A Methodology to Evaluate the Performance of Distribution Feeders Against Lightning: Fundamentals, Case Study and Computational Tool

Lightning is the main cause of service interruption on distribution feeders. Actions to reduce this problem depend of adequate design of structures, grounding and of the associated investments. In this paper the analysis is based on the flashover and backflashover calculation due to lightning using the Alternative Transients Program ATPDraw. Parametric studies using this software are performed to determine the sensitivity of the flashover and backflashover occurrence, taking into account some parameters of the distribution line. Models of the distribution system components are also presented. The models are based on the representation of the distribution line taking into account the frequency dependence of its electrical parameters. A dedicated software is developed, which allows analyzing the lightning performance of overhead distribution feeders as a function of the characteristics of different structures, groundings, soil resistivity and ground flash density. A summary of the procedures and calculation adopted in the application of the tool is presented.