Identifying plausible cascading events in system stability assessment

An implementation of the event tree approach is proposed to determine possible sequences of cascading failures with severe impact on a given power system. The algorithm takes into account protection systems hidden failures and transmission system equipments overload. At each level of the event tree development, the sequence probability order is computed and a filtering tool is used to identify possible harmful sequence. These are furthermore analysed with a time domain simulation tool in order to assess their impact on the power system. This paper contains the description of the event tree algorithm as well as examples of its practical application on the Nordic32 test system.