A closer look at NEM Mainland Frequency (at 100ms cadence) on Thursday afternoon 13th February 2025 (i.e. Part 2)

Back a week ago, we wrote quickly about ‘NEM Mainland Frequency wandering (somewhat more than ‘normal’) on Thursday afternoon 13th February 2025’.

But questions yesterday prompted us to extract the data for the day at 100ms cadence and firstly present in this 24-hour view:

… and then to ‘zoom into’ the 4-hour time range indicated – from 12:00 to 16:00 (NEM time) on the day:

So from this extraction we see that:

1)  The frequency remained below 50Hz for ~60 minutes:

(a)  from 13:01.42.3 (last at 50Hz)
(b)  to 13:59:22.1 (back at 50Hz)

2)  And it remained below 49.95Hz for ~25 minutes:

(a) from 13:26.02.9 (last at 49.95Hz)
(b)  to 13:48.23.1 (back at 49.95Hz)

3)  And the lowest point was actually below the NOFB briefly

… that was 49.832Hz at 13:31:23.4

So with this background, we might look further in a subsequent article (time permitting).