The thermal factor is one of the key factors influencing the microstructure of the crosslinked polyethylene(XPLE)insulation layer in the high-voltage cable.This study selects a 7 year serviced cable and a new cable respectively to prepare for sheet XPLE samples.Firstly,it conducts heating aging tests for the samples for 180 days at 105 ℃ and then short-term heating treatment for 20 h at constant temperature at 90～105 ℃.Afterwards,the study carries out the tests of crosslink degree,differential scanning calorimetry(DSC)and high field conductivity.The results reveal that in the early stage of aging,heating aging is contributed to crystallization of the XPLE and heating treatment is helpful to increase of fusing temperature and crystallinity,reduction of crystal size distribution and the electrical conductivity.With the increase of heating treatment temperature,the above parameters gradually reach to the optimal values and change reversely.As the aging degree deepens,the promotion effect of each parameter after the same heating treatment decreases,showing as reduction of the heating temperature corresponding to the optimal value of the parameter and gradual reduction of the difference with the non-aging sample.After 180 days of aging,all parameters are notably lower than those of the non-aging samples.The study indicates that short-term heating treatment at a reasonable temperature effectively enhances the internal crystallization characteristics and thermoelectric properties of XPLE after the heating aging.
关键词
高压电缆/交联聚乙烯/短时热处理/差示扫描量热/交联度/高场强电导
Key words
high-voltage cable/XLPE/short-term heat treatment/differential scanning calorimetry(DSC)/crosslink degree/high field conductivity
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万方数据