A closed-form solution for transmission line fault location using local measurements at a remote substation

This paper presents a novel approach for fault location of overhead transmission lines by voltage and current measurements in a remote substation. The method is applicable when not all of the transmission lines in an area are equipped with fault-locators, although there may be a critical substation (CS) in the area equipped with a digital fault recorder (DFR). In the proposed method, the circuit equations of the network are used to find the transfer function between the fault location and each voltage and current measurement in the CS. Next, two auxiliary variables are defined to transform the nonlinear fault location estimation problem into a linear least squares problem. A closed-form solution is then obtained for fault location. The proposed formulation obviates the need to use unsynchronized or synchronized measurements from any other substation. Moreover, the proposed formulation does not necessitate fault type classification or fault resistance estimation. Furthermore, the distributed parameter model of the transmission line is considered in order for the method to be applicable to long transmission lines. Electromagnetic transient simulations for a 15-bus test system confirm accurate fault location estimation on remote transmission lines for different critical substations considered in the network.