Interconnector Watch: Monday 29 June 2026

The standout story across the NEM at 06:30 AEST is V-SA (Heywood), which is binding at its export limit of 200.74 MW, pushing power from Victoria into South Australia. That constraint is directly reflected in the price spread: SA sits at $139.01/MWh against Victoria's $112.34/MWh — a $26.67/MWh differential that Heywood cannot fully arbitrage away while it remains at its ceiling. Murraylink (V-S-MNSP1) is also flowing VIC-to-SA at 81.61 MW, utilising about 61% of its 134 MW export capacity and providing a secondary transfer path, though it is not binding. Combined, both VIC-SA links are pushing roughly 282 MW westward, yet SA demand of 1,535.79 MW at that price level indicates local supply is still clearing at a significant premium to Victoria.

On the QNI corridor, NSW1-QLD1 is carrying 974.57 MW northward into Queensland (negative convention = flow to QLD), sitting at 93% of its 1,045.13 MW import limit — close to capacity but not formally binding this interval. The price differential supports this direction: Queensland clears at $93.89/MWh against NSW at $109.15/MWh, so the flow is moving against the price gradient, which warrants attention. Directlink (N-Q-MNSP1) adds a further 57 MW in the same QLD-bound direction at 41% of its 138 MW import capacity. The VIC-NSW interconnector (VNI) is carrying 508.67 MW from Victoria into NSW, utilising 85% of its 596.31 MW import limit — elevated but not binding. Tasmania's Basslink (T-V-MNSP1) is at zero flow this interval, with TAS pricing at a sharp $25.18/MWh against Victoria's $112.34/MWh; the flat Basslink position despite that $87/MWh spread is notable and may reflect scheduling constraints or hydro dispatch decisions.

Two active constraint notices are material to today's market. The I-OSC_STAB_MON constraint set, invoked following the planned Psymetrix PhasorPoint outage, remains active and contains equations on NSW1-QLD1, V-S-MNSP1, V-SA, and VIC1-NSW1 — four of the six monitored interconnectors. With AEMO's oscillation stability monitoring application offline, transfer limits on these corridors may be conservatively managed, which could explain why QNI is running hard toward its ceiling and Heywood is binding. The Buronga B Bus 7118 220kV isolator constraint (N-BU_7118 affecting V-S-MNSP1) was formally cancelled at 01:40 AEST this morning, restoring Murraylink's normal transfer limits, so that specific restriction is no longer active.

Traders should note that QNI's proximity to its import limit — combined with the oscillation monitoring constraint still active across multiple corridors — compresses the system's ability to respond to further demand increases in NSW or supply reductions in Queensland without price separation widening. The SA premium is effectively floored by the binding Heywood constraint and will persist until either SA local supply increases or the V-SA export limit rises. No losses data is available in this interval's dataset, so gross flow figures should be used with that caveat when