AusNet Services is undertaking this Regulatory Investment Test for Transmission (RIT-T) to evaluate options to provide ongoing voltage control services in North West Victoria.
The Project Specification Consultation Report (PSCR), which represents the first step in the RIT-T process in accordance with relevant clauses in 5.16 of the National Electricity Rules (NER) version151[1] and section 4.2 of the RIT-T Application Guidelines[2] was published in June 2020This report, the Project Assessment Draft Report (PADR), is the second stage of the RIT-T and provides information about the draft conclusions of the RIT-T.
The SVC at HOTS has been providing dynamic voltage and reactive power control services for an extended period (35 years) and is reaching the end of its serviceable-life. A failure of the SVC would mean that AusNet Services is unable to meet its obligation to provide voltage and reactive control capability services as outlined in the Network Agreement between AEMO and AusNet Services. Further, it would reduce the ability to maintain voltages in North West Victoria within the limits specified under clauses S5.1a.4 and S5.1a.5 of the NER (see extract in section 2.4.1) and clauses 110.2.2(a) and 110.2.3(a)[3] of the Victorian Electricity System Code. Consequently, a failed SVC would require emergency asset replacement to be undertaken as there are significant impacts to the power system and the wholesale electricity market.
AusNet Services identified a number of investments that may deliver more economical and reliable solutions to address the identified need, compared with the base case where the existing assets are kept in service and emergency asset replacements are implemented when the SVC fails. The credible network options considered in this RIT-T are:
- Option 1 – Replacement of the existing SVC with a modern equivalent SVC; and
- Option 2 – Replacement of the existing SVC with a synchronous condenser.
Since the PSCR, there have been updates to the capital cost assumptions for these options. The cost for Option 1 has decreased to $23.98 million, while for Option 2, the current estimate is $24.79 million.
Based on the cost-benefit assessment, AusNet Services confirms that replacement with a synchronous condenser (Option 2) is the most economic option as it provides the highest present value (PV) of net economic benefits in most scenarios and across all sensitivities investigated.
AusNet Services welcomes written submissions on the topics and draft conclusions presented in this PADR. Submissions should be emailed to rittconsultations@ausnetservices.com.au on or before 15 June 2021. In the subject field, please reference ‘RIT-T PADR Horsham Terminal Station Static Var Compensator.’
Assessments of the responses to this PADR will be presented in the Project Assessment Conclusions Report (PACR) which is intended to be published in July 2021
[1] Australian Energy Market Commission, “National Electricity Rule version151,” available at https://www.aemc.gov.au/regulation/energy-rules/national-electricity-rules/current viewed on 27 October 2020.
[2] Australian Energy Regulator, “Application guidelines Regulatory investment test for transmission,” available at https://www.aer.gov.au/system/files/AER%20-%20Final%20RIT-T%20application%20guidelines%20-%2014%20December%202018_0.pdf, viewed on 24 February 2021.
[3] “A transmitter must use best endeavours to maintain the normal voltage level at each point of supply with a nominal voltage at or above 100 kV within a range of plus or minus 10% of the voltage level nominated by VENCorp from time to time to the relevant transmitter and the relevant Participants which are supplied at that point of supply.” Office of the Regulator-General, Victoria, ‘Electricity System Code,’ available at https://www.esc.vic.gov.au/sites/default/files/documents/3d1fc9fd-18e0-4e10-a87a-e68ba2151a1a.pdf, viewed on 24 February 2021.