Differences in Voltage Dip Exposure Depending Upon Phase-to-Phase and Phase-to-Neutral Monitoring Connections

Voltage dip indices are estimated for a set of simulated and measured events. The simulated dips are obtained applying the method of fault positions on a large transmission network and the measured dips come from a one-year survey. The indices estimated to compare phase-to-phase and phase-to-neutral dips are SARFI-90, SARFI-70, SARFI-ITIC, and average voltage dip amplitude. Furthermore, the results are analyzed in terms of the cumulative distribution frequency of the voltage dip amplitude. The comparison of phase-to-phase and phase-to-neutral indices indicates that, at transmission level, phase-to-neutral dips are more frequent and more severe than phase-to-phase ones. However, these differences are reduced at the load connection level, where the phase and line voltages show similar performance for the monitored system