联合SF6气体分解产物和局放检测技术应用于盆式绝缘子潜伏性故障检测和定位

Application of combined SF6 gas decomposition products and partial discharge detection technology to detection and location of latent faults of basin insulators

  • 摘要: 特高压盆式绝缘子兼具机械支撑和电气绝缘的双重作用,特别是在特高压等级下,高电压/大电流/强载荷的长期联合作用其成为超长距离GIS/GIL管道的薄弱环节。另一方面,超长GIS/GIL管道中一般灌冲SF6绝缘气体,因此对于特高压盆式绝缘子存在金属界面-环氧树脂界面(固-固界面)和环氧树脂界面-SF6绝缘气体界面(固-气界面)等复杂界面环境,在特高压等级交流/直流电压长时间作用下容易产生界面局部高场强区域。且在大电流作用下,存在热胀冷缩机械应力作用,界面处区域在重复性/长时性拉/切应力作用下趋于出现空隙缺陷,因此同时出现局部放电信号。局部高温和局部电场集中同样导致SF6气体分解,由于盆式绝缘子环氧树脂固体材料存在其分解产物存在碳氟类分解产物,因此可联合SF6气体分解产物和局放检测技术应用于盆式绝缘子潜伏性故障检测和定位。基于此,本文从特高压盆式绝缘子环氧树脂与氧化铝混合体系电气性能切入,进一步分析盆式绝缘子拓扑结构优化设计,并将特高频技术和光声光谱技术应用于SF6气体分解产物和局放高灵敏度检测。在检测中重点关注CF4/SO2/CO等分解气体类型,局部放电重点关注固体绝缘件内部存在气泡和自由金属颗粒类型。研究表明:SF6气体分解产物和局放检测数据结果存在较强关联性,可通过数据智能融合算法实现特高压盆式绝缘子潜伏性故障检测和历史数据预测。本文研究结果对于特高压等级盆式绝缘子故障检修和运行维护具有良好指导意义和科研价值。

     

    Abstract: UHV basin insulator has the dual functions of mechanical support and electrical insulation. Especially under the UHV level, the long-term combined effect of high voltage/large current/strong load has become the weak link of ultra long distance GIS/GIL pipeline. On the other hand, super long GIS/GIL pipelines are generally filled with SF6 insulating gas. Therefore, for UHV basin insulators, there are complex interface environments such as metal interface epoxy resin interface (solid solid interface) and epoxy resin interface SF6 insulating gas interface (solid gas interface). Under the action of UHV AC/DC voltage for a long time, it is easy to generate local high field strength areas at the interface. Moreover, under the action of large current, there is thermal expansion and contraction mechanical stress, and void defects tend to appear in the interface area under the action of repetitive/long-term tensile/shear stress, so partial discharge signals appear at the same time. Local high temperature and local electric field concentration also lead to the decomposition of SF6 gas. Due to the presence of epoxy resin solid materials of the basin insulator and the presence of carbon and fluorine decomposition products, the combination of SF6 gas decomposition products and partial discharge detection technology can be applied to the detection and location of latent faults of the basin insulator. Based on this, starting from the electrical performance of the hybrid system of epoxy resin and alumina of UHV basin insulator, this paper further analyzes topology optimization design of basin insulator, and applies UHF technology and photo-acoustic spectroscopy technology to the high-sensitivity detection of SF6 gas decomposition products and partial discharge. In the detection, the type of decomposition gas such as CF4/SO2/CO shall be focused, and the type of bubbles and free metal particles in the solid insulation shall be focused on for partial discharge. The research shows that there is a strong correlation between the decomposition products of SF6 gas and the results of partial discharge detection data, and the latent fault detection and historical data prediction of UHV basin insulator can be realized through data intelligent fusion algorithm. The research results of this paper have the good guiding significance and scientific research value for the troubleshooting and operation maintenance of UHV basin insulators.

     

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