ABSTRACT
High-Impact Low-Probability (HILP) events in power systems historically involve a multitude of aspects, including diverse and disparate threats, failures and sequences of events. Each of these aspects are associated with different types of uncertainties. In practice, the analyst has to make trade-offs between computational efficiency and accuracy in the different aspects that are included in the analysis. Without a clear understanding of the specific problem to be solved and which aspects that are important to capture, elaborate quantitative analysis may be of limited value. This paper presents the development of a qualitative framework for analysing HILP events in power systems. By mapping aspects of power system HILP events to a bow-tie model, it provides a framework for defining, decomposing and delimitating decision problems related to such events. The framework may guide the analyst in the development and application of methods for quantitative analysis and for considering different types of uncertainties.
