【作者】 胡雨龙；

【导师】 陈伟根；

【作者基本信息】 重庆大学 ， 高电压与绝缘技术， 2002， 硕士

【摘要】 当SF6高压开关气体中的水分含量达到一定程度时，不仅会与电弧作用下的气体分解物反应产生毒性物继而引起设备的化学腐蚀，而且会使固体绝缘水平下降引起绝缘闪络，严重影响设备的电气性能、机械性能，造成许多严重的不良后果。论文阐述了SF6气体微水的来源及其危害。从湿度理论出发，研究了SF6气体中微水含量的变化规律及其对开关设备的危害程度之间的关系。针对现有规程标准中控制水分的指标的缺点和局限，提出了采用相对湿度作为监测特征量并转换为露点以直观表示设备绝缘状况：采用30％相对湿度及0℃以下露点作为监测的临界值与允许值；同时推导出了体积比单位在不同温度下的折算方法，以结合现有标准，综合分析，做出判断结论。通过性能比较、分析并结合在线监测的具体技术要求，选择、制备了具有物理吸附作用且能在0-100％相对湿度范围内全程连续检测的高分子薄膜湿度传感器。采用饱和盐溶液法得到相应级别的湿度标准，对传感器进行标定试验并采用相应的数据处理方法，建立了感湿特征量与气相湿度之间的数学关系，最终给出其数学模型和各种指标。设计了微量水分传感器的结构和相应标定、试验装置。试验表明，高分子薄膜电容式湿度传感器可用于SF6气体微水在线监测并能取得线性度、分辨率较好的检测数据。结合传感器特性，对传感器的信号采集与调理转换电路进行分析及具体设计。应用电容-频率转换的数字化测量方法具有较好的抗干扰效果和较高的测量分辨率，适宜于远距离传输和监测。采用了基于多周期同步法的PCI总线频率卡与工业控制微机接口，进行频率测量。提出了微水含量在线监测系统的工作原理及实施方案，设计了系统的整体硬件结构以提高测量的准确度和稳定度并降低温度的影响和杂散干扰。利用面向对象编程技术设计了在线监测系统的软件以控制信号采集与数据处理，并利用软件技术改善传感器静态、动态特性，应用数学方法进行线性化处理以提高测量准确度。引入并采用了模糊理论用于微量水分测量，使测量最大误差不大于5％，具有较高的精确度和复现性。同时提出基于单传感器的分批估计数据融合算法，优于算术平均值法，便于数据滤波。给出了不同温度下系统的频率测量值及监测数据结果。分析了在线监测系统采取的抗干扰措施。通过系统调试与测量，为在线监测系统的现场实施提供了良好的技术基础。更多还原

【Abstract】 When moisture content in SFg Gas-insulator switchgear reaches to a certain extent,It could be compounded with product of SF6’s decompose under arc action and then produces poison which results in chemic corrupt. At the same time,it also arouses the drop of insulated performance and bring on flashover of insulated surface. The electrical and mechanical characteristic is influenced by moisture content,as well as the badness would happen.This paper studies the source,change rule and quantitatively harm of moisture content in SF6 gas. Based the humidity theory,the paper adopts the relative humidity as the character value and puts forward using 30%RH and below 0C dew-point as the on-line monitoring critical value. It gives the method of volume ratio convert at the different temperature. With the standard value,we can conclude the result of moisture content.The paper studies the present situation and characteristic of sensors and brings forward using macromolecule polyimide-based capacitive humidity sensor in on-line monitoring system which has physical adsorption and can continuously measure between 0 to 100C. By adopting the method of saturated aqueous salt solutions,the paper designs the equipment to produce the humidity source and scale PI sensors. Based on the design and long period measurement of demarcated equipment,we get the lots of curve and data that shows the linear relation between capacity and moisture and good linearity and resolving power.According to disposal and analysis of sample data,it brings forward the principle and method of digital measurement-frequency measurement and designs the hardware system. The circuit suit for long-distance transmission and monitoring and has high precision and anti-jamming characteristic. It measures the frequency by PCI card which is base on the method of multi-period synchronization.The paper studies the mechanism of the monitoring system and gives it’s structure. Considering the practice,the software is compiled which is based on win98 DLL and used to control the sample and disposing data. As the same time,temperature compensation,curve fitting,fuzzy theory and data amalgamation are applied to ensure the precision of measurement and advances the veracity.The simulated experiment results show that the on-line monitoring system can present the variation of the moisture content in the SF6 gas and provide a good technique for on-line monitoring system.更多还原