Munno Para substation: energising for a greener future

Munno Para substation: energising for a greener future
The transformer being moved into position on the bench

ElectraNet’s greenfield high voltage Munno Para substation, with a forecast investment of between $30-$40 million, will soon be powering Adelaide’s northern suburbs.

ES&D talks with ElectraNet executive manager Network Services Simon Emms to hear how intelligent network planning and use of smart grid technology is being used to increase asset utilisation.

Responding to demographic change and an evolving economy, the Government of South Australia released a 30-year plan in 2010. The strategic plan for greater Adelaide suggested steady population growth and construction of more than 250,000 additional dwellings. In fact, the City of Playford is one of the fastest growing areas in the state, with the Australian Bureau of Statistics projecting its current population of 82,000 will double by 2026.

In its own studies, SA Power Networks identified a future load growth hotspot in the northern suburbs and, to support this growth, electricity transmission specialist ElectraNet began planning the new transmission substation at Munno Para. The substation site is located 33km north-east of Adelaide, close to existing high voltage transmission lines.

The site was designed to accommodate for future expansion, with space allowed for two extra transformer bays plus an additional capacitor bank.

Just one 40m high pole structure was required to cut-in the existing Blyth West to Para line to the Munno Para substation. What’s more, the positioning has reduced the number of additional transmission lines required to connect the new substation to the existing network, with ElectraNet executive manager Network Services Simon Emms saying it will provide important cost-savings for South Australians while minimising visual impact on the surrounding environment.

“The new Munno Para substation has been constructed close to existing 275kV and 66kV powerlines, which has constrained development costs and removed the need to build additional connecting transmission lines, keeping visual impacts to a minimum.

“The 275/66kV 225MVA ABB transformer was designed and built in Chongqing, China and shipped to Melbourne. It was successfully delivered to site and installed on February 28, 2015,” he said.

Smart Grid design standard IEC 61850 for power utility automation was integrated for the onsite control building to optimise electricity delivery.

After beginning construction in May 2014, energisation is planned for this October.

Change of plans

The search for a suitable site for the new Munno Para substation commenced in 2006. As part of the process, several sites were considered with a shortlist of three locations studied in greater detail.

Initial plans for the substation were presented in early 2012, with the community invited to provide feedback. In response to concerns from nearby landowners that the site – which was part of a state government project to boost open space and vegetation – would be ruined, a number of significant changes were made to the substation’s layout and design.

The revisions included moving the substation south, away from Dalkeith Road by an additional 30m, relocating the access driveway and planting a break in the vegetation border with mature plants to minimise nearby residents’ views into the site. The amendments struck the best possible balance between community input and technical, safety, security, environmental and cost-related requirements.

Water sensitive design

Onsite, the transformer is supported by a fibreglass SPEL Puraceptor oil capture containment system (Environmental Protection Authority Class 1) that will treat all flows, including stormwater runoff. In fact, the entire substation has been designed with water in mind, ensuring water is captured and utilised in a manner that will benefit the site and meet requirements for various Average Recurrence Interval (ARI) storm events.

Among the water-sensitive design elements is a 0.5m high earth mound to contain and redirect sheet stormwater runoff, and a 590 cubic metre capacity stormwater detention basin to capture site runoff.

Screening Vegetation

Moving the location of an access driveway left a gap in the thick vegetation buffer around the substation site. ElectraNet gave an undertaking to fill this gap with mature saplings, to help block views into the site.

Residents with a view of this vegetation gap were given the opportunity to help choose the 145 trees and shrubs, which were planted in July 2013, allowing time to establish during the cooler months.

While the substation site masterplan catered for the retention of as much of the existing vegetation as possible, additional landscaping has been planned for the site, to further improve the visual amenity for neighbouring residents and passers-by.

In line with the requirements of the Environmental Protection Authority’s Environmental Protection (Noise) Policy 2007, and associated legislation, detailed design incorporated 9m and 11m high noise attenuation walls.

Active community engagement also highlighted mitigating potential noise impacts would be a priority for neighbouring residents.