A collation of articles pertaining to some larger disruptions in system frequency (such as outside of the Normal Operating Frequency Band – NOFB).
On Wednesday 3rd December, the AEMO held its annual Intermittent Generation Forum and discussed a number of different aspects of challenges and opportunities, including with respect to the frequency weakness on Friday 31st October...
We can see that the frequency weakened late in the afternoon (Wednesday 10th December 2025), falling down towards the Normal Operating Frequency Band.
This late afternoon weakness in system frequency (on Sunday 30th November 2025) seems noteworthy.
An update of earlier article (from 8th Sept 2025) comparing Frequency Excursions with instances of large AggROT across Semi-Scheduled units - for 2025 Q3 and 2025 Q4 (ytd).
Extracted our high(er) speed readings highlights that the mainland frequency exceeded the NOFB for a period of the morning on Tuesday 11th November 2025.
I’m not sure if related to the severe weather warnings for both QLD and NSW today, but here’s a quick record of some afternoon weakness in frequency control on Saturday 15th November 2025.
Adding to the list of articles we've collated about the frequency disturbance on Tuesday 19th August 2025, we're copying in what AEMO published in its 2025 Q3 monitoring report about the glitch.
On or before 13th November 2025, the AEMO published its ‘Frequency Monitoring – Quarter 3 2025’ report:
In what seems to be a repeat of what happened last week Thursday 6th November 2025, some strange (and large) changes in 'Market Demand in Victoria appear to have driven a frequency excursion on...
Taking a quick look - after our ez2view ‘Notification’ widget triggered an alert for what appears to be Callide C4 tripping from close to full load (Sunday 9th November 2025 at 21:26 NEM time)
A quick snapshot at 13:56 (NEM time) on Friday 7th November 2025 of our live updating frequency monitor, with frequency having wandered south:.
Today, we have the advantage of ‘next day public’ data, so are able to peel some more layers of the onion (in this article 'Dispatch Error') - with respect to the significant Frequency Spike...
In the first hasty article about today's (Thu 6th Nov 2025) frequency spike, we see it quickly went past the NOFB. So, in this article, we look at how far ...
Given the large ramp in frequency around midday Thu 6th Nov 2025, coincident with a large apparent ramp in 'Market Demand' in Victoria, we suspect a data glitch.
A short note with this snapshot from our live frequency reading over the past hour showing a spike well outside of the Normal Operating Frequency Band on Thursday 6th November 2025
With respect to the ~17:00 period on Thursday 30th October 2025 (and the frequency drop, possibly outside the NOFB), we take a look at the Dispatch Error of individual Semi-Scheduled units to find patterns.
We take a second look at the frequency drop that occurred at ~17:01 (NEM time) on Thursday 30th October 2025.
Loy Yang B1 has returned to service on Sunday morning 2nd November 2025 following a planned outage, not without some wobbles.
We’ve just noted the frequency drop on Friday afternoon 31st October 2025, and so take a look at 'Aggregate Dispatch Error’, to see if it's likely we are correct in our hypothesis - that...
Yesterday afternoon, we quickly noted the ‘Frequency drop on Friday afternoon 31st October 2025’. Now, we take a closer look to highlight the lowest point (outside of the NOFB).