In the first hasty article, the pre-canned visualisation of our high-speed readings of system frequency are constrained to the bounds of the NOFB, and the frequency clearly climbed outside of them.
So I’ve extracted our data at 0.1 second cadence and present this 4-hour time range here:
The time period of interest:
Spans the range:
~12:30 (when the frequency appears to break out of the PFR deadband)
to ~12:50 (when the frequency returns within the PFR deadband
We’d need to check with ‘next day public data’ (time permitting on a future day) to see who was enabled for Contingency Lower FCAS at the time, because it does look like there was some resistance to the procession above 50.15Hz.
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.
A first article from me after starting to delve into a 14-hour time series of AEMO’s 4-second data for Tuesday 13th February 2024 (this one a trend of frequency to highlight points of interest).
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.
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 NOFB – down at 49.824Hz at 16:49:07.6.
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