电晕强度对HTV硅橡胶陷阱特性的影响

Influence of Corona Intensity on the Trap Characteristics of HTV Silicone Rubber

高温硫化(HTV)硅橡胶因具有优异的憎水性、憎水迁移性、憎水恢复性及其它显而易见的优越性而被广泛用作电力系统中合成绝缘子的外绝缘材料。为此,采用热刺激电流(TSC)技术对HTV硅橡胶在不同电晕强度老化后的陷阱特性进行了系统的试验研究,同时观测了硅橡胶在相应老化阶段表面形态的变化。试验结果表明,在不同的老化阶段,硅橡胶的陷阱特性变化呈现出不同的特点。随着电晕强度的增加,陷阱电荷量总体上呈增多趋势;在电晕作用时间较短时陷阱能级随电晕强度的增加而产生较小的变化;在电晕作用时间较长时,陷阱能级在电晕强度达到一定值时将被加深,之后随电晕强度的增加而逐渐变深。结合硅橡胶的扫描电子显微镜(SEM)结果,分析可知,电晕强度及电晕作用时间通过影响轰击硅橡胶表面的带电粒子的能量和持续时间,对其表面形态产生作用,进一步地引起硅橡胶陷阱分布特性的变化。

HTV silicone rubber has been widely used as the outer insulation material of composite insulators because of its outstanding hydrophobicity, hydrophobicity recovery properties, good electrical insulation and excellent weatherbility. Accordingly, the influence of corona intensity on the trap characteristics of HTV silicone rubber was investigated. The trap characteristics were measured by the thermally stimulation current（TSC） technique. Five levels of corona voltage were employed to deteriorate the silicone rubber samples. The TSC was measured for the samples after different deteriorating duration. Experimental results show that the variation trend of TSC curves with the corona intensity is not identical in different deteriorating periods. During the whole deterioration progress, the peak of TSC gradually increases with the improvement of corona intensity. The temperature corresponded to TSC peak, however, becomes higher only when the corona intensity is elevated to a certain value in given corona deterioration period. Along with the prolonging of deterioration duration, the greater the corona intensity, the higher the temperature corresponded to TSC peak. The calculated trap parameters reveal the trap charges increase with the improvement of corona intensity, while the trap energy level is not always deepened by the corona intensity.