Transformer bushing replacements

ElectraNet has identified the need to replace 101 transformer bushings fitted on 18 power transformers across ElectraNet’s transmission network based on their condition. The bushings were installed in the 1960s and 1970s and are now reaching, or past, the end of their technical lives.

The identified transformer bushings are located at the following 10 substations:

• Metropolitan substations – Para, Cherry Gardens and LeFevre; and
• Rural substations – Robertstown, Snuggery, Yadnarie, Murray Bridge/ Hahndorf PS1, Murray Bridge/ Hahndorf PS3, Berri and North West Bend.

On 22 August 2018 ElectraNet published a Project Specification Consultation Report (PSCR) under the Regulatory Investment Test for Transmission (RIT-T), as required by the National Electricity Rules clause 5.16. The report outlined that there was only one technically and economically feasible option which is to replace the end-of-life transformer bushings on a like-for-like basis.

On 11 December 2018 ElectraNet published a Project Assessment Conclusions Report (PACR) that maintains the initial conclusion that replacing the identified bushings in the next three years is the preferred option. This replacement work is estimated to have a total capital cost of $6.86 million ($2017-18).

Next steps

ElectraNet intends to commence work on replacing the identified bushings in January 2019. There are 101 transformer bushings, on 18 power transformers across South Australia that require replacing. We are planning to have all bushings replaced by 2021-22.