The week started with commotion in Queensland, when the VOLL price ceiling was reached, as illustrated in NEM-Watch (please click on the image for a larger view):
Please note the following in the above image:
(a) Despite a massive price differential between Queensland and NSW, the Directlink interconnector can be seen to be flowing from NSW into Queensland – which is counterintuitive.
This was occurring in order that NEMMCO could manage local system security issues in Northern NSW, as indicated in Market Notice #13878, which they published on the day.
(b) Closer inspection of the QNI interconnector will also reveal something strange occurring here – NEM-Watch shows that QNI was flowing north at 418MW and yet its maximum transfer limit was only 323MW in the northwards direction. This can be seen better in the following NEM-Watch chart:
NEMMCO has provided some guidance about why this occurred with the following market notices:
i. The first Market Notice (#13875), which they published on the day at just after 14:20, refers to the opening of the the NSW region 132 kV feeder 9W2.
ii. The second Market Notice (#13876), which they published at about the same time, refers to the short notice outage of Lismore SVC following the trip and arc of a Nth NSW 132kV line.
Reference to NEM-Review the day after the event can reveal the following: