In order to timely discover and differentiate the faults in optical fiber composite submarine cables

a novel multi-scale wavelet analysis-based detecting and diagnosing method is proposed in this paper.By this method

the Brillouin scattering frequency shifts in submarine cable fibers are first measured by using a Brillouin optical time-domain reflectometer and then the fault spots are detected and analyzed by using the dual-threshold method.The grounded faults are diagnosed by using the threshold method

but the ungrounded faults are decomposed in 8scale by using coif2wavelet basis.The research results indicate that anchor damage and overheating faults caused by partial discharges in plastic sheath can be effectively diagnosed by using the sensitivity of high frequency coefficient scale of wavelet decomposition to spatial distance.On the basis of analyzing the features of submarine cable faults

the effectiveness of this approach is verified by setting up the simulation data of submarine cable faults.