Simulation and Experiments of UHF Detection for Partial Discharge in Power Transformers

This paper presents simulation and experiments of UHF detection for partial discharge (PD) in power transformers. Simulations of PD electromagnetic waves propagating in simulated transformer tank, by finite difference time domain (FDTD) approach, were implemented to examine the effects of electromagnetic wave refraction and reflection by transformer components. Actual PD experiments in simulation transformer tank have been carried out for two typically artificial insulation defect models while the existing Hilbert fractal antenna was used for the PD measurement. Results show that UHF PD signals are mildly influenced by reflection from transformer components, while they are strongly susceptible to refraction by transformer components.