The fault characteristics of multi-converter DC system are complex and variable. How to use fault transient information for fault characteristic analysis and protection setting is one of the challenges faced by the development of DC power distribution system. In this article, the high-frequency characteristics of faults in DC systems are analyzed. Then based on the transient fault circuit analysis method, the frequency domain impedance model of typical converters is obtained. The model established in the higher frequency band is not affected by the control strategy and can provide a stable impedance value, which lays a theoretical foundation for the protection principle. At the same time, the characteristics of the high frequency impedance superposition of multi-converter system are also given, which provides a basis for system-level protection setting and coordination. Finally, the DC power distribution system model is established in PSCAD/EMTDC for simulation, and the results prove the accuracy and validity of the DC system model.

中文翻译：

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基于高频暂态分量的直流配电系统建模

多转换器直流系统的故障特性复杂多变。如何利用故障暂态信息进行故障特征分析和保护设置是直流配电系统发展面临的挑战之一。本文分析了直流系统故障的高频特性。然后基于暂态故障电路分析方法，得到典型变换器的频域阻抗模型。在较高频段建立的模型不受控制策略的影响，可以提供稳定的阻抗值，为保护原理奠定了理论基础。同时给出了多转换器系统的高频阻抗叠加特性，这为系统级保护设置和协调提供了基础。最后，在PSCAD / EMTDC中建立了直流配电系统模型进行仿真，结果证明了该直流系统模型的准确性和有效性。