局部过热状态下六氟化硫气体的分解特性

源自局部过热状态下六氟化硫气体的分解特性
重庆大学硕士学位论文
（专业学位）
学生姓名：潘建宇 指导教师：唐 炬 教 授
学位类别：工程硕士（电气工程领域）
重庆大学电气工程学院
二 O 一四年五月
Thermal Decomposition Characteristics of SF6 under Overheating Fault in SF6 Insulated Equipment
College of Electrical Engineering of Chongqing University, Chongqing, China May, 2014
重庆大学硕士学位论文
中文摘要
摘
要
由于六氟化硫气体（SF6）在常温常压下化学性质非常稳定，且具有优良的绝 缘灭弧性能，因而已被广泛用在电气设备的气体绝缘和灭弧介质。然而，经过探 索性实验发现，当 SF6 气体绝缘设备局部达到一定温度时，SF6 气体绝缘介质也会 发生分解并生成如 HF、SO2F2、SOF2 和 SO2 等特征分解产物。一方面，这些分解 特征气体具有强腐蚀性，会加速设备老化，造成绝缘强度下降，从而进一步危及 设备的安全。另一方面，SF6 局部过热分解特性和产生的特征气体又与运行中的设 备状态和故障类型有密切的关联关系。 因此， 通过检测 SF6 在过热状态下的分解组 份及其含量变化规律， 不仅可以弥补现有 SF6 分解理论的不足， 同时可以更进一步 完善对 SF6 气体绝缘设备内部局部过热性故障的监测和诊断， 实现 SF6 电气设备局 部过热性故障的早期预警。 本文在研制的局部过热下 SF6 热分解模拟试验平台上进行了大量试验， 通过气 相色谱仪、气相色谱质谱联用仪和傅里叶变换红外光谱仪对不同故障温度下 SF6 分解组分进行了定量测量。然后首先探索了 SF6 的初始分解温度，研究了 400℃以 下各分解组分在不同故障温度下的含量变化特性， 确定了 SF6 在过热状态分解时的 特征稳定组分，并阐述了各组分在过热状态下的形成机理。同时，本文进一步从 特征分解总量、 有效产气速率和特征产物含量比值这三个角度构建了表征 SF6 绝缘 设备过热性故障状态的特征量，并分析了各个特征量的表征能力。 研究结果表明：SF6 在 300℃时开始出现比较明显的分解，其分解产物主要有 CO2、SO2F2、SOF4、SOF2、SO2、H2S 和 HF，故障温度的升高将促进各分解组分 的形成，但促进规律各不相同；SOF2 和 SO2 是 SF6 最主要分解产物并选定特征稳 定产物，H2S 是在过热性故障温度达到一定程度（360℃）后才会出现的关键组分； 特征分解总量 TDC 能合理表征过热故障下 SF6 介质的整体分解劣化程度； 特征组分 的产气速率能有效反映 SF6 过热故障的发展趋势和严重趋势， 过热故障安全反应时 间 TMS 从 SF6 绝缘介质角度明确了过热故障发生到恢复的最大允许反应时间； 含量 比值 C(SO2)/C(SO2F2)和 C(SO2F2+SOF4)/C(SOF2)可以对该 SF6 气室内故障性质是否 属于局部过热性故障进行识别和判断， 有效过热关联比值量 RET 可以对过热故障温 度 300~400℃内的各故障温度值进行更准确的定量关联， 并得到了过热故障温度和 RET 的数学关联表达式。 关键词：SF6，过热性故障，热分解特性，特征量提取，故障表征
A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for Professional Degree
By Pan Jianyu Superviseed by Prof. Tang Ju Specialty: ME. (Electrical Engineering Field)
III
重庆大学硕士学位论文
目
录
目
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中文摘要..........................................................................................................................................I 英文摘要........................................................................................................................................ II 1 绪 论......................................................................................................................................... 1
II
重庆大学硕士学位论文
英文摘要
decomposition amount TDC can reasonably represent the overall degradation status of insulation medium SF6; component’s formation rate can effectively reflect the severity and development tendency of thermal fault of SF6 insulated equipment; Combining IEC standard, the obtained thermal fault maximum safe time TMS can accurately assess the largest duration time when equipment occurs thermal fault; component characteristic ratio C(SO2)/C(SO2F2) and C(SO2F2+SOF4)/C(SOF2) can qualitatively judge the fault property whether it belongs to thermal fault; the defined thermal correlation ratio TR can availably to differentiate the temperature point of thermal fault among 300~400℃. Key Words: SF6, thermal fault, thermal decomposition characteristics, feature extraction; fault recognization
I
重庆大学硕士学位论文
英文摘要
ABSTRACT
Insulation gas SF6 has stable chemical property and strong electronegativity, with excellent insulation and arc-suppressing performance. However, exploratory experiments find that SF6 will decompose into various components when temperature of SF6 insulated equipment reaches to some degree, such as SO2, SOF2, SO2F2, and HF. On one hand, these characteristic decomposed components is highly corrosive. They can accelerate aging speed and cause reduction of insulation strength, which will further jeopardize the safety of the SF6 insulated equipment. On the other hand, variance regularity of SF6 thermal decomposed component is close related with thermal fault type and status of SF6 insulated equipment. Hence, by detecting decomposed components and clarifying their variance regularity under local thermal fault, it can not only ameliorate the deficiency of SF6 decomposition theoretical system, but also improve the method of using decomposed component to monitor and diagnose local thermal fault in SF6 insulated equipment. As a result, it can lay solid foundation to realize early warning of thermal fault in SF6 insulated equipment. This thesis conducted serials of experiments on the designed SF6 thermal decomposition stimulation testing system, Gas Chromatograph, Chromatography-mass Spectrometry, and Fourier Infrared Spectroscopy were used to quantitatively measure decomposed components. Based on this, decomposition beginning temperature of SF6 under thermal fault was investigated, concentration variance regularity of each component with different temperature was analyzed, the most significant characteristic component under thermal fault was identified, and the formation mechanism of decomposed component was explained. Besides, this thesis established three types of feature parameters, namely, total decomposition amount, effective formation rate, and characteristic component ratio, to reflect thermal fault property and severity of SF6 insulated equipment, the representation ability of each feature parameter was also discussed. Result shows that: SF6 begins to decompose at 300℃ and contains CO2, SO2F2, SOF4, SOF2, SO2, H2S and HF; the improvement of fault temperature will promote the formation of decomposed components, but the influence regularity of each component is different; SOF2 and SO2 are the most stable characteristic components and H2S is the special component which occurs only when the temperature is above 340℃；total