Analytical Investigation of Lightning Strike-Induced Damage of OPGWs Based on a Coupled Arc-Electrical-Thermal Simulation

Abstract

This study investigated lightning-induced damage of optical fiber overhead ground wires (OPGWs) through damage measurements, numerical simulations and influencing factor analysis. A high-precision damage measurement method was proposed to calculate the lightning damage volume based on laser profile scanning and a developed data processing program. The time-and-space-varying current and heat flows obtained from an arc magnetohydrodynamic model were loaded on OPGWs by stepwise segmental injection to establish a coupled arc-thermal-electric model and simulate the heating and damage behavior of OPGWs. The comparisons indicated that the simulated metal phase transition region agreed well with the actual damage distribution, and the area surrounded by the aluminum melting point isotherm provided a good prediction of the arc sweep damage. The hysteresis of the temperature rise suggested that lightning damage was dominated by heat flow conduction rather than the Joule heating effect. Furthermore, the continuing current was the main cause of severe damage. The damage volume increased linearly with increasing charge transfer. As the discharge gap increases, the arc loading intensity decreases, but the damage volume undergoes a non-monotonic change, which is due to the complex variations in the arc attachment area regulated by the discharge gap and current intensity.