Structural upgrading strategy for electric power networks under seismic action

This paper presents a procedure to identify an optimal retrofitting strategy for electric power networks (EPN) subjected to seismic events. The optimization consists of the minimization, under economic constraints, of the probability of power cut-off at the nodes where electric energy is most needed in the post-earthquake situation; these nodes are referred to as critical nodes. The EPN model used herein has been presented earlier and is briefly reviewed in the text. The method to individuate the critical nodes, based upon the value of an index proposed in this study, is presented first; then the optimization procedure to select which elements of the EPN to upgrade is examined based upon a standard reliability study. Its effectiveness is tested against routinely used upgrading schemes for an existing EPN (the one of Sicily in Italy). It is shown that the optimization procedure is effective and leads to a significant saving of economic resources. Copyright (C) 2000 John Wiley & Sons, Ltd.