Protection systems against lightning-originated overvoltages in resonant grounded power distribution systems

A joint research project between AES Sul, the Federal University of Itajubá and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a resonant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost. The paper aims at illustrating the effectiveness of the presence of a surge arrester or an arcing-horn gap and its protective zone by means of simulations obtained with a computer code for the calculation of lightning induced voltages that takes also into account the steady-state voltage. The results of a statistical analysis for a single multiconductor line are eventually presented and discussed.