Characterization of phase-angle jump in radial systems using incremental voltage phasors

A methodology for characterizing the phase-angle jump associated to voltage sags in radial systems using incremental voltage quantities is presented in this paper. The incremental voltage phasor is defined as the difference between the pre-fault and the during-fault voltage phasors at the point of common coupling. The characteristics of this phasor are stated for different fault conditions as a function of system impedances. Both fault impedance and source neutral grounding impedance are considered in the analysis. Furthermore, the vector representation of phasors and impedance diagrams are employed as a graphical aid for understanding the incremental quantities behavior as a function of the system parameters. Finally, the theoretical analysis is confirmed using simulations in the ATP-EMTP environment. The results of this work can be useful in future works for fault classification and fault location in radial systems.