AEMO can confirm that AusNet Services energised the first temporary line yesterday afternoon on the dual circuit 500 kilovolt (kV) Victorian transmission line feeding the Victoria to South Australia interconnector and the Portland smelter (the Moorabool to Tarrone).
On 31 January, damage to transmission towers on the Moorabool to Mortlake and Moorabool to Tarrone transmission lines resulted in a separation between Victoria and South Australia at the Heywood Interconnector, as well as interrupting supply to the Portland aluminium smelter.
AEMO reconfigured the available transmission network to enable supply to the smelter, while also taking operational actions to minimise security and reliability risk to South Australia’s ‘islanded’ power system with no synchronous connection to the National Electricity Market (NEM).
These system security actions included operating increased levels of gas-powered generation, limiting or constraining the output of some wind and solar generators in South Australia and in south-west Victoria when necessary and directing South Australia’s grid-scale batteries to operate in a mode to stabilise the power system.
South Australia is now synchronously connected with the rest of the NEM, although the flows between the two states are limited, which is similar to the procedures followed when only one of the two 500 kV lines is in service.
AusNet Services has advised that the second temporary 500 kV line (the Moorabool to Mortlake line) is expected to be energised around February 28, weather permitting.
AEMO recognises and appreciates the cooperation and assistance provided by the energy industry during this unprecedented and complex mode of operation in place for more than two and a half weeks.