In AC/DC converter transformers under DC application, the electric field distributions are distorted due to the accumulated charge on pressboard. However, the time‐dependent characteristics of DC electric field stress in oil has not yet been clarified in detail. In this paper, we investigated the time and electric field space transition characteristics of DC electric field distributions in oil‐pressboard composite insulation systems. As a result, we quantitatively clarified that DC electric field stress strongly depends on the elapsed time and the location in the electric field space in oil. In particular, it was found that the most severe electric field stress in oil may emerge during the time transition process.

中文翻译：

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油压复合绝缘系统直流电场应力的时空过渡特性

在直流应用下的AC / DC转换器变压器中，电场分布由于压板上的累积电荷而失真。但是，油中直流电场应力随时间的变化特性尚未得到详细阐明。在本文中，我们研究了油压板复合绝缘系统中直流电场分布的时间和电场空间跃迁特性。结果，我们定量地阐明了直流电场应力在很大程度上取决于经过的时间和在油中电场空间中的位置。特别地，发现在时间过渡过程中可能出现油中最严重的电场应力。