Extension of Pulse-Sequence-Analysis for evaluating insulation PD characteristics

Pulse Sequence Analysis, (PSA), has been used as a tool in the analysis of partial discharge activity for some time. In PSA, captured sequential discharge data is analyzed and used in a number of formats in an effort to determine defect types, both manually and automatically. This paper uses standard voltage differential scatter plots to present the results from tests using three basic defect geometries in air, i.e. a needle and open ground plane, a needle and mica covered ground plane and a needle and polyethylene covered ground plane. Variations in the plots obtained, with increasing supply voltage, are shown for each defect configuration. Based on an examination of the pulse group characteristics obtained for each defect type, a novel 3D variation of the standard scatter plot is presented and variations in the resultant plots detailed.