为研究热老化时间及测试温度对油纸绝缘时域介电特性的影响,以及更好地应用时域介电响应技术评估变压器油纸绝缘老化状态,首先进行了不同热老化时间及不同测试温度下油纸绝缘绕组模型的极化/去极化电流(polarization and depolarization...为研究热老化时间及测试温度对油纸绝缘时域介电特性的影响,以及更好地应用时域介电响应技术评估变压器油纸绝缘老化状态,首先进行了不同热老化时间及不同测试温度下油纸绝缘绕组模型的极化/去极化电流(polarization and depolarization current,PDC)测试,然后通过扩展Debye模型实现时域介电测试技术间转换,深入研究了热老化时间及测试温度对时域介电特性及其特征参量的影响,最后提出运用时间及幅值平移因子构造电流标准主曲线以消除测试温度对时域介电特性影响的方法。结果表明:油纸绝缘时域介电特性及特征参量受热老化时间及测试温度影响较大;在应用时域介电响应技术评估变压器油纸绝缘状态时,必须考虑测试温度的影响,否则将导致评估结果失实;通过本文方法绘制的电流标准主曲线不仅能消除测试温度对时域介电特性的影响,还能实现在不额外延长实际测试时间的前提下,获得更多反映油纸绝缘状态的时域介电响应信息,并通过实验验证该方法的有效性。展开更多
The solubility of poly(phenyl glycidyl ether)s (PPGEs) depends on the stereoregularity.Different solvents and temperatures (CDCl 3/300 K or TCE d 2/350 K)were used in 13 C\|NMR characterization of these polymers.It wa...The solubility of poly(phenyl glycidyl ether)s (PPGEs) depends on the stereoregularity.Different solvents and temperatures (CDCl 3/300 K or TCE d 2/350 K)were used in 13 C\|NMR characterization of these polymers.It was necessary to investigate first the effect of temperature on the 13 C\|NMR spectra of PPGEs.It was found that all the 13 C NMR signals of PPGE were shifted to the lower magnetic field with the increase of the temperature.The temperature sensitivity of the 13 C NMR chemical shifts for different carbon atoms was different.The pendent CH 2 group was most sensitive to the temperature.The change of the 13 C\|NMR chemical shift for the pendent CH 2 group was mainly caused by the temperature change,and the effects of the solvent kind and the stereoregularity of the polymer were of minor importance.The change of temperature did not make any significant influence on the result of the stereoregularity calculation according to the 13 C\|NMR spectra for PPGEs.Utilizing the different temperature sensitivity of 13 C\|NMR signals for different groups,it is possible to separate the overlapped signals by choosing an appropriate temperature.This method was found especially useful in the 13 C\|NMR characterization of complex polymer samples.展开更多
文摘为研究热老化时间及测试温度对油纸绝缘时域介电特性的影响,以及更好地应用时域介电响应技术评估变压器油纸绝缘老化状态,首先进行了不同热老化时间及不同测试温度下油纸绝缘绕组模型的极化/去极化电流(polarization and depolarization current,PDC)测试,然后通过扩展Debye模型实现时域介电测试技术间转换,深入研究了热老化时间及测试温度对时域介电特性及其特征参量的影响,最后提出运用时间及幅值平移因子构造电流标准主曲线以消除测试温度对时域介电特性影响的方法。结果表明:油纸绝缘时域介电特性及特征参量受热老化时间及测试温度影响较大;在应用时域介电响应技术评估变压器油纸绝缘状态时,必须考虑测试温度的影响,否则将导致评估结果失实;通过本文方法绘制的电流标准主曲线不仅能消除测试温度对时域介电特性的影响,还能实现在不额外延长实际测试时间的前提下,获得更多反映油纸绝缘状态的时域介电响应信息,并通过实验验证该方法的有效性。
文摘The solubility of poly(phenyl glycidyl ether)s (PPGEs) depends on the stereoregularity.Different solvents and temperatures (CDCl 3/300 K or TCE d 2/350 K)were used in 13 C\|NMR characterization of these polymers.It was necessary to investigate first the effect of temperature on the 13 C\|NMR spectra of PPGEs.It was found that all the 13 C NMR signals of PPGE were shifted to the lower magnetic field with the increase of the temperature.The temperature sensitivity of the 13 C NMR chemical shifts for different carbon atoms was different.The pendent CH 2 group was most sensitive to the temperature.The change of the 13 C\|NMR chemical shift for the pendent CH 2 group was mainly caused by the temperature change,and the effects of the solvent kind and the stereoregularity of the polymer were of minor importance.The change of temperature did not make any significant influence on the result of the stereoregularity calculation according to the 13 C\|NMR spectra for PPGEs.Utilizing the different temperature sensitivity of 13 C\|NMR signals for different groups,it is possible to separate the overlapped signals by choosing an appropriate temperature.This method was found especially useful in the 13 C\|NMR characterization of complex polymer samples.