WHY?

In response to population growth and increased demand in northern Victoria, the Wollert to Euroa Pipeline maximum allowable operating pressure (MAOP) upgrade was required to increase the capacity of the 300 mm pipeline heading north from Wollert into New South Wales. The upgrade provides the ability to export into southern NSW while still providing for peak demand in Victoria at the one time.

It is part of APA’s Victorian Northern Augmentation Project, which also includes upgrade of the Wollert Compressor Station, flow reversal of the Springhurst Compressor Station, and construction of the Euroa Compressor Station (click here for more information about these projects).

When asked why APA opted for the upgrade as opposed to other capacity increasing options, APA Project Manager David Thek said “The pipeline was built in 1976 and is designed conservatively by today’s standards, making it possible to increase the MAOP.

“Where possible, increasing the capacity of an existing pipeline is cheaper and comes online quicker than the construction of a new one. The MAOP upgrade in conjunction with the new Wollert compressors provides a relatively cost-effective capacity increase.”

WHAT?

APA was required to review the construction documentation and operation records of the following facilities against the requirements of AS2885:

• The 300 mm pipeline between Wollert and Euroa – constructed in 1976;
• The Beveridge city gate – constructed in 2008;
• The Wallan city gate – constructed in 1976;
• The Broadford city gate – constructed in 1976;
• The Seymour (Puckapunyal) city gate – constructed in 1996;
• The Seymour city gate – constructed in 1976; and,
• The Wandong pressure limiter.

“Components which the review found were not appropriately rated – or where paperwork confirming they were appropriately rated was missing – were upgraded or replaced,” said Mr Thek.

After the review, it was found that the pipeline could be proven capable of dealing with an increase in pressure from 7,400 kPa to 8,800 kPa, but that records were missing for specific sections of the Wallan, Broadford, Puckapunyal and Seymour city gates. Additionally, a new line valve installation was required at the northern extremity of the upgrade at Euroa to protect pipe north of that point from the higher pressure.

As such, a number of works had to be undertaken, including a significant upgrade of the Wallan, Broadford and Seymour city gates, a minor upgrade and hydrotesting of existing pipework at the Puckapunyal city gate, a cut-in of dual line valves and a new pressure reduction station at Euroa, as well as minor upgrade works to the Wandong pressure limiter.

WHEN?

Work on the project began in early 2009 with the commencement of a substantial search and review of records. Final submissions were made to Energy Safe Victoria (ESV) outlining the condition of the pipeline and facilities, as well as the proposed upgrade works to bring them up to a standard suitable to increase the MAOP.

ESV provided their approval subject to completion of the upgrade works in September 2010. Site works commenced in mid-2010 and were completed early in 2011 with the pressure in the pipeline increased to 8,800 kPa for the first time on 23 March 2011.

WHO?

The project was managed by APA, with installation of the Euroa line valves and the Wandong upgrade works performed by Comdain, and the upgrade of the city gate sites performed by U-Fab. APA also utilised local contractors to perform the work, strengthening the company’s relationship with the community.

HOW?

The design of the upgrade was completed in-house by APA’s Asset Management and Engineering team in Dandenong.

“As the city gate sites are owned by Envestra and operated by APA, involvement was required from both sides of the business to ensure that the requirements of the owners of all assets were met,” said Mr Thek.

APA Asset Management and Engineering General Manager Mark Fothergill added “The condition of the pipeline was verified by in-line intelligent pigging performed by Rosen and an extensive program of field verification.”

As all of the site work was undertaken on operating assets, there was a need to comply with APA’s Permitting System.

“The co-operation of APA’s employees – particularly, their willingness to be flexible and work around project requirements – was invaluable,” said Mr Thek.

A construction safety management plan was also developed for both Comdain and U-Fab’s contracts and approved by ESV.

Commissioning involved increasing the pipeline pressure to 8,800 kPa over a six-hour period using the new Wollert compressors.

“In order to safely increase the pressure, approximately 25 APA employees and contractors were deployed along the pipeline to monitor pressure and report any abnormal changes to the pressure increase throughout the day,” said Mr Thek.

The pressure increase was co-ordinated by APA’s Transmission Operations group from Dandenong using reports from the field as well as the Dandenong control room. “A number of minor leaks were rectified on the day but the pressure was increased without incident,” said Mr Thek.

CHALLENGES

Mr Thek said prolific wet weather in central Victoria was the main challenge in completing the upgrade. “Excavation undertaken in Euroa in the first week of January this year required pumps and sheet piles to keep the groundwater under control,” said Mr Thek.