High-voltage silicone rubber composite insulators are widely used for outdoor insulation in power transmission lines. Silicone rubber, which is used as a housing material, gradually degrades with long-term use in the field. Therefore, to accurately determine the lifetime of composite insulators, it is essential to evaluate this degradation. This paper describes the results of depth profiling, which shows the change in the chemical composition caused by degradation, using laser-induced breakdown spectroscopy (LIBS). A remote LIBS system was constructed for application in in-situ degradation diagnostics. Field-aged insulators were irradiated with second harmonic Nd:YAG laser pulses at a distance of 10. The emission from the plasma was received by a telescope, and a spectroscopic analysis was performed. Energy dispersive X-ray spectroscopy (EDX) was performed for a comparative study. The emission intensity ratio of silicone to aluminum, which forms an alumina trihydrate filler, decreased by approximately 30% at the degraded surface compared to the undegraded bulk. A reduction in silicones at the degraded surface up to a depth of 300 was confirmed by LIBS and EDX measurements. These results show that remote LIBS using the ratio of silicone to aluminum as an index is a promising method for the in-situ diagnostics of composite insulators.

高压硅橡胶复合绝缘子被广泛用于输电线路的室外绝缘。用作外壳材料的硅橡胶随着在该领域的长期使用而逐渐降解。因此，为了准确地确定复合绝缘子的寿命，必须评估这种退化。本文介绍了使用激光诱导击穿光谱（LIBS）进行深度分析的结果，该结果显示了由降解引起的化学成分变化。构建了一个远程LIBS系统，以便在现场进行应用降级诊断。用距离为10的二次谐波Nd：YAG激光脉冲照射老化的绝缘子。用望远镜接收来自等离子体的发射，并进行光谱分析。进行了能量色散X射线光谱（EDX）进行比较研究。与未降解的块相比，在降解的表面上，形成三水合氧化铝填料的硅酮与铝的发射强度比降低了约30％。通过LIBS和EDX测量，可以确认在降解的表面上直至300深度的有机硅减少。这些结果表明，以硅铝比为指标的远程LIBS是一种用于复合绝缘子现场诊断的有前途的方法。