Fault Location for Distribution Networks Based on Node Voltage Equation

This paper proposed a method to estimate short-circuit fault location in electrical distribution networks using voltage sags data and current measured at the local substation. With the knowledge of bus impedance matrix, the bus voltage during the fault can be obtained for any fault in the network. Based on the non-liner profile characteristic of voltage sag measured at the bus, the paper proposed a new method. Firstly, voltage quantity for each section is expressed as a function of fault location and resistance base on the bus impedance matrix. The possible fault is estimated by incorporating the real and imaginary part of voltage sags into the node-voltage equation. Then, the method applies rank reasoning analysis to prioritize the possible fault locations due to the same electrical distance. In this method, the uncertainty of fault resistance is also considered. Through simulating for an 11kv typical test distribution network, the method´s validity and accuracy are proved.