Abstract
Insulating spacers are commonly used in the bus bars of metal clad switchgears and transformers, as well as in circuit breaker/cable compartments, to enhance the dielectric integrity of inter-phase and phase-to-ground insulation. This experimental investigation presents the role of dust pollution on the discharges due to impulse stresses on rod electrodes in the presence of such spacers. Gap length and spacer distances from the interelectrode axis were varied to investigate the effect of dust film on breakdown voltage and pulsative corona characteristics. The results show that the presence of a spacer considerably influences the effects of dust pollution on the discharge characteristics. The paper discusses the controlling mechanisms of these variations, as well as the impact of the observed results on the performance of air gaps in the power apparatus.