Aging site rapid diagnosis method for 10 kV XLPE cable based on polarization current measurement

Abstract

The invention discloses an aging site rapid diagnosis method for a 10 kV XLPE cable based on the polarization current measurement. According to the technical scheme of the invention, the Harmon approximation algorithm is improved when the fitting parameter n of the relaxation current is larger than or equal to 0 and smaller than or equal to 0.3, or is larger than or equal to 1.2 and smaller than or equal to 2. In this way, the application range of the Harmon approximation algorithm is expanded and the measurement time of the polarization current is greatly shortened according to the frequency range of a dielectric loss factor tan Delta determined based on the field actual need. Moreover, based on the improved Harmon approximation algorithm, the dielectric loss factor tan Delta at a corresponding frequency can be quickly and intuitively obtained, so that the cable aging condition can be judged based on the value of the dielectric loss factor tan Delta at the corresponding frequency. Therefore, by adopting the aging site rapid diagnosis method for the 10 kV XLPE cable based on the polarization current measurement, the aging condition of a field cable can be rapidly diagnosed. At the same time, the method is wider in application range and can reflect the cable aging condition more accurately. The requirement of the field time measurement can be met.

Description

technical field [0001] The invention relates to the field of aging assessment methods for insulating materials, and more particularly relates to a method for quickly evaluating the insulation of cross-linked polyethylene medium-voltage cables on site by using a polarization current method. Background technique [0002] Crosslinked Polyethylene (XLPE) cables are widely used in power transmission lines due to their excellent mechanical and electrical properties. The aging condition and remaining life of the cable insulation directly affect the stability of the power system, so the development of XLPE cable insulation diagnosis technology is of great significance for improving the stability of the power system. [0003] At present, a lot of research has been done on cable insulation diagnosis methods at home and abroad. Among them, the PDC (Polarization and Depolarization Current, PDC) method is an effective test method for detecting the aging of electrical equipment. It has th...

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Problems solved by technology

[0005] Aiming at the above defects or improvement needs of the prior art, the present invention provides a rapid on-site diagnosis method for 10kVXLPE cable aging based on polarization current measurement. The measurement time is measured, and the polarization current is quickly and intuitively converted into the dielectric loss factor tanδ at the corresponding frequency through the improved Harmon approximation algorithm, so as to judge the insulation condition of the cable according to the dielectric loss factor tanδ at the required frequency. In the prior art, due to the long measurement time of the polarization current, the process of converting the polarization current into the dielectric loss factor tanδ at the corresponding frequency is complicated, which makes it difficult for the PDC method to quickly diagnose the cable on site.

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