Breakdown of Composite Dielectrics: The Barrier Effect

The breakdown voltage of a rod to plate gap is largely affected by the insertion of an insulating paper in the gap and this is known as the barrier effect. The complicated characteristics of the breakdown were studied experimentally for dc, ac, lightning and switching impulse voltages. The explanation of these effects were attempted by considering the space charge distribution on the insulating paper. The trial to measure the space charge distribution was also made using an optical method.