This paper addresses the long-term aging of silicone rubber shedded insulators mounted horizontally, and specifically relates the experience from a highly monitored six-year trial of two composite cross-arms designed for 400 kV. Weather conditions and leakage currents were continuously monitored in this moist and temperate area. In addition, the growth of algae on the surface over time is reported. As expected for the coastal location, strong seasonal variation was seen in leakage currents and this is associated with wind direction and resulting weather variations. Leakage currents remained low but increased linearly with time. Despite apparent large areas of algae growth on upward-facing surfaces, and some associated loss of hydrophobicity on some surfaces, the leakage currents on the insulators continue to be satisfactorily low. Cleaning one of the insulators after five-and-a-half years temporarily returned the current to its original value. In the short-term, leakage currents were heavily dependent on relative humidity, and peak currents are shown to be strongly dependent on the length of preceding periods without precipitation. It is suggested that measurement of these variables may be used to evaluate surface condition and be an effective asset management tool.

中文翻译：

---

高压架空线路宽体复合绝缘子六年试验


本文讨论了水平安装的硅橡胶伞裙式绝缘子的长期老化问题，并特别介绍了针对 400 kV 设计的两个复合材料横担进行为期六年的高度监控试验的经验。在这个潮湿和温带地区，天气条件和漏电流受到持续监测。此外，还报告了表面藻类随时间的生长情况。正如对沿海位置的预期，泄漏电流存在强烈的季节性变化，这与风向和由此产生的天气变化有关。漏电流仍然很低，但随时间线性增加。尽管在朝上的表面上明显有大面积的藻类生长，并且某些表面上疏水性有所丧失，但绝缘体上的漏电流仍然令人满意地低。五年半后清洁其中一个绝缘体可以使电流暂时恢复到原来的值。在短期内，漏电流很大程度上取决于相对湿度，峰值电流很大程度上取决于之前无降水时期的长度。建议这些变量的测量可用于评估表面状况并成为有效的资产管理工具。