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Western Victoria Transmission Network Project (WVTNP)

Project overview

The Australian Energy Market Operator (AEMO) has proposed a 190km high-voltage overhead transmission line from the Sydenham Terminal Station to Bulgana Terminal Station.

The project proposes to deliver critical infrastructure required to unlock the renewable energy potential of western Victoria as a key Renewable Energy Zone, delivering clean and affordable energy to Victorians.

AusNet Services, which currently operates 6,500km of Victorian transmission lines, will deliver the overhead line through its commercial arm, Mondo.

The project is proposed to include:

  • A 220kV double circuit overhead line from Bulgana to a new terminal station north of Ballarat.
  • A 500kV double circuit overhead line from a new terminal station north of Ballarat to a new terminal station at North Sydenham.

Energy Safe Victoria

We are Victoria’s safety regulator responsible for electricity, gas and pipeline safety. Our role is to prevent harm by monitoring and enforcing compliance with Victoria’s energy safety legislative framework, comprising the Electricity Safety Act 1998 (Electricity Safety Act), the Gas Safety Act 1997 (Gas Safety Act) and the Pipelines Act 2005 (Pipelines Act) and regulations made under each of those Acts.

We are accountable to the Minister for Energy, Environment and Climate Change and our governing body is a three person Commission.

As part of our regulatory role we oversee:

  • major industry safety cases and the safety management schemes for the design, construction and maintenance of electricity, gas and pipeline networks across the State
  • bushfire mitigation programs, and
  • tree clearance around powerlines.

Environment Effects Statement process (EES)

The Western Victoria Transmission Network Project (WVTNP) is subject to an EES process. More information on the EES process can be found here.

The EES process precedes various statutory decisions that will be relevant to the route of the transmission line or the decision whether to proceed with the project.

As part of the EES process, AusNet Services (as the proponent) prepares draft technical studies and draft EES documentation for review by a Department of Environment, Land, Water and Planning (DELWP) Technical Reference Group (TRG).

The proponent is responsible for preparing an adequate EES that enables a rigorous, transparent and integrated assessment of the project’s potential environmental effects, including examination of the effectiveness and acceptability of proponent’s proposed measures to avoid, minimise, manage and offset environmental effects and related risks.

DELWP has convened an inter-agency Technical Reference Group (TRG) at the request of the Minister for Planning to advise DELWP and the proponent on scoping and adequacy of the EES studies and documentation, as well as coordination of the EES process with other statutory processes for the project.

ESV is represented on the TRG by senior electrical network infrastructure specialists. Our TRG representatives have extensive experience in the operations and safety of electrical networks.

We have provided, and will continue to provide, specific advice on safety and technical matters and have reviewed draft EES documentation where it relates to matters of safety in relation to the WVTNP.

We have also provided advice to the proponent on the safety of transmission lines relating to bushfire mitigation, line design and No Go Zones.

During this stage of the planning process, we are actively contributing to discussions involving safety of the transmission network to ensure safety risks are adequately considered and addressed and the best possible safety outcomes can be achieved in the final design.

We are monitoring materials published by AusNet Services in connection with the WVTNP that are relevant to our safety jurisdiction and will call out misleading or incorrect information.

ESV’s jurisdiction

The Electricity Safety Act 1998 (the Act), section 98 sets out general duties of major electricity companies (MECs), such as AusNet Services, to:

  • design, construct, operate, maintain and decommission its supply network (which includes transmission lines) to minimise as far as practicable
  • the hazards and risks to the safety of any person arising from the supply network;
  • the hazards and risks of damage to the property of any person arising from the supply network; and
  • the bushfire danger arising from the supply network.

If the project proceeds, we will require AusNet Services to demonstrate to our satisfaction that the design of the new transmission line minimises hazards and risks to the safety of people and property and bushfire danger as far as practicable as required under the Act.

To achieve this, AusNet Services must implement processes and procedures outlined in an ESV accepted Electrical Safety Management Scheme (ESMS) see more detail on this scheme below.

We are not a referral authority in planning for transmission and distribution lines and have no role in project planning, including deciding the proposed route of any proposed line, or whether it will be constructed either underground or overhead.

Definition of practicable

For the purposes of this duty under the Act, ‘practicable’ means practicable having regard to:

  • the severity of the hazard or risk in question;
  • the state of knowledge about the hazard or risk and any ways of removing or mitigating the hazard or risk;
  • the availability and suitability of ways to remove or mitigate the hazard or risk; and
  • the cost of removing or mitigating the hazard or risk.

This requires all reasonable measures to be implemented in order to reduce or remove risk, and so that cost impacts are not given excessive emphasis.

Electricity Safety Management System (ESMS)

The ESMS sets out matters such as the controls or standards a major electricity company applies to ensure the safety of its network. More information on ESMSs can be found here.

