[SLIGHTLY UPDATED] a sequence of events for what happened in Victoria through the day on Tuesday 13th February 2024 (via Timescale #1)

up until 11:35

Nothing to add at this point.

11:40

Event #1

For completeness with respect to the day it’s worth noting that there’s this separate event that occurred earlier – with respect to the sudden and unexpected loss of generation out of Stockyard Hill Wind Farm in the 11:35 and 11:40 dispatch interval, as shown in this snapshot here of the ‘Unit Dashboard’ widget in ez2view:

Note that this unit was then offline till late Tuesday night – so was not part of the production mix through Event #2 or Event #3 below.

11:45 to 11:55

Nothing to add at this point for these 3 x Dispatch Intervals.

12:05

At 12:03 the AEMO published Market Notice 114561 as follows:

__________________________________________________

Notice ID : 114561

Notice Type ID : Subjects not covered in specific notices

Notice Type Description : MARKET

Issue Date : Tuesday, 13 February 2024

External Reference : Variation to FCAS regulation raise requirements: NEM Mainland – 13/02/2024

__________________________________________________

AEMO ELECTRICITY MARKET NOTICE

Variation to FCAS regulation raise requirements: NEM Mainland – 13/02/2024

FCAS Raise regulation requirements have been increased.to manage frequency.

The following constraint set has been invoked.

F-MAIN_RREG_0450 at 1200 hrs.

Manager NEM Real Time Operations

We can see more detail about this ‘F-MAIN_RREG_0450’ constraint set in the ‘Constraint Set’ Details widget in ez2view, Time-Travelled at 12:05 on Tuesday 13th February:

Importantly, the scheduled invocation of this Constraint Set (which had the effect of increasing the requirement for Raise Regulation FCAS was to last until the 13:55 dispatch interval.

—

PS … on Friday 16th Feb 2024 we posted ‘Aggregate enablement of RaiseReg FCAS from units in the mainland (excluding Basslink) on Tuesday 13th February 2024’ you could see for more details.

12:10 to 13:00

Nothing to add at this point for these 11 x Dispatch Intervals.

13:05

(Perhaps this could be a dispatch interval of focus in a later article with respect to Timescale #2)

In this dispatch interval, which is before anything significant happened (at least as we know at this point) we’ll introduce three different screens from ez2view, all Time-Travelled back to 13:05 to show various aspects of the market at this point in time.

Let’s start with this view of the ‘VIC Region Schematic’ widget, which has been upgraded for v9.9 in preparation for the IESS changes in June 2024:

In this snapshot we see that (coincidentally) the Jeeralang A1 unit has switched on, and that the P5 predispatch forecasts move up slightly compared to where they currently are.

In the next snapshot, we include 3 different views of the ‘Forecast Convergence’ widget focused on various data points within Victoria:

More often than not I’d choose the ‘grid’ option that enables the user to ‘look up a vertical’ to see ‘that other dimension of time’ … but in this case it makes more sense to show the ‘chart’ option … in which case the AEMO forecasts are out to the right.

Third snapshot is the ‘Bids & Offers’ widget that’s filtered to just the VIC units (upgraded for v9.9 to show consumption as negative megawatts) and looking backwards 3 hours and forward 3 hours:

Note that the title bar colour here should be yellow, but I had many (many!) windows open to record this sequence and so the colours did not always work as intended.

13:10

Event #2

(Perhaps this could be a dispatch interval of focus in a later article with respect to Timescale #2)

The AEMO noted in Market Notice 114577 that …

At 1308 hrs 13/02/2024 a significant power system event occurred.

Description of event – Multiple tripping of generation and transmission lines in the Vic region

Transmission element(s) tripped – Moorabool Sydenham No1 and No2 500 kV lines tripped

Region/s – Vic

Load interrupted – in excess of 1000 MW

Generation volume tripped – 2300 MW

There’s much more that we’ll dig into via a follow-on article focused on Timescale #2, however for now it is worth highlighting that (as Linton Corbet highlighted in ‘Grid frequency on 13th February 2024’), the mainland frequency yo-yo-ed:

1)  Fell below 49.9Hz;
2)  Then rapidly rose as high as 50.12Hz;
3)  and then rapidly fell as low as 49.689 Hz between  13:09:56 and 13:09:57 (which is outside the Normal Operating Frequency Band – so there will be threads to explore here).

