Evaluating Lightning Channel-Base-Current Function Parameters for Identifying Interdependence of Wavefront and Tail by PSO Method

Abstract

Lightning channel-base-current (CBC) function parameters for negative first return stroke (NFS), negative subsequent return stroke (NSS), and positive first return stroke (PFS) are evaluated using particle swarm optimization (PSO) technique. In this paper, parameters ( I01 , I02 , τ 11 , τ12 , τ21 , τ22 , n1, and n2 ) in the sum of two Heidler's CBC function are identified using PSO as a tool for the typical (50%) and severe (5%) cases of NFS, NSS, and PFS reported by IEC Standard 62305-1, 2010. The result of PSO tuned CBC, the error between computed and measured as given in the standard was calculated and a good agreement was observed. Heidler's function parameters (HFPs) are also tuned to keep four constants with systematic variation of one out of all prominent parameters ( I m , (di/dt) max, tFD , tSD , and Q ) of full (front and tail) CBC wave of NFS and NSS. Interdependence between these parameters is scrutinized during resemblance of the computed and the measured CBC. This is an attempt to show that a PSO can be used for identifying HFPs to straightforwardly obtain the CBC full wave. Thus, the data generated and reported including extreme severe case (1%) can produce a tailor-made full wave of CBC. Furthermore, this approach will be needful in research related to the lightning CBC characteristics.