评估硅橡胶复合绝缘子老化的磁共振新方法  

Novel Magnetic Resonance Method for Assessing Aging Status of Silicone Rubber Composite Insulators

作　　者：余长厅 黎大健 陈梁远 赵坚 颜海俊 YU Changting;LI Dajian;CHEN Liangyuan;ZHAO Jian;YAN Haijun(Electric Power Research Institute of Guangxi Power Grid Co.,Ltd,Nanning 530000,China)

机构地区：[1]广西电网有限责任公司电力科学研究院

出　　处：《电工技术》2020年第1期121-124,共4页Electric Engineering

摘　　要：硅橡胶复合绝缘子的老化威胁着电网的安全,准确评估绝缘子老化状态是预防绝缘失效的必要条件。为此,提出了磁共振新方法来评估绝缘子的老化状态。首先,设计了一种单边磁共振传感器,传感器静态场沿垂直方向具有恒定的梯度,以便于测量不同深度的样品信息。其次,采用步进电机系统精确控制测量区域的穿透深度,在每个深度处使用CPMG脉冲序列获得横向弛豫衰减曲线。然后,利用基于傅里叶变换和带通滤波器的数据处理方法,提取所需深度层面样品的横向弛豫信息。最后,通过使用逆拉普拉斯变换获得每层的一维横向弛豫时间谱分布。试验对比了3种不同服务时间的220kV硅橡胶绝缘子,结果表明使用时间较长的绝缘子的弛豫时间较短。The aging of silicone rubber composite insulators threatens the safety of the power grid.An accurate evaluation of the insulator aging status is necessary for preventing insulation failure.In this paper,a novel unilateral nuclear magnetic resonance(NMR)method is proposed to evaluate the aging status of insulators.First,a single-sided NMR sensor is designed.The static field of the sensor possesses a constant gradient along the vertical direction to facilitate measurement of sample information at different depths.Second,a step motor system is employed to precisely control the penetration depth of the measurement area.At each depth,the transverse relaxation decay curves are obtained with the sensor by using the Carr-Purcell-Meiboom-Gill sequence.Third,a data-processing method based on FFT and band-pass filter is utilized.With this method,the transverse relaxation information of the sample with the desired depth level is extracted.Finally,one-dimensional transverse relaxation time spectrum distributions of each layer are obtained by applying the inverse Laplace transformation.The one-dimensional depth profiles taken from three kinds of 220 kV silicone rubber insulators with different service times are compared.The results demonstrate that the insulator with a longer service time is characterized by a shorter relaxation time.

关 键 词：老化状态 硅橡胶绝缘子 单边核磁共振 

分 类 号：TM216[一般工业技术—材料科学与工程]