—

From the perspective of Timeline #1 however, important to remember that the dispatch run for 13:10 was produced at 13:05 – so parameters like Price and Unit/Interconnector Targets were produced then … prior to the transmission collapse.  As such there are only a couple notable things that emerge here:

Remember that the unit outputs used in the 3 x widgets shown here are all based on ‘Final MW’ measurements when ez2view is in Time Travel … i.e.

1)  They are not Targets; but instead

2)  They are the SCADA snapshots taken at (or close to*) the end of the dispatch interval in focus

I’ve highlighted here that there were two particular stations that showed large drops in output across their units:

1)  Of the 4 x Loy Yang A units, it’s important to note that only 3 x Loy Yang A units are shown to have a substantial reduction in output:

(a)  in each case approximately 200MW lower

(b)  note that this is the dispatch interval before when all 4 units had tripped offline, which focused on the FinalMW for 13:15 (or the InitialMW for 13:20).

(c)  For reasons still to be determined specifically!

(d)  So the fact that (it appears) the drops in output across all four units were not synchronised is interesting, and worth further investigation.

2)  Less talked about on WattClarity (though Allan did note here), or elsewhere, was that all three Dundonnell units dropped to 0MW output …

(a)  We need to be clear that (at this point) the are still to be determined specifically!

(b)  Because it might have been because of transmission outage, or due to high wind cut-out, or for other factors.

In the second window it’s no surprise to see no real change in the predispatch expectations:

… and neither does it surprise that there’s no marked change in bids across Victoria (ENERGY supply shown here, but would not expect to see a change in relation to FCAS either, as the event had not yet happened):

So let’s move on…

13:15

(Perhaps this could be a dispatch interval of focus in a later article with respect to Timescale #2)

As highlighted in ‘Grid frequency on 13th February 2024’, the mainland frequency was below 49.85Hz (and so outside the Normal Operating Frequency Band) for this entire dispatch interval..

—-

For this dispatch interval, in highlighting the linkages for ‘big change in unit output’ across the VIC region (remembering this is focused on FinalMW) we see a bit of spaghetti:

Distilling it down, we see three key things have happened:

1)  All 4 units at Loy Yang A have dropped offline:

(a)  Important to note that this is still actually for unknown reasons at this point…

(b)  Despite the fact that elsewhere it’s been written up as trips (including in other WattClarity articles)

2)  The Murray hydro unit has significantly ramped up; and

3)  (remembering that Dundonnell is already offline) Numerous other renewable units have ramped down significantly:

(a)  Again with reasons unknown at this point;

(b)  Because there might be several causes, and we have not actually unfolded them!

—

As noted in ‘Grid Inertia in the Victorian Region drops with the coincident tripping of 4 x Loy Yang A units’, the Grid Inertia had dropped significantly in the VIC region at this point.

—

Here’s the ‘Forecast Convergence’ widget window:

… which shows a modest change in AEMO’s expectations.

Here’s the bids view for the 13:15 dispatch interval:

To understand the comment added on the image, let’s consider the 13:15 dispatch interval:

1)  Keep in mind that the ‘Gate Closure’ for bids is shortly before the start of the dispatch interval (let’s say 13:09:30 in this instance).

2)  With the transmission disruption occurring at 13:08 and not telegraphed by NEMDE until Market Notice publication at 13:22:13 … that means few participants would have realised something was happening.

3)  Perhaps either or both AGL (at Loy Yang A) or Tilt Renewables (for Dundonnell) might have had a head start in knowing – but even if they did, it would leave only ~1 minute to react (make sense of the situation, determine how to rebid, gain approval for that, and submit the rebid).

13:20

(Perhaps this could be a dispatch interval of focus in a later article with respect to Timescale #2)

As highlighted in ‘Grid frequency on 13th February 2024’, it was not until ~13:19 that the mainland frequency increased up back past 49.85Hz and so into the Normal Operating Frequency Band.

—-

At a more macro perspective, we see …

In this snapshot I’d like to initially highlight three developments:

1)  On the NSW side of the Snowy Region, there’s a large ramp up at the TUMUT plant.

… perhaps a timely reminder to review what Allan wrote with respect to ‘What’s happening around Wagga?’ as an illustration of how the complexities of the network sometimes are not 100% aligned with regional boundaries.

