Time domain assessment of power system stability in case of high share of non-synchronous generation – limitation analysis of electromechanical transient simulations

The transition from centralized synchronous generation to distributed renewable energy sources has introduced significant challenges to power system dynamics and stability. This shift disrupts traditional assumptions in modelling methodologies and calls for a re-evaluation of simulation practices. Power system frequency stability is widely analysed through time domain electromechanical transient simulation, where the electrical frequency is calculated by the swing equation. However, with the growing share of converter-based, non-synchronous generation, this approach becomes problematic, as the electromechanical description can only be applied to certain parts of the generation portfolio. Electromagnetic transient simulation covers the timespan of such transients, however require more complex modelling techniques. This paper explores the limitations of the classical electromechanical transient stability analysis by simulation studies, while also discussing key research advancements in the field and shows simulation results of the discussed methods for frequency stability analysis. Key words. Power system stability, electromechanical transient, non-synchronous generation