Method for evaluating residual service life of marine low-pressure rubber-insulated cable

Abstract

The invention discloses a method for evaluating the residual life of low voltage rubber insulation cable used on ships, comprising: processing thermal accelerated aging test on the insulation material of a cable sample; quickly simulating the aging process of the cable; attaining a cable service life equation based on the breaking elongation of the cable insulation material; in each time node of the thermal accelerated aging test, measuring the tangent value of dielectric loss angle of the cable insulation material, to obtain a cable service life equation based on the tangent value of dielectric loss angle of the insulation material and a tangent critical value of the dielectric loss angle at the end of the cable life; evaluating the service life of a low voltage rubber insulation cable of one standard via the two service life equations; according to the tangent value of dielectric loss angle measured in site, using the cable service life equation based on the tangent value of dielectric loss angle to evaluate the residual life of the in-situ cable. The method can quickly and accurately evaluate the residual life of cable in-situ.

Description

technical field [0001] The invention belongs to the technical field of insulation diagnosis of electrical equipment, relates to the diagnosis of the insulation state of low-voltage cables, and particularly relates to a method for evaluating the remaining life of low-voltage rubber-insulated cables used in ships. Background technique [0002] Most of the marine cables are low-voltage rubber insulated cables. The so-called low-voltage cables refer to cables with a rated voltage lower than 1kV. For ship power and lighting lines, the rubber insulated cables used during use, due to the oxidative decomposition of rubber, change the physical and mechanical properties of vulcanized rubber: harden, become brittle, form cracks on the rubber, air and moisture fill in the cracks. The above factors will accelerate the aging of the cable insulation layer material, and the narrow space in the cabin makes it difficult to implement inspection and maintenance, and it is difficult to find hid...

AI Technical Summary

Problems solved by technology

[0009] (1) Ship cables are rubber-insulated low-voltage cables. The research results of all the literature currently available are for medium and high-voltage power cables. The cable insulation materials are generally polyethylene (PE), cross-linked polyethylene (XLPE), polychloride Vinyl (PVC) and paper insulated cables (PILC), so ship cable insulation testing lacks the support of literature research results;

[0010] (2) Since the ship's cables are low-voltage cables, in other industries, such as the power industry, low-voltage cables have good accessibility, small replacement engineering, and destructive methods can be used for cable preventive tests. After problems are found, replace the cables in time to solve the problem , so the research on the insulation nondestructive testing method of low-voltage cables has not attracted enough attention, and there is also a lack of relevant standards and criteria, and the current cable test technology is obviously lagging behind the cable manufacturing technology and application technology. The original standards and regulations, such as " In the "Preventive Test Regulations for Power Equipment", only a small amount of space is used to mention the pre-test method after the cable is put into operation, which is not operable;

[0011] (3) Although the 0.1Hz sinusoidal voltage test, dielectric loss tangent value test and insulation resistance test can meet the technical requirements of ship cable inspection, there is currently no unit that has engaged in the evaluation of the insulation state of ship cables, and no engineering value has been retrieved. data, lack of references to historical data

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