A modern approach to differential partial discharge diagnosis

In this paper, a novel approach for differential electrical partial discharge measurement is presented. A computer-controlled measurement bridge is combined with a digital partial discharge measuring system. Partial discharge signals decoupled with two conventional measuring impedances are balanced and subtracted within the measurement bridge. Since partial discharge events occur as differential-mode signals within the circuit whereas disturbances from the voltage source or from ground occur as common-mode signals, the differential interpretation of the signals may lead to an improvement of the signal-to-noise-ratio. Like conventional measuring bridges, the measurement setup may consist of two devices under test or a combination of a device under test and a coupling capacitor. The…