A continuous parameter high frequency model based on travelling waves for transformer diagnostic purposes

In this contribution, a new continuous parameter model for power transformers, which is based on the travelling wave theory is suggested. In this modeling approach a small partial length along the winding is considered and a continuous circuit model is used to describe the partial differential equation (PDE) of the coil structure. This equation determines the characteristics of the voltage wave propagation along the winding. The experimental procedure of the PDE parameter optimization using measurements, which have been performed in the laboratory, is presented. The suggested model has been used to calculate the sectional winding transfer functions, which are required for a PD localization. Furthermore the results of a PD evaluation on a distribution transformer based on the new suggested model are illustrated.