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随着复合绝缘子挂网运行时间的增加,复合绝缘子的老化日趋严重。为了方便快捷地检测复合绝缘子的老化程度,文中根据复合绝缘子伞裙护套的结构特点,设计了一种U型的便携式低场核磁共振传感器。测量样品为挂网运行不同时间的硅橡胶复合绝缘子,采用CPMG脉冲序列激励,得到样品的CPMG回波衰减数据。对CPMG回波衰减数据进行双指数函数拟合分析,得到硅橡胶伞裙材料的等效横向弛豫时间参数:t2,short和t2,long。实验结果表明,硅橡胶伞裙的t2,long参数与其老化程度有很好的对应关系,具体表现为随着绝缘子老化程度的加剧,横向弛豫时间t2,long逐渐减小。
With the increase of composite insulator hanging net running time, the aging of composite insulators is becoming more and more serious. In order to detect the aging degree of composite insulators conveniently and rapidly, a U-shaped portable low field nuclear magnetic resonance sensor was designed according to the structural characteristics of composite insulator sheds. The measurement samples are silicone rubber composite insulators for different times of hanging net operation, and CPMG echo attenuation data of the samples are obtained by CPMG pulse sequence excitation. Two-exponential function fitting analysis of CPMG echo attenuation data was used to obtain the equivalent transverse relaxation time parameters of silicone rubber skirt material: t2, short and t2, long. The experimental results show that the t2 and long parameters of silicone rubber umbrella skirt have a good correspondence with the aging degree. The concrete manifestation is that with the aggravation of insulator aging, the transverse relaxation time t2 and long decrease gradually.