Evaluation of the Impact of IBR on the Frequency Dynamics in the Brazilian Power System
Bruno Pinheiro, M. C. Llerena Velasquez, Giovane Faria, A. F. C. Aquino, Diego Issicaba, Daniel Dotta
TL;DR
This paper addresses how rising inverter-based resources impact frequency dynamics in Brazil's large, interconnected power system. It introduces a measurement-based framework using PMU data and a variational mode decomposition (VMD) approach to separate system-wide (COI) and local frequency fluctuations, with a focus on regional variability and the Northeast region. Key findings show a collective degradation of system-wide frequency and greater local frequency volatility as IBR penetration increases, alongside evidence of converter-driven oscillations during a 2023 disturbance. The work underscores the need for regional inertia estimation and enhanced local-frequency monitoring to inform control strategies and maintain stability in high-IBR, large-scale grids.
Abstract
In this paper, the impact of inverter-based resources (IBRs) on the frequency dynamics of the Brazilian Interconnected Power System (BIPS) is evaluated. A measurement-based framework is proposed to assess the impact of IBR penetration on the system-wide and regional/local frequency dynamic. The analysis leverages data from a low-voltage wide area monitoring system (WAMS) and publicly available historical generation records from the Brazilian System Operator. A methodology is introduced to extract local frequency fluctuations across regions using a variational mode decomposition (VMD) approach. The findings reveal a continuous degradation in the system-wide frequency and local frequency variations, underscoring the need for enhanced regional monitoring and evaluation metrics to maintain frequency stability in large-scale interconnected systems.