KME’s added this comment to an earlier article where he says:
‘You can also see in this screenshot the VIC-NSW interconnector running counter-price. It’s been doing that all day – I saw over 1GW of counter-price flow earlier – with intervening periods of constraint when the NRM_NSW1_VIC1 constraint set has been invoked due to the accumulation of negative settlement residues.
I am not sure the costs of inadequate transmission from Wagga north-eastward are being accurately captured. Possibly (probably?) the need to activate RERT today would have been avoided if that south-westerly generation was available to the Sydney load centre.’
It’s worth adding in this snapshot here from ez2view that combines two widgets:
1) The ‘Interconnector Details’ widget, which we’ve used in articles here a number of times; but also
2) The ‘Swim Lanes’ widget that we’ve not used as frequently.
The top widget shows history and forecast data, and highlights that (remembering positive Target Flow is flow north from VIC to NSW) the interconnector’s not been allowed to flow north at all over the past 6 hours.
The bottom widget allows for a more granular tabular history for every Dispatch Interval … remembering that north is export:
(b) Allan’s article contains a table listing a number of different constraint equations … just in the window above we can see the effect of several:
ii. The ‘N>>NIL_4’ constraint equation; and
iii. The ‘N>>NIL_998’ constraint equation.
iv. Plus perhaps more (I’ve not looked comprehensively).
… each for slightly different purposes, but all of them (on these occasions) meaning VIC can’t export to NSW.
2) The negative residue constraint which Kevin notes is (on occasions) limiting the flow south so that VIC1-NSW1 can’t flow south either
… such as in the 17:50 dispatch interval noted here.