盆式绝缘子沿面放电是气体绝缘组合电器(GIS)的主要绝缘故障形式。为监测盆式绝缘子的绝缘状况,研究GIS内环氧树脂固体绝缘介质发生沿面放电情况下SF6特征分解产物的变化规律,在小型模拟平台上试验发现,CS2是盆式绝缘子沿面放电时SF6气...盆式绝缘子沿面放电是气体绝缘组合电器(GIS)的主要绝缘故障形式。为监测盆式绝缘子的绝缘状况,研究GIS内环氧树脂固体绝缘介质发生沿面放电情况下SF6特征分解产物的变化规律,在小型模拟平台上试验发现,CS2是盆式绝缘子沿面放电时SF6气体生成的产物,并在110 k V GIS母线段实体绝缘子沿面放电试验中得到验证。用B3P86量子化学理论计算方法,得出了SF6在盆式绝缘子沿面放电条件下CS2的产生途径和能量条件。试验与理论计算结果表明,盆式绝缘子等固体绝缘介质发生沿面放电时GIS的内部发生复杂的化学反应,会有多种途径生成CS2,且由盆式绝缘子等环氧树脂介质表面炭化后提供碳源。CS2是一种可用于GIS中盆式绝缘子沿面放电故障诊断的特征气体。将CS2作为特征气体应用于生产实际检测,成功发现多起运行中的GIS涉及盆式绝缘子沿面放电导致绝缘损坏的潜伏性缺陷。展开更多
Gas insulator switchgears(GISs),widely used in electric power systems for decades,have many advantages due to their compactness,minimal environmental impact,and long maintenance cycles.However,very fast transient over...Gas insulator switchgears(GISs),widely used in electric power systems for decades,have many advantages due to their compactness,minimal environmental impact,and long maintenance cycles.However,very fast transient overvoltage(VFTO)increases caused by a rise in voltage levels can lead to GIS insulation failures.In this paper,a generating system of VFTO and standard lightning impulse(LI)is established.The insulation characteristics of SF6 gas with and without insulators under VFTO and standard LI are investigated.Experimental results show that the 50%breakdown voltages of the inhomogeneous electric field rod-plane gap under positive VFTO and standard LI are higher than that under negative VFTO and standard LI.The research shows that the 50%breakdown voltage under VFTO could be lower than that under standard LI at 0.5 MPa for the negative polarity.Moreover,the polarity effect of the insulator without defect is different from that with defect.Similarly,the breakdown voltage of the defective insulator under VFTO could be lower than that under standard LI by 8%.The flashover channel under VFTO is seen as more than that under standard LI.Based on the analysis of discharge images and experimental results,it is concluded that the polarity effect is related to the distortion effect of ion clusters formed by SF6 on the electric field.Additionally,the steepness and front time of impulse plays an important role in the initiation and further development of discharge on insulator surface.Finally,the research shows that different discharge characteristics between VFTO and standard LI may be caused by different wave fronts and oscillation on the tails of the impulses.展开更多
文摘盆式绝缘子沿面放电是气体绝缘组合电器(GIS)的主要绝缘故障形式。为监测盆式绝缘子的绝缘状况,研究GIS内环氧树脂固体绝缘介质发生沿面放电情况下SF6特征分解产物的变化规律,在小型模拟平台上试验发现,CS2是盆式绝缘子沿面放电时SF6气体生成的产物,并在110 k V GIS母线段实体绝缘子沿面放电试验中得到验证。用B3P86量子化学理论计算方法,得出了SF6在盆式绝缘子沿面放电条件下CS2的产生途径和能量条件。试验与理论计算结果表明,盆式绝缘子等固体绝缘介质发生沿面放电时GIS的内部发生复杂的化学反应,会有多种途径生成CS2,且由盆式绝缘子等环氧树脂介质表面炭化后提供碳源。CS2是一种可用于GIS中盆式绝缘子沿面放电故障诊断的特征气体。将CS2作为特征气体应用于生产实际检测,成功发现多起运行中的GIS涉及盆式绝缘子沿面放电导致绝缘损坏的潜伏性缺陷。
文摘局部放电监测是实现气体绝缘组合电器(gas insulated switchgear,GIS)缺陷预警的重要依据和手段。DL/T639—1997《六氟化硫电气设备运行、试验及检修人员安全防护细则》等化学诊断法规程将S_2OF_(10)作为一种GIS局部放电特征气体列入常规检测范围。为探究S_2OF_(10)作为局部放电特征气体的有效性,在110k V GIS试验平台上设置典型放电模型,研究不同放电类型和放电程度下S_2OF_(10)随时间的变化规律,并通过B3P86/6-31G(d,p)量子化学计算揭示了S_2OF_(10)的生成机理。试验和理论计算均表明,S_2OF_(10)由自由基SF5、SF5O结合生成,放电状态下只有极少量的SF5、SF5O生成,且二者共存机会很小,GIS内不同放电类型和能量条件下,S_2OF_(10)均不会大量生成。结合对运行GIS放电气室气体组分分析结果,S_2OF_(10)不能作为一种有效的局部放电特征气体用于GIS潜伏性缺陷诊断。
基金supported by National Basic Research Program of China(973 Program)and Science and Technology Project of SGCC“Research on the Application of VFTO Key Techniques in Ultra High GIS Substation”(GYB17201400111).
文摘Gas insulator switchgears(GISs),widely used in electric power systems for decades,have many advantages due to their compactness,minimal environmental impact,and long maintenance cycles.However,very fast transient overvoltage(VFTO)increases caused by a rise in voltage levels can lead to GIS insulation failures.In this paper,a generating system of VFTO and standard lightning impulse(LI)is established.The insulation characteristics of SF6 gas with and without insulators under VFTO and standard LI are investigated.Experimental results show that the 50%breakdown voltages of the inhomogeneous electric field rod-plane gap under positive VFTO and standard LI are higher than that under negative VFTO and standard LI.The research shows that the 50%breakdown voltage under VFTO could be lower than that under standard LI at 0.5 MPa for the negative polarity.Moreover,the polarity effect of the insulator without defect is different from that with defect.Similarly,the breakdown voltage of the defective insulator under VFTO could be lower than that under standard LI by 8%.The flashover channel under VFTO is seen as more than that under standard LI.Based on the analysis of discharge images and experimental results,it is concluded that the polarity effect is related to the distortion effect of ion clusters formed by SF6 on the electric field.Additionally,the steepness and front time of impulse plays an important role in the initiation and further development of discharge on insulator surface.Finally,the research shows that different discharge characteristics between VFTO and standard LI may be caused by different wave fronts and oscillation on the tails of the impulses.