2)  All four interconnectors into Victoria have increased Target Flow into Victoria.

3)  The VIC dispatch price has spiked to the Market Price Cap

(a)  but interestingly the P5 predispatch price forecasts have not spiked

(b)  nor do they spike in the dispatch intervals below, as one might expect

(c)  for reasons still to be explored (though there is a hypothesis below).

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

As highlighted here, there’s a sharp difference in the aggregate volume offered for 13:20 compared to the (much higher volume) still offered for 13:25.

Why is this.  Hypothesising (i.e. it’s a guess – don’t hold me to it):

1)  Is this something related to Loy Yang A; or

2)  Collectively, is it something related to the crude form of auto-bidder currently used in the market?

Something to investigate further…

13:25

(Perhaps this could be a dispatch interval of focus in a later article with respect to Timescale #2)

Five minutes forward, and this is what we see…

Some of the gas-fired peakers are starting to ramp up.

The spot price is still at the Market Price Cap … but P5 Predispatch is still low!

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

As noted here, there’s an even larger mismatch between the bids used in dispatch for the VIC region for 13:25 and the (apparently thousands of megawatts larger) volume of bids taken into account in the P5 predispatch run:

1)  A quick check in this dispatch interval (by filtering further, not shown here):

(a)  I’ve confirmed that the Loy Yang A capacity is reduced to 0MW in the 13:25 dispatch interval for the first time … but still remains in the P5 predispatch run; whilst

(b)  Scanning quickly to Wind and Large Solar assets, appears that there is also a large mismatch between the 13:25 dispatch interval and P5 for the 13:30 dispatch interval.

2)  No wonder the P5 predispatch prices look subdued (and keeping in mind other factors, as well).

As a (somewhat) useful reference, it was at ~13:24 that i published the first article ‘4 Loy Yang A units simultaneously trip, on Tuesday 13th February 2024’ … but:

1)  that was after taking perhaps 10 minutes to react, write and publish

2)  and I’m not a trader … and WattClarity is not our revenue earner.

Let’s keep this in mind as we flip through.

13:30

With respect to the 13:30 dispatch interval, keep in mind that this is the first dispatch interval prior to which could possibly have read Market Notice 114577 about ‘Significant Power System Event’ that was published at 13:22:13.   Prior to that time, there may have been a large amount of guesswork going on …

Here’s the first window at 13:30:

There are no doubt other things that could be highlighted here, but I’ve highlighted the 4 x interconnectors and how in this dispatch interval we’re seeing some weird and wacky export and import limits of the type written about here (in response to customer question – GR Case 00006624).

Again – the spot price is still at the Market Price Cap … but P5 Predispatch is still low (but we’re starting to understand why)!

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

There’s still a mismatch shown here in volume offered at 13:30 compared to (P5 predispatch for) 13:35.

13:35

Here’s the ‘actual’ data for the 13:35 dispatch interval:

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

We see the mismatch here is lower than it was shown to be in the dispatch interval above.

One reason for this is that the Loy Yang A capacity has been removed (i.e. marked to 0MW) in the P5 and P30 predispatch time horizon.  Have not checked the Semi-Scheduled units.

However the P5 predispatch forecasts are still subdued … with the spot price is still at the Market Price Cap.  Needs further investigation…

13:40

Here’s the first window:

More weird and wacky interconnector limits (re GR Case 00006624).

In terms of the ‘Forecast Convergence’ widget focused window …

The spot price is still at the Market Price Cap … but P5 Predispatch is still low!

Here is the ‘Bids & Offers’ widget window …

Nothing to add at this point.

13:45

Here’s the first window:

In terms of the ‘Forecast Convergence’ widget focused window …

The spot price is still at the Market Price Cap … but P5 Predispatch is still low!

Here is the ‘Bids & Offers’ widget window …

Nothing to add, at this point.

13:50

Here’s the first window:

In this case I have highlighted an up-down-up pattern with prices – the spot price is still at the Market Price Cap, the P5 Predispatch is still low, but the P30 predispatch forecast is high!

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

Nothing further to add.

