Water tree characteristics have been investigated for low-density polyethylene by applying power-frequency ac voltages with high-frequency components, which are simulated output voltages of a pulse-width-modulation inverter. If we compare the water-tree length among single-frequency voltages, the water tree grows faster if the frequency is higher. However, if we superpose a power-frequency voltage onto the high-frequency voltage, the tree growth is suppressed. The tree length becomes shorter if the superposed power-frequency voltage is higher. This surprising result is explainable by considering that the zero-crossing of the applied voltage plays an important role for the tree propagation. In case that the high-frequency voltage is superposed onto a dc voltage, the dc voltage seems not to have any influence to the tree growth. This result can be also explained by considering the number of voltage reversals at the tree tip.
|ジャーナル||Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), Annual Report|
|出版ステータス||Published - 1997 12 1|
|イベント||Proceedings of the 1997 Annual Conference on Electrical Insulation and Dielectric Phenomena. Part 2 (of 2) - Minneapolis, MN, USA|
継続期間: 1997 10 19 → 1997 10 22
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