Saturday 08 March 2025
The rapid rise of renewable energy sources has brought about a new set of challenges for grid operators, as the increased integration of inverter-based resources (IBRs) like wind and solar power into the grid threatens to destabilize it. One of the key concerns is subsynchronous resonance (SSR), a phenomenon that can cause oscillations in the frequency range below 30 Hz, leading to stability issues and even blackouts.
To combat this issue, researchers have been working on developing new methods for identifying and mitigating SSR events. One such approach is frequency scanning, which involves injecting small perturbations into the grid and measuring the response of IBRs to determine their impedance characteristics.
In a recent paper, a team of researchers presented a comprehensive review of frequency scanning techniques used in the analysis of power systems with high renewable penetration. The authors categorized these methods into three main groups: white-box modeling, gray-box modeling, and black-box modeling, each with its own strengths and limitations.
White-box models assume that the IBR’s internal dynamics are fully known, allowing for detailed simulations of SSR events. However, this approach is often impractical due to the complexity of modern power converters. Gray-box models, on the other hand, combine measurements from sensors with simplified models of the IBRs’ behavior, providing a more realistic representation of the system.
Black-box modeling takes a more empirical approach, relying solely on measured data to identify SSR events. This method is often faster and less computationally intensive than white- or gray-box modeling but can be limited by the quality and availability of measurement data.
The authors also explored different perturbation shapes used in frequency scanning, including step, ramp, and chirp signals. Each shape has its own advantages and disadvantages, with chirp signals offering a good balance between accuracy and computational efficiency.
The review highlighted several challenges and limitations associated with frequency scanning, such as the need for high-quality measurement data and the potential for interference from other grid components. Nevertheless, the authors emphasized that this approach holds significant promise for improving the stability of power systems with high renewable penetration.
In addition to its applications in SSR analysis, frequency scanning has been shown to be useful in harmonic stability assessment and impedance-based local stability criterion development. These advancements have important implications for the design and operation of modern power grids, which will increasingly rely on IBRs to meet growing energy demands.
Cite this article: “Frequency Scanning: A Promising Approach for Ensuring Stability in Renewable Energy-Integrated Power Systems”, The Science Archive, 2025.
Renewable Energy, Grid Operators, Subsynchronous Resonance, Frequency Scanning, Impedance Characteristics, Power Systems, High Renewable Penetration, White-Box Modeling, Gray-Box Modeling, Black-Box Modeling
