Simulation analysis of effects of transformer windings on propagation characteristics of partial discharge electromagnetic waves

A simulation model for transformer windings is proposed to study the effect of the transformer windings on the propagation of electromagnetic (EM) wave induced by partial discharge (PD). The study is based on the size of windings in a 330 kV power transformer. A finite difference time domain (FDTD) method is used to analyze the propagation of PD EM wave in both internal and external windings. The effect of transformer windings on the propagation characteristics of PD electromagnetic waves is studied by applying PD pulse current signals in different places. This model is also used to study the effect of winding structures on the frequency spectrum of PD electromagnetic waves. The sum of the peak amplitudes in different bands and their proportions in the total sum are calculated through dividing the frequency spectrum into different bands. The calculation results are compared with those obtained in the places with and without obstacles (windings). It is found that the effects of transformer windings on the propagation characteristics of typical partial discharge electromagnetic waves are different in different places, and that the propagation characteristics depend on the location of PD according to windings. Windings increase the amplitude of EM waves from internal PD, especially in the frequency band 1 000 MHz-2 500 MHz; and make a strong attenuation of 30% on the amplitude of EM waves from external PD.