Fig. 1. Transmission line icing and tower collapse accidents

Fig. 2. Distribution of scattered light in the fiber

Fig. 3. Scattering in optical fibers

Fig. 4. Schematic of OTDR principle

Fig. 5. Schematic of the structure of the ROTDR system

Fig. 6. Schematic of the structure of the BOTDR system

Fig. 7. Schematic of the structure of the BOTDA system

Fig. 8. Schematic of optical fiber deformation caused by external vibration

Fig. 9. Schematic of Φ-OTDR system structure based on heterodyne coherent detection

Fig. 10. The equivalent density of iced wires at different icing thicknesses

Fig. 11. ADSS cable monitoring system based on BOTDA

Fig. 12. Diagram of multi-dimensional parametric distributed optical fiber sensing prototype system structure

Fig. 13. Spatial distribution of Brillouin scattering power spectra

Fig. 14. Two-dimensional distribution of vibration signals in space and time

Fig. 15. Distribution of vibration signal power accumulation value

Fig. 16. Spatial distribution of Brillouin scattering center frequencies