High-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

中文翻译：

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HVDC复合绝缘子在室外和室内环境中的全球经验

高压直流（HVDC）传输被称为绿色能量传输技术，由于其高功率传输能力和较低的功耗，最近已成为高压交流（HVAC）的有吸引力的替代方案。近年来，由于复合绝缘子在传统的陶瓷绝缘子中具有较高的疏水性和在污染环境中的良好性能，因此在直流输电线路上的使用迅速增长。绝缘子在直流线路上运行期间，由于单向电场的作用，容易积聚更多的污染物。潮湿条件下的污染物会使泄漏电流在绝缘子表面上流动。高分子绝缘子本质上是有机的，在电和环境应力的共同作用下会老化。为了充分了解直流复合绝缘子的长期老化性能，有必要进行详细调查。为此，本文重点总结了全世界复合绝缘子在现场和实验室条件下的老化性能经验。