Redeveloping ageing high-voltage substations in Tasmania
Client: Powercor Network Services
Location: Tasmania, Australia
Date: June 2012 – June 2014
Upgrading aged transmission assets to ensure ongoing service for safe, efficient and reliable power transmission.
Tungatinah Substation and Tarraleah Switching Station are integral to the Tasmanian 110 kV transmission network, connecting approximately 260 MW of generation into the state’s power network. The majority of primary and secondary assets at Tungatinah and Tarraleah were in poor condition and had exceeded their expected service life. The age of these assets (with some elements heritage listed) and congested layout, and their operational significance, presented some challenges for design and construction.
The project’s design and construction spanned two years and involved 56 110kV outages. The redevelopment work included replacing and reconfiguring the 110 kV primary equipment (including circuit breakers, disconnectors, instrument transformers, and redundant strung bus lattice structures) and replacing all protection and control equipment.
Foundations and bulk earthworks were engineered to ensure new foundations could be installed without jeopardising the structural integrity of existing operational equipment and to minimise outages. New primary plant support structures were designed to be standardised across the site to reduce fabrication time, lower complexity for installers, and reduce costs.
For the Tarraleah switchyard, existing lattice towers were reused in keeping with heritage requirements, reducing project costs and complexity of construction. At both sites detailed structural analysis allowed safe and efficient decommissioning of redundant lattice structures.
New cable management systems were designed to utilise existing cable management space taking into account a detailed installation and cutover sequence. This approach minimised unused space and reduce construction costs.
The DC supply arrangements at Tungatinah Substation were simplified and isolated using tripping over fibre optics. The capital cost of Tungatinah Substation’s bus zone protections was significantly reduced.
Temporary extra high-voltage fittings were standardised to minimise lower costs to reduce cut-over times.
Staged multi-layered diagrams where developed to clearly depicted the physical and electrical status of the site during project implementation, improving system security and operation. A Safety in Design process and reporting ensured safety, awareness and control of residual risks.
The redevelopment addressed significant asset management issues for the asset owner and improved the reliability of electricity transmission within Tasmania. The project was highly successful from the perspectives of safety, finance and implementation. The asset owner reported that the project’s success was so significant that further analysis was warranted to capture the elements of success so they can be repeated.