Partial Discharge Magnitude Variation with Voltage in Single Cavity and Double Cavities

In this paper a comparative study of cavity defects partial discharge in single and double cavities was performed at different applied voltages. The variation of the PD magnitudes and phase-resolved-patterns (PDPRP) are studied as a function of increasing supply voltage magnitude. The study is conducted on polymer insulation discs. Two test samples were prepared. Sample 1 consist of a cavity of 0.1 mm thickness and sample 2 with 2 of 0.1 mm cavities positioned 0.1 mm apart in the middle of the insulation. The PD magnitude of the double voids are affected significantly by the increase in applied voltage compared to the single cavity magnitude. The PDPRP however are invariant. An electric field simulation model was created using QuickField Software to investigate the electric field distribution profiles in the insulation model. The simulation results correlated with the measurement results.