Differentiation between Currents Flowing in Earth Wire caused by Coronas and Spark Discharges

Abstract

Dust explosions caused by electrostatic discharges sometimes occur during the pneumatic conveyance of powders and dust collection. This paper reports a method for detecting a precursory discharge between a charged metal body and a grounded body that occurs inside a duct or a silo. For the purpose of detection, currents flowing in an earth wire were measured when electrostatic discharges occurred inside the corresponding metal duct. As a result of the experiment, it was found that it may be possible to discriminate between a corona and a spark discharge by evaluating the rise time or frequency of the currents flowing in the earth wire when electrostatic discharges occur.