A study about the sources of error of impedance-based fault location methods

Impedance-based fault location methods are the most commonly ones used in practice due to their simplicity and low cost. However, the accuracy of such algorithms can be significantly affected by several sources of error, such as the fault resistance, the fault location, the source impedances, and the transmission line modeling. The aim of this paper is to evaluate the sensitivity of one-terminal and two-terminal impedance based fault location methods to parameters such as the fault resistance and the fault position. The mathematical modeling of three classical impedance-based fault location methods is presented and the influence of each possible error source in these algorithms is highlighted. The numerical tests are performed by considering a 500 kV transmission line simulated with Alternative Transient Program (ATP).