Network Limitations

We follow a clearly defined and efficient planning process for distribution network investment.

We apply the Network Planning and Expansion Framework in Chapter 5 of the National Electricity Rules (NER) published by the Australian Energy Market Commission (AEMC) where network limitations are initially highlighted in our Distribution Annual Planning Reports (DAPR’s).

For projects meeting criteria set by the NER, we apply the Regulatory Investment Test for Distribution (RIT-D) developed by the Australian Energy Regulator (AER).

With the RIT-D we identify the credible option that maximises the present value of the net economic benefit to all those who produce, consume and transport electricity in the National Electricity Market (NEM) operated by the Australian Energy Market Operator (AEMO). We consider both network and non-network solutions.

We forecast network limitations requiring corrective action at the following locations:

North Richmond — Zone Substation

We forecast prospective 11 kV fault levels at North Richmond (NR) zone substation will exceed the Electricity Distribution Code limit for 11 kV set by the Essential Services Commission (ESC).

We propose installing fault limiting reactors at NR to keep within the 18.4 kA rating for equipment at NR.

Project milestones:

  • December 2014 — Publish Notice of Determination under clause 5.17.4(c) of the NER
  • 2016 — Design
  • 2016/17 — Construction

 For more detail, please refer Downloads and related resources below.

Melton and Bacchus Marsh — Zone Substations and 66 kV Line

Maximum demand on Melton (MLN) and Bacchus Marsh (BMH) zone substations currently exceeds their N−1 ratings. We forecast load on the Brooklyn (BLTS) terminal station to BMH 66 kV line will exceed its rating over the 2016/17 summer.

We have identified credible network options, and have sought non-network options in 2014 to address the network limitations at MLN and BMH.

Project milestones:

  • August 2014 — Publish Non-network Option Report, MLN and BMH
  • January 2016 — Publish Draft RIT-D Project Assessment Report
  • September 2016 — Publish Final RIT-D Project Assessment Report
  • Before 2017/18 summer — carry out work to increase capacity or reduce load

For more detail, please refer Downloads and related resources below.

McIlwraith Place — 66 kV Cables

After we complete 66 kV works for Metro and CBD Security of Supply, load at risk will remain for an N−2 event involving 66 kV cables connected to McIlwraith Place (MP) zone substation.

We propose installing new 11 kV feeders at both Bouverie Queen (BQ) and at Waratah Place (WP) zone substations, to allow load transfers off MP.

Project milestones:

  • July 2014 — Publish MP to BQ & WP 11 kV feeders, Regulatory Test Report
  • No later than end of 2017 — Commission new 11 kV feeders at BQ & WP to reduce load at risk on the 66 kV cables to MP.

For more detail, please refer Downloads and related resources below.

Excluded RIT-D projects

From 18 September 2017, the Regulatory Investment Test for Distribution (RIT-D) will be extended to also apply to replacement-driven projects.

At that time, most network investments where the cost of the most expensive credible option to address a network need is more than $5 million must go through the RIT-D process.

Under the transitional arrangements for the implementation of the new rule, the following projects are excluded from the RIT-D:

  • replacement projects that have been “committed” to by a distributor on or prior to 30 January 2018; and
  • the second tranche of Rapid Fault Earth Current Limiters (REFCLs), in so far as they relate to replacement.

Distributors must publish and maintain a list of these excluded projects on their website, which is provided in the Downloads and related resources below.