PD detection under impulse voltage on an actual SF6 bus section with protrusion defects fixed on HV conductor

PD in an actual 220kV SF6 bus section with fixed protrusion defect on its HV conductor has been detected under impulse voltage by using a high frequency Rogowski coil. The variation of charge capacity, pulse magnitude, pulse number and the sequence characteristics in different time regions with curvature radius of protrusion (from 0.15mm to 5.5mm) and applied voltage (at 0.35MPa) has been studied. Through substantial repeated tests, the I_m(magnitude of current)-t(time region) and the I_st(first PD)-t(time tag) distributions of PD pulses have been obtained statistically. It reveals that the impulse voltage has a good capability of detection on pointed or obtuse protrusion fixed on HV side of GIS. This detection is significant to insulation condition diagnosis of GIS and is possible to be used as a supplementary means for AC PD test.