14 hours of trended (mainland) frequency on Tuesday 13th February 2024

This is another short article today (though perhaps not as obscure as the earlier one).

This also follows on from the ‘war and peace’ effort on Thursday 15th February 2024, when I posted an (initial) ‘sequence of events for what happened in Victoria through the day on Tuesday 13th February 2024 (via Timescale #1)’ … then updated later in the day to include what I labelled as Event #1.

Using the AEMO’s 4 second data, I’ve put this initial view together of AEMO’s measurements for system frequency on a (roughly) 4 second basis at the two mainland measurement points:

1)  NEM SOUTH … which is typically Melbourne; and

2)  NEM NORTH … which is typically Sydney.


With reference to the earlier chronological listing I have highlighted the rough times when Event 1, Event 2 and Event 3 occurred … plus also highlighted a few other interesting wobbles that we might look into further, as time becomes available.

There are several of us across the broader team (internal and external) who are diving into the AEMO’s 4-second data in order to understand more about what happened through the day on Tuesday 13th February 2024.

1)   Allan’s article earlier today focused on a narrow subsection of what I’ve boxed in as Event 2 – and even in that small subset of time Allan’s highlighted several interesting points:

(a)  The 3 x Dundonnell units tripped rapidly off first; and then

(b)  The 4 x Loy Yang A units came off:

i.  A bit more slowly; and

ii.  Not quite at the same times

2)  With frequency dropping to where it did after Stockyard Hill Wind Farm dropped offline (Event 1), from a starting point that was below 50Hz in the first place, we can see some of the motivation that might have driven AEMO to procure more RaiseReg FCAS from the 12:05 dispatch interval on the day.

… did it drop outside the Normal Operating Frequency Band?

3)  Readers will see that there’s plenty to delve into!


Stay tuned for more…

About the Author

Paul McArdle
One of three founders of Global-Roam back in 2000, Paul has been CEO of the company since that time. As an author on WattClarity, Paul's focus has been to help make the electricity market more understandable.

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