Fault location in low-voltage distribution networks based on reflectometry – A case study

Fault location can help transport and distribution system operators in their effort of minimizing supply interruption times. Nowadays, fault location devices are widely extended in the transport grid. However, the application of these solutions to distribution networks is not a feasible option due to the high cost of this equipment. Therefore, current research is focussed on costeffective fault location techniques which are adapted to electrical distribution networks. This paper presents results of a case study, conducted with detailed simulation models of two actual low-voltage (LV) distribution grids, using PSCAD software. One is a typical rural grid with long aerial lines, while the other is a typical urban grid with shorter line lengths which are mostly installed underground. The analysis is focussed on fault location based on travelling wave theory and reflectometry methods. The simulations include distributed parameter line models and a signal injector, in order to analyse the singular effects in the waveform which are caused by the special features of the LV network. It is shown that LV networks have some unique features which are not present in medium and highvoltage grids, which makes effective fault location more challenging. Observed issues are discussed and future work is proposed in order to overcome some of them