针尖曲率半径对硅橡胶电树枝老化特性的影响

针对硅橡胶材料电树枝老化特性展开了试验研究。采用针板电极结构，测量了不同针尖曲率半径的起树电压和电树枝形态。结果表明，硅橡胶的起树电压较低，抗电树枝老化性能较差，导致了硅橡胶预制式电缆附件故障频发；硅橡胶中的起始电树枝多以单枝状的通道形成为标志，随后发展为4种不同的电树枝形态。进而提出了硅橡胶电树枝形态发展模型，并以此讨论了不同形态的电树枝老化特性。研究还发现，现场实际运行的硅橡胶预制式电缆附件故障解体后发现了单枝通道起始电树枝，其在运行电压作用下容易发展为细枝型形态，但同样会引发电缆附件的击穿。试验结果为现场故障分析提供了参考依据。

Influence of Curvature Radius of Needle Tip on Characteristics of Electrical Treeing in Silicone Rubber

Studies on electrical treeing characteristics of silicone rubber (SIR) were carried out in this paper. Tree initiation voltage and electrical tree shape of different curvature radius of needle tip were measured. From the experiments, it was found that tree initiation voltage of SIR is so low that causes high failure rate of cable accessories. Electrical tree in SIR initiates mostly in a single branch named initiation tree, which will transfer to four kinds of electrical trees with different shapes. Electrical treeing characteristics were discussed by the model of tree shape propagation in silicone rubber. Meanwhile, initiation tree, withe-like tree and breakdown channel caused by withe-like tree mentioned here can be found in failed cable accessories. This indicates that the experimental results can be used as an explanation for the failure on site.