BREAKDOWN CHARACTERISTICS IN AIR GAPS WITH ARTIFICIAL FLOATING METALS UNDER DC VOLTAGE

The de breakdown characteristics of a sphere-to-sphere gap with conducting objects supported by an insulator rod in atmospheric air are investigated experimentally to provide fundamental parameters determining the breakdown voltage in the presence of floating objects around de power apparatus by an air insulation. The shape of tested floating objects made of metal is plate, needle or sphere. Experimental results show that the main factors affecting the breakdown voltage are the shape and size of floating objects, the object location and the gap length. If the object is placed at the location giving the lowest breakdown voltage, any object lowers the breakdown voltage below that without the relevant objects.