Continuous on-line partial discharge monitoring of power generators

Partial Discharge (PD) detection as a measure of defects and weakness in the insulation system of high voltage equipment has always been a matter of importance and interest in high voltage studies. On-line PD monitoring of rotating machines has not been easy because of the large disturbances coupled to the windings and measurement system by different sources such as the power network, slip ring brushes and excitation system thyristors. Since 1989, the High Voltage Engineering Department of ABB Corporate Research in Sweden has been involved in development of a new technique, called INTECH, for on-line detection and localization of partial discharges. The technique is based on the decoupling of the partial discharges by a pair or group of inductive sensors and treatment of the detected signals. This paper especially considers the aspects of application of INTECH to power generators