A Method for Calculating Hot Spot Temperature of Distribution Transformers with Foil Windings for Condition Monitoring

The current density distribution varies in line windings and foil windings of distribution transformers, resulting in differences in hot spot temperatures. Existing transformer condition monitoring algorithms based on port data are ineffective in addressing this issue, leading to underestimation of overheating risks in foil windings. This paper proposes a structural identification algorithm that enables online differentiation between line windings and foil windings. The algorithm is applied to the calculation of hot spot temperatures in windings. A correction factor is utilized to compensate for the calculated results of hot spot temperature using the existing model. Criteria for winding structure identification based on experimental data are provided.