Damage Characteristics of OPGWs Under Consecutive Lightning Strikes Based on a Coupled Arc-Thermal-Electric Simulation

This paper studied the damage characteristics of optical fiber overhead ground wires (OPGWs) under consecutive lightning strikes through artificial lightning experiments, numerical simulations and arc-OPGW interaction analysis. A magnetohydrodynamic (MHD) simulation model for consecutive lightning arcs was developed based on the similitude theory. The spatiotemporally varying thermoelectric fields obtained from arc simulation were applied to OPGWs by a stepwise partitioned loading approach to accomplish the coupled arc-thermal-electric analysis. The numerical model simulating the thermal damage behavior of OPGWs was verified by the high agreement between the simulated damage parameters and the experimental results. Under consecutive lightning strikes A, B and C, the damage volume varies non-monotonically with increasing discharge gap. The damaging effects of components A and B are characterized as slight distortion on the shallow surface of the strands. The strand fracture where severe melting and plastic deformation coexist is governed by the heat flow from the lightning arc of long-duration continuing current. In contrast, the Joule heating effect is negligible. The damaging effect of the lightning component in the successively applied lightning strike sequence is significantly stronger than its effect when applied alone, indicating the necessity of conducting consecutive lightning strike tests for OPGW performance assessment.