Evaluation of currents and charge in surge protective devices in low-voltage distribution networks due to direct lightning strikes

Abstract

This paper presents an evaluation of the values of currents and charges absorbed by surge protective devices (SPDs) connected in low-voltage open-wire overhead distribution networks in the case of direct lightning strikes to primary lines. The calculations have been performed using the ATP (Alternative Transients Program). The system's components modelling includes the insulation characteristics (voltage versus time to breakdown) of the primary and secondary insulators. A distribution transformer model for high frequencies which takes into account the load conditions. Several parameters of interest are taken into consideration in the analysis, such as ground resistances of poles and consumers, lightning strike position, front time and crest value of the stroke current values of the loads components and the secondary line length. (4 pages)