Damp defect positioning and diagnosis method based on distribution cable line

Abstract

The invention provides a damp defect positioning and diagnosis method based on a distribution cable line. The method comprises the following steps: step 1, testing cable data; step 2, inputting an impedance spectrum at the head end of the cable to position a local defect / intermediate joint of the cable, and obtaining a positioning spectrogram; and step 3, comparing the amplitude in the positioning spectrogram in the step 2 with the amplitude of the positioning spectrogram of the normal joint so as to diagnose the specific damp condition of the local defect of the cable / the intermediate joint. The method has the beneficial effects that when the damp condition of a plurality of intermediate joints is diagnosed, the reflection intensity of the judged joint can be compared with the reflection intensity of a normal joint, and the reflection intensity of the judged joint can also be compared with the reflection intensity of two adjacent front and back joints, so that the damp state of the judged joint is determined.

Description

Technical field [0001] The present invention relates to the field of wet cable distribution line is detected, and more particularly to a line based on the distribution cable damp defect localization and diagnosis. Background technique [0002] Typically the distribution cable laid in the cable channel or perennial water moist soil, should the cable sheath is damaged or linker intermediate waterproof performance degradation, the invasion of moisture to the cable easily harm the performance of cable insulation. And in the electric field, the cable semiconductive layer and the copper shield produces ions in hydrophilic chemical reaction, which makes the ions and water may gradually migrate into the main insulating layer of the cable, causing the cable insulation reduce, and even the formation of water trees, electrical treeing. Therefore, an urgent need to find a method of diagnosis of wet cables. Inventive content [0003] The present invention overcomes the disadvantages of the p...

AI Technical Summary

Problems solved by technology

[0002] Distribution cables are usually laid in cable trenches with perennial water or in humid soil. If the outer sheath of the cable is damaged or the waterproof performance of the intermediate joint is reduced, moisture will easily invade the cable and endanger the insulation performance of the cable.

Under the action of an electric field, the semi-conductive layer of the cable and the copper shielding layer will produce hydrophilic ions under the chemical reaction, which makes the water and these ions gradually migrate into the main insulating layer of the cable, resulting in the deterioration of the insulation performance of the cable. reduce, and even form water trees and electric trees

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