Effect of frequency depending coil resistance on transformer frequency response analysis (FRA) characteristics

Frequency Response Analysis (FRA) is a powerful diagnostic tool in detecting transformer winding deformation. In order to study the effect of different deformation scenarios transformer models have been developed. Detailed model is a well known modelling approach for these studies. Unfortunately some of these parameters are frequency dependent due to skin effect and proximity. They have been ignored for the sake of simplicity in some papers. This paper investigates the effect of skin effect on different frequency response analysis. It has been shown this factor affects the different characteristics in different degrees. Capacitive inter-winding characteristic was seen to be most affected by this factor.

Keywords:

frequency response analysis , transformer , transfer function , skin effect