Efeitos de descargas atmosféricas indiretas em redes de distribuição com topologia complexa

Abstract

When carrying out studies of the lightning induced, losses caused by soil resistivity are often not included in the signals traveling in the distribution line conductors. This is because in lines whose length is less than 1 km the effect of soil losses can be neglected. However, this premise was evaluated in small network segments containing few discontinuities such as transformers, surge arresters and consumer loads and no laterals. To assess whether this premise remains valid in a more realistic scenario, in this work, a network with complex topology, containing laterals, transformers, consumer loads, surge arresters and grounding, is simulated directly in the Alternative Transients Program (ATP). To include the effect of external electromagnetic fields on the transmission line conductors, external current sources, calculated with the Extended Modal-Domain Model (EMD), were connected to the JMarti line model available in ATP. Thereafter, the results are compared considering or not the soil resistivity for different distribution network configurations. The obtained results indicate that due to the characteristics of complex networks, mainly the presence of several discontinuities, including the influence of the ground in the signals that travel in the line conductors is necessary even when the network is composed only of lines smaller than 1 km.