Using the Temperature Dependency of the FRA to Evaluate the Pressure of the Transformer Press Ring

The frequency response analysis (FRA) is an effective method to detect the existing mechanical faults inside transformers. Some mechanical failures are due to the loss of press ring pressure and, therefore, detection of pressure loss can save the transformer from subsequent damage. This letter proposes a novel idea to evaluate the pressure of the press ring using the FRA. In this idea, after temperature stimulation, the FRA traces of different temperatures are compared without any need of a fingerprint from the past. The experimental results also support the functionality of the idea and show its early potential.