湿热环境硅橡胶含水率的激光诱导击穿光谱检测

Detection of Moisture Content of Silicone Rubber by Laser⁃induced Breakdown Spectroscopy in Humid and Hot Environment

湿热环境中,硅橡胶含水率过高会导致复合绝缘子老化加剧及温度升高等问题,目前缺乏一种能够对运行硅橡胶绝缘子含水率带电检测的手段。文中提出一种基于激光诱导击穿光谱技术的硅橡胶含水率检测方法,研究了延迟时间、激光能量等参数对于光谱质量的影响,并且比较了不同特征谱线强度与含水率的定标结果。结果表明,延迟时间为3μs时光谱质量最优,此时连续背景谱几乎衰减消失并且线性谱仍保持一定强度;激光能量较高时,水分在高温下蒸发对等离子体形态的影响程度提高,进而削弱特征谱线强度随含水率的变化趋势,激光能量为35.4、44.7 mJ时变化趋势较明显;H、O、N等元素谱线强度均与含水率之间具有一定的线性关系,其中激光能量为44.7 mJ时,O I 844.622 nm的定标结果拟合效果最好,拟合优度为0.8979,表明激光诱导击穿光谱技术能够对硅橡胶含水率进行定量分析,用于检测运行复合绝缘子的含水率,保障硅橡胶复合绝缘子的稳定运行。

Excessive moisture content of silicone rubber in the humid and hot environment can lead to such prob⁃lems as accelerating aging and rise of temperature of composite insulator.At present,there is a lack of a means for live detection of moisture content of silicone rubber insulator in operation.In this paper,a kind of method for mois⁃ture content detection of silicone rubber based on laser⁃induced breakdown spectroscopy is proposed.The effects of such parameters as delay time and laser energy on spectral quality are studied and the calibration results of different characteristic spectral line intensity and moisture content are compared.The results show that the spectral quality at the delay time of 3μs is the best and,at this time,the continuous background spectrum almost decays and disap⁃pears and the linear spectrum still maintains a certain intensity.In case of high laser energy,the degree of influence of moisture evaporation on plasma morphology is enhanced,and the variation trend of characteristic spectral line in⁃tensity with water content is weakened.The variation trend in the case of laser energy at 35.4 mJ and 44.7 mJ is more obvious.And there is a certain linear relationship between the spectral line intensity of H,O and N elements and the moisture content.When the laser energy is 44.7 mJ,the fitting effect of the calibration result of O I 844.622 nm is the best and the goodness of fit is 0.8979,indicating that laser⁃induced breakdown spectroscopy can quantitatively ana⁃lyze the moisture content of silicone rubber.It is used to detect the moisture content rate of the composite insulator in operation and assure stable operation of the silicon rubber composite insulator.