High-Frequency Traveling Wave Modeling of Transformers for Frequency Response Analysis

This paper demonstrates an advanced multi-conductor transmission line (MTL) model for high-frequency transient and also frequency response analysis studies in transformers. Traditional circuit-based approaches often fail to capture the complex electromagnetic interactions within transformer windings, especially under conditions induced by lightning strikes and switching operations. In contrast, the MTL approach effectively simulates the distributed nature of windings and phase interactions, representing a significant advancement in transient over-voltage analysis. The models in this paper are rigorously validated using a real-life transformer as a benchmark, serving as a reference to confirm their accuracy. Parameters are optimized through a particle swarm optimization (PSO) algorithm, facilitating efficient data exchange between PSCAD software and Python. The calibration process uses two CIGRE-recommended indices—the correlation coefficient (CC) and the Euclidean distance (ED)— to ensure precise alignment between simulated and measured waveforms. The results show that the MTL models accurately replicate the behavior of the real transformer, outperforming traditional approaches. This enhanced modeling capability not only deepens the understanding of electromagnetic interactions within transformer windings but also provides valuable insights for improving transformer design, refining system protection strategies, and minimizing the risk of equipment failures due to high-frequency transients.