PD Modeling in Transformer Winding by Multi-Conductor Transmission Line Model

To locate accurately the occurrence of a partial discharge in a power transformer winding, a wide frequency band model of the winding is required. In this paper awide frequency band Multi Conductor Transmission Line model (MTL) is employed to simulate the propagation of PD signal in transformer windings. The MTL model isbriefly reviewed and the related equations of the model are reformulated to easily simulate occurrence of a PD signal along the winding. Software is developed inMatlab to calculate the windings resonance frequencies and the magnitudes of overvoltages occurring between different disks along the winding. Then propagation of PDsignal in a power transformer (900MVA, 525kV), is simulated using he (MTL) modelwith frequency dependent parameters. Also this method is employed to model the laboratory transformer winding

Keywords:

Partial Diacharge , Transformers , Multi-conductor Tranmission Line Model