高压套管表带触指SF_(6)气氛中高温腐蚀特性研究

Research on High Temperature Corrosion Characteristics of Lamella of HV Bushing in SF_(6) Atmosphere

表带触指作为高压套管中电连接结构的关键部件,其接触劣化受到电、热、化学的联合作用。目前影响表带触指劣化腐蚀的关键因素尚不清楚,亟待开展相关研究。文中基于表带触指劣化试验系统开展了表带触指高温腐蚀特性研究:基于热力学原理分析了不同金属材料对SF_(6)气体分解产物的反应倾向;同时,开展了高温下表带触指在SF_(6)气体中的腐蚀试验,获得了不同过热分解条件下表带触指的腐蚀特性。研究发现,表带触指发生腐蚀反应的类型主要取决于温度最高点的位置和SF_(6)气体过热分解程度,SF_(6)过热分解初期氟化物的特征峰更强。当触指温度高于周边温度且SF_(6)分解程度较低时,表带触指主要受到氟化腐蚀,当SF_(6)分解程度较高时,表带触指主要受到硫化腐蚀。相关研究可为高压套管触指结构的过热故障分析及可靠性运行提供实践依据。

The lamella,as a key element of electrical connection structure in high⁃voltage bushing,the contacts deg⁃radation is affected by the combined action of electricity,heat and chemistry.At present,the key factors affecting the deterioration of the lamella are unclear and relevant research is urgently needed.In this paper,a research on the high temperature corrosion characteristics of the lamella is performed based on the lamella deterioration test system.Firstly,the reaction tendency of different metal materials to the decomposition products of SF_(6) gas is analyzed based on thermodynamics.Meanwhile,the corrosion test of the lamella at high temperature in SF_(6) is carried out,and the corrosion characteristics of the lamella under different superheated decomposition conditions is obtained.It is found by the research that the type of corrosion reaction of the lamella mainly depends on the position of the highest tem⁃perature point and the magnitude of thermal decomposition of SF_(6) gas.The characteristic peak of fluoride in the ear⁃ly stage of thermal decomposition of SF_(6) is stronger.When the temperature of the lamella is higher than the sur⁃rounding temperature and the SF_(6) decomposition degree is low,the lamella is mainly corroded by fluoride.In case of high SF_(6) decomposition,the lamella is mainly corroded by sulfur.The related research can provide a practical basis for the overheating fault analysis and reliable operation of the contact structure of high voltage bushing.