| Recently, the research of vegetable insulating oil has become a pop project at home and abroad. Flash point of vegetable insulating oil is higher than 300℃, so it is a fire resistant oil. It will not pollute the water and inhabited area, whose biodegradable percent is larger than 97%. The output and quality of oil corps are improved by using gene techniques, and the reserves of mineral oil become decreased, so vegetable insulating oil could be the green substitute as mineral oil. However, as a new insulation material, vegetable insulating oil is quite difference from mineral oil in physical & chemical properties and electrical properties. In this paper, the domestic and overseas research situation of vegetable insulating oil was summarized and analyzed; from the several aspects of optimizing the refining process of vegetable insulating oil, hydrogenation modification, dielectric properties and breakdown characteristics of transgenic rape-seed insulating oil and its oil-paper insulation, basic property of transgenic rape-seed insulating oil was researched, the advantage and disadvantage of rape-seed oil for using as insulating oil was also researched. The author of this article does experimental research in following aspects:①According to the chemical composition and molecular structure of vegetable oil, the basic principle to choose crude vegetable oil is brought forward, and the transgenic rape-seed oil is selected as crude oil of insulating oil finally. The refining process of vegetable oil based on orthogonal experiment and current refining technology of oil was optimized. Hydrogenation modification of rape-seed insulating oil is also studied to improve rapeseed oil's antioxidation ability. According to related standards of transformer oil, the physical & chemical properties of the rape-seed insulating oil are measured and analyzed. The results show that various physical and chemical properties of rape-seed insulating oil basically research transformer oil's standards.②Based on the research of the links between microscopic parameters and macroscopic parameters of insulating materials'dielectric properties, dielectric properties of rape-seed insulating oil and its oil-paper insulation are measured by using dielectric spectrum detection technique. The dielectric macroscopic parameters of rape-seed insulating oil and its oil-paper are analyzed from microcosmic aspects. The dielectric properties of mineral oil and its oil-paper are measured as well. Through comparative with dielectric frequency spectrums and temperature spectrums of two kinds of insulating oil and oil-paper, the results show that vegetable insulating oil and oil-paper insulation are of good dielectric characteristics.③Power frequency breakdown and impulse breakdown strength of rape-seed insulating oil are tested in reference of correlated test standards of insulating oil dielectric strength. The breakdown characteristics of rape-seed insulating oil are analyzed according to dielectric breakdown mechanisms. It is found that the breakdown voltage of rape-seed insulating oil is higher than mineral oil and the breakdown characteristic of rape-seed insulating oil is related to itself chemical components.④Because of oil-paper insulation's important role in transformer insulating, the paper also introduces an experiment and research on breakdown characteristics of rape-seed oil-paper insulation and oil-paper composite insulation structure. Above test results show that rape-seed insulating oil is favorable to improve breakdown voltages of oil-paper insulation structures, and they provide experiment basis for the insulation structure designing of environmental-friendly transformers.
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