Predictive maintenance of vacuum switchgear

The vacuum switchgear interrupts short circuit current with vacuum interrupter. The internal pressure of vacuum interrupter, which can only be measured in an undetached approach, is the key to the arc interrupting capability of vacuum switchgear. An electric field measurement based approach is developed in this paper. This approach and the magnetron discharge current measurement based approach are employed in combination to detect the internal pressure of the vacuum switchgear to facilitate the predict replacement of the vacuum interrupter of the switchgear. The magnetron discharge based approach is employed to calibrate the internal pressure within vacuum interrupter accurately offline and the electric field measurement based approach is employed to detect the deterioration trends online. The apparatus developed followed by the electric field measurement approach has been applied on three power utilities for about three years and the measured data with aforementioned two approaches are provided in this paper.