Performing reliable and reproducible frequency response measurements on power transformers

The Sweep Frequency Response Analysis (SFRA) has become a standard method to assess the mechanical and electrical integrity of the power transformer’s active part. It provides a very high sensitivity to evaluate possible damages after transportation or for troubleshooting after a specific event such as a near failure with high short-circuit forces. However, users often struggle to reach a high reproducibility which is essential for a reliable condition assessment. Deviations, caused by reproducibility issues, can lead to misinterpretation, unnecessary inspections or cost-intensive maintenance activities. This paper focuses on best practices in order to perform highly repeatable and reproducible SFRA measurements