Measurement method for detecting degree of aging of XLPE cable based on depolarization current approach

Abstract

The invention relates to a measurement method for detecting the degree of aging of an XLPE cable based on a depolarization current approach. First, the depolarization current of offline cable discharge is measured. Charging and short-circuit discharging are carried out on cross-linked polyethylene (XLPE) insulated cable samples of different specifications. In the charging process, a sample starts to be polarized under step excitation at a voltage U0, the duration of continuous polarization is tp, and the current flowing through the sample is a polarization current ip. After the voltage is removed instantaneously, the sample produces a discharge current in the opposite direction due to short circuit, namely, a depolarization current id. Then, the size of the aging factor A is calculated, and the degree of aging of the XLPE cable is judged. The aging factor of the cable is calculated based on the depolarization current, and the degree of aging of the cable is judged according to the relationship between the aging factor A and the insulation condition. The depolarization current approach can be applied to the detection of a whole cable. The test is faster, simpler, more sensitive and more accurate. No damage is caused to cables.

Description

technical field [0001] The invention relates to a cable aging measurement technology, in particular to a measurement method for detecting the aging degree of an XLPE cable based on a depolarization current method. Background technique [0002] Due to the electrical tree and water tree aging phenomenon caused by the long-term operation of the cable, the higher the aging degree, the worse the insulation performance of the cable. With the development of the national economy, the user's electricity load is increasing year by year, and cable faults caused by various reasons are becoming more and more frequent. In addition to human factors, most cable accidents are caused by cable insulation aging. Power outages caused by insulation aging may lead to huge economic losses and seriously endanger the safety of the power grid. Once a fault occurs, it will affect the safe and stable operation of the equipment and cause large-scale power outages. To this end, it is necessary to detect...

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Problems solved by technology

It should be pointed out that the withstand voltage test may cause some damage to the test product, thus affecting the insulation life

Insulation resistance and dielectric loss tangent test are the most commonly used detection methods in power systems, but the test results of this test method are single, and are limited by the capacitance of the cable. If the capacitance of the cable is not within the preset capacity range, the cable The measurement results of the insulation performance are not accurate enough to accurately reflect the aging degree of the cable

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