气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)机械缺陷是导致设备故障的重要因素,针对单测点、单证据机械缺陷诊断模型信息缺失和精度不足问题,该文提出一种多层融合振动数据分析的GIS设备机械缺陷诊断方法...气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)机械缺陷是导致设备故障的重要因素,针对单测点、单证据机械缺陷诊断模型信息缺失和精度不足问题,该文提出一种多层融合振动数据分析的GIS设备机械缺陷诊断方法。首先,基于真型GIS设备振动模拟平台试验研究测点位置与缺陷类型对振动行为的影响特性;然后,联合统计分析、模态分解、尺度变换方法提出机械振动信号整体与局部信息关注的复合参数分析方法,引入主成分分析开展多测点振动信息的特征层融合降维;最后,提出改进放缩权重的Dempster-Shafer(DS)证据理论和Bagging投票机制的强/弱基学习器决策层融合机制,联合构建多层融合振动数据分析的GIS设备机械缺陷诊断模型。结果表明:不同类型机械缺陷信号的响应幅值、特征频点和畸变程度存在显著差异,复合特征参量大小及分散程度各不相同;同时,测点位置对缺陷信号的复合振动特征参量的表现形式及分布区间也具有一定影响;基于多层融合数据分析的诊断模型实现缺陷有效识别,辨识准确率为98.66%,相比单一分类器诊断效果提升5.83%。该文可为GIS设备机械缺陷诊断方法提供有价值的参考。展开更多
当前国内外对气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)的异常振动,尤其是引发振动的激励源、多频振动产生机理等问题缺少实质性研究进展。首先,建立受力模型,研究引发GIS振动的激励源,得到引发分箱型GI...当前国内外对气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)的异常振动,尤其是引发振动的激励源、多频振动产生机理等问题缺少实质性研究进展。首先,建立受力模型,研究引发GIS振动的激励源,得到引发分箱型GIS振动的力源值,并指出正常运行状态,三相母线间电动力是主频振动的主要激励源。触头接触不良将导致触头斥力合力增大,地脚螺栓松动将导致系统固有频率的变化,影响非线性振动响应频谱特征;然后,将GIS按照薄壁圆柱壳进行研究,计算GIS壳体多阶固有频率,建立有效的非线性振动方程,首次利用解析方法揭示非线性GIS系统多频振动信号的产生机理;最后,研制成功振动信号采集系统,在550 k VGIS产品上设置典型机械缺陷,经实验验证,系统激发出的振动响应幅值极值点及频率与理论分析结果一致。论文的研究成果可为GIS机械缺陷的检测及诊断提供一定的支持和参考。展开更多
The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional densi...The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional density,optimized for projects with limited space as in offshore HVDC converter platforms,onshore HVDC converter stations and transition stations between different transmission media.Up to now,no standards for testing of gas-insulated DC systems are available,although pre-standardization work is in progress within CIGRE.Some tests can be performed as required in AC GIS standards.Special aspects of DC voltage stress,like the electric field distribution of insulators influenced by the accumulation of electrical charge carriers and the operation-related inhomogeneous temperature distribution,must be considered by additional electric and thermoelectric tests.For DC GIS,the experience of long-term performance is limited today.Although ageing is expected to be of lower importance,tests are recommended.This contribution summarizes the physical and technical background to design and develop compact DC switchgear assemblies using gas-insulated technology.It explains the developed modules of the substation and gives an overview of the performed tests.Furthermore,it provides an insight in the on-going standardization activities and describes applications in converter and transition stations,showing its space-saving characteristics.展开更多
This paper describes a realizable fabrication method to manufacture chemical gas sensors by using singlewalled carbon nanotubes(SWCNTs).The sensors were tested for the monitoring of SF_6 decomposition gas produced by ...This paper describes a realizable fabrication method to manufacture chemical gas sensors by using singlewalled carbon nanotubes(SWCNTs).The sensors were tested for the monitoring of SF_6 decomposition gas produced by partial discharge(PD) in GIS tank.The results showed a superior sensitivity,favorable reliability and good reproducibility. For further clarifying the relativity between sensor response and partial discharge activity,the discharge in GIS tank was monitored simultaneously through conventional pulse current method and a SWCNTs gas sensor,and the measurement results were put together for comparative analysis in this paper.The sensor response showed a great dependence on partial discharge characteristics.The sensor response increased nearly linearly with limits when the energy of discharge was persistently accumulated.Partial discharge power had a great influence on the response rate and the time delay.With the increase of partial discharge power,the response rate augmented almost in proportion while the time delay gradually becomes shorter with limits.The results were quite favorable to assess the partial discharge intensity and duration to some extent.Compared with pulse current method,the sensor was predominant to detect partial discharge exposed to constantly high levels of noise.It was capable of detecting partial discharge which was too weak to be detected with pulse current method.However,the sensor response didn't show much dependency on the apparent discharge of partial discharge.展开更多
