3D Scanning Solution for Innovative Maintenance and Repair of Hydropower Parts

3D Scanning Solution for Innovative Maintenance and Repair of Hydropower Parts

May 22, 2024

Hydropower is a brilliant example of how we’ve learned to use nature to create electricity to light up the world. But keeping these hydropower plants running smoothly is no small feat.

That’s where 3D scanning comes in. It’s a new way to check on the health of the hyrdropower parts and make sure everything is working right.

Advanced 3D scanning not only creates a digital twin of newly manufactured parts to identify deviations but also plays a crucial role in the maintenance and repair of these facilities.

From the huge Francis turbines that can tip the scales at staggering hundreds of tons to the intricate components hidden within, 3D laser scanning ensures every piece functions at its peak, safeguarding our sustainable energy sources for generations to come.

Join us as we explore the transformative impact of 3D scanning on the maintenance and repair of hydropower parts.

Hydropower stations vary in scale, but the ones on the larger end of the spectrum are a sight to behold. The parts are massive.

A Francis turbine, the most common type found today, can weigh 200 tons and measure nearly eight meters in diameter.

Hydropower stations feature sizeable parts, like this turbine

The sheer size of hydro parts complicates maintenance. It’s not easy to find a stock replacement. When a part breaks, you need to repair existing parts to keep the stations up and running.

This process demands skill and time. Regularly checking for wear, reverse engineering replacement sections, ensuring correct welding, machining parts into the intended shape… It’s no small feat.

Forward-thinking companies out there have discovered that new technologies can allow them to enhance the efficiency and precision of this process. Their secret weapon? 3D scanning.

Matthew Percival, a scanning service provider based in Canada, has witnessed this trend first-hand. Over the last decade, his business 3DRE has become the go-to scanning specialist for many hydroelectric facilities in British Columbia, and Percival himself has processed hundreds of hydro parts.

Recently he lent his skills to a hydro where pumice has been causing significant damage.

The facility has been leveraging 3D scanning workflows for two different steps: checking the wear and repair of a certain part, and digitizing the existing part for future replacements.

3D Scanning Workflows for Hydro Parts

Pumice are abrasive particles formed when super-heated, highly pressurized rock is rapidly ejected from a volcano. “The pumice in the water is wearing out all of the wicket gates, the runners, and other parts. It even makes holes right in the runners.

The plant needed to take out the damaged parts of the turbine, weld on them or put in a new plate, and then machine the weld to the right thickness,” Percival explains.

A portable 3D laser scanner and Geomagic Control X were used to inspect a draft tube, a large element fitted at the discharge of a turbine that decreases water’s exit velocity, and wicket gates, wing-like plates on the front of a generator that allow or stop the water flow into the turbine’s runner.

3DRE’s scanner of choice was Scantech’s TrackScan-P System, which has an optical tracker that allows large parts to be measured with or without targets.

3DRE needed to lift the part to capture its underside, and targets allowed them to move and scan the part at the same time. Two people completed the scan in 3 hours at a point spacing of 2 mm and a total of 11 million points of data.

3D scanning a draft tube with TrackScan-P
3D scanning a draft tube to check for signs of wear

To identify signs of wear on the tube, Percival created a deviation map. He loaded the scan data into Control X, used the Plot command, and used a minimum thickness of -1 mm and a maximum thickness of 15 mm to generate the color map below.

“I knew the part was designed with a 10 mm wall thickness and that information was the basis for the inspection. I found some coating on the interior, which is reflected in the wall thickness of 11.5 mm.

From this data, we were able to determine that there was no significant wear on the draft tube itself,” Percival says.

3D Reverse Engineering for As-built Models

In addition to inspecting the tube, the hydrostation wanted to create its as-built model, which would show the part exactly as it exists in use. This type of model could be used in the future to replicate the draft tube once repair is no longer viable.

“When parts of a draft tube get worn, you cannot simply order a new one from a manufacturer, is because each part of a draft tube varies and its ends are cast in place within the facility it is used in. You need to 3D scan a worn part and remake an as-build part,” Percival explains.

To create the as-built CAD, Percival used Geomagic Design X, Oqton software for easy 3D reverse engineering. Using the drawing as reference he modelled the body using the Design Intent feature, then modelled the ends as-built since the mating ends are fixed into concrete and do not move.

Finally, he exported the file with the Live Transfer option and made the fabrication drawings. The model will be useful in creating and machining replacement parts.

3D scan of a runner shows the amount of weld build-up

3D Scanning a Wicket Gate

While the 3D scan of the draft tube didn’t show any signs of wear, the wicket gates were a different story. “Wicket gates were wearing out because of the pumice in the water.

They had been repaired, and we scanned to inspect that repair and see if it was machined correctly,” Percival says.

Welding is used to repair these large parts, but it often results in excess material around the welded area.

This is machined to achieve a final shape that corresponds to the CAD model. 3D laser scanning is used to check if the process resulted in the right shape.

An analysis of the wicket gate wear

The evolution of scanners and advanced 3D scanning software are offering greater cost-effectiveness and expanded capabilities for hydropower stations.

As these technologies become more refined, a wider spectrum of users will be empowered to tackle grand manufacturing challenges, no matter how complex.

Source: 3D scanning and renewable energy -How hydropower plants leverage Geomagic Design X and Control X for maintenance and repair

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