Simulation of Partial Discharge Induced Electromagnetic Wave in Power Transformer

Abstract

This paper describes the numerical simulation of partial discharge (PD) in oil-filled power transformer using FDTD method (Finite Difference Time Domain). We investigate the effects of oil insulation medium and internal structures on the propagation of electromagnetic signal emitted from the partial discharge source. In this study, partial discharge is modeled as the Gaussian Pulse (pulse's width 1 ns). To observe the electromagnetic intensity and also the voltage distribution, three sensors are employed. The magnitude, frequency, and attenuation of the EM wave without internal structures and with internal structures are compared. The Results show that the EM wave intensity is attenuated while propagating through the oil insulation, iron-core, and windings. And the time arrival of each signal is different due to its distance from the PD source. The simulation results in both cases show that the first dominance frequency occurs in 1 GHz of frequency. However, the frequency spectrum of simulation with internal structures has resonance frequencies in the low region from 80 MHz to 300 MHz of frequency. These resonance frequencies occur because the windings are considered to be a loop antenna.