Building a new substation

Transcription

1 Building a new substation Building for the future

2 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 flow 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 transforming voltages, it measures and controls the flow 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

3 A typical substation While substations vary in design, they have a number of common features including: Transformers 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 flow of electricity. They can be used during maintenance to disconnect parts 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 flowing through substations and powerlines. All Powerlink substations include protection systems that detect unexpected electrical faults on the transmission network and automatically isolate the affected equipment. This allows us to manage and rectify unexpected faults. 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 part of the substation s safety system. Planning a new substation Powerlink, in consultation with Energex and Ergon Energy, undertakes annual planning for the electricity network. Our planning considers whether new substations are required to reinforce the main transmission grid or to reliably meet the population growth and demand forecasts in particular areas. Once a need has been identified, 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. 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 groups 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 identified and managed. It includes desktop studies, field studies, consultation and the preparation of an Environmental Impact Statement (EIS). The EIS is a formal report that examines the environmental, community and economic aspects of a project and identifies ways to manage any impacts. A Draft 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 identified in the EIS. All construction works are carried out in accordance with the EIS and EMP to mitigate and manage any potential environmental or community impacts. An Environmental Officer is also appointed to every project to ensure that Powerlink meets its environmental obligations. For detailed information about this process, please see our information sheet Consultation and Environmental Impact Assessments. 3

4 Constructing a substation Generally the construction of a substation can take one to two years depending on its size. The level and type of construction activity and equipment used may vary as construction progresses. Work is normally carried out by Powerlink s contractors. Powerlink s Construction Inspectors will also be on-site to ensure the work is performed to contract specifications. 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 necessary. 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. 2. 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 take 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. 3. Assembling equipment During this period, the electrical equipment is installed and the ancillary buildings that house control equipment are erected. Several steel lattice towers may be erected 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 traffic on the road. This stage can take around eight to 12 weeks. 4. 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 around the fence lines reinstated where necessary. Further rehabilitation or revegetation may also be completed. This stage typically takes around two to four weeks. 6. Maintaining the substation Powerlink will maintain the substation to ensure its reliability and safety. An annual review is generally conducted and any maintenance is carried out as required. 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 simple as replacing some ageing equipment over several days or weeks, or rebuilding certain 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 emergency. Measures will be taken with lighting and noise to minimise disruption to our neighbours during any out of hours work. 4

5 Explanations and frequently used terms Substation The role of a substation is to monitor and control the flow, stability, quality and voltage of electricity on the transmission lines connected to the facility. Equipment located within the substation is used to transform the voltage of electricity, protect the network, measure the flow of the electricity, and switch electricity between the different transmission lines and transformers on the grid. A substation is not a power station it does not generate electricity. Transmission line A transmission line is a powerline which is capable of carrying large amounts of electricity at high voltages. Transmission lines are larger and taller than the everyday 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 Management Plan (EMP) 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). Sustainable Planning Act 2009 (SPA) 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. Environmental Impact Assessment (EIA) An Environmental Impact Assessment (EIA) is the process to ensure any potential environmental, community or economic impacts associated with the project are identified and managed. Environmental Impact Statement (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 identifies 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

6 About Us Powerlink Queensland is a State Government Owned Corporation which owns, develops, operates and maintains the high voltage transmission network in Queensland. 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 seaboard. 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 that 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. Important 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 time. Before relying on this information you should contact Powerlink to check whether it is still current. More Information Other useful guides can be accessed from including: Consultation 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 (during business hours) us at website.enquiries@powerlink.com.au Visit 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 fibre. Created by a mill that is 100% energy self-sufficient. Monza Recycled is Certified Carbon Neutral by The Carbon Reduction Institute (CRI) in accordance with the global Greenhouse Protcol and ISO framework. Version May 2012