2022-04-282022-04-282021http://hdl.handle.net/20.500.11968/4633Incluye bibliografía.We introduce a novel framework to approximate the aggregate frequency dynamics of coherent generators. By leveraging recent results on dynamics concentration of tightly connected networks, and frequency weighted balanced truncation, a hierarchy of reduced-order models is developed. This hierarchy provides increasing accuracy in the approximation of the aggregate system response, outperforming existing aggregation techniques.6 p.MODEL AND CONTROLLER REDUCTIONPOWER SYSTEMSPreprint