Building a new substation
Building for the future
Key Points •
•
•
Prior to the construction of a new substation, we complete a State Government-approved process under the Sustainable Planning Act 2009 (SPA), which includes comprehensive environmental impact assessments and associated community consultation. Powerlink works closely with affected landowners both before and throughout construction to help minimise any impacts. Powerlink is committed to ensuring we meet our environmental obligations – all construction work is carried out in accordance with an Environmental Impact Statement (EIS) and an Environmental Management Plan (EMP) which outlines strategies and actions to manage any potential environmental and community impacts.
What is a substation? A Powerlink substation is normally a fenced facility connected to transmission lines that contains electrical equipment and ancillary buildings. Some substations convert high voltage electricity down to a lower level so it can be delivered to the distribution networks owned by Energex and Ergon Energy. Other substations connect power stations and industrial customers or control the ow of electricity on the transmission lines forming the State’s transmission grid. A substation is a key part of the transmission network – in addition to t ransforming voltages, it me asures and controls the ow of electricity on the grid, and switches transmission lines on and off to enable maintenance to be undertaken safely and to protect the network from electrical faults or equipment failure. Powerlink’s high voltage substations are much larger than the distribution substations operated by Energex and Ergon Energy. This is because the equipment used in a high voltage environment is typically much larger and requires more space than lower voltage equipment. In many instances, a Powerlink substation will contain equipment owned by both Powerlink and the local distributor, so that Energex or Ergon Energy can access the power and distribute it to the local community. It’s important to remember that substations are not power stations – they do not generate electricity. This information sheet refers to building a new substation, however similar activities may be undertaken to rebuild or refurbish existing substations. The information provided is intended as a guide only.
2
Building a new substation
A typical substation While substations var y in design, they have a numbe r of common features including: •
Transformer s – are one of the most integral pieces of substation equipment. They transform electricity from high voltages down to levels suitable for large industrial customers or distribution networks that ultimately supply businesses and households.
•
Circuit breakers – are switches which can be used to interrupt the ow of electr icity. They can be used during maintenance to disconnect part s of the substation and allow work to safely take place.
•
Busbars – transfer the electricity within the substation from the wires that feed into the substation and the powerlines leading out of the substation.
•
Protection equipment – monitors the amount of electricity owing through substations and powerlines. All Powerlink substations include protection systems that detect unexpected electrical f aults on the transmission network and automatically isolate the affected equipment. This allows us to manage and rectify unexpected f aults.
•
Earth grid – are wires buried just underneath the ground to ensure the equipment is ‘earthed’. You can’t see the grid, but it’s an integral par t of the substation’s safety system.
Planning a new substation Powerlink, in consultation with Energex and Er gon Energy, undertakes annual planning for the electricity network. Our planning considers whether new substations are r equired to reinforce the main transmission grid or to reliably meet the population growth and demand forecasts in particular areas.
Working with our environment Powerlink follows a State Government-approved process under the Sustainable Planning Act 2009 (SPA) when planning a new substation. Under this process, a comprehensive environmental study is undertaken once a site is selected. Community members and interest gr oups are invited to be involved with this process at an early stage. An Environmental Impact Assessment (EIA) helps ensure any potential environmental, community or economic impacts associated with the project are identied and managed. It includes desktop studies, eld s tudies, consultation and the preparation of an Environmental Impact Statement (EIS). The EIS is a for mal report that examines the environmental, community and economic aspects of a projec t and identies ways to manage any impacts. A Dr aft EIS is released for community feedback prior to the Final EIS being developed. This work results in an Environmental Management Plan (EMP) being developed, which outlines the actions we will take to reduce any impacts identied in the EIS. All construction works are carried out in accordance with the EIS and EMP to mi tigate and manage any potential environmental or community impacts. An Environmental Ofcer is also appointed to every project to ensure that Power link meets it s environment al obligations. For detailed information about this pr ocess, please see our information sheet – Consultation and Environmental Impact Assessments.
Once a need has been identied, we begin work as early as practicable to select a site. This provides advance notice of our plans to landowners, councils, developers and government departments. We also acquire land for substations, often by purchasing the site outright from the owner. In these cases ownership of the land transfers to Powerlink. In addition to constructing a new substation, from time-to-time we carry out construction work to replace ageing substations.
3
Constructing a substation Generally the construction of a substation can take one to two year s depending on it s size. The level and ty pe of construction activity and equipment used may vary as construction progresses. Work is normally c arried out by Powerlink’s contr actor s. Powerlink’s Construction Inspectors will also be on-site to ensure the work is performed to contract specications. The contractor’s Site Supervisor is in charge of the construction and safety on site. For safety reasons, only authorised Powerlink people and our contractors are allowed to enter the substation site. 1.
Preparing the site
Site preparation involves: •
Marking the boundary of the substation site and erecting safety fences.
•
Removing any vegetation as necessar y.
•
Levelling and possibly raising the site and compacting soil if required.
•
Excavating drains if needed.
•
Stabilising any new embankments (batters).
These activities may create some temporary noise and dust. However, we endeavour to limit this activity to times when neighbours will be least affected. This stage can take around eight to 12 weeks.
3.
