Expert advice and a fast reconnection turnaround for the Heywood Interconnector

Cressy HI Repair

When a mini-tornado knocked out an essential part of AusNet Services’ transmission network in late summer 2020, Zinfra’s renowned transmission line team were immediately called in to assess the damage and provide emergency repairs to the Heywood Interconnector, minimising its potential impact across state lines.

At the end of January 2020, following the devastating bushfires across much of the Eastern seaboard, Western Victoria was hit by extreme weather via a small tornado which waged havoc across rural communities and farming properties, knocking out AusNet Services’ transmission line between the Moorabool and Heywood terminal stations (TS) and badly damaging a number of towers. Its impact had the potential to be far worse as this line is part of the national electrical grid and the interconnection between South Australia and Victoria, transmitting electricity between the two states.

With a strong, responsive working history spanning more than a decade, AusNet Services rang Zinfra’s senior Transmission Line Project Manager, James Morton to appraise the situation and lead the emergency repairs. Zinfra has an outstanding team of linesmen and with a long-standing relationship to AusNet Services and history of reliably delivering high voltage transmission line works, Morton was called directly to provide an informed, efficient response.

Zinfra immediately set up a site to manage what had been damaged and developed a plan to get the Moorabool TS to Heywood TS 500kv transmission line operational. Directing a comprehensive team of more than 30 Zinfra transmission line field workers, regular subcontractors including Lincon, EWP and Quinlans for cranes and other geo-equipment including frannas and semi-trailer transportation, and labour support from other industry peers (TransGrid, Beon), Zinfra oversaw the installation of multiple modular emergency restoration structures (ERS). These were supplied by AusNet Services and support a temporary 500kv operational line until a permanent solution through reinstatement of the damaged assets can be delivered, which should be completed by Q3-2020.

The temporary line comprises a series of 60m high aluminium tower structures, installed along the existing easements, each of which had to be trucked in to each tower site, a complex manoeuvre with multiple stakeholders that Zinfra needed to consult with and manage. The Lindsay modular ERS comprise five basic building blocks: column sections, foundations, gimbal articulating joints, guy plates and post insulator supports which can be quickly assembled, secured and safely climbed by up to four technicians at a time to install the all-important conductor wires.

This is a remarkable achievement by all involved to construct 3.5km of double circuit 500KV line in just over 4 weeks under emergency conditions.
James Morton: Project Manager

For this 3.5km line length, approximately 90km of conductor (quad wire) was required to replicate and recreate the 500kV line. This was a colossal effort by Zinfra’s tight knit TL crew led by Morton, supported by Walter Fiedler and Aaron Dwyer, to get the two circuits back into service and energised for AusNet Services, safely and in record time. The team have now worked together for more than ten years, with an outstanding safety and delivery track record. Up to 50 team members rotated on 21/7 day shifts to get the job complete with minimal impact to the national grid, keeping SA’s electrical supply constant.

On completion, Morton commented, “the second line was cleared for energisation at 1:00pm today (3rd March 2020). This is a remarkable achievement by all involved to construct 3.5km of double circuit 500KV line in just over 4 weeks under emergency conditions. I would like to acknowledge the efforts of Walter Fiedler and Aaron Dwyer for their planning and management of field crews - Beon, Transgrid and all the sub-contractors involved, Nick Petracca for his HSE support and all the crews that put in long hours to assist AusNet Services re-energise this essential part of their Transmission Network”.

Australia’s transmission system is undergoing transformation and constant upgrade to manage ever-growing power loads, as new renewable energy sources are built and come on line across the country. As asset owners develop the capability and capacity of their networks, Zinfra will continue to partner with and add value for our clients, making a positive contribution to Australia’s energy infrastructure.