Cascading failure model of AC-DC system and blackout mechanism analysis

Because more and more DC systems come into use, it is necessary to analyze the role of DC systems in cascading failures. In this paper, blackout model of AC-DC system is proposed. To save computation time, short-circuit voltage, instead of detail time domain simulation, is used to evaluate the impact of AC system fault on DC system. And an AC-DC OPF of multiple islands is proposed to analyze the controllability of DC system in the background of cascading failure. With this model, simulation is performed on a reconstructive IEEE 30 bus test system. The result shows that appropriate dispatching operation on DC interconnection system can decrease more risk of blackout, comparing to AC or AC/DC interconnection system.