Power grids vulnerability is a key issue in society. A component failure may ntrigger cascades of failures across the grid and lead to a large blackout. nComplex network approaches have shown a direction to study some of the problems nfaced by power grids. Within Complex Network Analysis structural nvulnerabilities of power grids have been studied mostly using purely ntopological approaches, which assumes that flow of power is dictated by nshortest paths. However, this fails to capture the real flow characteristics of npower grids. We have proposed a flow redistribution mechanism that closely nmimics the flow in power grids using the PTDF. With this mechanism we enhance nexisting cascading failure models to study the vulnerability of power grids. n We apply the model to the European high-voltage grid to carry out a ncomparative study for a number of centrality measures. `Centrality’ gives an nindication of the criticality of network components. Our model offers a way to nfind those centrality measures that give the best indication of node nvulnerability in the context of power grids, by considering not only the nnetwork topology but also the power flowing through the network. In addition, nwe use the model to determine the spare capacity that is needed to make the ngrid robust to targeted attacks. We also show a brief comparison of the end nresults with other power grid systems to generalise the result.