Connecting Sydney

Energy Source & Distribution looks at the latest substation developments powering Australia’s largest city.

At 5.30pm on Tuesday 1 February, 2011, New South Wales reached its highest recorded peak demand for electricity at 14,580 MW. A heat-wave in Sydney caused a series of blackouts in the city’s inner west, affecting thousands of residents.

Ausgrid (previously known as EnergyAustralia) crews worked to carry out permanent repairs on the inner-west electricity network after faults occurred on two major cables supplying the Enfield zone substation. At its peak, the interruption to power supply affected about 12,000 homes in parts of Croydon Park, South Strathfield, Enfield, Burwood Heights and Belfield.

Ausgrid staff worked ahead of schedule in extreme heat to re-gas the transmission cables and carry out extensive jointing of 11,000 V cables.

“At peak times during the extreme hot weather, demand for power increased to very high levels,” an Ausgrid spokesperson said.

“This was an added challenge as we worked to reconnect homes and maintain supply by other means including rerouting power from other parts of the network.”

As New South Wales sizzled under extreme heat, work continued on a massive capital works upgrading the city’s substations. Ausgrid commissioned seven new major substations in the first six months of this financial year. The transmitter invested $20,500,000 in the six months from July – December 2010 to replace equipment in major substations, such as protection systems and transformers.

“(Ausgrid’s) $8 billion record capital works program is underway across our network which requires us to balance the resources we have available with the large volume of work taking place, including the construction of the Balgowlah North substation,” Ausgrid project manager, Stuart Donaldson told Energy Source & Distribution.

“The wet weather experienced over summer also posed a challenge with crews having to overcome significant wet weather delays during the construction phase.”

New South Wales transmitter, TransGrid is likewise investing $569 million as part of the Western Sydney supply project to secure Sydney’s power supply for the future. This project is TransGrid’s biggest-ever investment in Sydney’s transmission network.

The project includes the construction of a new 330 kV substation at Hyland Road, Greystanes (Holroyd Substation), a new 330 kV substation at PottsHill (Rookwood Road Substation), construction of new underground electricity cables between the two new substations and an upgrade to the existing overhead transmission line between Sydney West substation at Eastern Creek and the new Holroyd substation.

The project will help reinforce the electricity supply to the growing inner-western areas of Sydney, where peak summer demand is forecast to increase by around 20 per cent over the next decade.

The annual growth of these areas is 80 MW, the equivalent of electricity used by 60,000 average homes, or a quarter of NSW’s average growth in peak demand. Sydney’s population is expected to increase by 1.1 million in the next 25 years, with an additional 640,000 new homes and almost seven million square metres of new commercial space.

With Sydney and its outlying areas continuing to grow and consume more electricity every day, Energy Source & Distribution looks at the Ausgrid and Transgrid substation projects that will keep the lights on in New South Wales.


Top Ryde 

Substation features: Two 132,000 V to 11,000 V 50 MVA transformers, two 11,000 V earthing transformers and a 132,000 V GIS busbar.

Ausgrid’s new Top Ryde substation is edging towards completion with crews starting work on the electrical fit out.

The two-storey substation will house two 132,000 V to 11,000 V 50 MVA transformers, with provisions for installation for a third future transformer.

Other equipment to be installed includes two 11,000 V earthing transformers, with provision for a third, and a 132,000 V GIS busbar, rated at 1600 amps incorporating three sections and allowing for two incoming feeders.

Two groups of 11,000 V switchgear with provision for a third will also help Ausgrid meet the growing demand for power in the northern district.

Civil works at the Gardener Avenue site commenced in April 2009 after two years of planning and discussions with the Ryde Council, Department of Planning and the local community.

The consultation period resulted in changes to the initial proposal including altering the layout of the internal electrical equipment to reduce the levels of electric and magnetic fields further below Australian and international guidelines.

The first stage of the project involved the demolition of the existing buildings over about six weeks, followed by bulk excavation of the site.

The new equipment will help supply about 10,000 homes and businesses in Ryde, Putney, Gladesville and Tennyson Point.