为确保光学麦克风在电气设备内部应用的安全可靠性,文中选定聚氨酯、聚四氟乙烯、环氧树脂、聚醚醚酮和酚醛树脂作为封装材料,进行光学麦克风与电气设备相关的环境相容性试验,并采用扫描电子显微镜(scanning electron microscope,SEM)...为确保光学麦克风在电气设备内部应用的安全可靠性,文中选定聚氨酯、聚四氟乙烯、环氧树脂、聚醚醚酮和酚醛树脂作为封装材料,进行光学麦克风与电气设备相关的环境相容性试验,并采用扫描电子显微镜(scanning electron microscope,SEM)和傅里叶变换红外(Fourier transform infrared,FTIR)光谱仪对试验前后的材料性能进行检测。结果表明:聚氨酯表面易浸润变压器油且有明显颜色变化,不适用于油浸式变压器,但可用于水听器、空气和常温环境中;聚四氟乙烯与变压器油的相容性较好,可用于油浸式变压器、气体绝缘开关设备(gas insulated switchgear,GIS)和温度变化较大的场景;其余材料与电气设备的相容性不佳,适用性有待进一步研究。文中提出的封装材料与环境相容性试验的检测方法可为光学麦克风封装材料选型提供有益借鉴,具有一定的工程实用价值。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
In order to guarantee safe operations, low energy discharge within gas insulated switchgear （GIS） should be detected as soon as possible before they develop severely and cause final breakdown failures. This paper ai...In order to guarantee safe operations, low energy discharge within gas insulated switchgear （GIS） should be detected as soon as possible before they develop severely and cause final breakdown failures. This paper aims to present a GIS discharge diagnosis technique adopting gaseous decompositions. To reach this aim, needle-plate electrode and the sphere-plate electrode with metallic particles on the plate are designed to simulate two kinds of low energy discharge, namely, corona discharge and spark discharge, respectively. After sampling and analyzing the gases, different yields of gaseous by-products under different types of low energy discharge are obtained. Based on the decomposition mechanisms reported by previous researches and the experiment results, it can be concluded that S2OF10, SO2F2 , and SO2 can be used as the characteristic gas to identify low energy discharge; the increment of S2OF10 can indicate the occurrence of low energy discharges while the volume ratio between SO2F2 and SO2 can define the type of low energy discharge.展开更多
文摘气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)机械缺陷是导致设备故障的重要因素,针对单测点、单证据机械缺陷诊断模型信息缺失和精度不足问题,该文提出一种多层融合振动数据分析的GIS设备机械缺陷诊断方法。首先,基于真型GIS设备振动模拟平台试验研究测点位置与缺陷类型对振动行为的影响特性;然后,联合统计分析、模态分解、尺度变换方法提出机械振动信号整体与局部信息关注的复合参数分析方法,引入主成分分析开展多测点振动信息的特征层融合降维;最后,提出改进放缩权重的Dempster-Shafer(DS)证据理论和Bagging投票机制的强/弱基学习器决策层融合机制,联合构建多层融合振动数据分析的GIS设备机械缺陷诊断模型。结果表明:不同类型机械缺陷信号的响应幅值、特征频点和畸变程度存在显著差异,复合特征参量大小及分散程度各不相同;同时,测点位置对缺陷信号的复合振动特征参量的表现形式及分布区间也具有一定影响;基于多层融合数据分析的诊断模型实现缺陷有效识别,辨识准确率为98.66%,相比单一分类器诊断效果提升5.83%。该文可为GIS设备机械缺陷诊断方法提供有价值的参考。
文摘当前国内外对气体绝缘金属封闭开关设备(gas insulated metal enclosed switchgear,GIS)的异常振动,尤其是引发振动的激励源、多频振动产生机理等问题缺少实质性研究进展。首先,建立受力模型,研究引发GIS振动的激励源,得到引发分箱型GIS振动的力源值,并指出正常运行状态,三相母线间电动力是主频振动的主要激励源。触头接触不良将导致触头斥力合力增大,地脚螺栓松动将导致系统固有频率的变化,影响非线性振动响应频谱特征;然后,将GIS按照薄壁圆柱壳进行研究,计算GIS壳体多阶固有频率,建立有效的非线性振动方程,首次利用解析方法揭示非线性GIS系统多频振动信号的产生机理;最后,研制成功振动信号采集系统,在550 k VGIS产品上设置典型机械缺陷,经实验验证,系统激发出的振动响应幅值极值点及频率与理论分析结果一致。论文的研究成果可为GIS机械缺陷的检测及诊断提供一定的支持和参考。
基金supported by the Federal Ministry for Economic Affairs and Energy, Germany (FKZ:03ET7511C)the Bavarian Ministry of Economic Affairs, Regional Development and Energy (FKZ:IET-1208-0018)
