換流變壓器閥側(cè)套管絕緣故障檢測技術(shù)研究
發(fā)布時(shí)間：2018-09-11 06:31
【摘要】：換流變壓器閥側(cè)套管是重要的電力設(shè)備,其絕緣性能的好壞關(guān)系著套管乃至換流變壓器的安全性、可靠性。干式SF_6氣體絕緣直流套管因其優(yōu)良的電氣性能,越來越多的被應(yīng)用于換流變壓器,然而當(dāng)前針對其絕緣檢測技術(shù)方面的研究較少,鑒于此,本文針對干式SF_6氣體絕緣直流套管的絕緣特征量進(jìn)行了研究工作,設(shè)置了電容屏豁口缺陷、金屬微粒缺陷、受潮缺陷3種缺陷套管模型,并制備了正常電容芯子進(jìn)行比對。本文的研究內(nèi)容與成果如下:測量了不同套管模型在工頻高壓和不同頻率低電壓下介質(zhì)損耗因數(shù)和電容量。在工頻高壓下,受潮缺陷的介質(zhì)損耗因數(shù)最大,而金屬微粒缺陷芯子電容量最大。從頻域介電譜測試結(jié)果來看,不同缺陷套管電容芯子電容量和介質(zhì)損耗因數(shù)都隨頻率的減小而增大,但不同缺陷套管電容芯子兩項(xiàng)參數(shù)增加的幅度不同。四支電容芯子電容量的差別隨施加電源頻率的減小而減小,介質(zhì)損耗因數(shù)差別則隨施加電源頻率的減小而增大。進(jìn)行了直流局部放電試驗(yàn),測試了套管電容芯子直流局放特征量。不同缺陷電容芯子放電量和放電次數(shù)存在較大差異,金屬微粒缺陷電容芯子隨著放電量的增大,放電次數(shù)先增多后減少,并在35 pC附近達(dá)到最大值;電容屏豁口缺陷電容芯子放電集中在30 pC以下,且分布較為均勻。受潮缺陷電容芯子放電集中在25 pC以下,且放電次數(shù)較多。通過計(jì)算偏斜度、陡峭度和局部峰值個數(shù),確定了不同缺陷套管此3個特征參數(shù)的范圍。測試了套管電容芯子在直流局部放電情況下SF_6氣體的分解產(chǎn)物。在SF_6氣體分解產(chǎn)物檢測試驗(yàn)中,三種缺陷情況下SOF_2、SO_2F_2、SO_2的含量在檢測初期增長較快,金屬微粒缺陷和受潮缺陷情況下SO_2產(chǎn)氣率比CF_4高,而電容屏豁口缺陷正好相反。選擇SOF_2/SO_2F_2、CF_4/SO_2、(SOF_2+SO_2F_2)/(CF_4+SO_2)三種組分含量的比值作為表征不同缺陷的特征值,經(jīng)過計(jì)算得到三種缺陷特征組分比值。不同缺陷的特征組分比值范圍不同,可用該比值表征不同的缺陷類型。本文通過對干式SF_6氣體絕緣直流套管絕緣特征量進(jìn)行探索性研究,得到的結(jié)果及結(jié)論對套管絕緣檢測提供了重要支持,具有實(shí)際應(yīng)用價(jià)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.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：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.
【學(xué)位授予單位】：華北電力大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM41
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