Effect Of UV Radiation On Performance Of Silicone Rubber Material At High Altitude

Composite insulators are widely used in the generation,transmission and distribution lines.Especially,the majority suspension insulators in the ultra-high voltage construction are composite insulators.However,as the increase of service time,it is necessary to study the aging condition of insulators,particularly the unavoidable effect from ultraviolet radiation.In this article,aging of silicon rubber resulting from ultraviolet radiation is studied from two aspects,including:artificial 5000 hours aging with UVA340 and UVB313EL Ultraviolet lamps in the laboratory;and naturally aging in the high altitude area and flat area.Taking curing time into consideration,three different silicon rubber samples-overcured,normal,undercured-are been chosen.The physical&chemical properties and space charge trap features remain the parameters of concern under the UV radiation.For the physical and chemical properties,the hardening rate of undercured silicon rubber is the slowest,and that of the overcured silicon rubber is the fastest;hydrophobicity of overcured silicon rubber is the best,the lost rate of hydrophobicity of undercured is relatively faster;the mechanical property of undercured silicon rubber is better than the others.For the space charge characteristics,trap charges variation as time increasing shows two stages,and in the former stage,the comparison of space charge quantity of three samples is:undercured,normally cured,overcured,and for the later stage is:overcured,normally cured,undercured.The effect of UVB makes this change occurred much earlier The performance degradation trends of naturally aged and artificially aged silicon rubber are similar,and the order of magnitudes of space charge parameters are the same.According to the experiment results,the silicon rubber is affected by multi factor under real operating condition,which lead to that the aging results of artificially aging and naturally aging cannot be compared quantitatively,but the aging results can used as reference for utilization of silicon rubber in the high altitude area.