New high frequency multi-conductor transmission line detailed model of transformer winding for PD study

The first step of partial discharge (PD) detection is to obtain a model through which the winding behavior is monitored precisely in high frequencies. The multi-conductor transmission line (MTL) model is one of the best models conducting the PD studies. It is worth to say that one of the main problems of the MTL model is that it considers the windings in a parallel way as well as equal length. Solving the mentioned problem can decrease the simulation error relating to the PD detection. This paper presents an accurate approach in order to solve the problem. This modified MTL model uses the circular effect of windings. Considering the windings circular is one of the important parameters which should be evaluated with respect to PD signal propagation. This method has been applied on a 20 kV transformer winding. The simulation and experimental results show the powerful performance of circular multi-conductor transmission line (CMTL) model in comparison with the MTL model.