基于核磁共振原理的复合绝缘子老化问题研究

Aging Detection of Composite Insulator with Nuclear Magnetic Resonance Theory

复合绝缘子老化的检测方法主要有直接观测法、紫外成像法、红外成像法、超声波法、电场分布法、憎水性检测法、泄漏电流检测法等。由于以上各种检测方法都有各种各样的不足之处而未能得到广泛的使用,笔者提出用核磁共振仪对使用不同年限的复合绝缘子进行实验,找出了能够表征复合绝缘子老化程度的特征量——横向弛豫时间和波峰面积。同时用阻抗分析仪测量复合绝缘子的相对介电常数,与横向弛豫时间和波峰面积比较,三者的变化规律相同,进而证明选取该特征量能够合理反应复合绝缘子的老化程度。

The existing composite insulator aging detection methods,such as direct observation method,ultraviolet imaging method,infrared imaging method,ultrasonic method,electric field distribution method,hydrophobicity measurement method,and leakage current measurement method,are deficient.Therefore,the authors carried out lots of experiments on the composite insulators of different service years based on nuclear magnetic resonance to measure the inversion parameters,and achieved two characteristic quantities-horizontal relaxation time and area of wave crest which can represent the aging state of insulators.Relative permittivity of the composite insulators was measured by impedance analyzer to compare with horizontal relaxation time and area of wave crest,and the same trend of three parameters shows that the horizontal relaxation time can reasonably reflect the aging state of insulators.