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Bandar ‘Abbās, Iran

Ahmadi-Joneidi I.,Niroo Research Institute | Rezaei M.,Niroo Research Institute | Kahuri H.,Hormozgan Regional Electrical | Sahragard J.,Hormozgan Regional Electrical | Sayani A.,Hormozgan Regional Electrical
Life Science Journal | Year: 2013

Ceramic insulators are used in electrical substation. As outdoor insulators, the ceramic insulators are subjected to environmental stresses. In particular case, the insulators may severe high pollution exposure. Several methods are presently available to improve performance of post insulators under contaminated conditions. Recently, adding of hydrophobic agent on the insulators surface was present to improve the feature of ceramic insulators under polluted condition. The chief concerns with this method are the time of effectiveness of the coating, and insulator performance with time in service. This paper presents investigations on the performance of two different room temperature vulcanized (RTV) silicone rubber coating on the ceramic insulators after 7 and 11 years of field exposure respectively. The characteristics of RTV silicon rubber coated insulator were analyzed, such as, visual inspection, contact angel measurement and material diagnostic technique have been used to detect defective in service RTV Coated silicone rubber insulators. The coating content of some surface regions decreased as degradation increased. Scanning electron microscopy, thermo-gravimetric, attenuated total reflectance, fourier transform infrared spectroscopy analysis and energy dispersive x-ray analysis used to identify the elemental composition of samples. The changes in the surface morphology and material structure were examined before and after the ageing. Source


Rezaei M.,Niroo Research Institute | Ahmadi-Joneidi I.,Niroo Research Institute | Parhizgar A.,Niroo Research Institute | Kahuri H.,Hormozgan Regional Electrical | Sayani A.,Hormozgan Regional Electrical
Life Science Journal | Year: 2013

Insulators in the field experience synergistic effects of temperature, UV radiation, rain, clear mist, and contamination. One of the problems related to outdoor polymeric insulator is erosion and tracking of the weathershed which can affect the reliability of power system. This paper presents investigations on the performance of outdoor 63 kV silicone rubber insulators after seven years of field exposure. The insulator performances were evaluated in laboratory by measurements of leakage currents under clean fog and salt fog conditions. Also visual inspection, hydrophobicity classification and material diagnostic technique have been used to detect defective in service silicone rubber insulators. The polymer content of some surface regions decreased as degradation increased. Scanning electron microscopy, Thermo-Gravimetric, attenuated total reflectance-Fourier transform infrared spectroscopy analysis and energy dispersive x-ray analysis used to identify the elemental composition of virgin and aged surface of insulator. Peak values of leakage current and cumulative charge are measured in clean fog and salt fog chamber. Also, inclined plane tracking and erosion resistance test have been done on the silicone rubber samples. The changes in the surface morphology and material structure were examined before and after the ageing. Source

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