Abstract :
The paper is concerned with the relation between neutral earthing resistance, line length and the corresponding voltage produced on the sound phases when a 3-phase radial feeder sustains a single-phase earth fault. Only steady-state conditions are considered. Conventional analytical expressions are modified to produce a graphical presentation of these relationships, and the vector loci of the potential of earth at the fault point are established for all possible ranges of the relevant parameters. Vector charts, drawn to scale, are given for typical 11 kV and 33kV feeders. Possible application to the selection of lightning arresters is indicated.
