The primary connection between South Australia and the National Electricity Market (NEM) remains out of service due to a fallen transmission tower on the Tailem Bend - South East 275 kilovolt (kV) transmission lines on Saturday 12 November, which caused both circuits to trip.
ElectraNet is investigating the extent of the damage and will update expected restoration time.
South Australia’s transmission network remains in a secure operating state, and the Murraylink high voltage direct current connection between South Australia and Victoria is operational. However, the measures in place to manage power system security (Distributed PV Contingency) as experienced on Sunday (13 November) are expected to remain until the Tailem Bend - South East transmission lines are restored.
With South Australia’s effective disconnection to the NEM and forecast low demand periods during spring, AEMO will continue to work with ElectraNet, SA Power Networks and market participants to assess options to maintain system security.
This may include cancelling planned outages for transmission maintenance, increasing electricity demand by directing scheduled load into service or curtailing large-scale generation.
If these measures aren’t sufficient to avoid the risk of major supply disruptions, the curtailment of commercial, industrial and residential rooftop solar PV may be required as a last resort to maintain grid stability.
On Monday, AEMO determined that the rolling sum of the uncapped market ancillary ‘lower reg’ services price (a category of frequency control services) in South Australia exceeded the cumulative price threshold of $1,398,100 over the previous 2016 trading intervals.
Under the National Electricity Rules, AEMO applied an administered price cap of $300/MWh for all market ancillary services in South Australia until the end of the trading day (4am AEST). The administered price cap sets the market ancillary service price to $300/MWh if the uncapped ancillary service price exceeds $300/MWh in a trading interval.
AEMO will continue to monitor the rolling sum of the uncapped market ancillary service prices and issue further market notices as required. If the rolling sum of the uncapped market ancillary service prices exceeds the cumulative price threshold at the end of the trading day, then the administered price cap will be applied until the end of the next trading day.
A table of market ancillary service prices is available on the NEM Data Dashboard.