Space Charge Measurement Using a Small Sphere as a Probe

Abstract

A method for measuring the space charge produced by impulse corona in an air gap has been developed, using a small sphere as a probe. The probe is located far from the corona volume, and is connected to earth through resistance or capacitance. The probe induces a current or charge by electrostatic induction from the space charge. Since the induced charge on the probe is proportional to the space charge, it is possible to analyze the magnitude and polarity of the space charge from the probe signal. It is also possible to analyze the temporal variation caused by corona growth or movement of the space charge.