Improving sensitivity of FBG strain sensor embedded in polymer attached at transformer core

In this work, a methodology to measure deformation directly in the iron core of a power transformer using optical sensors is presented. The vibration of a power transformer is mostly generated in the core. Therefore, a clip support of a carbon fiber reinforced polymer with embedded fiber Bragg gratings (FBG) sensors was manufactured. The optical clip sensor can be operated in a wide range of frequencies. The sensitivity can be controlled by varying the stiffness of the clip. The static and dynamic characteristics of this sensor embedded in the carbon fiber were verified and presented through the finite element method and experimental tests were conducted. Through a comparison of results with a non-encapsulated FBG sensor, the clip sensor achieved an average sensitivity of over 19 % and 10 % at the frequency peaks of 60 Hz and 240 Hz, respectively.