Measurement of Charge Density Distribution in Negative Corona on a Coaxial Cylinder Model Using Sound Wave

Abstract

A device for charge density measurement is designed and implemented. The sound wave is used to modulate the space charge slightly and periodically, so that the variable electric-field signal will be produced. A numerical model is established to determine the relationship between charge density and the electric-field signal. A coaxial cylinder model is set up in the laboratory, and the distribution of charge density, which agrees well with theoretical results, is obtained eventually. Measured distribution has a well-known declining-shape curve, with a minimum value of ${\hbox {1.87}}\times 10^{-5} {\rm C/m}^{3}$ around the cylinder and a maximum value of ${\hbox {1.52}}\times 10^{-4} {\rm C/m}^{3}$ around the wire.