In this paper, a liquid circulation system is constructed whereby gas bubble dynamics and electrical signal evolution preceding the oil gap breakdown are registered in stationary and flowing transformer oil. Based on a number of repetitive tests, two types of breakdown are classified: one takes place after bubble growth and originates in the bubble or the mixture of liquid and gas when the applied voltage is in the negative half-cycle; the other follows streamers resulting from the protrusion of bubble tip in the positive half-cycle. For each type of breakdown, partial discharge (PD) pulse is captured preceding the breakdown. As the oil flow rate varies, bubble dynamics change but the characteristics of each breakdown remain. In addition, it is found that oil breakdown voltage is improved as the flow rate increases. In terms of PD occurrence and bubble growth, the role of gas bubble in oil breakdown initiation, as well as the effect of oil flow on breakdown, is discussed.

中文翻译：

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气泡在流动变压器油击穿中的作用

在本文中，构建了一个液体循环系统，其中在静止和流动的变压器油中记录了油隙击穿之前的气泡动力学和电信号演变。根据多次重复试验，将击穿分为两种类型：一种发生在气泡生长后，在外加电压处于负半周时起源于气泡或液体和气体的混合物；另一个跟随正半周气泡尖端突出产生的流光。对于每种类型的击穿，在击穿之前捕获局部放电 (PD) 脉冲。随着油流量的变化，气泡动力学发生变化，但每次击穿的特征仍然存在。此外，发现随着流量增加，油击穿电压提高。