Frequency scanning

Improving grid stability through frequency scanning

AEMO is currently investigating how ‘frequency scanning’ can be used in connection assessments and operation of the electricity grid to identify poorly tuned control systems or network oscillations resulting from inverter-based resource (IBR) related interactions. Early identification of these oscillations gives engineers a better opportunity to make system design changes that avoid these issues becoming costly or time-consuming in later stages of the process.

Progress to date

The frequency scanning proof of concept began in mid-2024 as a recommended action from the Power System Analysis Tools – Future Requirements independent review. Three proof of concept stages have been completed and the final stage, testing the method on active renewable energy projects is now underway, with results expected in late 2025.

Initial results indicate that this method will help renewable energy projects connect to the grid faster, more reliably, and with fewer technical and project schedule risks. The proof of concept has demonstrated:

• Oscillations associated with IBR design can be easily identified early in the generator connections process.
• Connecting parties can design IBR controllers to reduce the risk of oscillations at a specific network location without access to restricted NEM wide models.
• The approach uses existing Electromagnetic Transient (PSCADTM) models without exposing Original Equipment Manufacturers to additional intellectual property risk.
• Consistent results across multiple frequency scanning tools in the market today, including open-source tools, which offers engineers a range of vendors.

While not mandatory, frequency scanning could help connecting parties and network service providers de-risk the generator connections process.

AEMO has now published two reports on frequency scanning, an overview of the method and initial findings, and an in-depth analysis of the proof of concept.

The first report, released in July 2025, provides:

• An introduction to the frequency scanning method.
• An explanation of the challenges we are trying to solve.
• An overview of the proof of concept and initial findings.
• Example of an application in the connections process.
• Additional references as a means of knowledge sharing.

The second report, released in November 2025, provides an in-depth analysis covering:

• A detailed methodology of each stage of the proof of concept.
• An analysis and validation of results from each stage.
• Initial learnings using frequency scanning tools.

The in-house developed frequency scanning tool (Frequency-domain Admittance-based Stability Tool [FAST]) used in the trials is also available on request.

For any queries on these reports, or how frequency scanning could assist in connection assessments or to request a copy FAST, please contact [email protected]