Yesterday we looked at how ‘NEM Mainland Frequency drops below the NOFB, on Tuesday 12th November 2024’ and ‘A closer (though still cursory) look at NEM Mainland Frequency in a data extract on Tuesday 12th November 2024’ … centered on a drop in frequency at ~10:41 NEM time in conjunction with trips of units at Yallourn Power Station.
Reporting elsewhere
In his comment here on the first article, Liam noted:
‘Guardian reporting a boiler tube leak unit 3, and trip triggered when isolating that unit. Perhaps a mistake in a switching sequence?’
… which led me (on Wednesday morning) to the update ‘Victorian coal plant goes offline after leak in boiler tube’ by Peter Hannam here:
Using ‘Next Day Public’ data…
Utilising ez2view with ‘Next Day Public’ data this morning, we quickly take a look at each of the four units.
YWPS1 … offline planned outage
As noted with the snapshot from ‘Generator Outages’ widget in the first article, this unit is offline on a planned outage with expected return to service on Sunday 17th November 2024 .
So note that:
1) it played no role in what happened on Tuesday 12th November 2024.
2) I also wonder if this unit is also amongst those Peter includes as ‘up and running by tomorrow morning’ noting:
(a) The noted return to service is some days away still
(b) Albeit that the MT PASA DUID Availability data for this week is stale, not having been updated since Saturday 9th November for 18:00.
YWPS2 … tripped, but back online later Tuesday
As captured in this snapshot from the alert triggered by the ‘Notifications’ widget in ez2view, YWPS2 began its return to service in the period just prior to 16:55 NEM time:
Reviewing the trend of data, we see this unit dropped from 367MW (InitialMW) to 22MW (FinalMW) in the dispatch interval ending 10:45 NEM time, thereafter to 1MW (FinalMW) at 10:50 and then to 0MW at 10:55.
1) So slower than for YWPS4:
(a) … though perhaps still inevitable that it was coming offline?
(b) Will need to think of the effect on frequency drop if a not-so-rapid as YWPS4 decline
2) That’s why the time offline appeared to be later than for YWPS4 in the ez2view ‘Notifications’ widget snapshot included at the bottom of this first article.
We can see this in the snapshot from the ‘Unit Dashboard’ widget in ez2view focused on this period (looking back 1 hour):
This image is now populated with ‘next day public’ data – and nothing in the bidding to the 10:50 dispatch interval anticipated that this unit would come offline. There was a rebid that arrived at AEMO at 10:49:30, however (taking effect for 10:55 given Gate Closure #2), that noted:
‘Adj avail bands portfolio redist YWPS OOS SL’
We see this here:
YWPS3 … offline for tube leak
The case for this unit is different (as noted by Peter Hannam above), in that this unit commenced reduction in load at ~08:35 NEM time on Tuesday morning.
We can see this in the snapshot from the ‘Unit Dashboard’ widget in ez2view focused on this period (looking back 3 hours):
In this case, there was a rebid received at the AEMO at 08:53 noting:
‘Adj avail PASA tube leak SL’
We see this here:
YWPS4 … tripped, but not yet back online (as at 06:15 Wednesday 13th November 2024)
With this one, we see this unit dropped from 357MW (InitialMW) to 0MW (FinalMW) in the dispatch interval ending 10:45 NEM time … hence the ez2view ‘Notifications’ widget snapshot included at the top of this first article.
We can see this in the snapshot from the ‘Unit Dashboard’ widget in ez2view focused on this period (looking back 1 hour):
Similar to the case for YWPS2 … and arriving at the AEMO simultaneously (i.e. 10:49:30) that noted:
‘Adj avail bands portfolio redist YWPS OOS SL’
We see this here:
Note that, as we hit publish here, this unit remains offline on Wednesday morning 13th November 2024.
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