高压GIS设备插接结构载流磨损特性研究和电接触性能劣化分析

Current-Carrying Wear Characteristics of High-Voltage GIS Plug-in Structure and Analysis on Deterioration of Electrical Contact Performance

触指作为电连接部件,具有结构简单、体积小和适合批量制造等特点,现普遍应用于大功率电气互连场合,如SF_(6)气体绝缘组合电器(gas insulated switchgear,GIS)中触指被广泛应用在断路器、母线和隔离开关等关键部件内.触指长期承受电、热和力的集中作用,作为插接结构的关键部件,其电气载流、磨损性能对于GIS设备的安全稳定运行至关重要.本文中以GIS设备中常用的表带触指为研究对象,在自主搭建的电接触试验平台中开展了表带触指的静态及动态磨损特性试验,研究了极板表面镀层、电流幅值及电极材料等因素对表带触指电连接结构载流磨损性能的影响规律.研究发现,表带触指的法向压力高于10 N时,接触电阻变化较为稳定;在载流磨损条件下,电流幅值越大,触指触头的劣化越严重,并会与SF_(6)气体发生腐蚀反应;即使通流大小在触指额定范围内,载流导体表面未镀银时,由于触指的过热腐蚀将导致接触电阻在磨损中期最大值达到14 mΩ,严重高于正常接触电阻值.本文的研究成果可为GIS设备内部插接结构的选型、结构设计和故障分析提供重要依据.

As an electrical connection component,the contact finger has the characteristics of simple structure,small volume and suitable for batch manufacturing and it is now widely used in high-power electrical interconnection occasions,such as the contact fingers in SF_(6)gas insulated switchgear(GIS),which are widely used in key components of circuit breakers,buses and disconnectors.As the key component of the plug-in structure,the contact finger bears the concentrated effect of electricity,heat and force for a long time,and its electrical current carrying capability and wear resistance are critical to the safe and stable operation of GIS equipment.In this paper,the static and dynamic wear characteristics of the contact finger,which was commonly used in GIS equipment,were studied on the self-developed electrical contact experimental platform;The influence of electrode plate surface coating,current amplitude,electrode material and other factors on the current carrying wear performance of the contact finger electrical connection structure was studied.It was found that when the normal pressure of the contact finger of the strap was higher than 10 N,the change of contact resistance was relatively stable;under the combined action of current carrying and wear,the greater the current amplitude was,the more serious the deterioration of the contact finger would be,and the contact finger would corrode with SF_(6)gas;even if the current flow was within the rated range of the contact finger,when the surface of the current carrying conductor was not silver plated,the contact resistance will reach 14 milliohms in the middle of wear period due to overheating corrosion of the contact finger,which was seriously higher than the normal contact resistance.The research results of this paper can provide an important basis for the selection,structural design and fault analysis of the internal plug-in structure of GIS equipment.