QNI upgrade nears completion as ninth capacitor bank installed

QNI capacitor bank works at the Transgrid Tamworth substation
QNI capacitor bank works at the Transgrid Tamworth substation

The last capacitor bank of Transgrid‘s Queensland-NSW Interconnector (QNI) upgrade has now been installed, with the project almost 90 per cent complete. 

The QNI project, which will increase the transfer capacity of electricity between Queensland and NSW, has included the installation of the new 330kV capacitor banks to provide additional power support. Eight are already energised and connected to the NSW grid.

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Transgrid project director Colin Mayer said, “The capacitor banks are significant electrical components required for the QNI project. They enable the future injection of reactive power into the high voltage grid to provide voltage support and facilitate power system stability in the event of any disturbance or equipment failure.

“With this final capacitor bank installation at Tamworth, the program for new installations is complete, which is a significant milestone for the project.” 

Energisation of the capacitor banks, which support the connection of the new equipment to the grid, has been completed at Transgrid’s Armidale and Dumaresq substations and is almost complete at Tamworth. The ninth capacitor bank will be energised in March 2022, when system outages are available after the summer peak energy window. 

“Preparation for the latest installation at the Tamworth substation involved the relocation of the Muswellbrook to Tamworth Transmission Line landing span conductors and decommissioning of a redundant transmission tower. 

“Energisation of Static Var Compensators at Tamworth and Dumaresq substations is on track for April 2022. Specialists from Siemens Energy in India are now onsite at Dumaresq, making it happen,” Mayer said. 

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Work on QNI has involved upgrades to substations and transmission lines, with the replacement of 58 transmission towers with new taller twin pole structures. 

The QNI project, approved by the Australian Energy Regulator (AER) and fast tracked with the support of the NSW and Federal Governments, is expected to provide net benefits of $170 million to electricity customers and producers.