A traveling wave natural frequency-based single-ended fault location method with unknown equivalent system impedance

Abstract

SUMMARY Single-ended traveling-wave fault location methods have difficulties in identifying the incident traveling wave and its corresponding reflection from the fault point. Thus, the algorithms' accuracy is always affected by wave-front identification. In this paper, a novel single-ended fault location method based on traveling wave natural frequencies is proposed for transmission line. The key of this method is to extract natural frequency and to achieve system parameters, of which system equivalent impedance is difficult to obtain accurately in practical application. By means of analyzing the influence mechanism of system impedance in the existing location algorithms based on natural frequencies, and assuming that the system resistance and inductance are parameters to be identified, a nonlinear objective function is constructed by several natural frequencies, then its local optima is solved by Nelder–Mead search algorithm to get the computing impedance. The correct system reflection angle under corresponding frequency can be attained by this computing impedance and accurate fault location can be finally estimated. The reliability and adaptability of the proposed method are verified by PSCAD/EMTDC-based simulation. Fault location result is independent of fault distance, fault type and transition resistance; meanwhile, during the computing process the accuracy of fault location can be evaluated. Copyright © 2015 John Wiley & Sons, Ltd.