The operator of a hydroelectric power plant located in Chancy-Pougny, in Rhône, France, and Cetim’s experts carried out several analyses and investigations on a one-hundred year old waterwheel in order to ensure that it was in good working order.
Built in 1920, the Chancy-Pougny power plant is located on the border between France and Switzerland, between the municipalities of Avully (Canton of Geneva) and Challex (Ain, France). Société des Forces Motrices de Chancy-Pougny (SFMCP), its operator, opted to replace four Francis turbines with more modern Kaplan-type equipment and to retain the fifth turbine, which is 100 years old. In 2016, to guard against any failures, the company tasked Cetim’s experts with determining the secret of the design and manufacture of the fifth wheel in order to then identify the appropriate procedures for in-service support over the upcoming forty years.
Control wheel
Samples were taken from one of the replaced wheels (25 tonnes and 5.5 meters in diameter), carefully stored and transferred to Cetim’s laboratories for a series of examinations which included the characterisation of the various moulded or lami-nated steels, identification of the wheel and hub assemblies, destructive tests on a number of components, 3D scan of a blade for possible replacement or repair welding in addition to tensile tests. “Once this phase of collecting data was completed, checks had to be carried out on site to determine that wheel No. 5 was indeed identical”, stated Emmanuel Maginot, project engineer at the Compagnie Nationale du Rhône. After taking the necessary precautions to protect the safety of people and equipment, Cetim’s experts were able to scan the blades, model the assembly, identify specific characteristics, the metal sheets added on as well as the welds performed during previous maintenance campaigns.
A technical maintenance file
Upon completion of these analyses, they provided SFMCP with a complete report and, most importantly a technical maintenance file, a sort of handbook of maintenance procedures that takes into account the collected data and past knowledge. “This handbook of proce-dures is extremely valuable”, explained Emmanuel Maginot. It tells us exactly what to do and how to do so in the event of a problem. With this compilation of instructions we are confident in our ability to keep this wheel in good working order”, he added.
Based on physical elements and the results of investigations, Cetim’s experts are able to identify the design and manufacturing methods of a structure in service and determine the instructions to be applied to ensure it is kept in good working order.