13:55

Here’s the first window:

I’ve highlighted in this snapshot the Market Notice relating to forecast LOR2 later in the day.  Did not note it at the time, but it was MN114589 published at 13:52 as noted here:

‘________________________________________________

 Notice ID : 114589
Notice Type ID : LRC/LOR1/LOR2/LOR3
Notice Type Description : MARKET
Issue Date : Tuesday, 13 February 2024
External Reference : PDPASA – Forecast Lack Of Reserve Level 2 (LOR2) in the VIC Region on 13/02/2024
__________________________________________________

 AEMO ELECTRICITY MARKET NOTICE

 AEMO declares a Forecast LOR2 condition under clause 4.8.4(b) of the National Electricity Rules for the VIC region for the following Period:

 [1.] From 1430 hrs 13/02/2024 to 1600 hrs 13/02/2024.
The forecast capacity reserve requirement is 562 MW.
The minimum capacity reserve available is 384 MW.

 AEMO is seeking a market response.

 AEMO has not yet estimated the latest time at which it would need to intervene through an AEMO intervention event.

 Manager NEM Real Time Operations’

In terms of the ‘Forecast Convergence’ widget focused window …

Here is the ‘Bids & Offers’ widget window …

Nothing further to add.

14:00

We’ll leave the from ez2view snapshots at this point, and only add in commentary or images when we feel they are useful (based on the limited review performed to date).

14:05

Nothing to add at this point.

14:10

Nothing to add at this point.

14:15

Yesterday with a NEMwatch snapshot for the 14:15 dispatch interval I wrote that ‘Supply to lost load appears restored in Victoria … but Loy Yang A will take longer’.

At this dispatch interval, the ‘Market Demand’ is sitting at 7,778MW … which turns out to be the highest point in the day.  Because shortly afterwards …

14:20

… at 14:18 the AEMO announced its intention to commence RERT Negotiations.  This was noted (and copied into) in the article ‘AEMO to commence RERT negotiations in VIC’ here.

As noted earlier Wednesday in ‘Some *initial* headline questions following the transmission damage, unit trips & loss of load, initiated on Tuesday 13th February 2024’, I did not see anything further about either RERT being contracted, or RERT being dispatched.

—

But in MN114607 (which they published later at 14:35:06) the AEMO noted that a Load Shedding Direction in the VIC Region had been given to, to commence at 14:20 … as copied into the article ‘Load Shedding Direction in the Vic Region’ article.

14:25

Nothing to add, at this point.

14:30

At 14:27 the AEMO notified of an ‘Actual LOR3’ in the VIC region.

This was recorded yesterday in the ‘Chronology of (300MW) load shedding in Victoria on Tuesday 13th February 2024’ article.

—————-

Keep in mind that (as noted in MN114589 published at 13:52 and noted above), it was the 14:30 dispatch interval in which the forecast LOR2 was forecast to commence!

There’s an obvious question here, about ‘what changed?’.

14:40

At 14:35:06 the AEMO notified (in MN114607) of Load Shedding Direction in the VIC Region. … which we then copied into the article ‘Load Shedding Direction in the Vic Region’ article.

14:45

Nothing to add at this point.

14:50

Nothing to add at this point.

14:55

Nothing to add at this point.

15:00

Nothing to add at this point.

15:05

Nothing to add at this point.

15:10

At 15:06 the AEMO published MN114625 as an update on ‘Significant power system event – Victoria region – 13/02/2024’ as follows:

‘__________________________________________________

 Notice ID : 114625
Notice Type ID : Emergency events/conditions
Notice Type Description : MARKET
Issue Date : Tuesday, 13 February 2024
External Reference : Significant power system event – Victoria region – 13/02/2024
__________________________________________________

 AEMO ELECTRICITY MARKET NOTICE.

 At 1308 hrs 13/02/2024 the Moorabool Sydenham No1 and No2 500 kV lines tripped.

There have been reports of towers on the ground.

 In the Victorian region
1000 MW of customer load lost during the fault has been restored
2690 Generation tripped

 The AEMO instructed loadshed of 300 MW is being progressively restored.

 Updates will be provided as additional information becomes available.

 This Market Notice is issued in accordance with NER clause 4.8.3.

 Manager NEM Real Time Operations’

We did not record this at the time … only later in the day.

————–

At 15:08:04 the AEMO notified of direction for Load Restoration.

This was recorded yesterday in the ‘Chronology of (300MW) load shedding in Victoria on Tuesday 13th February 2024’ article.

15:15

At 15:13:39 the AEMO notified of completion of Load Restoration.

This was recorded yesterday in the ‘Chronology of (300MW) load shedding in Victoria on Tuesday 13th February 2024’ article.

