Method for determining cross-linked polyethylene insulation voltage tolerance index of alternating-current cable

Abstract

A method for determining the cross-linked polyethylene insulation voltage tolerance index of an alternating-current cable comprises the steps of preparing a cross-linked polyethylene cable insulation test block, preparing and pre-processing a pin electrode, manufacturing a sample for an electrical tree test, conducting an electrical tree triggering test, processing data, obtaining the electrical tree triggering time and voltage in a voltage stepping-up test, conducting a constant-voltage test under the same voltage, measuring the electrical tree triggering time, and obtaining the cross-linked polyethylene insulation voltage tolerance index of the alternating-current cable through calculation. The method overcomes the defects of a traditional breakdown type accelerating electrical aging test that requirements for equipment are high, operation is difficult, a large amount of time and labor is needed, and the dispersity of design parameters is high, the measured cross-linked polyethylene insulation voltage tolerance index of the high-voltage alternating-current cable is stable, reliable and low in dispersity, and short-time and long-term voltage resistance of cable insulation can be reflected truly and effectively. The method can be adopted by both insulation design of new cables and remaining life evaluation of operating cables and provides a powerful guarantee for long-term stable operation of cables.

Description

technical field [0001] The invention relates to a method for determining the voltage withstand index of cable insulation materials, in particular to a method for determining the voltage withstand index of AC cable XLPE insulation. Background technique [0002] In recent years, in newly installed AC lines with a voltage level of 150kV and below, XLPE insulated cables have become the first choice, and their usage has greatly exceeded that of traditional oil-paper insulated cables; Cable usage is also on the rise. As early as more than ten years ago, AC 500kV XLPE cable products had passed the test and put into practical operation in Japan. In comparison, the overall development level of the domestic cable industry is still lagging behind, lacking independent research. [0003] The electrical aging performance of insulating materials is the basis for insulating structure design and reliability evaluation, and the voltage withstand index is a key parameter. The study found th...

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Problems solved by technology

[0011] In order to solve the above-mentioned problems in the prior art, the object of the present invention is to provide a method for determining the insulation voltage withstand index of AC cable XLPE, which overcomes the high requirements for equipment, difficult operation, time-consuming and labor-intensive design of the breakdown test. The shortcoming of large parameter dispersion, the method proposed in the present invention needs few samples, simple operation, and the voltage withstand index determined according to the method has small dispersion and high accuracy. It can be used in the evaluation of the remaining life of the active cables, which provides a strong guarantee for the long-term stable operation of the cables

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