The Influence of Metalic Protrusion and Surface Discharge Faults on Air Decomposition By-Products Under Different Electrode Materials

Air decomposition products can be used to detect different partial discharge (PD) defects but the metal materials in a PD area can significantly affect air decomposition by-products characteristics. Disregarding the effect of metal materials on such characteristics inevitably result in certain errors when using them to diagnose the metallic protrusion and surface discharge defects. This paper investigates the influence regularity on different decomposition by-products of air such as Ozone, NO
x
, NO
2
and NO of the commonly metal materials used in high voltage equipments such as copper (Cu) and stainless steel(SS). Firstly, an experimental platform is established to simulate air decomposition by-products under a protrusion as well surface discharge defects and the influence regularities of Cu and SS on the concentration and generation rate of air by-products are obtained. Results show that Cu produces more air decomposition by-products as compared with SS in all defects under study. Secondly, an empirical mathematical relationship is proposed for rate of generation of air by-products under these partial discharge defects. This study leads to indirect way for online fault diagnostics in air.