Condition assessment of MV switchboards: performance of a new sensors for partial discharge monitoring

Condition assessment of MV switchboards requires effective, but not expensive, solutions to become a common practice. On the other hand, failure of a switchboard component can cause cascade effects and outage of other apparatus, in addition to significant economic losses due, e.g., to lack of energy availability. A major property to evaluate switchboard health and reliability is partial discharges, being a direct cause of failure of organic insulation systems. A new type of partial discharge sensoring is presented in this paper, which relies upon capacitive divider embedded in switchboard bushings. Testing the embedded bushing sensor in factory on switchboards, in presence of defective components as cable terminations and bushings, it is shown that the bushing sensor is able to provide good sensitivity, compared to other sensors, as well as good capability to locate the cabinet and identify the type of source generating partial discharges.