换流变压器阀侧套管绝缘故障检测技术研究
发布时间：2018-09-11 06:31
【摘要】：换流变压器阀侧套管是重要的电力设备,其绝缘性能的好坏关系着套管乃至换流变压器的安全性、可靠性。干式SF_6气体绝缘直流套管因其优良的电气性能,越来越多的被应用于换流变压器,然而当前针对其绝缘检测技术方面的研究较少,鉴于此,本文针对干式SF_6气体绝缘直流套管的绝缘特征量进行了研究工作,设置了电容屏豁口缺陷、金属微粒缺陷、受潮缺陷3种缺陷套管模型,并制备了正常电容芯子进行比对。本文的研究内容与成果如下:测量了不同套管模型在工频高压和不同频率低电压下介质损耗因数和电容量。在工频高压下,受潮缺陷的介质损耗因数最大,而金属微粒缺陷芯子电容量最大。从频域介电谱测试结果来看,不同缺陷套管电容芯子电容量和介质损耗因数都随频率的减小而增大,但不同缺陷套管电容芯子两项参数增加的幅度不同。四支电容芯子电容量的差别随施加电源频率的减小而减小,介质损耗因数差别则随施加电源频率的减小而增大。进行了直流局部放电试验,测试了套管电容芯子直流局放特征量。不同缺陷电容芯子放电量和放电次数存在较大差异,金属微粒缺陷电容芯子随着放电量的增大,放电次数先增多后减少,并在35 pC附近达到最大值;电容屏豁口缺陷电容芯子放电集中在30 pC以下,且分布较为均匀。受潮缺陷电容芯子放电集中在25 pC以下,且放电次数较多。通过计算偏斜度、陡峭度和局部峰值个数,确定了不同缺陷套管此3个特征参数的范围。测试了套管电容芯子在直流局部放电情况下SF_6气体的分解产物。在SF_6气体分解产物检测试验中,三种缺陷情况下SOF_2、SO_2F_2、SO_2的含量在检测初期增长较快,金属微粒缺陷和受潮缺陷情况下SO_2产气率比CF_4高,而电容屏豁口缺陷正好相反。选择SOF_2/SO_2F_2、CF_4/SO_2、(SOF_2+SO_2F_2)/(CF_4+SO_2)三种组分含量的比值作为表征不同缺陷的特征值,经过计算得到三种缺陷特征组分比值。不同缺陷的特征组分比值范围不同,可用该比值表征不同的缺陷类型。本文通过对干式SF_6气体绝缘直流套管绝缘特征量进行探索性研究,得到的结果及结论对套管绝缘检测提供了重要支持,具有实际应用价值。
[Abstract]:Valve side bushing of converter transformer is an important power equipment, its insulation performance is related to the safety and reliability of casing and converter transformer. Dry SF_6 gas insulated DC bushing is more and more widely used in converter transformers because of its excellent electrical performance. However, there are few researches on the insulation detection technology at present, in view of this, In this paper, the insulation characteristics of dry-type SF_6 gas insulated DC sleeving are studied. Three kinds of defect casing models are set up, such as capacitor gap defect, metal particle defect and dampened defect, and the normal capacitance core is prepared for comparison. The main contents and results of this paper are as follows: dielectric loss factor and capacitance of different casing models are measured at different frequency and low voltage. At power frequency and high voltage, the dielectric loss factor of damped defect is the largest, while the capacitance of metal particle defect core is the largest. From the dielectric spectrum measurement results in frequency domain, the capacitance and dielectric loss factor of different defective casing capacitive cores increase with the decrease of frequency, but the amplitude of the two parameters of different defect casing capacitive cores is different. The difference of the capacitance of the four capacitor cores decreases with the decrease of the frequency of the applied power supply, and the difference of the dielectric loss factor increases with the decrease of the frequency of the applied power supply. DC partial discharge test was carried out, and the DC discharge characteristic of bushing capacitor core was tested. The discharge quantity and discharge times of different defect capacitive mandrel have great difference. With the increase of discharge quantity, the discharge times of metal particle defect capacitor core increase first and then decrease, and reach the maximum value near 35 pC. The discharge of capacitor core is below 30 pC, and the distribution is more uniform. The discharge of capacitive core with dampened defect is below 25 pC, and the discharge frequency is more. By calculating the deflection degree, steepness degree and the number of local peak values, the range of these three characteristic parameters of different defective casing is determined. The decomposition products of SF_6 gas under DC partial discharge were measured. In the test of SF_6 gas decomposition products, the content of SOF_2,SO_2F_2,SO_2 increases rapidly in the early stage of detection under three kinds of defects, and the gas production rate of SO_2 is higher than that of CF_4 under the condition of metal particle defect and damped defect, but the defect of capacitor screen gap is just the opposite. The ratio of SOF_2/SO_2F_2,CF_4/SO_2, (SOF_2 SO_2F_2) / (CF_4 SO_2) components was chosen as the eigenvalue of different defects, and the ratios of three defect characteristic components were calculated. The range of characteristic component ratios of different defects is different, which can be used to characterize different defect types. In this paper, the insulation characteristics of dry SF_6 gas insulated DC sleeving are studied. The results and conclusions provide important support for the insulation detection of the sleeving, and have practical application value.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41
