Sensitivity in partial discharge detection

Acoustic sensors are extensively used for detecting the partial discharge (PD) in power equipment. Picking up the PD signals from different positions can help locate where PD occurs. As for noise, the intensity of PD impulses should be strong enough to be detected by the acoustic sensor. In this study, we evaluated the performance of the acoustic sensor and RF coils in two different configurations. In the first configuration, the RF coils detect PD impulses from an area larger than that sensed by the acoustic sensor. In the other configuration, the two types of sensor detect the PD signals from the same area. Results show that the sensitivity of RF coils is 40-100 times higher than that of the acoustic sensor in the two configurations. Occurrences of PD impulses seen on the 500-MHz scope reveal that RF coils can sense far more PD signals than the acoustic sensor. In sum, RF coils show high sensitivity and better performance in locating PD in power equipment.