Air Insulation Characteristics and Discharge Mechanism in Electrode Structure with Fixed Multiple Particles

The high electric field generated by conductive particles significantly reduces the strength of air insulation. Thus, understanding the effects of conductive particles on the insulation characteristics of air is essential to ensure the operation and stability of a power facility based on air insulation. The purpose of this paper is to provide knowledge to understand the breakdown process caused by conductive particles. This paper presents the insulation characteristics of air in an electrode structure with fixed-multiple conductive particles, and proposes a breakdown development model based on the corona discharge mechanism. Experiments on ac breakdown in atmospheric air were conducted by varying the electrode gap and by using several types of fixed-multiple particle arrangements. It is interesting that the breakdown voltages of air were almost equal for the electrode structures with fixed-single and multiple particles. For understanding the breakdown process, the current waveforms were measured during the corona development. Corona discharges associated with multiple particles are first observed in the positive period of the applied voltage. The breakdown development model including this corona characteristics was proposed based on the electron generation mechanism during the positive and negative period of the applied voltage.