Polarization and dielectric behavior of ac-aged polyethylene
Polarization and dielectric behavior of ac-aged polyethylene
复制标题
交流老化聚乙烯的极化和介电性能
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
P. Scarpa
中科院分区：
文献类型：
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作者：
D. Das;P. Scarpa
用高场极化和介电松弛行为研究了交变电场作用下交联型聚乙烯(XLPE)和低密度聚乙烯(LDPE)在室温潮湿环境中的老化机理。在本研究中，介电频谱数据在10/sup-5/至10/sup 6/hz的频率范围内及其比较分析被用来提供老化的电学模拟模型。从脱附电流计算出10/sup-5/至5/spl×/10/sup-2/hz频率范围内的介电数据，而电桥测量提供了10 hz至10/sup 6/hz频率范围内的数据。此外，还进行了热瞬变电流和热刺激放电电流的测量，以确定交流老化聚乙烯中的极化和空间电荷积累。在本工作中观察到了极化行为和介电弛豫行为之间的相关性。XLPE电缆样品和LDPE扁平样品的介电行为表现为簇间(低频)电荷交换和簇内(高频)电荷运动，前者随着老化的进行而变得更加主导。在室温潮湿环境中交流老化的XLPE电缆样品，除了观察到准直流过程外，还观察到了符合分数幂定律的弛豫峰。
High field polarization and dielectric relaxation behavior have been used to study the aging mechanisms of crosslinked polyethylene (XLPE) and low density polyethylene (LDPE) aged at constant alternating electrical field stress in a humid environment at room temperature. For this study, the dielectric spectroscopy data in the frequency range of 10/sup -5/ to 10/sup 6/ Hz and their comparative analysis, have been used to provide electrical analog models of the aging. The dielectric data in the frequency range of 10/sup -5/ to 5/spl times/10/sup -2/ Hz were calculated from the desorption current, whereas bridge measurements provide the data in the frequency range of 10 Hz to 10/sup 6/ Hz. In addition, thermal transient current and thermally stimulated discharge current measurements have been carried out in order to determine the polarization and space charge accumulation in ac aged polyethylene. A correlation has been observed in the behavior of polarization and dielectric relaxation in the present work. The dielectric behavior of the XLPE cable samples and of the LDPE flat samples show a presence of both the inter-cluster (low frequency) charge exchange and the intra-cluster (high frequency) charge motion, the former mechanism becoming more dominant as the aging progresses. For the XLPE cable samples ac aged in a humid environment at room temperature, relaxation peaks obeying the fractional power law have been observed in addition to a quasi-dc process.