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- 2015
电老化与加速水树老化对交联聚乙烯绝缘理化特性的影响
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Abstract:
为了研究电老化(ETA)和加速水树老化(AWTT)对交联聚乙烯(XLPE)绝缘理化特性的影响,分别对ETA和AWTT的实际电缆试样进行红外光谱(FTIR)、X射线衍射(XRD)和热质量分析(TG)测试,分析其理化特性随着老化的变化规律。建立了AWTT的微观模型,从微观形态变化、陷阱的形成角度对老化机理进行了深入分析。结果发现:ETA和AWTT试样绝缘内R1R2CCH2、―OH键均出现上升趋势,AWTT试样羟基增长速率大于ETA试样,而两种老化过程中双键的增加速率相当;ETA试样电缆绝缘结晶度先上升后下降,AWTT试样电缆绝缘结晶度呈下降趋势;ETA与AWTT都使得绝缘热稳定性下降,ETA试样的微分热质量(DTG)曲线未出现分峰现象,AWTT试样DTG曲线在老化后分裂出多个峰,老化时间越长分裂的峰越多。对试验结果进行分析,在老化过程中,理化特性的变化规律可以由微观模型结合陷阱的变化进行合理解释,老化过程中产生的陷阱对绝缘性能产生重要影响。
To reveal the effects of electrical aging test (ETA) and accelerated water tree aging test (AWTT) on physicochemical properties of XLPE insulation, the actual cable samples of ETA and AWTT were tested by infrared spectroscopy (FTIR), X？？ray diffraction (XRD) and thermogravimetric analysis (TG), and the changing rule with aging of physicochemical properties was analyzed. A microscopic structure model of AWTT was established, and aging mechanism was deeply discussed from the aspects of morphology and the formation of traps. It is found that R1R2CCH2 and ―OH in ETA and AWTT samples tend to increasing. The growth rate of ―OH in AWTT samples is higher than that in ETA samples, while the growth rates of double bond in both ETA and AWTT samples are almost the same. The crystallinity of ETA samples increases first and then decreases, while that of AWTT samples becomes smaller, and the thermal stability of ETA and AWTT samples gets worse. Peak separation in DTG curves of ETA samples is not found, but multiple peaks can be found in the DTG curves of AWTT samples and more peaks are found after a longer aging period. The results suggest that the established model combing with the change of charge traps well explains the change of the physicochemical properties during aging, and the traps exert obvious effect on insulating properties of XLPE
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