Analysis of influencing factors of lightning strike damage of optical fiber composite overhead ground wire in distribution network

Optical fiber composite overhead ground wire (OPGW) is vulnerable to lightning strikes and causes ablation damage. The ablation arc involves a complex nonlinear electromagnetic heat plasma discharge process. In this paper, the strong and weak coupling relationship between electromagnetic thermal fluids during the development of lightning dynamic arc is fully considered, and the dynamic ablation model of OPGW lightning strike process in distribution network is established. The simulation test of lightning strike ablation damage of OPGW in distribution network is carried out, and the influence of transferred charge, OPGW cross section and lightning current component on lightning strike damage of OPGW is compared and analyzed. Through the establishment of OPGW lightning experimental platform, the influence of transfer charge and OPGW section on OPGW lightning damage is studied, and the lightning strike phenomenon of continuous lightning current BC component on OPGW of distribution line is simulated. In the experiment, the transfer charge of lightning current C component and OPGW model are changed to simulate the damage effect of OPGW under different lightning amplitudes and different models. The simulation results show that the amount of transferred charge increases from 50C to 150C, the ablation depth increases by 4.6 times, and the ablation area increases by 11.5 times. The small cross section of OPGW is greatly affected by the damage, but its overall performance is less affected. The continuous ablation of lightning arc at high temperature is the main cause of lightning damage of OPGW. The ablation depth and ablation area of A+B+C component of multiple lightning current are 34.75% and 61.5% larger than those of A+C component of continuous lightning current, respectively. The maximum difference between the experimental results and the simulation results with the ablation depth as the control is not more than 7.2%. Therefore, the appropriate OPGW model should be selected according to the local lightning disaster situation and construction conditions.