Integrated Model for Lightning Strikes on a Tall Structure: Application to a Wind Turbine System

This article presents an integrated model of the lightning channel and tall structure on the ground for lightning analysis, by considering their interaction. An extended distributed circuit is proposed for modeling the lightning channel, by including the dynamic behavior of the corona sheath. The nonlinear, nonuniform, and time evolution characteristics of the lightning channel are taken into account. Meanwhile, the wire structure on the ground is modeled with the partial element equivalent circuit method. A lumped voltage source is introduced to ensure an 'undisturbed' current waveform at the attachment point. A procedure is provided to determine this voltage source in a nonlinear circuit. The proposed model is verified with the experimental data of lightning-striking tall towers. This model then is applied to simulate lightning surges on a wind turbine system. A comparison with the simple current source model is made. Significant oscillation is found with the simple current source model, which is not in correspondence with the observation result under natural lightning.