@inproceedings{e86f8ee40b5e4b3b8f5485e90364caff,

title = "Role of the voltage zero-crossing in the growth of water trees - Effect of superposition method of a high-frequency voltage and a low-frequency voltage",

abstract = "The authors have examined the effects of superposition of a low-frequency ac voltage and a high-frequency ac voltage on the growth of water trees in polyethylene, and have made it clear that the number of voltage zero-crossings is a decisive factor of water tree growth. In the present research, a short-duration high-frequency (2 kHz) voltage was superposed repeatedly onto a continuously applied low-frequency (0.5, 1.0, 3.0 or 5.0 Hz) voltage in synchronous with the low-frequency voltage either at its positive and negative maxima or at each zero-crossing point. By applying such superposed voltages to a low-density polyethylene sheet with a water needle electrode and a counter plane electrode, the length of a grown water tree was evaluated. As a result, it has become clear that the water tree length is longer when the high-frequency voltage is superposed at each zero-crossing point of the low-frequency voltage. This result supports the above-mentioned assumption that the number of voltage zero-crossings plays a significant role in the growth of water trees.",

keywords = "Aging, Cable insulation, Fault diagnosis, Insulation, Insulation life, Power cables, Space charge, Trees (insulation)",

author = "Y. Ohki and H. Ishikawa and G. Morita and T. Konishi and Y. Nakamichi and M. Tanimoto",

year = "2008",

doi = "10.1109/CMD.2008.4580294",

language = "English",

isbn = "9781424416219",

series = "Proceedings of 2008 International Conference on Condition Monitoring and Diagnosis, CMD 2008",

publisher = "IEEE Computer Society",

pages = "328--331",

booktitle = "Proceedings of 2008 International Conference on Condition Monitoring and Diagnosis, CMD 2008",

note = "2008 International Conference on Condition Monitoring and Diagnosis, CMD 2008 ; Conference date: 21-04-2008 Through 24-04-2008",

}