TransGrid PACR: Maintaining compliance with performance standards applicable to Murrumburrah substation secondary systems

Market Network Service Provider
StageProject Assessment Conclusions Report
ConvenorAEMO NSP
Accepting submissions?No

TransGrid has recently published a Project Assessment Conclusions Report for maintaining compliance with performance standards applicable to Murrumburrah substation secondary systems. 

TransGrid has identified that the secondary systems at Murrumburrah substation have reached a condition that reflects the end of serviceable life. As it is superseded by new technology at the manufacturer level and the existing technology becomes obsolete, spare parts become scarce and the ability of any primary asset connected to the substation to reliably operate will be at risk.

Murrumburrah substation will continue to play a central role in the safe and reliable operation of the power system throughout and after the transition to a low-carbon electricity future. It forms part of the Southern New South Wales network and is located within an area of interest for new renewable connections. Murrumburrah substation is a customer connection point supplying the Essential Energy 66 kV network in the South Western Region of New South Wales. 

Provision of redundant protection schemes to ensure the transmission system is adequately protected is a Network Performance Requirement under Schedule 5.1 of the National Electricity Rules (NER), therefore the condition issues affecting the secondary systems at Murrumburrah substation must be addressed. If the failure to provide functional secondary systems due to technology obsolescence is not addressed by a technically and commercially feasible credible option in sufficient time (by 2022/23), the likelihood of not recovering from secondary systems faults and not maintaining compliance with NER performance requirements will increase.

Continued deterioration of the secondary systems at Murrumburrah substation will accelerate the depletion of spares which will lead to a situation where TransGrid is unable to operate the secondary systems in accordance with clause 4.6.1 of the NER.  The proposed investment will enable TransGrid to continue to meet the standards for secondary systems availability set out in the NER, and to avoid the impacts of taking primary assets out of service. Consequently, it is considered a reliability corrective action under the RIT-T.

TransGrid published a Project Specification Consultation Report (PSCR) for maintaining compliance with performance standards applicable to Murrumburrah substation secondary systems in July 2020. In the PSCR TransGrid presented three credible network options that would meet the identified need from a technical, commercial, and project delivery perspective.

No submissions were received in response to the PSCR during the consultation period which closed in October 2020 and no additional credible options have been identified.

Since the time the PSCR was published, the cost estimate factors for Option 1 (complete in-situ replacement of protection and control systems) have been adjusted to reflect the latest estimated resourcing requirements to implement the preferred option. This resulted in an increase to the total cost estimate from $5.6m to $6.7m. An ongoing safety risk associated with the site 415V (AC) distribution system was also identified since publishing the PSCR, and has been incorporated into the safety and environmental risk input. TransGrid recalculated the NPV analysis for this PACR using updated risk inputs and an updated capital expenditure estimate for Option 1, and the outcome had no impact on the ranking of the options. 

Option 1 remains the preferred option at this stage of the RIT-T process. This option is estimated to have a capital cost of $6.7 million +/- 25% and is expected to be completed by 2022/23. TransGrid is the proponent of the proposed network project.
In accordance with the requirements of the National Electricity Rules, a summary of the PACR is made available on the AEMO website. A copy of the PACR can be obtained from TransGrid’s website or by emailing

Cookies help us improve your website experience.
By using our website, you agree to our use of cookies.