Behavior of phase voltages due to faults in radial power systems: An educational tool

A study of the impact of the means of grounding on the voltage sag and swell characterization is presented in this paper. Only temporary overvoltages and undervoltages caused by faults are considered. The voltage divider model is employed, and the symmetrical components are used to obtain the phasor voltages at the point of common coupling as functions of the means of grounding of the system and the distance between the point of common coupling and the fault location. A computational tool that shows the phasor behavior during a fault event is developed. Also, a zone classification is proposed based on the location of voltage vectors depending on the fault type. This zone classification may be a cornerstone for new methods of fault classification and location in future works.