Influence of sugar as a contaminant on outdoor insulation characteristics of insulators in a substation

This paper attempts to address the influence of sugar as a contaminant on outdoor insulation characteristics of insulators in a substation. Strong discharge activity was occurred under relative humidity less than 80% on insulators in a 500 kV substation at south China. A preliminary viewpoint that sugar as a contaminant leads to this strong discharge was drawn by investigating pollution sources around the substation and analyzing pollution layer conditions of discharged insulators. In order to further confirming this viewpoint and proposing the appropriate solutions for avoiding this discharge activity, the outward appearance, the surface conductivity, the discharge inception voltage and the flashover voltage of glass insulator and room temperature vulcanized (RTV) coated insulator under sugary and non-sugary contamination were investigated in detail in the lab. Furthermore, the hydrophobicity and hydrophobicity transference of RTV coated insulator were also investigated. The research results show that sugary contamination is very absorbent and viscous, outdoor insulation characteristics of insulators covered with sugary contamination are worse than that covered with non-sugary contamination, but outdoor insulation characteristics of RTV coated insulator covered with sugary contamination is still better than that of non-RTV coating insulator with non-sugary contamination. So it is still a specific solution to inhibit the discharge activity of insulators in the substation by spraying RTV coating. Of course, removing the sugar canes themselves from this area is the best solution.