Cable defect identification method based on U-Q curve under fixed oscillation frequency

Abstract

The invention relates to a cable defect identification method based on a UQ curve under a fixed oscillation frequency. The method is characterized in that the following steps: respectively manufacturing a tested defective cable with a conductor tip defect, a shielding damage defect, a suspension potential defect and an insulation radial defect; when oscillatory wave voltage is applied, the frequency of the oscillatory wave voltage is kept unchanged by adjusting the capacitance of a frequency modulation capacitor connected with the tested defective cable in parallel; in the boosting process, increasing the effective value of the applied oscillatory wave voltage by stages, and keeping the voltage of each stage for a period of time; in each pressurization stage, calculating the equivalent apparent local discharge capacity of each pressurization stage; drawing UQ relation curves of different defect types; by comparing the characteristics of the UQ relation curves of different defect types,realizing the identification function of different types of cable defects. According to the invention, the function of identifying different cable defect types under the UQ curve based on the fixed oscillation frequency is realized, and the problem of effectively detecting the types of the cable defects is solved.

Description

technical field [0001] The invention belongs to the field of cables and measurement and testing, in particular to a method for identifying cable defects based on U-Q curves at a fixed oscillation frequency. Background technique [0002] At present, urban power transmission networks basically use cable transmission lines, which have the characteristics of stable transmission performance, high safety and strong adaptability. In cable transmission lines, XLPE cables are widely used due to their good physical, chemical and mechanical properties. , its safety and reliability are directly related to the normal operation of the urban power system. As an important equipment in the power system, the insulation condition of the cable is very important to the stable operation of the power system. The evaluation of the insulation condition of the power cable is very important for the maintenance of the power grid. The safety and stability of the cable insulation is of great significance...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art, to provide a reasonable design, fast and accurate and reliable cable defect identification method based on the U-Q curve at a fixed oscillation frequency, which solves the problem of identifying the types of cable defects in actual engineering. Problems with Effective Detection

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