Frequency response modeling for device analysis

In many industrial activities, the assessment of the good condition of the devices involved in these activities is an important issue. The condition assessment is usually carried out taking some measurements of the device and postprocessing them somehow. One approach about taking measurements is in either the frequency or the time domain (which are mathematically equivalent through the Fourier transform). This approach is very appreciated in cases such as electrical transformers in order to check whether some windings have been displaced or not after a high current (caused for instance by a short-circuit or by a lightning). The frequency response analysis (FRA) for transformer advanced maintenance is very useful in this case due to this fault being difficult to detect by means of any other procedure and its consequences could be serious. A procedure to model the frequency response is presented in this paper. It has been oriented to implement a modeling aided analysis for electrical transformers maintenance. However, this approach can be extended to different cases in which the frequency response modeling is required, adapting both the model and the algorithms to each particular case.