Was that a data glitch that saw lunchtime ‘Market Demand’ ramp in Victoria by 1,812MW?
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.
frequency disruption
A collation of articles pertaining to some larger disruptions in system frequency (such as outside of the Normal Operating Frequency Band – NOFB).
Major spike in mainland frequency, on Thursday 6th November 2025
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
Large under-performance across Solar Farms as the main driver of frequency wobbles on Thursday afternoon 30th October 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.
A second look at the frequency drop on Thursday evening 30th October 2025
We take a second look at the frequency drop that occurred at ~17:01 (NEM time) on Thursday 30th October 2025.
Loy Yang B1 returns to service after planned outage – not without a few wobbles (and frequency drop)
Loy Yang B1 has returned to service on Sunday morning 2nd November 2025 following a planned outage, not without some wobbles.
A quick look at Dispatch Error on Friday afternoon 31st October 2025, with the frequency drop
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...
A second look at the frequency drop on Friday afternoon 31st October 2025
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).
Frequency drop on Friday afternoon 31st October 2025
A short note with this snapshot of a 6-hour long frequency trace on Friday afternoon 31st October 2025, to capture what looks like another VRE-induced frequency wobble earlier this afternoon.
Frequency wobbles on Thursday afternoon 30th October 2025
A short article highlighting some frequency wobbles on Thursday afternoon 30th October 2025.
Frequency drop with trip of Callide B2 on Tuesday evening 28th October 2025
A short note to capture the trip of Callide B2 on Tuesday 28th October 2025 in the five minute period prior to 21:01 (NEM time) that day.
Sharp mainland frequency drop, with trip of CPP_4 on Sunday evening 26th October 2025
The Callide C4 unit tripped from 420MW in the 5 minutes to 18:36 (NEM time) on Sunday evening 26th October 2025, delivering a sharp drop in mainland frequency.
Two *big concerns* that we urge the Nelson Review panel to (re)consider (with respect to Invisible Responses) following review of the Draft Report
With All Energy happening this week in Melbourne, plus the clock ticking down on preparations at the Nelson Review Panel for their final report, I've reached back to the NEMdev conference to write about...
Taking a first focused look at the 16:50 dispatch interval on Thursday 16th October 2025 (with frequency dropped below NOFB) … Part 3
In Part 3 of this series with respect to Thursday 16th October 2025, we focus on when a large collective under-performance across all Semi-Scheduled Wind Farms and Solar Farms dragged the frequency outside the...
Peeling the second layer of the onion, with respect to the (SemiSched-induced) frequency weakness on Thursday 16th October 2025
Having already noted the ‘Weakness in frequency stability on Thursday afternoon 16th October 2025’, we take a look at the causes - for the four high-profile dispatch intervals.
Aldoga Solar Farm on Sunday 12th October 2025 – Part 2
In this article we inspect power deviations from dispatched units that would have contributed to the frequency rise, and the deviations that would have contributed to the correction.
Weakness in frequency stability on Thursday afternoon 16th October 2025
The worst periods of frequency stability on Thursday 16th October 2025 were *not* with the simultaneous trip of YWPS3 and YWPS4, but rather later and the day - and look similar to patterns seen...
Simultaneous trips at YWPS3 and YWPS4 on Thursday 16th October 2025
A short note on Thursday 16th October 2025 to record both Yallourn Units 3 &4 tripping during the 13:35 dispatch interval (NEM time) today.
Small spike in Mainland Frequency, with (apparent) ~400MW trip of demand in Queensland on Tuesday morning 14th October 2025
It appears that there was some large(ish) trip in demand somewhere on the Queensland network, given the spike in frequency at ~07:28 on Tuesday 14th October 2025.
Two bouts of >2 hours of Non-Conformance at Aldoga Solar Farm on Sunday 12th October 2025
A quick initial look at two lengthy periods of Non-Conformance at Aldoga Solar Farm on Sunday 12th October, with the first period seeing large negative Dispatch Error, and a blip in system frequency.
NEM Mainland Frequency wanders south as the sun sets, on Thursday 2nd October 2025
A very short article recording another instance of frequency wandering south as the sun is setting (this one on Thursday 2nd October 2025).