文摘The development of high-voltage direct current gas-insulated switchgear assemblies(DC GIS)of rated voltages up to±550 kV has been completed.DC GIS provide a compact technical solution with a high functional density,optimized for projects with limited space as in offshore HVDC converter platforms,onshore HVDC converter stations and transition stations between different transmission media.Up to now,no standards for testing of gas-insulated DC systems are available,although pre-standardization work is in progress within CIGRE.Some tests can be performed as required in AC GIS standards.Special aspects of DC voltage stress,like the electric field distribution of insulators influenced by the accumulation of electrical charge carriers and the operation-related inhomogeneous temperature distribution,must be considered by additional electric and thermoelectric tests.For DC GIS,the experience of long-term performance is limited today.Although ageing is expected to be of lower importance,tests are recommended.This contribution summarizes the physical and technical background to design and develop compact DC switchgear assemblies using gas-insulated technology.It explains the developed modules of the substation and gives an overview of the performed tests.Furthermore,it provides an insight in the on-going standardization activities and describes applications in converter and transition stations,showing its space-saving characteristics.
基金Supported by National Natural Science Foundation of China(50707023)
文摘This paper describes a realizable fabrication method to manufacture chemical gas sensors by using singlewalled carbon nanotubes(SWCNTs).The sensors were tested for the monitoring of SF_6 decomposition gas produced by partial discharge(PD) in GIS tank.The results showed a superior sensitivity,favorable reliability and good reproducibility. For further clarifying the relativity between sensor response and partial discharge activity,the discharge in GIS tank was monitored simultaneously through conventional pulse current method and a SWCNTs gas sensor,and the measurement results were put together for comparative analysis in this paper.The sensor response showed a great dependence on partial discharge characteristics.The sensor response increased nearly linearly with limits when the energy of discharge was persistently accumulated.Partial discharge power had a great influence on the response rate and the time delay.With the increase of partial discharge power,the response rate augmented almost in proportion while the time delay gradually becomes shorter with limits.The results were quite favorable to assess the partial discharge intensity and duration to some extent.Compared with pulse current method,the sensor was predominant to detect partial discharge exposed to constantly high levels of noise.It was capable of detecting partial discharge which was too weak to be detected with pulse current method.However,the sensor response didn't show much dependency on the apparent discharge of partial discharge.
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.
基金Supported by the Scotland-China Higher Education Research Partnership for Ph. D. Studies ([2010]6044)
文摘In order to guarantee safe operations, low energy discharge within gas insulated switchgear （GIS） should be detected as soon as possible before they develop severely and cause final breakdown failures. This paper aims to present a GIS discharge diagnosis technique adopting gaseous decompositions. To reach this aim, needle-plate electrode and the sphere-plate electrode with metallic particles on the plate are designed to simulate two kinds of low energy discharge, namely, corona discharge and spark discharge, respectively. After sampling and analyzing the gases, different yields of gaseous by-products under different types of low energy discharge are obtained. Based on the decomposition mechanisms reported by previous researches and the experiment results, it can be concluded that S2OF10, SO2F2 , and SO2 can be used as the characteristic gas to identify low energy discharge; the increment of S2OF10 can indicate the occurrence of low energy discharges while the volume ratio between SO2F2 and SO2 can define the type of low energy discharge.
