ac aging and space-charge characteristics in low-density polyethylene polymeric insulation
ac aging and space-charge characteristics in low-density polyethylene polymeric insulation
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DOI：
10.1063/1.1868880
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发表时间：
2005-04-15
影响因子：
3.2
通讯作者：
Zhong, LS
中科院分区：
文献类型：
--
作者：
Chen, G;Fu, M;Zhong, LS
在目前的工作中，已作出努力，以调查在低密度聚乙烯（LDPE）的空间电荷动力学的影响，交流老化。200 μ m的LDPE膜在环境温度下在50 Hz的各种电应力水平下老化不同的时间。老化后的样品中的空间电荷动态监测使用脉冲电声技术。结果表明，交流老化条件下的空间电荷与外加电场的大小、电压的持续时间以及电极材料有关。通过与未老化样品的结果比较，老化样品的结果提供了交流老化后陷阱特性改变的直接证据。负空间电荷存在于材料的本体中，并且电荷的总量随着老化时间而增加。电荷量随所施加的场而增加。电荷衰减测试表明，电荷被捕获在深陷阱中。这些深陷阱被认为是在老化过程中形成的，并与注入电荷引起的变化有关。通过使用不同的电极材料，如金、黄铜合金和载有炭黑的聚乙烯，发现电极在电荷的形成中具有重要作用，因此随后由电荷引起的变化。在直流偏压下老化样品的电荷动力学不同于没有交流老化的样品，表明交流老化带来的变化。通过傅里叶变换红外光谱仪和拉曼显微镜的化学分析表明，在交流老化后，材料的本体中没有发生可检测到的化学变化。最后讨论了交流条件下空间电荷积累对材料寿命的影响。深陷空间电荷的存在导致电应力增强，这可能缩短绝缘系统的寿命。(C)2005年美国物理学会。
In the present work efforts have been made to investigate the influence of ac aging on space-charge dynamics in low-density polyethylene (LDPE). LDPE films with 200 mu m were aged under various electric stress levels at 50 Hz for various times at ambient temperature. Space-charge dynamics in the samples after aging were monitored using the pulsed electroacoustic technique. It has been revealed that the space charge under ac aging conditions is related to the level of the applied field, duration of the voltage application, as well as the electrode materials. By comparing with the results of unaged sample the results from aged sample provide a direct evidence of changing trapping characteristics after ac aging. Negative space charge is present in the bulk of the material and the total amount of charge increases with the aging time. The amount of charge increases with the applied field. Charge decay test indicates that the charges are captured in deep traps. These deep traps are believed to form during the aging and related to change caused by injected charge. By using different electrode materials such as gold, brass alloy, and polyethylene loaded with carbon black, it was found that the electrode has an important role in the formation of charge, hence subsequent changes caused by charge. The charge dynamics of the aged samples under dc bias differ from the sample without ac aging, indicating changes brought in by ac aging. Chemical analysis by Fourier transform infrared spectroscope and Raman microscope reveals no detectable chemical changes taken place in the bulk of the material after ac aging. Finally, the consequence of the accumulation of space charge under ac conditions on the lifetime of the material has been discussed. The presence of deeply trapped space charge leads to an electric stress enhancement which may shorten the lifetime of the insulation system. (C) 2005 American Institute of Physics.