Sulphur hexafluoride(SF_(6))is widely used in gas insulation,and its decomposition products can be used to diagnose potential insulation failures.Quick and accurate detection of decomposition products can help to unde...Sulphur hexafluoride(SF_(6))is widely used in gas insulation,and its decomposition products can be used to diagnose potential insulation failures.Quick and accurate detection of decomposition products can help to understand equipment-operating conditions in time.In this study,the decomposition products of SF_(6)/air gas mixtures under different pulsed discharge voltages were studied.It was found that the main products were SOF_(2),SO_(2)F_(2),SO_(2),CF_(4)and SOF_(4),and the yields of SOF_(2),SO_(2)F_(2),SO_(2)and SOF_(4)increased with the number of discharge pulse.The productive rate of SOF_(2),SO_(2)and SOF_(4)were positively correlated with the discharge voltage,and when the discharge voltage increased from 5 to 15 kV,their yields after 50,000 discharges increased by 49%,120%and 1100%,respectively.The productive rate of SOF_(2)and SO_(2)were positively correlated with the proportion of air in the gas mixtures while that of SOF_(4)was opposite.When the proportion of air increases from 0%to 90%,their yields after 50,000 discharges became 270%,3169%and 10%of the originals,respectively.In addition,the productive rate of SO_(2)F_(2)was not affected by discharge voltage and the proportion of air in the gas mixtures.SO_(2)F_(2),SOF_(2),SOF_(4)and SO_(2)can be used as the basis for judging the discharge failures and the discharge degree of power equipment.展开更多
目的采用双定性双定量相似度作为评价指标,建立复方丹参片(CSMT)HPLC指纹图谱的全质量控制方法。方法采用RP-HPLC法以Century SIL C18BDS柱(250 mm×4.6 mm,5μm);以色谱指纹图谱指数F为目标函数优化选择指纹图谱检测条件,确定流动...目的采用双定性双定量相似度作为评价指标,建立复方丹参片(CSMT)HPLC指纹图谱的全质量控制方法。方法采用RP-HPLC法以Century SIL C18BDS柱(250 mm×4.6 mm,5μm);以色谱指纹图谱指数F为目标函数优化选择指纹图谱检测条件,确定流动相组成是质量分数为1%的醋酸水溶液-质量分数为1%的醋酸甲醇溶液低压梯度洗脱,紫外检测波长290 nm,柱温(30.00±0.15)℃,进样量5μL。以双定性相似度均值和双定量相似度均值为参量通过对20批复方丹参片进行系统聚类分析确定用其中10批生成复方丹参片对照指纹图谱(RFP),以此RFP为标准对总计20批复方丹参片采用双定性双定量相似度法进行质量评价。结果以丹酚酸B(SAB)为参照物峰,确定40个指纹峰,建立了复方丹参片HPLC指纹图谱。用双定性相似度评价15批样品的化学成分数量和分布比例都合格,但其中仅8批双定量相似度合格,为质量完全合格品。其它7批含量明显偏低,生产时应根据双定量相似度偏低程度提高投料量或者适当增大服用剂量。其余5批都存在化学成分和分布比例不合格特征,有2批含量相似度合格和3批含量相似度明显偏低。结论在OTC中随机选择的20批复方丹参片,无明显的劣质品出现,若按指纹图谱技术控制则出现明显的质量差异,因此所建立的具有较好精密度和重现性的复方丹参片的HPLC指纹图谱,完全适用于复方丹参片的生产质量控制。试验证明了双定性双定量相似度法是宏观定性定量评价中药复方制剂质量的最理想和最客观的指纹图谱评价技术。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
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
基金National Natural Science Foundation of China,Grant/Award Number:51877170Fundamental Research Funds for the Central Universities。
文摘Sulphur hexafluoride(SF_(6))is widely used in gas insulation,and its decomposition products can be used to diagnose potential insulation failures.Quick and accurate detection of decomposition products can help to understand equipment-operating conditions in time.In this study,the decomposition products of SF_(6)/air gas mixtures under different pulsed discharge voltages were studied.It was found that the main products were SOF_(2),SO_(2)F_(2),SO_(2),CF_(4)and SOF_(4),and the yields of SOF_(2),SO_(2)F_(2),SO_(2)and SOF_(4)increased with the number of discharge pulse.The productive rate of SOF_(2),SO_(2)and SOF_(4)were positively correlated with the discharge voltage,and when the discharge voltage increased from 5 to 15 kV,their yields after 50,000 discharges increased by 49%,120%and 1100%,respectively.The productive rate of SOF_(2)and SO_(2)were positively correlated with the proportion of air in the gas mixtures while that of SOF_(4)was opposite.When the proportion of air increases from 0%to 90%,their yields after 50,000 discharges became 270%,3169%and 10%of the originals,respectively.In addition,the productive rate of SO_(2)F_(2)was not affected by discharge voltage and the proportion of air in the gas mixtures.SO_(2)F_(2),SOF_(2),SOF_(4)and SO_(2)can be used as the basis for judging the discharge failures and the discharge degree of power equipment.
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 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.
