退役高压电缆附件绝缘状态及理化性能分析

Analysis of Insulation State and Physicochemical Property of Retired High-Voltage Cable Accessories

为了探究长期服役对高压电缆附件老化状态的影响,研究退役电缆附件的绝缘特性及理化性能。以三元乙丙橡胶(EPDM)和硅橡胶(SIR)两种退役电缆附件绝缘为研究对象,测试其力学性能、微观结构及化学成分,测试并分析其介电性能和绝缘状态。结果表明,EPDM样品中C-O-C键的出现以及SIR样品分子链上有机基团的减少可作为电缆附件绝缘老化的标志,附件的绝缘老化在宏观上表现为力学特性的下降;经历老化或击穿事故的电缆附件,其分子链在电、热等综合作用下断裂成小分子,小分子可能重结晶,导致样品晶型及聚集状态的改变;经历严重老化的电缆附件,其介电性能发生明显劣化。样品理化性能及介电性能的改变可基本反映电缆附件的绝缘及老化状态。

In order to investigate the effect of long-term service on the aging state of high-voltage cable accessories,this paper studied the insulation characteristics and physicochemical properties of retired cable accessories.Taking two types of retired cable accessories of ethylene-propylene-diene monomer(EPDM)and silicone rubber(SIR)as research objects,the mechanical properties,microstructure,and chemical composition were tested,and the dielectric properties and insulation status were tested and analyzed.The results show that the obvious appearance of the C-O-C bond and the continuous reduction of organic groups on the molecular chain indicate a decline in mechanical properties on a macro level.For cable accessories that have undergone aging or breakdown accidents,the molecular chain are broken into small molecules under the combined effects of electricity and heat.These small molecules may recrystallize,resulting in changes in the crystal form and aggregation state.Meanwhile,the dielectric properties are obviously deteriorated for severely aged cable accessories.The changes in physicochemical properties and dielectric properties of the samples can reflect the insulation and aging state of the cable accessories.