The Influence of Induction Motors on Voltage Sag Propagation—Part II: Accounting for the Change in Sag Performance at LV Buses

This paper describes the influence of induction motors (IMs) on voltage sag characteristics at low-voltage (LV) buses. This influence is particularly pronounced in case of low magnitude and long duration voltage sags. Even though the conventional magnitude duration representation of voltage sags in the presence of IMs is not completely accurate, it is very convenient as it can be directly linked to a standard way of recording/reporting voltage sags. The equivalent rectangular sags developed in this study take into account the effect of IMs and establish voltage sag performance more accurately at LV buses in the distribution network. The methodology developed is not limited to simulation-based voltage sag studies. It can be equally well applied as a “postprocessor” to finely tune the results of monitoring distribution systems as its inputs are “classical” voltage sag magnitude duration tables. The automated procedure for counting and characterization of voltage sags at LV distribution buses is illustrated on a 295-bus generic distribution network.