From the installation of vibration protection to commissioning
As part of the complete replacement of the Vièze power plant command and control system, the calculation and measurement team supported CIMO in identifying and resolving vibration problems.
CIMO commissioned HYDRO to completely replace the command and control system of units 1 and 2 at the Tine power plant in Monthey. As part of this replacement, the calculation and measurement team ensured the implementation of vibration protection.
The first phase involves advising CIMO on the choice of equipment capable of performing the vibration protection function. To do this, HYDRO can draw on experience gained from more than 120 units equipped with vibration protection and over 10 different supplier systems installed in its fleet.
Installation and commissioning
Installation and implementation take place without any particular problems. The entire new system is fully tested during cold commissioning according to HYDRO procedures.
During the initial start-up of the machine (hot commissioning), high vibration levels are measured. HYDRO therefore uses its portable acquisition equipment, which is capable of recording vibration signals up to several tens of kHz. Interference on one of the sensors is detected, caused by the saturation of the measuring system due to the impact of sheets of water. As an expert in resolving this type of problem, HYDRO replaces the measuring system with a sensor based on a different technology, with no significant effect on the schedule.
Resolving an issue on the injector crosspiece
During the final full-load tests, the vibration levels irregularly and unpredictably exceed the expected values. The analysis then indicates a hydraulic problem on the machine.
Dynamic pressure sensors installed upstream of the injectors reveal significant pressure fluctuations. The characteristic frequencies of these disturbances have a direct correlation with the mechanical vibrations observed. An inspection of the distributor then reveals an accumulation of leaves stuck on the crosspiece of an injector. This localised obstruction generates a signal whose characteristic frequencies increase with the flow rate, without showing a correlation with the rotational frequency of the machine, contrary to what is usually observed.
Cleaning restores normal operation, allowing the machine to operate across its full power range without abnormal vibration.
HYDRO expertise
Thanks to its wide-ranging expertise, HYDRO is able to support its customers in a large number of areas related to vibration protection:
- Choice or, where necessary, adaptation of the protection system
- Commissioning of the system (cold and hot) including definition of thresholds
- Complete analysis and diagnostics of machines based on vibration signals
- Machine balancing
- Experimental modal analysis
