Three-dimensional simulation of UHF signal propagation in transformer using FDTD method

Partial discharge in transformer can be detected and localized on-line using UHF technique. The first step for achieving this goal particularly the PD localizing is creation of simulation environment. In this paper three dimensional simulation is done using the FDTD method. The created simulation environment by FDTD was compared with CST software. The results of the two simulation environment had a good match with together. Consideration of the transformer active part is the feature of this simulation. Simulation results show that UHF electromagnetic (EM) waves can transmit from the radial ducts width between adjacent coils of high voltage winding. It was observed that the energy of received signal is proportional the oil duct width. Also it was observed that if the PD current pulse is steeper, signal energy and peak of the received signal would be reduced.