We have informed AusNet Services of our requirement they deliver a safety risk assessment as part of an ESMS to apply to any new transmission line, ensuring safety management systems are appropriate.

The assessment must confirm the proposed safety management system mitigates bushfire risk as far as practicable and is appropriate for the design of the new line.

The ESMS must include a Bushfire Mitigation Plan (BMP) to specify how bushfire risk arising from the network will be minimised as far as practicable.

There is no ESMS application or formal design for the WVTNP currently before ESV for decision.

Bushfire Mitigation Plan (BMP)

As electricity has the potential to cause a fire if a fault occurs, there is a legislative requirement that the risk of bushfire danger is minimised as far as reasonably practicable.

This doesn’t mean that there is no risk, it means that AusNet Services must take steps to minimise the risk as far as reasonably practicable.

The Act requires AusNet Services to prepare and submit to ESV for acceptance a plan for its proposals for mitigation of bushfire in relation to its transmission network (known as a Bushfire Mitigation Plan or BMP). More information on the requirements of BMPs can be found in the Energy Infrastructure Safety Management Policy.

The BMP

  • specifies preventative strategies and programs in place to mitigate the risk of network caused bushfire, and
  • specifies the management systems, processes and procedures in place to operate and maintain the network during times/in zones of high bushfire risk, and responding to bushfire emergencies.

The Electricity Safety (Bushfire Mitigation) Regulations 2013 (Vic) (BFM Regulations) prescribe particulars that must be included in a BMP, including that it outline the policies and procedures it will implement to mitigate the risk of starting a bushfire.

Regular audits of BMPs

We regularly audit major electrical companies (MECs) to ensure their BMPs meet all regulatory requirements and the MEC is implementing the policies and procedures documented in the plan correctly.

Typical initiatives to reduce risk include:

  • keeping vegetation clear. This includes cutting or removing trees that may fall and touch the overhead line,
  • inspecting the line using the latest techniques and technology such as LIDAR and helicopters with high resolution visual, thermal and corona cameras,
  • inspecting the assets using competent qualified specialised resource in a timeframe that is regulated in the BFM Regulations,
  • design of the towers in accordance with the latest standards, and
  • electrical protection schemes that operate at very high speed if a fault occurs, to shut off the line (in the case of transmission lines this will often be before the line hits the ground) and reduce the energy available to start a fire.

Monitoring compliance to accepted plans

We regularly conduct both systems (office based) audits and outcomes (field based) audits to review compliance with ESMSs and BMPs, ensuring processes and work practices are being carried out as documented in those documents and in accordance with requirements stated in the Act.

Audit topics or areas of focus are reviewed and determined annually in a systematic and structured approach informed by:

  • analysis of all major risks, including critical control priorities,
  • critical control relationships to system audit findings,
  • review of previous ESMS audit findings,
  • review of field audit findings, and
  • analysis of causal factor trends of serious incidents reported to ESV.

The outcomes of our audit programs are provided each year in our publicly available Electrical Network Safety Performance Report into the safety performance of Victoria’s major electricity companies.

The report includes the five distribution businesses (AusNet Services, CitiPower, Jemena, Powercor and United Energy) and the three transmission businesses (AusNet Services, Basslink and Transmission Operations Australia).

Enforcement activity

Where a potential non-compliance is identified, we will assess and determine our enforcement response based on the available action that is proportionate to the nature of the offence, the actual harms caused, significance of potential risk outcomes, and the conduct of the regulated entity responsible for the non-compliance.

For more information on our approach to compliance and enforcement please read our current policy. The principles outlined in the policy are that we will take action that is:

  • Targeted
  • Proportionate
  • Consistent
  • Factual
  • Impartial
  • Proactive
  • Constructive

Transmission line design

Material published publicly by AusNet Services indicates it is intended the design standard for the proposed new 500 kV overhead transmission lines will require 15 metres ground clearance. This is a higher minimum ground clearance than existing transmission lines in Victoria and is six metres greater than the nine metre minimum ground clearance required by the relevant Australian Standard (AS/NZS 7000).

The additional ground clearance provides an opportunity for AusNet Services to safely permit taller farming equipment in transmission easements than would be allowed in existing transmission line easements elsewhere in Victoria and in Australia more broadly.

Based on the publicly available information, there may be instances where transmission towers are closer together than the rest of the line section. This is likely to mean the minimum ground clearance will be greater than 15 metres in that section. We estimate that it might be 18 or 20 metres. This may allow AusNet Services to permit higher harvesting equipment or other equipment within the easement between those two towers.

