Influence of Metal Particles on Discharge Characteristics of Insulating Oil under Lightning Impulse

In this paper, a research work on the influence of metal particles on lightning impulse discharge characteristics of transformer insulating oil is carried out. The main research contents are as follows: The lightning impulse discharge test platform for insulating oil was established. The influence of the development characteristics and breakdown characteristics of the streamer in the insulating oil with different metal particle concentration under pre-breakdown voltage was studied. The discharge characteristics of pure insulating oil and particle-containing granular insulating oil were compared and analyzed. The breakdown characteristics of insulating oil with different metal particle concentration under different oil gaps were measured, and the influence of metal particles on the lightning breakdown characteristics of insulating oil was obtained. The results show that the metal particles promote the initiation and development of the streamer in the oil. The stop length and development speed of the streamer are positively correlated with the particle concentration, while the initial voltage of the insulating oil is negatively correlated with the breakdown voltage and the particle concentration.