Improved Modeling and Influencing Factors Analysis of the Sliding Motion of Arc Roots Along OGW During Lightning Strikes

When an overhead ground wire (OGW) is struck by lightning, the sliding motion of arc root (hereafter referred to as sliding motion) causes various lightning-induced damage mechanisms. To provide a data-based foundation for the analysis of damage mechanism and improvement of existing lightning-induced damage test method, it is necessary to analyze this sliding motion. In this article, a sliding motion model along the OGW was established based on the arc chain model. The proposed model was verified by an OGW rupture case caused by sliding motion and a needle-wire discharge experiment. Using the model, the factors influencing the sliding displacement of arc root (hereafter referred to as x(root)) were analyzed. The results showed that in the case of return stroke, the influence of nonuniform wind velocity distribution in the boundary layer and thermal buoyancy can be neglected. x(root) is positively correlated with the wave tail time but independent of the wave head time. In the case of continuing current, the nonuniform distribution of wind velocity in the boundary layer and thermal buoyancy can influence the results of x(root), with maximum errors exceeding 50% and 25%, respectively. In addition, the contribution of wind to the sliding motion can be neglected.