PDF(Pubmed)
Abstract：
Composite insulators have been widely used in power grids due to their excellent electrical-external-insulation performance. Long-term operation at high voltage levels accelerates the aging of composite insulators; however, there is a scarcity of research on aged composite insulators operating at 500 kV for over ten years. In this paper, the mechanical, electrical, and microscopic properties were tested on different sheds along a 500 kV composite insulator that had been running for 18 years. Additionally, the results were compared with a new insulator and the standards for live insulator operation. The results showed that the aging of the high-voltage end of composite insulators was the most serious. The results of the physical properties test indicated that the insulator\'s hardness was compliant but its tensile strength and break elongation did not meet standards. Under wet conditions, the pollution flashover voltage decreases by about 50% compared to the new insulator. Combined with the microscopic test results, the shed skeleton structure could be damaged and the filler might be lost during the aging process of polydimethylsiloxane (PDMS). The hardness of the insulator would increase by the precipitation of inorganic silicon; however, inorganic silicon might destroy the hydrophobicity and other properties of insulator sheds. These results can provide theoretical references for insulator life prediction and operation protection.
摘要：
复合绝缘子以其优良的电气外绝缘性能在电网中得到了广泛的应用。在高电压水平下的长期运行加速了复合绝缘子的老化；然而，在500kV下运行超过十年的老化复合绝缘子的研究很少。在本文中,机械,电气,在运行了18年的500kV复合绝缘子的不同棚子上进行了微观性能测试。此外,结果与新的绝缘子和标准的带电绝缘子操作进行了比较。结果表明，复合绝缘子高压端老化最为严重。物理性能测试结果表明，绝缘子的硬度是合格的，但其拉伸强度和断裂伸长率不符合标准。在潮湿条件下,与新绝缘子相比，污闪电压降低了约50％。结合显微镜检测结果,聚二甲基硅氧烷（PDMS）老化过程中，脱落骨架结构可能被破坏，填料可能丢失。绝缘体的硬度会由于无机硅的沉淀而增加；然而，无机硅可能会破坏绝缘壳的疏水性和其他性能。研究结果可为绝缘子寿命预测和运行保护提供理论参考。
