In this paper, a fast fault detection scheme for voltage source converter based high-voltage direct current (VSC-HVDC) transmission systems is proposed. Based on Bergeron model equations, the remote terminal voltage of an adopted transmission system is calculated in terms of the local measured current and voltage signals. Subsequently, the computed voltage of the remote terminal is compared with the corresponding actual measured-communicated value. Provided that the considered transmission system is functioning well, the difference between the computed and measured voltages is almost zero. However, a considerable virtual voltage arises for fault conditions. When the voltage difference exceeds a predetermined threshold, a fault condition can be detected. Although a reliable communication link is required, the delay for detecting the fault is not caused by the communication time. For evaluation purpose, a detailed simulation is developed using PSCAD/EMTDC with various fault locations, including the cases near the inside or outside of the protected transmission system. The results corroborate a fast detection scheme depending on a moderate sampling/processing frequency level. A high security level is verified even with the worst external faults, or with the misaligned measured samples at the terminals. This corroborates the suitability of the proposed scheme for protecting multi-terminal HVDC systems.

中文翻译：

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用于VSC-HVDC输电系统故障检测的虚拟差分电压方案

本文提出了一种基于电压源换流器的高压直流输电系统快速故障检测方案。基于Bergeron模型方程式，根据本地测得的电流和电压信号来计算所采用的传输系统的远端电压。随后，将远程终端的计算电压与相应的实际测量通信值进行比较。如果考虑的传输系统运行良好，则计算电压和测量电压之间的差值几乎为零。但是，对于故障情况会产生相当大的虚拟电压。当电压差超过预定阈值时，可以检测到故障状况。尽管需要可靠的通信链接，检测故障的延迟不是由通信时间引起的。为了进行评估，使用PSCAD / EMTDC开发了具有不同故障位置的详细模拟，包括受保护传输系统内部或外部的情况。结果证实了根据中等采样/处理频率水平的快速检测方案。即使存在最严重的外部故障或端子处的测量样品未对准，也可以确保达到较高的安全级别。这证实了所提出的方案用于保护多端HVDC系统的适用性。结果证实了根据中等采样/处理频率水平的快速检测方案。即使存在最严重的外部故障或端子处的测量样品未对准，也可以确保达到较高的安全级别。这证实了所提出的方案用于保护多端HVDC系统的适用性。结果证实了根据中等采样/处理频率水平的快速检测方案。即使存在最严重的外部故障或端子处的测量样品未对准，也可以确保达到较高的安全级别。这证实了所提出的方案用于保护多端HVDC系统的适用性。