A 12-day inspection was cut down to just 2 days thanks to the Elios 3. Discover how VZU Plzen used drone technology to remotely inspect a penstock.
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Access Penstock inspections used to require custom scaffolding on a trolley and work at height in confined spaces - with the Elios 3 this was no longer necessary, giving VZU Plzen safe and easy access. |
Safety When the scaffolding trolley was used, any problems would have required emergency responders to rescue inspectors. Now with the Elios 3, the risks were drastically reduced. |
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Data Quality The Elios 3 provided 4K video and a LiDAR point cloud, providing a comprehensive inspection. 4 other companies had attempted to inspect this penstock but only VZU Plzen and their Elios 3 got the desired results. |
Speed Using the Elios 3, VZU Plzen completed the inspection in just 2 days, compared to the typical 12-day process required with a scaffolding trolley - an 84% reduction in inspection time! |
At the heart of a hydroelectric dam is the penstock: a controlled gate and tunnel structure that delivers water from the reservoir behind the dam to the powerhouse and turbines where electricity is generated.
Penstocks must be carefully maintained to ensure they are able to operate safely. Dam operators must carefully balance the pressure put on penstocks by both high water flow and increasing demand for energy production. Penstock failure is a catastrophic event that dams must avoid as it can paralyze operations for months if not longer.
Penstock inspections must determine the baseline condition of the penstock, document changes, and provide necessary information for planning maintenance. However, the inspection is often costly and complex, requiring work at height or in confined spaces depending on the size of the penstock. There is no one-method-suits-all system for inspecting penstocks due to their varieties in size and shape. However, VZU Plzen found an innovative solution to inspect a massive 700-meter penstock: the Elios 3.
VZU Plzen is a specialized research and testing institute that was called to inspect a penstock in the Czech Republic. In the past, this penstock was inspected by creating a custom trolley made of scaffolding that could be slowly lowered through the penstock. It would take 5-6 days to construct the structure, hours or days to inspect the penstock, and then another 5 days to dismantle the trolley. If that trolley gets stuck, emergency responders have to be called in to get inspectors safely out of the space. The dam operators wanted a safer, faster, and better means of inspection - which is why VZU Plzen turned to the Elios 3.
VZU Plzen has significant experience in non-destructive testing and has worked on projects ranging from surface treatment and life span assessments of assets to dynamic testing or lab testing materials. With asset owners and operators, VZU Plzen tests and deploys unique inspection methods to overcome industry challenges. They use both remote technology such as the Elios 3 and various handheld tools to collect data in challenging environments. They know the Elios 3 offers them many benefits regarding safety, access, and data quality for complex inspections.
The Elios 3 is a powerful inspection tool ideal for confined spaces like this. The unique features that made it suitable for this project include:
Using the Elios 3 for a drone penstock inspection meant that VZU Plzen would have a tool that could guarantee remote access to the confined space and gather critical data without people having to be suspended in a custom trolley within the penstock. The team was kept safe while the drone provided more detailed data than had been available previously in a fraction of the time.
The Elios 3 drone is often deployed in dangerous or confined spaces to reduce unnecessary human entry into these spaces
VZU Plzen had 2 major tasks: inspect plugs in the penstock as well as provide an overall condition assessment. The penstock was 700 meters long, and detailed inspections could be time-consuming. The task put to VZU Plzen was not easy: 4 other companies have attempted to inspect this penstock with various drone and robotics solutions but none have succeeded. VZU Plzen intended to be the first.
To prepare, VZU Plzen’s inspection team used an industrial brewery to test different flight conditions and plans. They completed flights in assist, sports assist, and ATTI modes to determine the best flight mode for their mission while simulating the conditions of the penstock in the brewery. They ensured they could gather clear RGB data from the 12 MP camera the Elios 3 carries, along with a LiDAR scan. The LiDAR scan would make it possible to navigate in the dark environment while the RGB camera would be used for the visual inspection of the plugs.
The VZU Plzen team spent a long time finalising their plans ahead of the inspection to ensure the success of the mission.
The plugs in the penstock are used to fill the void between the tubing and the original rock excavated during construction. Any faults or defects in the structure must be carefully evaluated at the risk of the penstock needing maintenance or repair work which could impact operations.
After VZU Plzen had planned a safe, remote drone inspection for the penstock, they went to the site.
After initial safety checks, the VZU Plzen team split into two groups. The first group would fly the Elios 3 from the bottom of the penstock while the other would wait for it at an access hatch at the top of the penstock. This would allow the team to use the entirety of the battery for inspection rather than flying back and forth to change batteries between flights.
The Elios 3 pilot stood at the bottom of the penstock on an access platform which was dozens of meters above a large pipe and drop into the turbine at the entry point. The team then walked 500 meters to reach the slope area where they could conduct the inspection. Despite the immense environment around them, they focused on the job at hand: the Elios 3 inspection. After initial test flights in the space as well as checks with the battery capacity, the drone was ready. The inspection itself progressed smoothly and at the end the Elios 3 was flown safely to the waiting team at the top of the penstock.
The team flying the drone stayed in a safe location while the Elios 3 explored the inner structure of the penstock
This marked a momentous occasion as it was the first successful flythrough of the penstock! Afterward, the VZU Plzen team repeated the process to collect additional data on the condition of the plugs, taking time to fly close to the shapes before completing the flythrough. The overall inspection took 2 days: one day of planning and one day of the inspection itself - an 84% reduction compared to the 12+ day process with the trolley!
This was an exciting mission for VZU Plzen, who were determined not to fail like the 4 other companies had. Remote inspections of this nature push inspectors and traditional equipment to their limits, which is why tools like the Elios 3 are such game-changers for simplifying inspections while eliminating safety concerns. All of the team were in secure locations during the inspection rather than working for prolonged periods at height, on scaffolding, or a custom trolley.
After the inspection, the VZU Plzen team used Inspector to generate a report and shared it with the dam owner. The challenge of this mission helped the VZU Plzen develop new skills and find a creative solution to a massive obstacle. They provided clear analysis and assessments of their results and shared this information with the dam operator. The clear report and level of detail and accuracy within the data ensured the success of the project and thus, demonstrated the value of VZU Plzen’s unique skills.
See the full project video on VZU Plzen's website
VZU Plzen will continue to use their Elios 3 drone to inspect the most challenging environments, keeping their inspectors safe while gathering accurate and detailed data. It is an exciting demonstration of the benefits of the Elios 3 in the power generation industry, as well as how penstock inspections can be simplified today - not just in the future.
Interested in learning more? Discover the Elios 3 for power generation inspections today!