High Frequency Power Transformer Modelling for Frequency Response Analysis Studies

Frequency response analysis (FRA) has been widely utilized to detect winding and core deformations within power transformers. While the measurement technique has been well-developed and standardized, the interpretation of the FRA signature is still a challenging area that calls for more research, in order to establish standard and widely-accepted interpretation codes. To investigate the impact of various winding deformations on the transformer FRA signature, a reliable high frequency transformer model is required. This paper presents two high frequency transformer models based on the electrical distributed parameters circuit and numerical representation that are to be used for FRA studies. The electrical parameters used in both models are obtained through simulating a 10-kV A transformer using a three-dimensional finite element analysis, so as to mimic a transformer's real operation. The calculated parameters are then employed within the two proposed models to acquire FRA signatures which are then analyzed and compared. The results show that both methods are suitable to model power transformers for FRA studies.