Simulated Analysis and Protection Optimization Induced Lightning Overvoltage of Port Crane Festoon Cables

Port cranes, with their tall metallic structures operating in exposed coastal environments, are highly vulnerable to lightning strikes. The festoon cable system, critical for power and signal transmission, represents a key point of vulnerability due to its limited insulation resilience against induced lightning overvoltages, often leading to operational failures and safety hazards. This study investigates the lightning protection of these cables using the ATP-EMTP electromagnetic transient simulation platform. An equivalent model of the crane girder and festoon cable system was developed to analyze the characteristics of induced overvoltages when lightning strikes the girder. The protective efficacy of both cable shielding and surge arresters was rigorously evaluated. Simulation results reveal that while an external shielding layer can significantly suppress overvoltage in the core conductor by 71.4%, it concomitantly elevates the shield’s own potential, creating a risk of insulation breakdown. Furthermore, the performance of conventional shielding degrades under the dynamic bending conditions typical of crane operation; at a 0.5 m bending radius, shielding effectiveness drops to 15.0 dB, whereas a highly flexible shielding maintains a superior effectiveness of 33 dB. To address these challenges, an optimal protection configuration is proposed, involving the connection of both inner and outer shielding layers to surge arresters with a common ground. Analysis of the surge arrester’s energy ab-sorption confirms the robustness of this design. The findings demonstrate that this integrated approach provides the most effective overvoltage mitigation. This research offers a practical theoretical foundation and valuable engineering insights for the enhanced insulation coordination and lightning protection design of port crane cable systems.