I’ve not been posting about this type of frequency disruption in recent months (focused elsewhere) but worth 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:
Here’s a quick look at the live frequency trace for the mainland over the past hour:
Paul was one of the founders of Global-Roam in February 2000. He is currently the CEO of the company and the principal author of WattClarity. Writing for WattClarity has become a natural extension of his work in understanding the electricity market, enabling him to lead the team in developing better software for clients.
Before co-founding the company, Paul worked as a Mechanical Engineer for the Queensland Electricity Commission in the early 1990s. He also gained international experience in Japan, the United States, Canada, the UK, and Argentina as part of his ES Cornwall Memorial Scholarship.
Next layer of the onion, in investigating the eerily similar (and closely related) frequency spikes outside the NOFB on Friday 10th April 2026 and Saturday 11th April 2026.
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.
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.
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 when VRE is difficult to forecast/dispatch. Stay tuned…
1 Commenton "Loy Yang A3 offline on Tuesday afternoon 20th May 2025 – small frequency drop"
If the NEM at the time was about 21GW then yes, the bump is about right for the loss of 300MW odd. Interesting the relatively slow recovery. Must be about the deadband setting. I thought the magic batteries were bidding in for small signal raise????
If the NEM at the time was about 21GW then yes, the bump is about right for the loss of 300MW odd. Interesting the relatively slow recovery. Must be about the deadband setting. I thought the magic batteries were bidding in for small signal raise????