Abstract The AC breakdown channel of multi-layer insulation was investigated with samples laminated between spherical electrodes under high and low values of applied field stresses. Both samples with butt-gap and without butt-gap immersed in liquid nitrogen (LN2) were used. In addition, the breakdown strength and the voltage-time characteristics of both types of samples were also determined. It was found from the experimental data that the butt-gaps play a decision role in the shape and position of breakdown path as well as the magnitude of the breakdown strength and the lifetime index. However, creepage discharges at the interfaces between layers become more pronounced at a lower value of applied electric field stress. The degradation of insulation layers was found to depend on the value of the applied field stress as well as the sequence of layer in the multi-layer samples. Finally, the breakdown mechanism for multi-layer insulation was suggested.

中文翻译：

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高温超导电缆PPLP多层绝缘交流击穿通道

摘要 用夹在球形电极之间的样品在高和低外加场应力值下研究了多层绝缘的交流击穿通道。使用了浸入液氮 (LN2) 中的带对接和不带对接的两种样品。此外，还测定了两种样品的击穿强度和电压-时间特性。从实验数据中发现，对接间隙对击穿路径的形状和位置以及击穿强度和寿命指标的大小起着决定性作用。然而，在施加的电场应力值较低时，层间界面处的爬电放电变得更加明显。发现绝缘层的退化取决于施加的场应力值以及多层样品中层的顺序。最后，提出了多层绝缘的击穿机制。