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.