Low-temperature electric tree aging assessment method based on direct-current harmonic wave superposition

Abstract

The invention discloses a low-temperature electric tree aging assessment method based on direct-current harmonic wave superposition. The insulating state of an insulating material for a high-temperature super-conduction direct-current voltage cable is effectively assessed by an electric tree length method. The method comprises the following steps: 1) preparation of an epoxy resin testing sample based on a needle-plate electrode: connecting a needle electrode to a high voltage, grounding a plate electrode, placing the sample on a plate electrode, and fixing the sample between two transparent glass sheets by adopting a needle-plate electrode system; 2) carrying out an experiment by using an electric tree experiment system device in a low temperature environment; 3) observing the internal electric tree aging condition of the sample through an electric tree observing device; and 4) performing calculation by adopting a ScreenRuler virtual ruler. Through adoption of the low-temperature electric tree aging assessment method, the aging degree of the insulating material for the high-temperature super-conduction direct-current voltage cable can be effectively assessed by an electric tree length measuring method.

Description

technical field [0001] The invention belongs to the field of high-voltage equipment, and in particular relates to a low-temperature electric branch aging evaluation method based on direct current superimposed harmonics. Background technique [0002] With the rapid development of the power industry and the expansion of the grid scale, the requirements for power transmission are getting higher and higher, and superconducting cables have become a hot direction for future development. High-temperature superconducting (HTS) cables, as the next-generation power transmission medium, are widely used in power transmission systems at home and abroad because of their almost non-resistance characteristics, high-capacity, low-loss transmission, and compact structure and easy laying. In practical applications, epoxy resin insulating materials are widely used in the accessories of high-temperature superconducting cables because of their excellent electrical and physical and chemical proper...

AI Technical Summary

Problems solved by technology

The resulting insulation breakdown seriously endangers the safe and stable operation of the power system.

[0003] For the operation process of high-temperature superconducting DC cables, they are under a certain amplitude of DC voltage, and the converter transformer will appear harmonic voltage due to the conversion of AC and DC voltages, which will lead to the occurrence of DC superimposed harmonics in superconducting DC cables. The appearance of composite voltage will have an adverse effect on the normal operation of the DC cable, and it will easily cause the aging and breakdown of the electrical branches of the DC cable insulation, which seriously threatens the safety and service life of the cable insulation.

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