Recently a number HVdc circuit breakers (CBs) based on various dc current interruption principles have been developed and a few are put in operation. However, due to a lack of practical experience, no clearly defined requirements that the HVdc CBs should satisfy exist. To define and refine justified test requirements, a thorough understanding of the interactions between the internal components of the HVdc CB and the stresses on these components under real dc fault current interruption condition is necessary. In this paper, an experimental dc CB based on the active current injection technique is setup in a high-power laboratory to investigate the performances of the main components; namely, the vacuum interrupter (VI) and the metal oxide surge arrester (MOSA). The performances of three different designs VIs are investigated and it is found out that each of the VIs behave completely different. The key parameters having impact on current interruption performance of the VIs are identified and analyzed in detail. Moreover, the performance of a MOSA, designed for HVdc CB application, is also investigated by applying energy per volume ranging between $\text{70}\!-\!\text{220}\;\text{J/}\text{cm}^\text{3}$ at temperature as high as $\text{250}$ °C. In order to find out the performance limit of the MOSA for this application, successive high-energy tests are performed until electro-mechanical failures occur in the MO varistors. Various failure modes such as fracturing and puncture are observed. The detailed analysis of these failure mechanisms during destructive tests and the root causes are presented.

中文翻译：

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高压直流断路器主要部件电应力的实验研究

最近，已经开发了许多基于各种直流电流中断原理的 HVdc 断路器 (CB)，其中一些已投入使用。然而，由于缺乏实践经验，HVdc CB 应满足的明确要求不存在。为了定义和改进合理的测试要求，必须彻底了解 HVdc CB 的内部组件与这些组件在实际直流故障电流中断条件下的应力之间的相互作用。在本文中，基于有源电流注入技术的实验性直流断路器在大功率实验室中设置，以研究主要组件的性能；即真空灭弧室 (VI) 和金属氧化物避雷器 (MOSA)。研究了三种不同设计 VI 的性能，发现每个 VI 的行为完全不同。对影响VI当前中断性能的关键参数进行了详细的识别和分析。此外，还通过在 $\text{70}\!-\!\text{220}\;\text{J/}\text 之间施加每个体积的能量来研究为 HVdc CB 应用设计的 MOSA 的性能{cm}^\text{3}$ 在高达 $\text{250}$ °C 的温度下。为了找出用于此应用的 MOSA 的性能极限，进行连续的高能测试，直到 MO 压敏电阻出现机电故障。观察到各种故障模式，例如破裂和穿孔。介绍了破坏性测试过程中这些失效机制的详细分析和根本原因。