Contribution to the Measurement of HVDC Partial Discharges Inception Voltage of Natural Gases

In this paper, a comparative study of DC Partial Discharge Inception Voltage (PDIV) performances are presented. The goal is to determine the role of breakdown ageing on the DC PDIV. Two natural gases were used: CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and Dry (Synthetic) Air in a range of pressure 1 - 6 bar. A reduced-scale GIL vessel is used with a grounded pin. The PDIVs are measured before breakdown ageing and after breakdown ageing. The results showed that PDIVs levels of aged gases are lower than PDIV of non-aged gases. GCMS analysis showed that aged gases contain some traces of decomposition products provoked by arcing and interaction with the solid insulation material (PTFE). On the other hand, traces of arcing impact at the inner electrode are observed and affect the PDIVs levels.