Design of a one-sided, impedance-based transmission line fault locator using line topology and source impedances

The article discusses an algorithm for a one-sided, impedance-based (transmission) line fault locator using line topology. Standard one-sided impedance-based fault locators, included in the digital protection systems [2], [3], [4], [8] compute the distance to the fault using the symmetrical components of line impedance. Section 5 demonstrates that this method of determining the distance to the fault exhibits significant inaccuracies in the case of a non-transposed line. The designed algorithm eliminates this inaccuracy, as it computes the distance to the fault with regard to impedance of corresponding phase, or more precisely the faulty loop. Moreover, the algorithm reflects the source impedances on both sides of the line and therefore eliminates or decreases the influence of power from the opposite side to determine the distance to the fault.