Development of Optical Fiber Sensors Based on Brillouin Scattering and FBG for On-Line Monitoring in Overhead Transmission Lines

A distributed on-line temperature and strain fiber sensing system based on the combined Brillouin optical time domain reflectometry (BOTDR) and fiber Bragg grating (FBG) technology is presented and investigated experimentally for monitoring the overhead transmission lines. The BOTDR sensing system can be used to measure the temperature of transmission lines (Optical Phase Conductor, OPPC or Optical Power Ground Wire, OPGW) which is helpful for monitoring the dynamic ampacity and icing forecasting. In order to effectively monitor the distortion of transmission line induced by the climatic fluctuation and natural disaster, e.g., ice coating and hurricane wind, a quasi-distributed FBG strain sensing system is connected in series with the insulator, integrated into the BOTDR system. The results showed the proposed system was effective and reliable for the monitoring of overhead transmission lines.