Events classification and operation states considering terrorism in security analysis

Security assessment has been related to contingencies produced by internal causes, such as operating failures or external, such as short-circuit caused by incidental atmospheric conditions in system components. However, terrorism actions could be considered as the largest threat to the power infrastructure in some countries. The robustness and security of a power system has to be related to the ability of the system to support contingencies due to terrorism actions. Therefore, methods and techniques should be developed with the main aim of improving power system security against terrorism. To collaborate to this effort this paper proposes an extension of a well known classification of events and operating states. A classification that includes internal and external natural and unnatural or man caused events is important for proposing new security analysis methods that consider event uncertainties. Natural events are mainly random while unnatural event uncertainty are ambiguous, vague or confuse and some kind of expert elicitation should be applied. In Colombia during year 2002 about 500 towers were destroyed by terrorists. These kinds of events are the main cause of security problems in the power system.