Transient-Based Fault Location on Three-Terminal and Tapped Transmission Lines Not Requiring Line Parameters

In this paper, fault location on three-terminal and tapped transmission lines without requiring line parameters is presented, which mitigates the effect of line parameter variations due to weather and loading conditions on fault-location accuracy. For three-terminal lines, a fault-location method is presented, which utilizes postfault measurements of all three terminals. For tapped lines, two methods are presented. The first one uses postfault measurements of the main two terminals. The second one needs one cycle of prefault measurements at the main terminals as well. Synchronized transient-based measurements are used in methods proposed in this paper. In all of the presented methods, the fault-location problem is converted to an optimization problem and then solved to find the line parameters and the accurate location of the fault. The simulations are carried out by alternative transients program/electromagnetic transients program (ATP/EMTP) software, and the presented algorithms are executed by MATLAB. Simulation results assess the effects of fault resistance, type, and inception angle on the accuracy of the presented methods. Further discussion is also provided on the impacts of synchronization errors, noisy measurements, and nonresistive faults.