Beaconsfield West 

Substation features: Two new 132 kV gas-insulated switchgear, installation of a third 330/132 kV transformer on the southern site and installing two 132 kV 160MVAr capacitor banks.

The first major electricity supply point to Sydney’s inner metropolitan area, located in the Sydney suburb of Alexandria, Beaconsfield West was first commissioned in 1979.

With a $144 million investment to redevelop the substation, the contract for the design and construction of the new substation was awarded to UGL

Infrastructure in early 2010 and ABB is the selected supplier of switchgear.

TransGrid’s redevelopment of the substation involves the construction of two new buildings on either side of the existing substation. Each building will house 22 switchbays with 132 kV 50 kA GIS. The two GIS installations will be interconnected by four circuits of three phase encapsulated 132 kV 50 kA Gas Insulated Line (GIL). The GIL will span the site on an elevated gantry.

The substation will feature two sets of modular control buildings (MCBs) with these to be located on the roof of the GIS buildings. The existing substation also has two 330/132/11 kV 375MVA outdoor oil-filled transformers, with the combined capacity to supply around 600,000 average homes. As part of the works, a third 330/132/11 kV 375 MVA outdoor oil-filled transformer and two 132 kV 160 MVAr capacitor banks will be installed at the substation. Toshiba has been selected to provide the new transformer and ABB will supply the additional capacitor banks.

The upgrade will increase the capacity of the substation by around 50 per cent and allow TransGrid to meet increasing electrical demand in the Sydney inner metropolitan area, provide increased reliability, and to allow for the replacement of the aging switchgear.

The existing substation is required to be kept in service throughout the redevelopment project. The staging of the project and site layout required complex staging in order to incorporate TransGrid’s future plans for 330 kV GIS installations at the site. The construction of two new GIS installations are on schedule and expected to be commissioned in November 2011 and November 2012.

After the commissioning of these switch rooms, Ausgrid will connect each of its 13 existing 132 kV oil-filled cables to TransGrid’s new GIS via XLPE cable extensions. Ausgrid’s cable works are expected to take place during late 2014.



Substation features: A new 330 kV substation adjacent to the existing switching station at Tomago, including two new transformers.

Joint planning between Transgrid and Ausgrid identified the need for an additional 132 kV bulk supply point north of Newcastle. The project is a $52 million investment to install a new 330 kV substation adjacent to the existing switching station at Tomago, including two new transformers. The upgrade will provide an additional 132 kV supply of electricity to the north of Newcastle.

Newcastle’s Tomago substation is an existing 330 kV switching station commissioned in 1983. The switching station is located in the Tomago Aluminium Smelter complex, providing a direct connection with the smelter, which employs 1200 people and produces more than half a million tonnes of aluminium each year, contributing more than $1.5 billion annually to the Australian economy.

The contract for the construction of the new substation was awarded to Jemena Asset Management in February 2009. The two transformers for stage one of the project were manufactured by Areva and Toshiba.

This project will allow TransGrid to meet increasing electrical demand in the Newcastle metropolitan area and Lower Mid-North Coast, providing higher levels of reliability to the region. After its completion, the Tomago Substation will have the capacity to supply the equivalent of around half a million average homes.

The new 132 kV switching station will be directly connected to Ausgrid’s new Tomago Zone Substation, north of the site.



Substation features: 132,000 V and 11,000 V switchgear.

Ausgrid recently commissioned its new Kogarah zone substation in Sydney’s south to help supply around 25,000 homes and businesses in Kogarah, Rockdale, Hurstville and Sans Souci.

The $100 million project included the decommissioning of Ausgrid’s existing Carlton substation and the construction of a new architect-designed substation.

Construction and fit out of the substation took place over two-and-a-half years.

The project also included construction of two 132,000 V circuits from Peakhurst to Kogarah substation via Hurstville North substation, with an approximate length of about 9.4 km.

