Whiplash on VIC1-NSW1

With the ‘Notifications’ widget inside of our ez2view software I’ve set an alert looking at large changes in aggregate generation in any given region from one dispatch interval to the next.  This alert has been triggering increasingly frequently with respect to the VIC1-NSW1 interconnector, such as it did early this evening on Sunday 18th June 2023.

This article is a quick review of what happened today in the 17:05 and 17:10 dispatch interval – setting the scene to be able to dive in further later at some time.

Here’s a snapshot of two copies of the ‘NEM Map’ widget – on the left Time-Travelled to 17:05 this evening and on the right to 17:05:


In annotations on the image I have highlighted a couple things:

1)  The VIC1-NSW1 interconnector shows a reversal of 1,404MW in Target Flow over a 5-minute period:

(a)  At 17:00 it’s exporting 1,043MW from VIC into NSW

… at this time constrained by the Export Limit

(b)  At 17:05 it’s importing 361MW from NSW into VIC

… at this time constrained by the Export Limit also … even though it is importing.

2)  The NSW generation has ramped up by 1,464MW

3)  The VIC generation (measured by aggregate FinalMW in time-travel) has ramped down by 818MW

… remembering that Market Demand is ramping up at this time of evening.

Here’s the ‘Interconnector Details’ widget at 17:05 showing the significant reversal of flow:


Also highlighted is the ‘N::N_DTKV_2’ constraint equation … which is part of the Outage on the Dapto to Kangaroo Valley 330kV line (i.e. line 18her) discussed here last week, and currently underway (currently invoked in the ‘N-DTKV_18_WG_CLOSE’ constraint set).


More later, as time permits…

About the Author

Paul McArdle
One of three founders of Global-Roam back in 2000, Paul has been CEO of the company since that time. As an author on WattClarity, Paul's focus has been to help make the electricity market more understandable.

3 Comments on "Whiplash on VIC1-NSW1"

  1. The reversal of flow on VNI and the increase of 1464 MW in NSW generation appears to result from the dispatch of ~1400MW of Tumut3 at that time. Upper Limit was already generating 600 MW. AEMO published a document on 3 November 2017 https://www.aemo.com.au/-/media/Files/Electricity/NEM/Security_and_Reliability/Congestion-Information/2017/Interconnector-Capabilities.pdf which notes (Section 2.3) that the nominal capacity of VNI is highly dependent on the Snowy generators’ output. This seems to indicate that the Snowy transmission capacity is not sufficient to simultaneously support high VNI flows and high hydro output.

  2. It certainly seems like, under some constraint situations, TUMUT3 is able to ramp up and take advantage of high NSW prices, pushing out cheaper Victorian generation even to the point of causing counter-price flows into Victoria.

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