Lightning performance of aerial distribution lines with neutral wire and conductive poles

This paper presents a set of formulas to compute the peak-value of LIVs on aerial distribution lines, considering the presence of a multi-grounded neutral in the line. The formulas are used in conjunction with the Monte Carlo method for the assessment of lightning flashover rates of aerial distribution lines, considering soil resistivity values from 0 to 10 kΩ·m. It is considered the effect of multi-grounded neutral on conductive poles and the lightning performance is assessed from phase-to-ground and phase-to-neutral lightning induced voltages. The results show that lines without neutral wire are subjected to relatively high indirect flashover rates, even if they are well insulated. If the same lines are equipped with a neutral wire and this wire is attached to the conductive pole directly or by means of a weak insulator, the flashover rate due to direct flashes remains almost the same, but the flashover rate due to indirect flashes falls abruptly. This behavior is observed even if the line is built over very high resistivity soils (e.g., several kΩ·m).