Probabilistic analysis of partial discharge in power transformer due to the presence of spherical particle

The paper deals with the partial discharge in a power transformer due to presence of metallic particle in a transformer oil or mineral oil. A conducting particle is assumed to be present in the oil, between High Voltage (HV) winding and pressboard inner cylinder gap. It is assumed that particle moves in random direction along with the transformer oil. Probabilities of Partial Discharge (PD) have been calculated by assuming various field intensification factor β and threshold voltages. Simulations have been carried out to find the probability of partial discharge at different oil velocities. Results of this paper show that the probability for the occurrence of partial discharge varies with respect to field intensification factor β, threshold voltage and velocity of the oil, as particle is also assumed to move with the same velocity of oil. It is observed that probability of PD increases with β for a given threshold voltage.