The vibro-acoustics measurement (VAM) method focuses on the mechanical integrity of the On Load Tap Changer. The OLTC is a mechanical switching device used to regulate the system voltage by adjusting the transformers turns ratio. Due to the thermal and mechanical stresses generated during the switching of the load current, various OLTC components such as the contacts can suffer wear and tear over their lifetime.
Therefore, the new TESTRANO 600 accessory VAM1 records a detailed vibration pattern produced during the switching operation by using piezoelectric sensors. These sensors are temporarily mounted to the power transformer tank via magnets.
The results are compared to reference data such as a fingerprint or previously recorded data. Mechanical deviations in the OLTC will lead to a changed vibration pattern and thus become detectable.
The VAM solution can be performed either offline or while the power transformer is still connected to the grid.
Key Features
» Easy installation of sensors using magnets
» Synchronous VAM and DRM measurement
» Motor current analysis
» Can be performed both offline and online
» Applicable on resistive- and inductive-type OLTC
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