Distribution Network Impact Assessment with Geometrically Identified Strike Points: An Approach

This paper presents an algorithm to generate direct and indirect strike points for lightning impact assessments. The proposed method uses the Electrogeometric Model to define the strike range limit, such that the generated events fall inside the range that would cause insulation failure. In this way, the non-potential strike events are excluded before carrying out additional computations, without requiring any complex algorithm for the event filtration. This method has been implemented to assess 17 arrester-based protection schemes with different arrester spacings. The assessment revealed the overvoltage impact levels at different nodes of the network concerned in the case study. It is proposed that the commonly accepted fact that the impact level generally increases with the increasing arrester spacing, may not be always true. Instead, there can be a range of spacing distances with abnormalities. Also, it was noted that the severity ranking of the distribution transformers in the assessed network varied with the protection scheme. Thus, it is recommended to perform a prior analysis in implementing a planned protection scheme.