Analysing the Causes of the Italian and Swiss Blackout , 28 th September 2003 Chris

On the 28 September 2003, a blackout affected more than 56 million people across Italy and areas of Switzerland. Estimates vary for the number of fatalities that were directly related to the loss of power. 30,000 people were trapped on trains. Several hundred passengers were stranded on underground transit systems. There were significant knock-on effects across other critical infrastructures. Many commercial and domestic users suffered disruption in their power supplies for up to 48 hours. The immediate trigger for the blackout stemmed from a fault in the Swiss transmission system. The consequences of the initial failure propagated across the border affecting the networks in France, Slovenia, and Austria. It also led to a domino effect that ultimately led to the separation of the Italian system from the rest of the European grid. The 2003 blackout, therefore, has immense importance for the future development of European energy policy. The immediate causes of the failure acted as a catalyst for longer term, technical vulnerabilities to do with the regulation and monitoring of energy transfers and the algorithms used to predict potential distribution problems. The 2003 power failure also had managerial and human factors causes; these arguably included an over-reliance on computer-based decision support systems. The following paper applies accident investigation techniques to represent and reason about the complex interactions between these causes. In particular, we use Violation and Vulnerability (V2) diagrams to map out the causal factor behind this engineering failure. This article is a companion paper to a previous study that applied the same analytical techniques to the US and Canadian blackout, 14 August 2003 (Johnson, 2006).