Diagnostic Interpretation of Mechanic Oscillations of Power Transformers

Continuous monitoring of transformers in the electrical grid can supplement asset management. Thus monitoring, especially of power transformers, is slowly entering common practice if both, benefit gained by monitoring and additional costs meet reasonably. Most continuous measurements concentrate on oil temperature, fault gases and electric issues, naming partial discharges as the most prominent representative. In contrast to the aforementioned, this contribution discusses the mechanical status of transformers' active parts and methods given to measure its status, namely vibration measurements. At first, vibrations are evaluated using a laboratory setup. It consists of a distribution transformer with variable core clamping forces and vibration sensors which measure directly on different…