DC corona discharge from a wire particle floated with a micro-gap in parallel plate electrodes

A conductive particles existing in a high electric field could deteriorate the performance of insulating system due to electric discharge via the particles. In the case when the particles are around of the high voltage electrode, the position of the particle affects the aspect of the electric discharge. Corona onset and breakdown voltage from a metallic wire particle were investigated under the condition of the wire particle with a length of ranging from 6 to 12 mm and a diameter of 0.25 mm inserted a parallel plate electrode with a spacing of 20 mm or 30 mm. When the particle was close to the negative electrode, corona discharge occurred stably and the corona onset voltage was increased with the gap length bellow 0.8 mm. In contrast, when the particle was close to the positive electrode, breakdown always occurred without stable corona discharge. At the middle region between the electrodes, the corona onset voltage kept almost constant.