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The synchronization of the voltage and current from different terminals is generally unachievable in the power grids at mountainous area, which leads to the fault location method with synchronized data to be impossibly utilized. This paper proposes a voltage distribution based fault location scheme with asynchronous data for three-terminal transmission lines. At first, the faulty section is identified by the voltage computed from each terminal due to the boundaries formed by fault point and tee-point. Since the fault current is stable after the transients decay, the asynchronous calculated voltage and current from the terminals without faults can be synchronized by their angle differences to form the voltage and current at faulty section near the tee-point. Then, the voltage distribution of the faulty section can be obtained from the tee-point and the terminal to find the intersection point of them. In order to fully utilize the fault characteristics in the voltage and current, the earth mode and the minimum of the voltage distribution are applied to optimize the fault location results for grounding faults and multi-phase faults, respectively. Moreover, the robustness of the proposed fault location scheme is thoroughly validated by the simulation of PSCAD/EMTDC. At last, a set of the field data acquired by wave recorders is applied to test the feasibility of the proposed approach. [ABSTRACT FROM AUTHOR]

• This paper proposes a fault location method based on directional traveling wave principle for wind power transmission line. • The similarity of forward current traveling wave and reverse current traveling wave at both ends of line is higher after external fault, while similarity of forward current traveling wave and reverse current traveling wave at both ends of line is lower after internal fault. • Discrete Frechet distance is utilized to calculate similarity coefficient of forward traveling wave and reverse traveling wave at both ends of transmission line. The short-circuit current from the new energy power generator presents special characteristics such as frequency shift, restricted amplitude, unequal positive and negative sequence impedance, high percentage of harmonic content, etc., resulting in the risk of misoperation or rejection of conventional protection. By analyzing the propagation characteristics of traveling wave in the transmission line after the fault, this paper reveals difference between traveling wave waveforms at both ends of the line under internal fault and external fault. The similarity between forward traveling wave and reverse traveling wave at both ends of line is higher when an external fault occurs, while the similarity between the forward traveling wave and reverse traveling wave is lower after internal fault. According to this difference, a pilot protection algorithm based on discrete Frechet distance is proposed, which can calculate similarity coefficient of forward traveling wave and reverse traveling wave at both ends of line to construct protection criteria, and then identify internal and external fault. Through the analysis of PSCAD/EMTDC and experiment platform of hardware-in-the-loop test verify that the proposed protection algorithm can accurately and reliably distinguish internal and external fault. [ABSTRACT FROM AUTHOR]

Due to the complex structure of the T-connection transmission lines, it is extremely difficult to identify the reflected travelling wave from the fault point and that from the connection point by the measurement from only one terminal. According to the characteristics of the structure of the T-connection transmission line, the reflection of the travelling wave within the line after the failure of different sections in T-connection transmission line are analyzed. Based on the lattice diagram of the travelling wave, the sequence of travelling waves detected at the measuring terminal varies with the fault distance and the faulty section. Moreover, the sequence of travelling waves detected in one terminal is unique at each faulty section. This article calculates the arrival time of travelling waves of fault points at different locations in different sections to form the collection of the travelling wave arrival time sequence. Then the sequence of travelling waves of the new added fault waveforms is extracted to compare with the sequences in the collection for the faulty section identification and fault location. This proposed method can accurately locate the fault with different fault types, fault resistances and system impedances by only single-terminal fault data. Both Power Systems Computer Aided Design/ Electromagnetic Transients including DC (PSCAD/EMTDC) and actual measurement data are implemented to verify the effectiveness of this method. [ABSTRACT FROM AUTHOR]