Abstract This paper presents a three-terminal fault location algorithm based on the unsynchronized voltage and current phasors acquired from the digital relays or the Intelligent Electronic Devices (IEDs) installed in three terminals. The idea is to extend a two-terminal fault location scheme using synchrophasors to an approach regarding the three-terminal line structure with unsynchronized sampling. Firstly, a Voltage Comparison Scheme (VCS) is proposed to simultaneously identify a faulted line branch and derive the synchronization angle between the ends of the remaining two healthy branches. Subsequently, the Modified Secant-based Algorithm (MSA) is suggested to synchronize the measurements of the faulted-branch end as well as locate a fault at the same time. The effectiveness and the performance of the proposed idea have been validated by an extensive series of simulations under various fault conditions with the use of the 161 kV overhead transmission-line parameters of the Taiwan Power Company (Taipower).

中文翻译：

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一种基于非同步采样的三端输电网故障定位新方法

摘要 本文提出了一种基于从安装在三端的数字继电器或智能电子设备（IED）中获取的不同步电压和电流相量的三端故障定位算法。这个想法是将使用同步相量的两端故障定位方案扩展到关于具有非同步采样的三端线路结构的方法。首先，提出了电压比较方案（VCS），以同时识别故障线路分支并推导出其余两个健康分支的端部之间的同步角。随后，建议使用基于修正割线的算法 (MSA) 来同步故障分支端的测量以及同时定位故障。