Lightning overvoltages on complex low-voltage distribution networks

This paper presents a theoretical investigation on lightning overvoltages on low-voltage (LV) networks installed in urban areas. The combined effect of lightning-induced voltages and transferred lightning surges through distribution transformers is taken into account. It is shown that an accurate estimate of lightning overvoltages on LV networks that have a neutral conductor grounded at the transformer pole require the consideration of the medium voltage line and its electrical connections with the LV line. It is also shown that if the stroke location is relatively close to the evaluated LV line it is possible to neglect the influence of other LV lines in the estimation of peak overvoltages on the connected loads. Finally, it is shown that load overvoltages are strongly dependent on the assumed load model, which suggests that simplified load models must be viewed with caution in studies of lightning overvoltages on LV networks.

► Lightning overvoltages on complex LV networks are investigated.
► Lightning-induced voltages and transferred lightning surges are both studied.
► Inclusion of MV lines is necessary for accurate estimate of LV surges.
► For close stroke locations, adjacent LV lines are not needed for estimating peak voltages on loads.
► Load overvoltages are strongly dependent on assumed load model.