As noted by others (such as Allan here on 6th November 2020), control of system frequency improved markedly with the (re)introduction of ‘Primary Frequency Response’.
In more recent times, readers here will have noted we’ve been taking a closer look of frequency performance – including via our own high(er*)-speed frequency measurements, including noting some frequency disruption events in recent times.
* with respect to speed, everything is relative.
With the better control of frequency:
1) we’re more accustomed to seeing it oscillate in a narrower band of (say) 49.95 to 50.05Hz
2) or, in other words, well within the NOFB.
That’s why some wobbles in the past 24 hours of performance stick out – as captured in this snapshot at 08:22 (NEM time) on Friday 1st November 2024 morning:
With the area (roughly) highlighted, we thought we’d extract the data and have a more detailed look:
… with a bit of manipulation to divide up into specific dispatch intervals over a 90-minute period from 13:30 to 15:00 (NEM time) on Wednesday 31st October 2024.
Now, curiosity has kicked in … but other commitments have intervened … so this is to be continued as Part 2 when time permits.
Dont forget the initial event can often create harmonics on the system in the region that the frequency analyser is sampling at. Can create initial false high/low values.