Mainland System Frequency drops through the floor with ‘Significant Power System Event’ on Tue 13th Feb 2024

The AEMO published Market Notice 114577 at 13:22:13 (NEM time) today, as follows:

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MARKET NOTICE
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From :              AEMO
To   :              NEMITWEB1
Creation Date :     13/02/2024     13:22:13

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Notice ID               :         114577
Notice Type ID          :         POWER SYSTEM EVENTS
Notice Type Description :         Emergency events/conditions
Issue Date              :         13/02/2024
External Reference      :         Significant power system event – 13 Feb 2024

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Reason :

AEMO ELECTRICITY MARKET NOTICE.

Significant power system event – 13 Feb 2024

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

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

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END OF REPORT
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Occasionally in earlier articles we have mentioned we’re monitoring system frequency on the mainland at (relatively) high speed.  Here’s what the standard chart (focused on the NOFB) looks like (clearly dropping through the floor):

So if I was to guess (caveat – perhaps wild and woolly guess) a rough sequence, perhaps:

Step 1 = (perhaps due to storm or other weather event?) the Moorabool Sydenham No1 and No2 500 kV lines tripped

Step 2 = trip of transmission disconnects ~1,000MW of consumption … spiking the frequency

Step 3 = generator protection systems kick in and trip Loy Yang A and perhaps other things … which crashes frequency.

More to come …