During this period, the electr ical equipment is installed and the ancillary buildings that house control equipment are erec ted. Several steel lattice towers may be erec ted using cranes and elevated work platforms. These towers support the wires from the transmission lines that connect to the substation. Internal roads are sealed and a road base is laid on the remainder of the substation site. Heavy equipment such as high voltage transformers may be delivered at this time. These transformers are very large, weighing hundreds of tonnes and measuring around 20m long, 5m wide and 8m high. Because of their size, transport can be slow. Delivery is often completed early or late in the day when there is less tr afc on the road. This stage can take around eight to 12 weeks. 4.
Installing foundations
Usually, a large excavator or boring machine is used to create foundations. Concrete is poured and left to cure and the foundation is completed. Trenches and roadways will also be excavated during this stage. This stage can t ake around eight to 10 weeks. Following the completion of this stage, heavy excavation vehicles and equipment are no longer required on-site and the potential for disruption from noise or dust is reduced.
Testing and commissioning the substation
A series of thorough inspections and commissioning tests are carried out before the substation is put into service. This stage can take around six to 10 weeks. 5.
Reinstating the site
The substation site will be left tidy and embankments and other areas ar ound the fence lines reinstated where necessary. Further r ehabilitation or revegetation may also be completed. This stage typically takes around two to four weeks. 6.
2.
Assembling equipment
Maintaining the substation
Powerlink will maintain the substation to ensure i ts reliability and safety. An annual review is generally conducted and any maintenance is carr ied out as r equired. The life of a substation is about 40 to 50 years. Replacement and refurbishment work may need to be completed from time-to-time. This may be as sim ple as replacing some ageing equipment over several days or weeks, or rebuilding cert ain sections of the substation which could take several months. At times, we may need to work outside of normal work hours to undertake essential maintenance or respond during an emer gency. Measures will be taken with lighting and noise to minimise disruption to our neighbours during any out of hours work.
4
Explanations and frequently used terms Substation
Environmental Management Plan (EMP)
The role of a substation is to monitor and control the ow, stability, quality and voltage of electr icity on the tr ansmission lines connected to the facility. Equipment located within the substation is used to transform the voltage of electricity, protect the network, measure the ow of the electr icity, and switch electricity between the different tr ansmission lines and transformers on the grid. A substation is not a power station – it does not generate electricity.
An Environmental Management Plan (EMP) documents the actions Powerlink will take to manage and minimise environmental and social impacts that might result from the design, construction or operation of the transmission line. The EMP is developed as part of the Environmental Impact Statement (EIS).
Transmission line A transmission line is a powerline which is capable of carr ying large amounts of elect ricity at high voltages. Transmission lines are larger and taller than the ever yday distribution powerlines which deliver electricity to your home and business. Transmission lines are normally built on tall steel towers or concrete and steel poles. Environmental Impact Assessment (EIA) An Environmental Impact A ssessment (EIA) is the process to ensure any potential environmental, community or economic impacts associated with the project ar e identied and managed. Environmental Impact St atement (EIS) The written report that is produced as part of the EIA process. An Environmental Impact Statement (EIS) examines the environmental, community and economic aspects of proposed projects and identies ways to manage any impacts. The EIS is an important part of Powerlink’s consultation process and is advertised for public comment. Included in the EIS is an Environmental Management Plan (EMP).
5
Building a new substation
Sustainable Planning Act 2009 (S PA) The Sustainable Planning Act 2009 (SPA) is legislation which seeks to manage the process and effects of developments and ensure coordination and integration of local, regional and state planning.
About Us
More Information
Powerlink Queensland is a State Government Owned Corporation which owns, develops, operates and maintains the high voltage transmission network in Queensland.
Other useful guides can be accessed from www.powerlink.com.au including:
Our network of high voltage substations and transmission lines extends 1,700km from Cairns to the New South Wales border – approximately half of Australia’s eastern seab oard. Powerlink’s transmission network is the central link in the electricity supply chain, transporting electricity from power stations where it is generated, to distributors Energex, Ergon Energy and Essential Energy t hat deliver electricity to around two million customers. Powerlink also transports electricity directly to industrial customers and to New South Wales via the Queensland/New South Wales Interconnector transmission line. Powerlink does not generate or buy or sell electricity – we simply transport it ‘in bulk’ from wherever it is generated across our high voltage transmission network to where it is needed. For more information see our About Powerlink Queensland information sheet. Import ant note: The contents of this information sheet are current at the time of print and are indicative only. Powerlink reserves the right to change its policies and procedures from time to tim e. Befo re rel ying on this i nforma tion yo u shoul d conta ct Power link t o check w hethe r it is still current.
•
Consultat ion and Environmental Impact Assessments
•
Understanding designation for transmission line infrastructure
•
Understanding resumptions for transmission line infrastructure
•
Maintaining our network and easements
Contact Us •
Call FREECALL 1800 635 369 (during business hours)
•
Email us at
[email protected]
•
Visit ww w.powerlink.com.au, or write to: Network Property Powerlink Queensland PO Box 1193 VIRGINIA QLD 4014
Printed on Monza Recycled – 30% pre-consumer, 25% post consumer waste and 45% forest managed bre. Created by a mill that is 100% energy self-sufcient. Monza Recycled is Certied Carbon Neutral by The Carbon Reduction Institute (CRI) in accordance with the global Greenhouse Protcol and ISO 14040 framework. Version May 2012
