A water tree accelerated aging method for XLPE medium voltage cables

Abstract

The invention discloses an accelerated aging method for a water tree of a crosslinked polyethylene intermediate voltage cable. The accelerated aging method comprises the following steps: selecting the crosslinked polyethylene intermediate voltage cable, and disassembling a metal shielding layer; peeling external semiconductor layers at two ends of the cable, and taking the two ends of the cable after the external semiconductor layers are peeled as persevered edge surfaces and remaining part as an effective segment of the cable; penetrating a crosslinked polyethylene cable of the effective segment of the cable by a needle or a drill for insulation, manufacturing defects, and winding the metal shielding layer on the external semiconductor layer of the effective segment of the cable; connecting an outgoing wire on the metal shielding layer; wrapping the effective segment of the cable with a sleeve, respectively performing water blocking treatment at two ends of the sleeve, filling a saline solution in the sleeve, and enabling the outgoing wire to extend out of the sleeve; grounding the core of the cable, and enabling the outgoing wire to be connected with a high voltage power supply so that the cable can be aged. According to the method, the testing apparatus is simple, the cable samples are easily manufactured, the aging period is short, the outer water tree can be effectively generated on the insulating layer of the crosslinked polyethylene cable, the method more accords with the actual situation, and the method has higher research value.

Description

technical field [0001] The invention relates to the field of power cable detection, in particular to a water tree accelerated aging method for cross-linked polyethylene medium-voltage cables. Background technique [0002] Power cables using cross-linked polyethylene (XLPE) as the main insulation have superior electrical properties, good heat resistance and mechanical properties, and are easy to lay and install. Since most cables are directly buried or laid in pipelines, after the cables are put into operation, they will be affected by electrical, mechanical, chemical, heat, light and other factors, which will cause aging and affect their life. The water tree aging of XLPE cable insulation during operation has always been the most important fault form in the natural aging fault of cables, which affects the safe and stable operation of cable lines. Therefore, the research on water tree insulation of XLPE cable insulation is of great significance to ensure the safe and stable o...

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: (1) The aging period is long, and the sample must withstand the water tree aging process accumulated for several months or even longer under the specified voltage; (2) The experimental method is complicated and cumbersome

This method has the following defects: (1) The requirements for the electrode are high, and the surface of the electrode must be well integrated with the slice (the cross-section usually needs to meet the Rogowski cut plane), otherwise there will be electric field distortion points and partial discharge

(2) The device is complex, and it is necessary to customize the test device according to different cable cross-sections

(3) Only slices with water trees can be made, but no test samples can be provided for laboratory research on the power cable detection and diagnosis system

(4) Applying a voltage of 10,000V to a cable sample with a thickness of 1mm will easily lead to direct breakdown of the cable sample

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