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GIS设备用表带触指电连接结构接触电阻的分形理论计算与分析
(1.国网安徽省电力有限公司电力科学研究院, 安徽 合肥 230601;2.西安交通大学 电气绝缘与电力设备国家重点实验室, 陕西 西安 710049)
Calculation and Analysis of the Electrical Contact Resistance of the Strap Contacts Used in GIS Equipment Based on the Fractal Model
(1.State Grid Anhui Electric Power Research Inst., Hefei 230601, China;2.State Key Lab. of Electrical Insulation and Power Equipment, Xi'an Jiaotong Univ., Xi'an 710049, China)

Abstract:Contact resistance of an electrical connection structure (ECR) is an important indicator to evaluate the reliability of the electrical contact system. The strap contact is an important electrical connection component in eco-friendly insulating gas GIS equipment. Its ECR will affect the total resistance of the equipment. Factors such as the excessive current flow, the conductor vibration, and the improper installation can also leads to poor electrical contact, local overheating of the strap contacts, insulation discharge and other failures, which is directly related to the operation stability of environmental protection gas GIS equipment. To study the mechanism and regularity of ECR, MATLAB and laser confocal microscope were used to capture the grayscale image of the contact area in this paper. The nominal contact area Aa and fractal dimension D of the contact area were obtained. Using the fractal theoretical model, the contact resistance of the strap contact was numerically calculated. The rationality and accuracy of applying the fractal theoretical model to analytically calculate the contact resistance of the electrical connection structure was verified through ECR test measurements. Since ECR is closely related to the actual contact area, the elastic deformation, the first elastic-plastic deformation, the second elastic-plastic deformation and the plastic deformation during the electrical contact process of the strap contact were studied. What's more, the effect of different fractal dimensions on the actual contact area of the electrical contact was studied. The research found that the fractal theoretical model can be used for the theoretical calculation of ECR for the strap contact of the GIS equipment. It was obtained that the larger the fractal dimension of the electrical contact surface, the earlier the contact deformation enters the elastic-plastic stage, and the easier it is to enter the second elastic stage. In the plastic deformation stage, the more complex the surface morphology, the smaller the actual contact area required to achieve the same bearing capacity. The research results are helpful for the optimal design of the eco-friendly insulating gas GIS electrical connection structure, and can provide a theoretical basis for the multi-physics calculation of the eco-friendly insulating gas GIS equipment electrical connection structure and the state evaluation of the electrical contact performance.

YANG Wei,ZHU Taiyun,REN Ting,WANG Qingyu,JIN Shoufeng.Calculation and Analysis of the Electrical Contact Resistance of the Strap Contacts Used in GIS Equipment Based on the Fractal Model[J].Advanced Engineering Sciences,2023,55(4):11-20.