Cascading failures of power grids caused by line breakdown

Summary In recent years, several large blackouts have drawn much attention to security problems in electric power transmission systems all over the world, which were triggered by initial minor disturbances and caused by cascading failures. Many models for cascading failures in power grids based on node attacks have been proposed, where only one kind of load is involved. In real power systems, however, strict measures are normally taken to protect the nodes, i.e. the power stations, so that failures at the nodes can hardly occur. It is much easier for transmission lines to break down, which may lead to cascading failures in entire power systems. Hence, a new model involving active and reactive loads and considering transmission line failures instead of node failures is proposed to understand cascading failures of power grids. When a transmission line breaks down, its load is redistributed to its neighbouring lines according to their respective capacities. It is well known that a power grid's topology and connectivity play a key role in determining its dynamic behaviour. Therefore, cascading failures of power grids with typical topologies, i.e. random, small‐world and scale‐free networks, are investigated using the model proposed and considering transmission line breakdowns. Finally, the model's effectiveness is validated employing real data of the European power grid. Copyright © 2014 John Wiley & Sons, Ltd. A new model involving active and reactive loads and considering transmission line failures is proposed to understand cascading failures of power grids. Cascading failures of power grids with typical topologies are investigated using the model proposed. Finally, the model's effectiveness is validated employing real data of the European power grid, and it turned out that, in order to prevent the occurrence of cascading failures, the loads between edges connected with the same node need to be balanced.