Electric Machine Vibration Measurements Based on Fiber Optic Sensor Technology - Preliminary Results

In hydro power plants (HPP) vibration monitoring is usually provided for various parts of hydro generating equipment including relative shaft vibration, bearings absolute vibration, turbine cover vibration, thrust bearing axial vibration, stator core vibrations, stator bar vibrations, and stator end winding vibrations. For vibration measurement and detection of irregular operating states, portable system consisting of the laser source, affordable telecommunication optical fiber, signal conditioning and processing unit, notebook for storage and data analysis is presented in the paper. The fiber optic sensor, based on the principle of interferometer, is used as a passive vibration detector of very low amplitudes instead of ubiquitous piezoelectric, micro-electro-mechanical systems (MEMS) or noncontact capacitive proximity sensors due to strong electromagnetic fields especially near high power energy sources as is the case in HPPs. Developed portable measuring system is experimentally verified on small scale laboratory setup and obtained results are compared to the ones obtained by traditional sensors. Through research and on-site measurements, the goal is to develop an algorithm that will allow off-line as well as on-line early detection of abnormal operation of hydro turbine generator unit. In this paper preliminary results obtained in HPP Dale for various operating conditions showing regions of increased vibrations are presented. The intention of this study is to develop a novel embedded vibration monitoring unit closely connected to other monitoring and protection systems compatible with emerging smart grid standards.