The Impact of Peak Current Distribution on the Calculation of Backflashover Rate of Transmission Lines

This work presents an investigation of the effect of cumulative peak current distribution on the calculation of the lightning performance of high voltage transmission lines in terms of backflashover rate. The evaluations considered the current distributions proposed by CIGRE, IEEE, and the one based on data measured at Morro do Cachimbo station, Brazil. The results obtained by the systematic application of the CIGRE methodology to calculate the backflashover rate of typical 138-kV transmission line indicated a large difference between the outages related to MCS distribution in comparison with those of CIGRE and IEEE distributions. In some cases, differences in the range of 45 to 80% are indicated, denoting the importance of an adequate definition of this parameter on calculations of the lightning performance of transmission lines.