Transgrid Project Specification Consultation Report: Maintaining compliance with performance standards applicable to protection relays

Market Network Service Provider, National Electricity Market
StageFirst Stage
ConvenorAEMO NSP
Accepting submissions?Yes
Submissions close15/01/2024

Transgrid has published the Project Specification Consultation Report (PSCR) for Maintaining compliance with performance standards applicable to protection relays. This RIT-T includes 419 protection relays at various locations on the ACT and NSW transmission network, based on their assessed condition. Publication of this Project Specification Consultation Report (PSCR) represents the first step in the RIT-T process.

The identified protection relays will reach the end of their technical life by 2027/28, with manufacturer support, access to spares and defects rates being the largest drivers for remediation. The risk of reliably protecting primary assets increases as technology becomes superseded by the manufacturer, manufacturer support ceases and spare parts become scarce.

Redundant protection schemes are required to ensure the transmission system is adequately protected as outlined in the Network Performance Requirement under Schedule 5.1 of the National Electricity Rules (NER), therefore the condition issues affecting the identified protection relays on the ACT and NSW transmission network must be addressed.

If the failure to provide functional protection schemes due to technology obsolescence is not addressed by a technically and commercially feasible credible option in sufficient time (by 2027/28), the likelihood of not recovering from secondary systems faults and not maintaining compliance with NER performance requirements will increase. 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.

In the PSCR Transgrid has presented one credible network option that would meet the identified need from a technical, commercial, and project delivery perspective. The optimal commercially and technically feasible option presented in this PSCR – Option 1 (individual replacement of 419 identified assets across 48 sites within the regulatory period) – is the preferred option to meet the identified need at this stage of the RIT-T.

Transgrid welcomes written submissions on materials contained in this PSCR. Submissions are due on 15 January 2024.

In accordance with the requirements of the Rules, a summary of the Project Specification Consultation Report is made available on the AEMO website. A copy of the PSCR can be obtained from Transgrid’s website or by emailing

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