A collation of articles pertaining to Thursday 16th October 2025.
On this day we saw several separate events:
1) A coincident trip of YWPS3 and YWPS4 saw System Strength in Victoria the reason for AEMO Direction
2) Later in the afternoon we saw some weakness in frequency control, caused by VRE uncertainties.
In Part 4 of this evolving Case Study, we take a closer look (using 4-second data) at the 12 x offending Semi-Scheduled units that appear to have played a large role in driving frequency...
In Part 3 of this series with respect to Thursday 16th October 2025, we focus on when a large collective under-performance across all Semi-Scheduled Wind Farms and Solar Farms dragged the frequency outside the...
Having already noted the ‘Weakness in frequency stability on Thursday afternoon 16th October 2025’, we take a look at the causes - for the four high-profile dispatch intervals.
The worst periods of frequency stability on Thursday 16th October 2025 were *not* with the simultaneous trip of YWPS3 and YWPS4, but rather later and the day - and look similar to patterns seen...
A quick follow-on early Friday morning 17th October 2025 to note that both YWPS3 and YWPS4 made it back online overnight.
Following the simultaneous trips (on Thu 16th Oct 2025) of YWPS3 and YWPS4, we take a look at current return to service expectations.
System frequency remained within the NOFB, appears well managed given the supply loss approached 600 MW.
Following the simultaneous trip of units at Yallourn, directions to Jeeralang Power Station were issued for maintaining System Strength in Victoria.
A short note on Thursday 16th October 2025 to record both Yallourn Units 3 &4 tripping during the 13:35 dispatch interval (NEM time) today.