特高压直流用高导热纳米复合绝缘子耐电痕特性研究

Study on Characteristics of Tracking Resistance of Silicon Rubber Composite Insulators with High Thermal Conductivity for UHVDC Transmission Lines

随着特高压复合绝缘子的大规模应用,复合绝缘子的耐电痕能力成为亟待研究的问题。为此,通过基于IEC 60587标准的耐电痕实验以及实验过程中的热放电图谱,研究了高导热纳米复合硅橡胶在高压直流下的耐电痕特性。所用纳米复合硅橡胶材料为室温硫化硅橡胶基体添加纳米氮化硼(BN)。实验结果表明,随着纳米氮化硼颗粒质量分数的提高,硅橡胶复合材料试样表面放电区域的最高温度得到抑制,试样表面温度超过60°C的区域面积增大,停止放电后试样表面温度下降速度升高。实验结果还表明,纳米复合硅橡胶的电蚀损失质量和电蚀深度比未添加纳米颗粒的硅橡胶有明显的下降。因此含有纳米氮化硼颗粒的硅橡胶有较好的抑制热量积累能力,且耐电弧侵蚀增强,能够有效提高硅橡胶的绝缘能力。

Since ultra high voltage （UHV） silicone rubber composite insulators are widely applied in China, the tracking resistance of silicone rubber insulators becomes an issue urged to be studied. Therefore, on the basis of tracking and erosion tests in IEC 60587 and the thermal images obtained in the tests, we investigated the tracking resistance of silicone rubber nanocomposites with high thermal conductivity under HVDC. The silicone rubber nanocomposites were prepared with RTV silicone rubber and nano boron nitride （BN） as matrix and fillers, respectively. The tests indicate that, with the increase in BN concentration, the maximum temperature on the discharge region is inhibited, the dissipation region that temperature exceeds 60 ℃ expands, and the decreasing of temperature after discharges is accelerated. Besides, the weight loss and erosion depth decrease due to the addition of BN fillers. It is concluded that adding nano BN into silicone rubber can significantly reduce the accumulation of heat on discharge region and improve the rubber in resistance against tracking and erosion, and hence enhance the rubber＇ s insulation performance.