Partial discharge and breakdown properties in N2, CO2, dry air and sf6 initiated by metallic particles fixed on high voltage conductor and attached on spacer surface at AC voltages

Summary

This paper reports partial discharge (PD) and breakdown (BD) properties initiated by two kinds of defects such as 5-10 mm metallic particles fixed on the high voltage (HV) conductor or attached on the spacer surface at AC voltages. PD signals like electromagnetic (EM) waves and PD magnitude (apparent charges) were measured at 0.55 MPa. An actual GIS busbar with a spacer was used in the experiments, and the gases tested were natural-origin gases (N2, CO2, dry air) and SF6. It was found from the BD experiments that surface flashover marks caused by the particles attached on the spacer surface were quite different between the natural-origin gases and SF6. PD inception voltages caused by the two kinds of defects were much lower than the BD voltages in every gas. This fact showed that the PD measurements to find out those defects in the natural-origin gases would be possible at reduced voltages as well as the case in SF6 gas-insulated systems. The frequency spectrums by the EM waves initiated by the particles suggested that the PDs caused by the particles on the HV conductor will be more influenced by the kind of gases than the cases of the PDs by the particles on the spacer surface.

Additional informations

Authors

PRESSER, KUSCHEL, WEI PING WO, Piasecki, NAJAFI, CHARLES

Keywords

partial discharge, metallic particle, dry air, CO2, N2