Blackouts in Power Transmission Networks Due to Spatially Localized Load Anomalies

In this paper we study cascading blackouts in power transmission networks due to spatially localized load anomalies. The term “spatially localized load anomalies” means that the overloaded nodes in the graph representing the power transmission network are concentrated in a small zone of the graph. Typically these anomalies are caused by extreme weather conditions localized in some parts of the region served by the power transmission network. We generalize a mathematical formulation of the cascading blackout problem introduced in [1] and later developed in [2]. This mathematical formulation of the blackout problem when the load of the network is perturbed randomly allows the study of the probability density functions of the measure of the size of the blackout generated and of the occupation of the network lines. The analysis presented shows that spatially localized load anomalies of a given “magnitude” can generate blackouts of larger size than the blackouts generated by a load anomaly of the same magnitude distributed proportionally on the entire network. Load anomalies of this last type have been studied in [1], [2]. The previous results are obtained studying the behaviour of the Italian high voltage power transmission network through some numerical experiments.