The dream team behind the Gordon outage

15 December 2023



A planned outage may sound simple, but undertaking one like the recent Gordon power station outage was no easy feat for the 65-strong team.

 

Gordon Power Station is our largest, sitting at a 432MW generating capacity. So, shutting it down requires meticulous planning and organisation…and a very large team!

 

Just some of the Gordon outage 'dream team'.

 

Gordon Power Station was commissioned in the 1970-80s, fed by Lake Gordon and Lake Pedder. These two lakes combined make up the largest water storage in Tasmania, and the largest in Australia. Water from the lake travels down a 137-metre vertical shaft - the 'inlet tower' - to the underground power station. Once it is used to generate hydropower, it is sent on its way back to the Gordon River. 

 

Check out the video below to learn more about how hydropower is generated at Gordon Power Station!

 

 

Every 4-5 years, our Major Maintenance team undertakes repair and general maintenance on the intake gate, which sits at the bottom of the inlet tower. This gate is designed to shut off the flow of water to the underground power station.

 

Michael McMillian, Supervisor of Major Maintenance, shared his insights into the outage, and what helped to get the station back up and running smoothly.

 

"The Gordon intake has a condition in the concrete called 'alkaline silica reaction' where the concrete actually grows inwards and outwards, so we need to monitor it regularly."

 

A bulkhead being lowered into place on the Gordon Power Station Inlet Tower. 

 

"The outage allows us to safely measure the internal diameter of the cylinder inside the intake to ensure it isn't going to get jammed when it needs to be dropped, such as in an emergency."

 

A skilled dive team came in to clean off the trash screens and check their structural integrity. At a depth of 37 metres each dive, no wonder the dive scope methodology was 37 pages long!

 

The divers also helped to place six bulkheads between the trash screens and the intake gates. These bulkheads ensure that the intake gate can be raised and the water is blocked off to allow teams to undertake work – a bit like a plug behind a plug. 

 

Watch the video below to learn more about how the bulkheads are used, from the 2019 Gordon Intake Outage!

 

 

Engineers first made a 3D print of a screen so the divers could do their assessment before descending into the deep where visibility is limited. A mobile crane was used to set up the divers' barge and hyperbaric chamber, which is a safety precaution to treat decompression sickness - a well-known risk of deep diving.

 

The intake crane was vital for the outage's success. It sits on top of the intake and lifts everything from personnel to stoplogs. Crane operators are specially trained to operate this piece of equipment and for this outage, two new crane operators were trained.

 

The equipment needed was 5 demountable buildings, 2 containers full of speciality tools, a mobile crane, a semi-trailer and 2 boats... talk about an impressive list!

 

Divers making their way out to the inlet tower on Lake Gordon.

 

"While the intake was shut down, we also did works to the station. That included water way inspections, Bus Bar maintenance, tail race inspections and maintenance, Gordon 3 machine maintenance and replacing Gordon 1 turbine runner nose cone."

 

Major outages like this take time – there's 2 weeks for set up, 34 days of outage works and then another 2 weeks to demobilise. That's 62 days in total.

 

The Major Maintenance team are pros at constantly moving around the state, undertaking an average of 12 outages a year! Those who were deployed to Gordon are now back on the tools at Tungatinah and Tarraleah as part of the ongoing outage and upgrade program.

 

A massive thank you to the outage team for their amazing efforts!

 

Want to get behind the scenes of Gordon Power Station and Gordon Dam? Check out more videos on our Youtube.

 

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