficiencies of the prior art, it is therefore an object of the present invention to at least solve one or more of the above-mentioned problems occurring in the prior art, in other words, to provide a method, system, device and medium for detecting defects of an external insulation device of an electrical power system, which satisfy one or more of the above-mentioned needs, so as to achieve the purposes of reducing repetitive calculation of electromagnetic wave propagation paths and improving the efficiency of the back projection imaging. In order to achieve the aim of the invention, the invention adopts the following technical scheme: in a first aspect, the present invention provides a back projection imaging method for defect detection of an external insulation device of an electric power system, including the steps of: S1, selecting any detection azimuth as a reference detection azimuth, and acquiring electromagnetic wave propagation path data of each pixel point in an imaging area under the reference detection azimuth by adopting an electromagnetic wave propagation path calculation method to form reference path distribution; S2, rotating the reference path distribution by a preset angle along the symmetry axis of the tested equipment by utilizing the axisymmetric structural characteristic of the external insulation equipment of the power system to obtain the path distributi