With the increasing of the service time of silicone rubber insulators in the power system,the aging problem of the silicone rubber insulators has been more serious. In order to measure the aging of insulators,and according to the structure of the insulators,we designed a portable nuclear magnetic resonance(NMR)sensor with a Ushape structure. The composite insulators with different service years had been measured,and a Carr-Purcell-Meiboom-Gill(CPMG)sequence was employed as the excitation. The CPMG echo atte...