Having doubts about the condition of an asset is never nice. Especially when it comes to disassembly for inspection and associated downtime. This is what happened to the operator of a hydro storage power plant. The unit in question is a so-called Francis turbine. This turbine is used to pump a water reservoir up to a certain level during night time, when electricity is cheap. During daytime the water is released through the turbine to a lower level and generates electricity. Francis turbines are the most common type of water turbine due to their ability to operate over a wide-range of water head (typically from 40m to 600m). Especially in mountain areas this is a very effective way of energy storage.
The asset owner was not sure of the state of the turbine and wanted to make a detailed assessment of the interior. The area of interest was within the water flow path, which is not designed for human access and is a very confined space. Such a situation would usually mean a costly disassembly of the turbine in order to perform an in-depth inspection.
In order to avoid downtime and the tremendous cost for disassembly the customer decided to perform the inspection using a mobile robot. After a rapid evaluation & simulation on the turbine interior dimensions, it was decided to use GE Inspection Robotics’ BIKE platform for this mission. The BIKE was therefore equipped with 2 advanced inspection tools:
Advanced Visual Inspection
- Two 4K 360° Cameras, one in the front, 2nd at the back — For high resolution 360° overview of the entire interior. The video footage was stored for documentation purposes and can be reviewed at any point in time.
- 3D Phase Measurement Borescope (GE’s Mentor Visual iQ) — For precise 3D measurements of findings, this enables detailed assessment of pitting, corrosion, scaling or cracks.
Once the BIKE was equipped with its new inspection devices, it was able to enter the turbine and perform all necessary inspections. The on-board Overview Cameras allowed for navigation; the 360° cameras provided the full visual overview needed and any feature of interest was measured with the GE Mentor Visual iQ Borescope. Being able to perform those measurements lifted all doubts from the customer and avoided a costly disassembly work.
«For the last 20 years I have been dreaming of entering such a machine. With this technology we did not only avoid an opening of the unit, but also get a deep understanding of the in-situ condition.»
Furthermore, the BIKE capabilities impressed the customer as it provided a look inside a turbine that was not possible before. By pushing the limit of what is possible, the BIKE opened a new perspective allowing for a safer and more reliable operation of Francis turbines.
Equipping a robot such as the BIKE is, of course, not a stroke of luck, it comes with intent. GE Inspection Robotics’ robots are designed as modular platforms. Simply said, it is wheels and a brain to bring tooling and inspection equipment to the area of interest. As such, it is possible to assemble additional sensors or tools in a very short time.
We look forward to its next expedition.