Method for evaluating insulation aging state of rubber-plastic cable

Abstract

The invention discloses a method for evaluating an insulation aging state of a rubber-plastic cable. The method includes the steps of an aging accelerating step of allowing a large current to flow through an intact rubber-plastic cable under a constant temperature and humidity condition until the main insulation material in the rubber-plastic cable is broken down, letting the total time be T, taking N-1 time points at the same time interval within the total time T, recording the time points as t1, t2, ..., tn-1 sequentially, and letting t0=0 and tn=T; a comparison database establishing step of sampling the main insulation material in the rubber-plastic cable at various time points from t0-tn, conducting a scanning electron microscope test, a laser diffraction particle size analysis, a dielectric spectrum test, a fluorescence spectrum analysis and an X-ray diffraction analysis, a thermogravimetric analysis, an electric pulse test and a tensile test, and establishing the correspondence between the above test or analysis data and the various time points from t0-tn correspondence in a comparison database; and an evaluating step of determining the remaining life of the rubber-plastic cable according to the data of the main insulation material the rubber-plastics cable under test.

Description

technical field [0001] The invention relates to a method for evaluating the aging state of rubber and plastic cable insulation in the field of cable testing. Background technique [0002] Compared with oil-immersed cables and gas-insulated cables, rubber-plastic power cables have the advantages of simple laying and convenient maintenance. The current power grid with a voltage level of 10-220kV has mainly used rubber-plastic cables whose main insulating material is low-density polyethylene. The design value of the operating life of general rubber and plastic power cables is 20 to 30 years, but the actual operating life of the cables is inevitably limited by the surrounding environmental conditions, load current and fluctuations. Rubber and plastic cables are subjected to electrical stress, thermal stress, and mechanical stress. And under the joint action of environmental stress, the insulation performance of the main insulating material will gradually age and deteriorate, and...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for evaluating the aging state of the rubber and plastic cable insulation, which can overcome the single defect of the test data of the traditional evaluation method for the aging state of the rubber and plastic cable insulation The validity of the assessment is improved

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