Drop in mainland system frequency on 26 May 2025

Posted by Linton CorbetTuesday 27th May 2025  3:03 PM   Topic: 2025-05-26

Looking back over yesterday’s data we noted an unusual drop in system frequency in the afternoon.

The measurements (0.1 second readings) indicated frequency ducked just below the NOFB briefly, reaching 49.843 Hz.

The chart below presents the timeseries in two clices- zoomed-out and zoomed in.

Chart of mainland system frequency on 26 May 2025.

 

 

The decline was gradual, taking a full 5-minutes to reach the nadir at just before 16:57:30.

  • Not the typical signature of a large generator outage.
  • Potentially a collective ‘off-target’ situation stemming from difficulties predicting VRE at the time. Though this has not been verified.

We’ve posted this to note the event. Further analysis might follow, time permitting.

 

 

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About the Author

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Linton Corbet
Linton is a Senior Software Engineer and Market Analyst, who joined Global-Roam in August 2020. Before joining the company, Linton worked at the Australian Energy Market Operator (AEMO) for seven years, including four years as an analyst within their demand forecasting team. Before entering the energy sector, he worked as an air quality scientist in the Czech Republic.

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