Research on strain and temperature measurement of OPGW based on BOTDR

OPGW(Optical Fiber Composite Overhead Ground Wire) is an important part of high voltage transmission lines with characteristics of wide distribution and long distance. It is difficult for routine inspection and status detection by traditional method. So, it is necessary to monitoring the status of OPGW using distributed optical fiber strain and temperature measurement device. In this paper, the strain and temperature calibration experiment of composite optical fiber in OPGW was completed using BOTDR (Brillouin Optical Time Domain Reflectometry). The difference of Brillouin frequency shift coefficients to strain and temperature and initial frequency shifts between different optical fibers were compared. The method to accurately locate connections was provided using distributed Brillouin frequency shift curves. The status monitoring for running OPGW was realized and the data was analyzed. Results indicate that, the frequency shift coefficients to strain and temperature of single mode fibers in one OPGW are almost the same, which are 0.05MHz/μ(epsilon) and 1.05MHz/°C, but the initial frequency shifts are different with 20MHz range. The Brillouin frequency shifts at fiber connections in change obviously, which can serve as locating basis for connections. The topography, span, mark-height and climate affect the strain and temperature distribution of OPGW.