—-

Last dispatch interval at the the $16,600/MWh ( Market Price Cap )

15:20

At 15:19:41 the AEMO notified of cancellation of LOR3 in the VIC Region.

This was recorded yesterday in the ‘Chronology of (300MW) load shedding in Victoria on Tuesday 13th February 2024’ article.

—-

It was also the 15:20 dispatch interval when the price dropped from the $16,600/MWh ( Market Price Cap ) down to -$999.99/MWh (close to the Market Price Floor)

15:25

Spot price remains at -$999.99/MWh (close to the Market Price Floor).

15:30

At 15:27 the AEMO published MN114641 about ‘Widespread abnormal conditions’ as follows:

__________________________________________________

 Notice ID : 114641
Notice Type ID : Reclassify contingency events
Notice Type Description : MARKET
Issue Date : Tuesday, 13 February 2024
External Reference : Reclassification of non-credible contingency event due to existence of widespread abnormal conditions – VIC region(s).
__________________________________________________

 AEMO ELECTRICITY MARKET NOTICE.

 AEMO has identified that a non-credible contingency event impacting the power system is more likely to occur and is considered reasonably possible because of the existence of widespread abnormal conditions namely severe weather in the VIC region.

 AEMO has therefore reclassified the occurrence of a non-credible contingency event involving multiple plant due to these abnormal conditions as credible.

 Need for further measures is being monitored and further measures may be implemented in line with the Power System Security Guidelines (SO_OP_3715).

 Manager NEM Real Time Operations

We did not record this at the time … only on Wednesday afternoon in ‘Some *initial* headline questions following the transmission damage, unit trips & loss of load, initiated on Tuesday 13th February 2024’ here.

————-

Spot price remains at -$999.99/MWh (close to the Market Price Floor).

15:35

Spot price remains at -$999.99/MWh (close to the Market Price Floor).

15:40

Spot price rises up, to -$792.29/MWh (close to the Market Price Floor).

15:45

Event #3

It was at 15:43 that we know* that there was some tripping of the Hazelwood transformers.

We know this (*) based on MN114643 published at 16:13:14 and copied soon after into the article ‘More network tripping on Tue 13th Feb 2024 – at Hazelwood terminal station’ here.

—–

Spot price rises above $0/MWh, to $191.60/MWh.

15:50

It was at 15:43 that we know* that there was some tripping of the Hazelwood transformers.

We know this (*) based on MN114643 published at 16:13:14 and copied soon after into the article ‘More network tripping on Tue 13th Feb 2024 – at Hazelwood terminal station’ here.

—–

Spot price rises up, to -$792.29/MWh (close to the Market Price Floor).

15:50 to 16:05

Nothing to add at this point for these Dispatch Intervals.

16:10

It was in the 16:10 dispatch interval that Loy Yang A2 started to ramp back up … as noted slightly afterwards in ‘Loy Yang A2 unit the first (of four) units coming back online’ here.

16:15

MN114643 was published at 16:13:14 (relating to the tripping of some Hazelwood transformers at 15:43) and copied soon after into the article ‘More network tripping on Tue 13th Feb 2024 – at Hazelwood terminal station’ here.

16:20 to 17:30

Nothing to add at this point for these Dispatch Intervals.

17:35

It was at 17:35 that the Victoria Department of Energy reported that there were 6 transmission towers down … which was then copied over into the article ‘Victoria’s Department of Energy reports *six* transmission towers down in Victoria’ here.

From 13:08 to 17:35 there had been growing speculation – but (at least as far as I am aware) no firm confirmation that this was the case.  That’s almost 4.5 hours which, at the same time:

1)  Seems a short time to actually have the relevant people physically get to site (in the midst of a storm and power outage) to confirm the situation; but also

2)  A 4.5 hour gap in which ‘nature abhors a vacuum’  … as previously noted when I’d posted ‘13 headline questions and observations following the long-term islanding, starting Friday 31st January 2020’.

17:40 to 21:30

Nothing to add at this point for these Dispatch Intervals.

21:35

It was in the 16:10 dispatch interval that Loy Yang A3 started to ramp back up … as noted slightly afterwards in ‘Loy Yang A3 starts up, as the second (of 4) units to return to service’ here.

21:40 onwards

Nothing to add at this point from this point forwards….