TransGrid PSCR: Managing asset risks at Forbes substation

Market Network Service Provider
StageProject Specification Consultation Report
ConvenorAEMO NSP
Accepting submissions?No
Submissions close09/11/2020

TransGrid has recently published a Project Specification Consultation Report (PSCR) which presents options for mitigating risks caused by the deteriorating condition of transformers at Forbes substation. 

There are two transformers are Forbes substation (No.1 Transformer and No.2 Transformer), which are used to change the voltages levels. Different voltages are used for generation, high voltage transmission and local distribution. 

Forbes 132/66 kV substation is located on TransGrid’s Central NSW network. The substation connects the Essential Energy distribution network and supports approximately 200 MW of existing renewable generation in the area. 

The transformers at Forbes substation are essential for the safe and reliable transmission of electricity to the Central NSW network. If the deteriorating asset condition at Forbes substation is not addressed by a technically and commercially feasible credible option in sufficient time (by 2022/23), the likelihood of prolonged and involuntary load shedding in the Central West will increase.

In addition to the market benefit of avoided prolonged and frequent involuntary load shedding, the proposed investment will also assist TransGrid to manage and mitigate safety risks that would otherwise arise from continued deterioration of asset condition. Rectifying the worsening condition of the transformers will reduce safety risks, as well as lower planned and unplanned corrective maintenance costs. However, these costs are of small magnitude compared to the cost of prolonged and frequent involuntary load shedding and do not affect the preference amongst the options.

TransGrid considers that there are two credible options that would meet the identified need from a technical, commercial, and project delivery perspective. 

The optimal commercially and technically feasible option presented in the PSCR – Option 1 (replacing No.1 and No.2 transformers with new 132/66 kV 60 MVA transformers) – is the preferred option to meet the identified need. 

The estimated capital cost of this option is approximately $9.1 million +/- 25 per cent. TransGrid is the proponent of the proposed network project.

TransGrid welcomes written submissions on materials contained in this PSCR. Submissions are particularly sought on the credible options presented and from potential proponents of non-network options that could meet the technical requirements set out in this PSCR. Submissions are due on 9 November 2020.

In accordance with the requirements of the National Electricity Rules, a summary of the PSCR 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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