A method and system for classifying and locating internal insulation defects in gis

Abstract

The invention discloses a method and system for classifying and positioning internal insulation defects of a GIS. The method comprises the following steps: setting built-in UHF sensors at the positions, parallel to a bus bar, on the inner side of a hand hole cover plate of each air chamber of a GIS cavity; amplifying and filtering UHF signals sent by each UHF sensor, carrying out analog-digital conversion on the UHF signals sent by each UHF sensor, and then inputting the UHF signals after analog-digital conversion; obtaining time domain features through time-frequency analysis and obtaining wavelet coefficients through wavelet analysis by a signal feature extraction and identification device for receiving the UHF signals from an FPGA chip; after feature vector normalization processing of the combination of the time domain features and the wavelet coefficients, adopting a support vector machine device to train feature vectors, and obtaining an optimal penalty factor (C) and a gamma function parameter (g) by comparing classification accuracy; and constructing a support vector machine model (SVM), wherein the support vector machine model (SVM) is used for identifying the extracted UHF signals so as to judge the species and positions of the insulation defects.

Description

technical field [0001] The invention belongs to the field of electrical technology, and relates to live detection technology of electric equipment, in particular to a GIS internal insulation defect classification and positioning method and a GIS internal insulation defect classification and positioning system. Background technique [0002] GIS (Gas Insulated Metal Enclosed Combined Electrical Appliance) is a very critical device in the power system. If a fault occurs during operation and cannot be dealt with in time, it may bring serious harm to the operation of the power grid. During the processing, manufacturing and operation of GIS, it is difficult to avoid internal insulation defects. Under the action of high voltage, insulation defects will produce electric field distortion and partial discharge phenomenon. On the one hand, the partial discharge phenomenon is the characterization and manifestation of insulation defects. On the other hand, partial discharge will lead to...

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Problems solved by technology

[0004] However, the rising edge of the partial discharge current is extremely steep, generally at the ns level, so the frequency range of the excited UHF signal reaches several GHz, and the duration is about tens of ns

It is more difficult to directly identify UHF signals, and has higher requirements for hardware equipment

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