Method for predicting service life of direct-current self-healing metallized film capacitor

Abstract

The invention discloses a method for predicting the service life of a direct-current self-healing metallized film capacitor, and the method comprises the steps: measuring the capacitance C0 and the test voltage Ui of the direct-current self-healing metallized film capacitor before a test, and carrying out an aging test; measuring the capacitance of the direct-current self-healing metallized film capacitor at preset intervals to record capacitance values Cx at different moments and a capacitance difference delta C between adjacent measurements; disassembling the direct-current self-healing metallized film capacitor to obtain a film capacitor core; disassembling the film capacitor core layer by layer to obtain an aged internal film sample; counting the lost areas of the metal electrode in the multiple sections of samples to obtain area loss data at different positions, and analyzing the area loss data through logarithmic normal distribution to obtain a fitting result so as to calculate the average lost metal electrode area Sn of each breakdown point; and drawing images on Weibull coordinate paper according to the failure probability phi and the service life t to obtain a model that the service life of the capacitor is influenced by the self-healing characteristic of the local metallized film.

Description

technical field [0001] The invention belongs to the aging technical field of DC self-healing metallized film capacitors, and in particular relates to a life prediction method for DC self-healing metallized film capacitors. Background technique [0002] Metallized film capacitors have self-healing properties because their nanometer-thick metal electrodes can recover their insulating properties after evaporation loss under the action of high-current heat formed during the electroweak point breakdown process in the medium. This feature endows metallized film capacitors with high reliability and large capacity, and is widely used in engineering fields such as UHV AC and DC transmission systems and flexible DC transmission systems. In actual operation, the self-healing process of the metallized film continues to occur, so that the loss of the metal electrode leads to a decrease in the capacity of the capacitor, and then the life of the capacitor ends, which ultimately affects the...

AI Technical Summary

Problems solved by technology

In actual operation, the self-healing process of the metallized film continues to occur, so that the loss of the metal electrode leads to a decrease in the capacity of the capacitor, and then the life of the capacitor ends, which ultimately affects the safe and reliable operation of the engineering system where the capacitor is located.

However, the existing life evaluation methods for self-healing metallized film capacitors are limited, so it is of practical significance to explore the prediction method of the end of life of metallized film capacitors

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