[Abstract]:Valve side bushing of converter transformer is an important power equipment, its insulation performance is related to the safety and reliability of casing and converter transformer. Dry SF_6 gas insulated DC bushing is more and more widely used in converter transformers because of its excellent electrical performance. However, there are few researches on the insulation detection technology at present, in view of this, In this paper, the insulation characteristics of dry-type SF_6 gas insulated DC sleeving are studied. Three kinds of defect casing models are set up, such as capacitor gap defect, metal particle defect and dampened defect, and the normal capacitance core is prepared for comparison. The main contents and results of this paper are as follows: dielectric loss factor and capacitance of different casing models are measured at different frequency and low voltage. At power frequency and high voltage, the dielectric loss factor of damped defect is the largest, while the capacitance of metal particle defect core is the largest. From the dielectric spectrum measurement results in frequency domain, the capacitance and dielectric loss factor of different defective casing capacitive cores increase with the decrease of frequency, but the amplitude of the two parameters of different defect casing capacitive cores is different. The difference of the capacitance of the four capacitor cores decreases with the decrease of the frequency of the applied power supply, and the difference of the dielectric loss factor increases with the decrease of the frequency of the applied power supply. DC partial discharge test was carried out, and the DC discharge characteristic of bushing capacitor core was tested. The discharge quantity and discharge times of different defect capacitive mandrel have great difference. With the increase of discharge quantity, the discharge times of metal particle defect capacitor core increase first and then decrease, and reach the maximum value near 35 pC. The discharge of capacitor core is below 30 pC, and the distribution is more uniform. The discharge of capacitive core with dampened defect is below 25 pC, and the discharge frequency is more. By calculating the deflection degree, steepness degree and the number of local peak values, the range of these three characteristic parameters of different defective casing is determined. The decomposition products of SF_6 gas under DC partial discharge were measured. In the test of SF_6 gas decomposition products, the content of SOF_2,SO_2F_2,SO_2 increases rapidly in the early stage of detection under three kinds of defects, and the gas production rate of SO_2 is higher than that of CF_4 under the condition of metal particle defect and damped defect, but the defect of capacitor screen gap is just the opposite. The ratio of SOF_2/SO_2F_2,CF_4/SO_2, (SOF_2 SO_2F_2) / (CF_4 SO_2) components was chosen as the eigenvalue of different defects, and the ratios of three defect characteristic components were calculated. The range of characteristic component ratios of different defects is different, which can be used to characterize different defect types. In this paper, the insulation characteristics of dry SF_6 gas insulated DC sleeving are studied. The results and conclusions provide important support for the insulation detection of the sleeving, and have practical application value.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM41
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