Hydrophobicity and insulated resistance of composite insulators with biological contamination
Biological growth has been observed on insulators installed all over the world. However its impact on the electrical performance is not well known. This paper described the investigations on the performance of post insulators with biological growth at a converter station. Both the ceramic and composite insulators were investigated. Two kinds of biological agents, lichen and mold were found on the composite insulator surface, but interestingly, no biological agent was found on the surface of ceramic insulators in the same environment condition. Lichen concentrated on the upper surface and mold on the lower surface. It seemed that the impact of lichen growth on the hydrophobicity is low, but hardly no hydrophobicity when mold growth. In addition, the insulated resistance test was carried out on the biologically contaminated insulators with and without salt water. Results show that whatever the surface was dry or not, high resistance were obtained with only less biological agent growth at the edge of insulators, but declined sharply when most of the surface was covered with lichen and mold. Therefore, it is strongly recommended to remove the mold, with which most the insulator surface is covered.
Performance and Diagnostics of Biologically Contaminated Insulators
Biological growth has been observed on insulators installed all over the world. However, so far, its impact on insulator performance is not well known. This paper summarizes a majority of the work published in the field. Based on the gathered experiences, it can be concluded that microbiological growth is unlikely to cause severe degradation of the rubber housings of non-ceramic insulators. Furthermore, it seems that the impact of growth on the insulator performance is rather low. Techniques available for detection and characterisation of growth on insulators are also described and discusses. Among those, laser-induced fluorescence (LIF) spectroscopy has been found to give good results in remote detection of micro-organisms
Pioneer 10 Observations of the Ultraviolet Glow in the Vicinity of Jupiter
A two-channel ultraviolet photometer aboard Pioneer 10 has made several observations of the ultraviolet glow in the wavelength range from 170 to 1400 angstroms in the vicinity of Jupiter. Preliminary results indicate a Jovian hydrogen (1216 angstrom) glow with a brightness of about 1000 rayleighs and a helium (584 angstrom) glow with a brightness of about 10 to 20 rayleighs. In addition, Jupiter appears to have an extensive hydrogen torus surrounding it in the orbital plane of Io. The mean diameter of the torus is about equal to the diameter of the orbit of Io. Several observations of the Galilean satellites have also occurred but only a rather striking Io observation has been analyzed to date. If the observed Io glow is predominantly that of Lyman-α, the surface brightness is about 10,000 rayleighs.