Research on the measurement of space charge based on sound impulse

The space charge is one of important reasons affecting corona discharge, which is closely related to corona discharge mechanism, initiation and maintenance condition. How to acquire the distribution of space charge is always a puzzle which has not been settled. A space charge measurement method is proposed in this paper. Sound pulse makes the vibration of space charge, which results in the generation of electric field signal. Finite difference method is used to gain the relation between the space charge density and sound pressure. A set of contactless measuring systems are developed which can be used for real time measuring of the space charge distribution on a multi-needle-to-plate geometry. The system consists of an arbitrary custom-made sound generator and an electric field antenna.. Through finite difference method, space charge density can be obtained. The results gained by sound impulse method are compared with the result calculated by corona current method. Good agreements verify the validity of the proposed method.