The problem of fault location has been studied deeply for transmission lines due its importance in the power system. Nowadays the problem of fault location on distribution systems is receiving special attention mainly because of the power quality regulations. This paper presents some of the most relevant methods for fault location in radial power systems. Additionally here is presented an hybrid fault location algorithm which takes advantage of both, the algorithmic and the knowledge based methods. The obtained results from fault location methods help utilities in both network operation and network planning.

This paper compares two electric fault location techniques, [1]&[2]. Using prefault and fault data (voltages and currents) and a model of the network, the algorithms can give an approximation of the actual fault location. They were chosen because the final aim is to implement them on a real distribution network, where we have registered faults with the prefault and fault information, and where the parameters of the network are known. Both techniques were implemented on simple lines and tested through simulations. The results obtained, showed that Ratan Das algorithm was giving better approximations to the actual fault. On a second step the algorithms were implemented on a real distribution network. The results also showed that Ratan Das algorithm give better results and is less sensible to fault impedance, a parameter that in the majority of cases is unknown. An application with a graphical user interface has been created to execute the methods, but also to execute the necessary previous steps: obtain the phasors of the fault, either through a simulation or loading actual registered faults, graphical representation of waveforms and phasors... In conclusion, the Saha method is easy to implement but an evaluation of the fault resistance is needed, and this let the method to be more sensible at uncertainties.