BREAKDOWN CHARACTERISTICS IN AIR GAPS WITH ARTIFICIAL FLOATING METALSUNDER DC VOLTAGE

The de breakdown characteristics of a sphere-to-sphere gap with conduc ting objects supported by an insulator rod in atmospheric air are inve stigated experimentally to provide fundamental parameters determining the breakdown voltage in the presence of floating objects around de po wer apparatus by an air insulation. The shape of tested floating objec ts made of metal is plate, needle or sphere. Experimental results show that the main factors affecting the breakdown voltage are the shape a nd size of floating objects, the object location and the gap length. I f the object is placed at the location giving the lowest breakdown vol tage, any object lowers the breakdown voltage below that without the r elevant objects.