Lyapunov Exponent for Evaluation and Ranking of the Severity of Grid Events on Extra-Large Power Systems

In this paper, a method to evaluate and rank the severity of events in extra-large power systems is proposed. The methodology is based on the analysis of the transient behavior of electrical frequency following severe disturbances on the system. Three different evaluation criteria such as damping of oscillation, speed variation and amplitude of the oscillation were implemented among other things in the sophisticated Lyapunov Exponent approach to assess the severity of a system event. To demonstrate the effectiveness of the proposed approach, simulations results on the initial dynamic model of Continental Europe from ENTSO-E using the commercial power system software DigSilent PowerFactory were performed to represent on a realistic form the transient behavior of the system. The study cases shown here, were carefully selected among more than 30 000 possible event combinations. The proposed algorithm can be used to analyze and compare the impact of topology changes in the future power grid e.g. massive introduction of renewable energy sources (RES) as prognosticated by several European energy policies.