腐蚀性硫化物对特高压套管油纸绝缘特性及安全运行影响的研究

This project is to study the corrosive sulphide phenomenon, which can cause the insulation failure. Based on the special structure "oil - paper - aluminum foil" of UHV bushing with small size, less oil, aluminum foil and the insulating paper alternately winding copper core, a series of accelerated aging experiments will be applied to oil-paper insulations under thermal, electrical condition. The following contents will be investigated: the mechanism and influence factors of sulfide generation in oil-paper; the deposition of sulfide on insulation paper and migration and diffusion dynamic model of it in "oil-paper- aluminum foil"; the influence of corrosive sulfide on the physi-chemical and electrical properties of oil-paper, and also the charicteristics to indicate the corrosive degree under AC, DC, AC and DC superposition and polarity reversal field; the space charge characteristics of different degree of sulfide deposition on insulating paper , and by the finite element method, the distribution of electric field were studied , the fault mechanism of oil paper insulation caused by corrosive sulfide was preliminary explored. Through the exprimental results and theoretical analysis in this project, on one hand, the generating mechanism and influencing factors of corrosive sulfide in UHV bushing was deeply understood; on the other hand, the fault mechanism of oil paper insulation caused by corrosive sulfide in UHV bushing was explored, which has important academic value and practical significance in engineering to improve the safe operation of transmission and distribution equipment.

本课题以一种引发绝缘故障的因素-油硫腐蚀现象为研究对象，针对特高压套管体积小，油量少、铝箔与绝缘纸交替缠绕铜芯这一“油-纸-铝箔”的特殊结构，通过电、热作用下的油纸绝缘加速老化试验，分别研究油纸绝缘系统中腐蚀性硫化产物的生成机理及影响因素，硫化产物在“油-纸-铝箔”系统中的沉积及迁移规律和扩散动力学模型，不同沉积程度的腐蚀性硫化产物在交、直流、交流与直流叠加及极性反转电场作用下对油纸绝缘理化、电气参量的影响及表征，以及不同沉积程度的腐蚀性硫化产物对绝缘纸空间电荷特性的影响，并通过有限元法研究其电场分布，初步探索腐蚀性硫化产物引发油纸绝缘故障机理。预计通过本项目的试验及理论分析研究结果，一方面深入认识在特高压套管中腐蚀性硫化产物生成机理及影响因素；另一方面初步探索特高压套管中腐蚀性硫化产物引发油纸绝缘故障的机理，对提高输变电设备的安全运行具有重要的学术价值和工程实际意义。

本课题以一种引发绝缘故障的因素-油硫腐蚀现象为研究对象，针对特高压套管体积小，油量少、铝箔与绝缘纸交替缠绕铜芯这一“油-纸-铝箔”的特殊结构，通过电、热作用下的油纸绝缘加速老化试验，分别研究油纸绝缘系统中腐蚀性硫化产物的生成机理及影响因素，硫化产物在“油-纸-铝箔”系统中的沉积及迁移规律和扩散动力学模型，不同沉积程度的腐蚀性硫化产物在交、直流、交流与直流叠加及极性反转电场作用下对油纸绝缘理化、电气参量的影响及表征，以及不同沉积程度的腐蚀性硫化产物对绝缘纸空间电荷特性的影响等，初步探索腐蚀性硫化产物引发油纸绝缘故障机理。通过本项目的试验及理论分析获得以下结论，在温度、腐蚀性硫浓度、电场等因素影响下铝箔与铜杆的油硫腐蚀产物生成机理及分布规律，即铝箔腐蚀产物为DBDS-Aln，主要存在于绝缘油，而铜的腐蚀产物为硫化亚铜主要沉积在绝缘纸上。并分别研究其对绝缘油纸基本理化和电气性能的影响；得到了铜的存在会加速铝箔的油硫腐蚀这一结论，并提出铝箔油硫腐蚀会引起油中气体异常，即氢气超标；同时提出了腐蚀产物的扩散模型并加以验证；此外，还针对特高压直流套管较为特殊的运行工况（交直流叠加、极性反转）,研究套管模型的击穿及空间电荷特性。本项目研究一方面深入认识在特高压套管中腐蚀性硫化产物生成机理及影响因素；另一方面初步探索特高压套管中腐蚀性硫化产物引发油纸绝缘故障的机理，对提高输变电设备的安全运行具有重要的学术价值和工程实际意义。