Abstract The transient characteristics of the bipolar short-circuit fault on a loop DC distribution network with blocking converters are studied in this paper. A protection principle based on the integrals of the line differential current is proposed after analyzing the characteristics of the line differential current during an internal fault and an external fault. The protection criterion and setting method are also presented. Moreover, after analyzing the adaptability of the proposed protection method under the circumstance where the converters cannot be blocked promptly due to large transition resistance, a criterion for quick blocking is given. The proposed protection method demonstrates such advantages as high anti-transition resistance, none-susceptibility to converter blocking and low sampling frequency requirement, thus can provide selective and reliable protection for the DC distribution network with blocking converters. The proposed protection method is validated by a loop DC distribution network model with blocking converters in PSCAD/EMTDC.

中文翻译：

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基于差动积分的直流配电网闭锁双极短路保护方法

摘要 本文研究了带闭塞换流器的回路直流配电网双极短路故障的暂态特性。在分析了内部故障和外部故障时线路差动电流的特性后，提出了一种基于线路差动电流积分的保护原理。还介绍了保护标准和设置方法。此外，在分析了所提出的保护方法在转换器因过渡电阻大而不能及时闭锁的情况下的适应性后，给出了快速闭锁的判据。所提出的保护方法具有抗过渡电阻高、对转换器闭锁不敏感和采样频率要求低等优点，从而可以为具有阻塞变换器的直流配电网络提供选择性和可靠的保护。所提出的保护方法通过 PSCAD/EMTDC 中带有阻塞转换器的回路直流配电网络模型进行了验证。