A probabilistic model to evaluate characteristics of lightning channels in two-layer soils and application

Lightning-caused breakdown channels in ground may be intercepted by buried cables and suffer damage. Assessment of the possibility of such occurrences is important in the design of protection schemes and mitigating strategies. Existing models are based on diffusion of lightning current into the homogeneous soil. They do not model breakdown channel formation in ground and ignore soil non-homogeneity. In this paper a representative two-dimensional model is presented which accounts for the random growth of channels in two-layered non-homogeneous soils. The influence of lightning current magnitude, geometric configuration and soil parameters has been considered. The results obtained are in agreement with observed phenomenon. The suggested model provides a means for complete assessment of the lightning performance of buried cables.