As part of the project, a 120 m x 2.4 m diameter ‘thrust bore’ tunnel was created under the adjacent railway line to provide a suitable route for the 132,000 V cables connecting to Peakhurst. The tunnel supports two 132,000 V circuits and 16 11,000 V circuits.

Construction of the tunnel and substation building took place concurrently to ensure the overall project was not delayed.

The completed building is spread over four levels and houses both 132,000 V and 11,000 V switchgear.


Balgowlah North

Substation features: 132/11 kV and 33/11kV hybrid zone substation. 

Ausgrid has entered the installation phase of its new Balgowlah North substation project.

Construction of the $30 million substation project began in September 2009 following a lengthy community consultation period.

Once complete, the Balgowlah North zone substation will replace the existing heritage-listed Balgowlah substation at the intersection of Boyle and Griffith Streets.

Ausgrid crews recently installed 11,000 V switchgear and 132,000 V panels at the Quirk Road site of the new substation following the arrival of three new transformers before Christmas.

Work is also underway to connect the new substation to the Warringah subtransmission substation in Frenchs Forest via a six kilometre route of new 132,000 V cables. The $32 million cable project is part of Ausgrid’s $301 million investment in Sydney’s Northern Beaches region to 2014. A new 33,000 V underground cable link is also being established to connect the substation to the existing overhead network.

“We’re installing IEC61850 compliant relays, such as our feeder protection relays, at Balgowlah North. This will enable the substation to take advantage of IEC61850 in the future,” Ausgrid project manager, Stuart Donaldson said.

“The Balgowlah North substation will have a substation control system. When our protection relays trip, this information will be relayed back to the SCS which will then flag the local substation indicators, such as the human machine interface and the control room.

IEC61850 compliant relays, such as feeder protection relays, will be installed at Balgowlah North, enabling the substation to take advantage of IEC61850 in the future.

“The Balgowlah North substation will have a substation control system (SBS). When our protection relays trip, this information will be relayed back to the SCS, which will then flag the local substation indicators, such as the human machine interface and the control room,” Mr Donaldson said.

Commissioning of the new Balgowlah North substation and completion of the high-voltage cable link are scheduled for later this year.



Substation features: A 330 kV gas-insulated switchgear (GIS) building with a 330 kV GIS installation in breaker and half configuration, as well as two 330/132 kV
375 MVA transformers.

The Holroyd substation is one of two substations being constructed as part of TransGrid’s Western Sydney supply project.

The area selected for the substation is a site on Hyland Road, Greystanes in inner-western Sydney. The site was selected by TransGrid for the development of the substation due to its proximity to existing Integral Energy 132 kV transmission line infrastructure, which connects to TransGrid’s Sydney West substation in Eastern Creek.

Prior to TransGrid’s purchase of the site in 2008, the site was owned by Holroyd City Council and used by the community for recreational purposes. As part of the purchase agreement, TransGrid relocated and rebuilt the facilities on adjoining council property.

The Holroyd substation will include a 330 kV gas insulated switchgear (GIS) building with a 330 kV GIS installation in breaker and half configuration, as well as two 330/132 kV 375 MVA transformers. Combined, these transformers have the capacity to supply more than half a million average homes. The substation will act as a bulk supply point for the inner west, connected to Integral Energy’s local distribution network via two 132 kV transmission line feeders.

The substation will also feature a transportable modular control building (MCB). The MCB will house all of the equipment necessary for the protection, monitoring and control of the high-voltage system and communication equipment to provide interconnection to TransGrid’s

network control room at Eastern Creek. Additionally, it also includes ancillary power supply systems including low- voltage switchgear.

By having a completely removable control building at the substation, TransGrid will be able to replace large control components and secondary systems of the substation, without major power disruptions.

MCBs are now being used in all of TransGrid’s new substations to increase the efficiency of equipment upgrades and secondary system replacements. This is important as monitoring and control equipment have a 10-15-year design life, compared to 40-50 years for substation high-voltage equipment.

The base of the 330 kV GIS building at Holroyd Substation will also include a cable basement for connection of future 330 kV cables to the switchgear.

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