A Single Busbar Model for Dynamic Studies of Power Systems Frequency

The increasingly higher penetration of renewable generation, progressively substituting classical synchronous machines, creates a scenario where the system inertia is significantly reduced. This poses new challenges for the frequency response of power systems — temporary power imbalances result now in deeper frequency excursions and greater rates of change of frequency with potential operational and protective challenges. Classical remedial actions as under-frequency load shedding, spinning reserves and primary frequency regulation play a central role along with novel technological strategies as synthetic inertia. The assessment of these alternatives for frequency control and protection requires suitable models where topological aspects of the network can be put aside. This paper describes the developing of a new modeling tool that, departing from the time response of the frequency of a system facing power imbalances, builds an equivalent single busbar model. It does so by first computing an approximation of four parameters that capture the essence of the frequency transient for the grid, which then refines using a genetic algorithm. The user can configure the set of lumped equivalent device models present in the single busbar model. Results of its application to the Argentine-Uruguayan system are described and commented.