Discharge detection and measurements

Discharge measurements provide a sensitive, nondestructive means of detecting minute defects in insulation. The successful application of discharge-detection techniques depends on an appreciation of the following: the conditions in which discharges occur, the factors which affect the discharge magnitude and recurrence frequency, and the various mechanisms of deterioration and breakdown by discharges. After considering the behaviour of discharges, this survey summarises the basic requirements for discharge detection, and gives details of techniques used for measuring and locating individual discharges and for determining the total energy dissipated by all the discharges in a system. There is also a brief survey of discharge measurements applied to bushings, cables, capacitors, transformers and generators.