Managing the Risk of Hummock to Ardrossan West 132 kV Line Failure

Project Overview

We are proposing to replace the Hummocks to Ardrossan West 132 kV transmission line located in Yorke Peninsula region in South Australia to maintain safe and reliable electricity supply to customers.

This Regulatory Investment Test for Transmission (RIT-T) Project Specification Consultation Report (PSCR) identifies the need to replace the F1803 Hummocks to Ardrossan West 132 kV transmission line in its entirety and to decommission the existing line as the preferred option to manage the risk of conductor and conductor hardware failure on this transmission line in the 2024-2028 period.

The Hummocks to Ardrossan West 132 kV transmission line is a radial transmission line that connects the Lower Yorke Peninsula region to the South Australian transmission network and the National Electricity Market. Condition assessment undertaken on this transmission line has identified that the conductor and conductor hardware are in poor condition and have reached the end of their technical and economic lives and require replacement by 2028 period to manage the increased risk of unsafe operation and involuntary load shedding.

The ‘identified need’ is to efficiently manage the risk of asset failure.

The identified need for this project is to continue to provide safe and reliable electricity transmission services in South Australia at a prudent and efficient cost. Specifically, the identified need for this Regulatory Investment Test for Transmission (RIT-T) is to efficiently manage the risk of failure of conductor and conductor hardware on the Hummocks to Ardrossan West 132 kV transmission line identified in this report.

We have classified this RIT-T as a ‘market benefits’ driven RIT-T as it is being progressed to manage the risk of asset failure and thereby deliver positive net benefits to customers.

A full cost benefit assessment has been undertaken, comparing the risk cost reduction benefits of replacing the full transmission line in its entirety, to the option of refurbishing the transmission line, including replacing the conductor and conductor hardware against the cost of the base case of ‘do nothing’ option.

Full line replacement is the only credible option.

There is only one economically feasible option, which is to replace Hummocks to Ardrossan West 132 kV transmission line in its entirely and to decommission the existing line by 2028.

The estimated capital cost of this option is approximately $34.6 million.

This is below the threshold requiring us to complete a Project Assessment Draft Report (PADR) under NER clause 5.16.4(z1). This RIT-T is therefore exempt from the need to produce a PADR.

There is no feasible role for non-network options in addressing the identified need for this RIT-T.

ElectraNet does not consider that a non-network option can meet the identified need for this RIT-T.

This is due to the unique and specific role that the line insulation systems play in transmitting electricity.

Nevertheless, for completeness and consistent with the requirements of the RIT-T this PSCR sets out the technical characteristics a non-network option would need to have.

Closing Date: 10 October 2024

Status: Consultation Closed

Closing Date: 06 January 2025

Status: Consultation Closed