Experience with optical partial discharge detection

Partial discharge (PD) diagnostics was used to evaluate electrical insulations of high voltage equipment as a quality control and to detect insulation deterioration. Improvements, new developments as well as lower costs of sensors, electronics and processing units are some reasons for the increasing usage of PD measurements. The paper presents investigations in the area of optical partial discharge measurement technique. In an overview, PD measurement systems were presented, advantages and disadvantages of the optical method were discussed. An unconventional optical partial discharge detection system was developed and comparative measurements to a conventional electrical PD measurement system were accomplished. The system was tested by using a PD source in air or alternatively in oil to evaluate the sensitivity and the impulse behaviour in correlation to the conventional measurement technique.