Feasibility of the Overall Recycling of 220 kV Retired Composite Insulator Core Rods
Liu Hechen1,2, Hu Rufa1, Liu Yunpeng1,2, Li Le1, Liu Jie3
1. Hebei Key Laboratory of Green and Efficient New Electrical Materials and Equipment North China Electric Power University Baoding 071003 China; 2. State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China; 3. State Grid Hebei Electric Power Company Electric Power Research Institute Shijiazhuang 050021 China
Abstract：The simple manufacturing process and high hydrophobicity of composite insulators solves the pollution flashover problem in polluted areas. Therefore, composite insulators are widely used in China’s power system. However, early composite insulators are being retired in batches. Landfill dumping, discarding, and other methods are typically used for the disposal of the retired composite insulators. This approach causes wastage of resource and harms the environment. Because of the protection of silicone rubber outer sheath, the external environment has a limited effect on the core rod. The core rod exhibits high recycling value after retirement. In order to promote the high-value utilization of retired insulator cores, the degree of performance degradation and microstructure of retired composite insulator core rods for 220 kV are investigated, and the reuse value and rapid performance evaluation methods of retired core rods are explored. Firstly, the high-voltage, middle, and low-voltage sections of the 220 kV retired composite insulator core rods were considered. The physical, thermal, electrical and mechanical characteristics of the retired core rods were compared with those of new core rods. The results reveal that compared with new core rods, the epoxy resin matrix content of the retired core rods is only reduced by 1.31%, with no penetration phenomenon after 30 minutes of dye penetration, and saturated moisture absorption is less than 0.008%. The physical and chemical properties remain good; The breakdown strength of retired core rods is maintained to be higher than 20 kV/mm, and the maximum leakage current is maintained within 50 μA after 6 days of boiling. These results reveal excellent electrical strength and insulation performance of the retired core rods; The tensile strength, bending strength and shear strength are kept above 640 MPa, 1 500 MPa and 130 MPa respectively, and the retired core rods still exhibit high mechanical bearing strength. Secondly, the microstructure of retired core rods was considered. The results reveal that their porosity is relatively low, with no obvious large pores. The small pores of 10 μm3 are mainly present, effectively inhibiting the development of breakdown process and water infiltration; The epoxy resin matrix and fiber interface exhibit excellent adhesion, absorbing a large amount of fracture energy during load-bearing failure, which helps to fully utilize the fiber strength and is the reason why retired core rods can still maintain high mechanical strength. Finally, by sorting the performance degradation of retired core rods, it is found that their electrical performance decreases more significantly, and the degree of performance degradation in the high-voltage section is relatively high. Therefore, electrical performance can be used as a method to quickly evaluate the value of reuse, and the middle and low voltage sections can be prioritized in the overall reuse process. The retired core rods exhibit excellent physical and thermal properties, electrical strength, insulation performance, and mechanical bearing capacity, and have high reuse value. Priority can be given to overall reuse for electrical insulation components such as composite insulators, or for mechanical bearing components, to promote the high-value utilization of retired core rods.
刘贺晨, 胡如法, 刘云鹏, 李乐, 刘杰. 220 kV退役复合绝缘子芯棒整体回收再利用可行性研究[J]. 电工技术学报, 2024, 39(11): 3433-3443.
Liu Hechen, Hu Rufa, Liu Yunpeng, Li Le, Liu Jie. Feasibility of the Overall Recycling of 220 kV Retired Composite Insulator Core Rods. Transactions of China Electrotechnical Society, 2024, 39(11): 3433-3443.
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2024, Vol. 39 
