Tasmanian demand drop on 16 August 2025 – part 2
We follow on from A 292MW drop in "Market Demand" in Tasmania, on Saturday 16th August 2025 enlisting this "Part 2" to understand the sequence of events using 4-second data.
frequency disruption
A collation of articles pertaining to some larger disruptions in system frequency (such as outside of the Normal Operating Frequency Band – NOFB).
Frequency change with Yallourn unit 2 trip
We assess whether the trip at Yallourn 2 on 26 August 2025 was large enough to drive a frequency disturbance.
Peeling the onion a little more – Solar Farm performance on Tuesday 19th August 2025, with the frequency spike to 50.2Hz
As the 5th article in an evolving series that progressively explores the (apparent self-forecasting glitch and) frequency spike on Tuesday 19th August 2025, we take an early look at Solar Farm performance.
An updated tabular list of instances of large AggROT across Semi-Scheduled units
Earlier today we trended the incidence of large Aggregate Raw Off-Target across all Semi-Scheduled units. In this updated tabulated list, we list each of the largest instances from January 2024 to June 2025.
Three broader questions (re)triggered by the Frequency Spike on Tuesday 19th August 2025
The (concerning) frequency spike across the NEM in the middle of the day (Tuesday 19th August 2025) has triggered many proximate questions - understandable - but also has raised these 3 Broader Questions.
Mainland Frequency Spikes to 50.2 on Tue 19th August 2025
On Tuesday the 19th of August between 11:45 and 12:20 there was a significant frequency deviation on the mainland.
Loy Yang A2 apparent trip from 443MW on Wednesday 25th June 2025
A very short midday article on Wednesday 25th June 2025 noting this apparent trip of LYA2 unit from 443MW just prior to 11:31 (NEM time).
Frequency wobbles on Tuesday 17th June 2025
A quick look at two particular instances of (relatively small) frequency disruption on Tuesday 17th June 2025.
Which units show large positive Dispatch Error for 15:40 on Monday 16th June 2025
Following on from Linton's article (about the frequency drop at 15:40 on Monday 16th June 2025) we take a look at the largest harmful Dispatch Errors across the full fleet of units ... and...
Drop in mainland frequency on 16 June 2025
In reviewing system frequency on the 16th of June, 2025, we observed a drop that reached below the NOFB.
Sharp drop in frequency on Friday morning 13th June 2025, with trip at Newport Power Station
I’ve not yet had time to fully investigate, but thought it worth recording the sharp drop in frequency that appears to have occurred shortly after 07:30 NEM time on Friday 13th June 2025.
A quick look at system frequency, with 2 x coal units offline overnight into Saturday 31st May 2025
It’s fitting to book-end the week with a look at frequency performance overnight (into Saturday 31st May 2025) with two coal unit outages in NSW overnight to see what happened in terms of more...
Poor dispatch performance of VRE (collectively) on Monday 26th May 2025 sufficiently large to drive frequency outside of NOFB
Prior to the Brisbane session of the Nelson Review Panel (on Thu 29th May 2025) we take a look at Dispatch Error in the 16:15 dispatch interval on Monday 26th May 2025 to see...
Drop in mainland system frequency on 26 May 2025
The measurements indicated frequency ducked just below the NOFB briefly, reaching 49.843 Hz.
Loy Yang A3 offline on Tuesday afternoon 20th May 2025 – small frequency drop
A short note because of a 295MW drop in output from Loy Yang A3 just prior to 14:06 (NEM time) on Tuesday 20th May 2025.
Drop in NEM Mainland Frequency appearing to coincide with trips at New England Solar Farm, on Saturday 19th April 2025
We take a quick look, after AEMO noted that at 13:51 (NEM time) the New England Solar Farm No.1 and No.2 both tripped.
Mainland system frequency on April 10, 2025, associated with VIC transmission outage
High speed frequency measurements provide a deeper understanding of how the system responded to the unplanned 500kV line outage.
582MW (instantaneous?) drop in ‘Market Demand’ in Victoria delivers large System Frequency spike – Thursday 10th April 2025
Noting a large 582MW drop in ‘Market Demand’ in Victoria this morning (Thu 10th April 2025) – as captured in this ‘Notification’ alert in ez2view at 08:31 (NEM time).
Frequency drop with trip of Callide C3 on Friday 4th April 2025
A quick record of unit trip at CPP3, and associated frequency drop, on Friday 4th April 2025.
Frequency excursion on Monday 31st March 2025
A very short article to note an apparent mainland frequency excursion (just prior to 17:00 NEM time on Monday 31st March 2025).