Automated In Situ Repairs of Damaged and Aging Infrastructure
RQ1: Can an automated cavitation repair robot be developed to effectively repair cavitation erosion damage on Francis and Kaplan turbine runners and draft tubes?
Reclamation has the unique opportunity to work closely with GE to test and evaluate the performance of their cavitation repair robot, specifically its performance for hydropower applications. This question will also explore whether there are any other benefits such as reduced personnel exposure to high physical and health hazards, and reduced maintenance outage times and maintenance costs while still maintaining or increasing repair quality standards.
RQ2: Can the approach in RQ1 be adapted to repair a variety of existing components and hydropower infrastructure.
DED are well-established process's capable of printing parts in a variety of materials with resulting mechanical properties that would be suitable for use on Reclamation structures. RQ2 would explore using this technique, in conjunction with 3D scanning, to print a repair area directly onto a damaged part.
RQ3: What scenarios warrant repair of existing equipment versus AM production of a new part?
Reclamation has been invested in producing new parts with AM. While there are benefits to this method, there are also benefits to repairing damaged parts using AM as a repair technique. Reclamation could benefit from both of these part replacement/repair techniques, with certain parts or situations being better suited for one or the other process. RQ3 will explore the performance and feasibility of repairing existing equipment with AM versus AM production of a new part to determine which scenarios, service conditions, or parts would best benefit.
Need and Benefit
Cavitation is a major issue for Reclamation hydropower plants creating increased scheduled and unscheduled maintenance that require significant outage time for weld repairs. Studies have shown that the repair of cavitation damage is the costliest turbine maintenance item on a hydroelectric generator, and along with generator repairs are two of the major reasons for increased downtime in hydroelectric power installations. The cost of these repairs continues to rise. Another major expense of cavitation erosion is the lost revenues incurred due to the lack of power production of the generator while weld repairs are being made. There is considerable maintenance setup and planning time involved to conduct this type of repair. This requires longer outage durations then other turbine maintenance tasks. Extensive maintenance outages for cavitation weld repairs will continue to be a future challenge as more Reclamation hydropower units are asked to achieve a higher unit availability to compensate for increased demands in water and power due to the impact of climate change and the increased need for reliable power as well as to accommodate power supply issues from new renewable sources tied to the grid.
Damage from corrosion and erosion can occur on other large components in dams, water conveyance, and hydropower facilities such as penstocks, gates, valves, and pipelines. Repairs to this damaged infrastructure is a ideal application of a robotic welder such as being investigated in this research. As Reclamation's infrastructure ages, it's becoming increasingly difficult to source new parts to replace damaged components. In some cases, parts are no longer manufactured, designs are patent protected, and repairing the part may be the quickest and most feasible way to ensure continued operation. An automated repair process has the potential to increase worker safety, quality, and production rates.
New technological advancements are constantly being developed, many of which can be used for applications within the hydroelectric industry. New robotic technology and associated robotic welding and measurement techniques have been developed which can be used on hydroelectric equipment such as turbines, draft tubes, penstocks, and pipelines. Promising benefits with these technologies include increased personnel safety, weld efficiency and speed, weld quality and reliability, and lower cost of maintenance for weld repairs located in inaccessible areas. These new technologies and techniques must first be proven though before implementation. This proposed research explores the use of these promising new technologies through final development and testing of a newly invented turbine cavitation weld repair robot on actual Reclamation turbine runners. A secondary benefit is the potential to expand this technology's use into additional equipment and repair scenarios beyond turbine runner repair.
The benefits, major impact, and ultimate goal of this research work is to enable the rapid, efficient repair of Reclamation's cavitation damaged and expensive / hard-to-acquire metal parts. Recent advances in robotics technology are transforming the way business is done across a wide variety of industries, from mature segments like the automotive and robotic manufacturing sectors, to new uses such with deployments in the medical and construction fields. In the past, welding was often thought of as a job that would be difficult to automate. However, advancements in artificial intelligence, hardware engineering, and motion control are allowing robots to take on more complex tasks. Robotic welding has certain benefits that make the robotic welding process a popular alternative to manual metal repair. Robotic welding automates the welding process and can provide certain benefits that manual welding cannot achieve.
Contact the Principal Investigator for information about partners.
Contact the Principal Investigator for information about these documents.