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Information about several papers discussed at the International Conference on Condition Monitoring and Diagnosis (CMD) held from April 21-24, 2008 in Beijing, China is presented. Topics include the fundamentals of partial discharge detection, condition monitoring of generators and phenomena and mechanisms of aging, degradation and failure. The event featured several executives in the industry including Hitoshi Okubo, Michael Muhr and Toshikatsu Tanaka.

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. [ABSTRACT FROM PUBLISHER]

An investigation into the effect of surface roughness on corona discharge for a 30-year operating conductor in the first 500-kV transmission line in China is presented. Many substances were found to adhere to the conductor surface. Corrosion and deposits had rendered the operated conductor surfaces much rougher than those of the new one. The results show that surface roughness has a significant impact on corona discharge, and the corona inception voltage of the operated conductor would be reduced while the audible and radio noise would be increased. [ABSTRACT FROM AUTHOR]