Formation and propagation characteristics of pseudo-wavefronts of optical polarization states signal inside OPGW under lightning strikes

Abstract

Lightning strikes on Optical Fiber Composite Overhead Ground Wires (OPGW) result in a phenomenon where the current traveling wave along the OPGW’s outer stranding propagates faster than the optical signals inside the fiber. This leads to the emergence of pseudo-wavefronts ahead of the optical polarization state signal after lightning strikes OPGW, introducing errors in lightning point localization based on the optical polarization state. This paper investigates the formation and propagation characteristics of pseudo-wavefronts. The study employs theoretical analysis and simulation to examine the process of optical polarization state formation during OPGW lightning strikes. Additionally, it conducts comparative analyses between laboratory-simulated OPGW lightning strikes and field measurements obtained from OPGW lightning monitoring systems. The results affirm the existence of the proposed pseudo-wavefront phenomenon, which substantially impacts the precision of lightning point localization. Notably, the duration of pseudo-wavefront effects increases with greater distance from the lightning point and higher lightning current amplitudes. These findings raise questions regarding the suitability of traditional wavefront calibration methods based on the traveling wave approach. This research contributes valuable insights for the practical implementation of lightning point localization methodologies relying on OPGW self-sensing technology.