Fiber Bragg Gratings Hydrogen Sensor for Monitoring the Degradation of Transformer Oil

In this paper, two fiber Bragg gratings (FBGs) sensors, which are based on different palladium (Pd) coatings ratios, was proposed to detect the dissolved hydrogen gas content in transformer oil. The FBG samples were prepared using a physical vapor deposition technique. Two samples were prepared with different Pd coating compositions. The first sample was coated with 100% Pd (Pd-100), and the second sample was coated with mixture of Pd chromium (Pd58Cr42) that has a ratio of 58:42. Pd-100 sensor showed faster response to dissolved hydrogen than the Pd58Cr42 sensor. In addition, the Pd-100 sensor exerted higher strain at lower dissolved hydrogen content to the FBG compared with the Pd58Cr42 sensor. The Pd-100 sensor has higher sensitivity, and the response range is limited to lower hydrogen content. This paper has showed the potential of using alloy like chromium to the Pd metal to enhance the dissolved hydrogen detection range.