The regulatory framework that applies to activities in the vicinity of transmission lines is as follows:

  • the Electricity Safety (General) Regulations 2019 (Vic) contains duties that apply to the public at large in connection with the supply networks of major electricity companies such as AusNet Services,
  • these duties take the form of offence provisions that limit various conduct by the public in connection with supply networks, including by reference to various minimum distances that must be observed around supply networks (see regulations 603-619), and
  • the public is permitted to do things that would otherwise be prohibited if the written permission of the owner or operator of the supply network is obtained or, if the permission is refused, an exemption is granted by us (see regulation 703).

Severe weather impacts

New overhead transmission lines are required to be designed to the latest Australian design standards (AS/NZS 7000:2016 Overhead Line Design).

It is our expectation that AusNet’s ESMS application will demonstrate the design of the proposed transmission line is in accordance with AS/NZS 7000:2016 Overhead Line Design.

The structural design requirements in AS/NZS 7000 are more onerous than the requirements that were in place when much of the existing Victorian transmission network was designed and built. The requirements for selection of wind speeds in transmission line design in accordance with AS/NZS 7000 are set by AS/NZS 1170.2:2021 (Structural design actions, Part 2: Wind actions).

Agricultural activity impacts

AusNet services has published A guide to living with transmission line easements (Easement Guide), which outlines the permitted usage around existing transmission lines. This guide explains:

  • Prohibited uses of transmission line easements,
  • Operation of large water spray irrigators of the gun type, and
  • Fuelling of and repairs to vehicles, plant and equipment.

ESV has reviewed the Easement Guide and we are satisfied the information in it is consistent with AusNet Service’s obligations under the Act and regulations that we monitor and enforce and will ensure public/land user safety if followed correctly .

The Easements Guide provides an outline of activities permitted or not permitted under a transmission line. It notes the different activities permitted under the 500 kV and 220 kV transmission lines and is in accordance with the No Go Zone Restrictions found in the Electricity Safety (General) Regulations 2019 (Vic) (General Regulations).

AusNet Services has also produced the Landholder Guide: Land access, easements and compensation, a specific guide to assist those who may be affected by the proposed transmission line, developed in response to key themes from community comments. We suggest both guides are read together.

Our expectation is the Easement Guide will be updated to reflect any conditions specific to any final design.

Fuelling of and repairs to vehicles, plant and equipment

The Easement Guide sets out prohibited activities such as repairing and refuelling machinery, loading or unloading trucks, parking trucks and storage of fuel in the vicinity of the easement.

Use of irrigation equipment

The Easement Guide sets out activities permitted or not permitted under a transmission line. This guideline notes the different activities permitted under the 500 kV and 220 kV transmission lines.

In summary, the following applies for irrigation equipment:

Farming activity Permitted
(500 kV)
Permitted
(220 kV)
Notes
Use of centre pivot and lateral moving irrigators Yes Yes

For 500 kV

Are permitted to operate up to 8.6m height (due to No Go Zone restrictions) and subject to an AusNet Services safety assessment which must be sought prior to operating.

Maximum height of machinery cannot exceed 8.6m (due to No Go Zone restrictions).

 

For 220 kV

Are permitted to operate up to 4.6m height (due to No Go Zone restrictions), subject to an AusNet Services safety assessment which must be sought prior to operating.

Maximum height cannot exceed 4.6m (due to No Go Zone restrictions).

Use of rain gun irrigators No No Large water spray irrigators of the gun type are not permitted to operate within the easement due to safety risks and potential damage to electricity infrastructure.

Boom type irrigators

The regulations do not prescribe a distance that a boom type irrigator must be from the transmission line. This distance will depend on the spray distance, how the stream of water breaks into droplets, and volume of water sprayed, etc.

GPS use

The Global Positioning System (GPS) uses radio signals in frequencies (spectrum) reserved for radio navigation services.

It is unlikely that GPS interference is due to a transmission line as there is a line of sight to the various satellites or cells used for the location service.

Calculations show the conductors of a power line are too thin to have any significant effect. However, GPS can be affected when close to large amount of metal such as silos, metal sheds, etc.

Being too close to a tower may have some minor affect, but due to the large amount of air space between the tower lattice steel work, the chance of this is extremely low.

A number of farmers are using a differential GPS (DGPS) to auto steer farm equipment with a 1-2 centimetre accuracy allowing the operator in the cabin to concentrate on other tasks.

We understand that a DGPS utilises radio frequencies to communicate with the base station in a band that has a higher likelihood of interference from high voltage power lines compared to typical satellite GPS systems, which operate in the 1-2 GHz frequency range and are largely immune to power line interference.

We are aware of instances of DGPS interference from transmission lines (NSW and Queensland) for equipment in close proximity (essentially within the easement) to high voltage transmission lines. We understand this can happen but is rare.

We are advised that the issue can generally be avoided through transmission line design and type testing of transmission line hardware. ESV will seek to understand how AusNet Services will mitigate this risk as part of their design of the Transmission line.