The Murraylink 220 MW ±150 kV HVDC Light bipolar interconnector is believed to be the world’s longest underground power transmission system, connecting the Riverland region in South Australia and Sunraysia region in Victoria through converter stations at Red Cliffs in Victoria and Berri in South Australia.
The controllable interconnection allows power to be traded in either direction between the two States, and provides enough electricity to meet the needs of around 200,000 households. ABB's HVDC Light transmission system comprises extruded (oil free) cables buried in the ground and an HVDC Light converter station at each end of the link.
The order was placed by Murraylink Transmission Company Pty. (TransÉnergie Australia), a subsidiary of TransÉnergie, the transmission division of Hydro-Québec, Canada. It is now owned by Energy Infrastructure Investments consortium and operated by the APA Group.
Network reliability is improved in terms of power supply and system voltage control, as the converter stations can both transmit power and support the AC voltage of surrounding networks, an important feature for the weak Berri network at the edge of the South Australian system.
From its near tri-state border site, Murraylink can deliver power from South Australia, Victoria, NSW and the Snowy River generation in either South Australia or Victoria, using existing corridors.
Key reasons for the choice of voltage source converter (VSC)-based HVDC technology include: 1) buried cables, enabling use of existing rights-of-way and speeding up the permit/approval process; 2) reactive power control to support weak AC networks; 3) compact converter station layout, and 4) modular, factory-tested design for a short field testing and commissioning period.
The Murraylink project earned several Australian state and national awards for both environmental and engineering excellence.