Voltage Sag Estimation in Radial Distribution Systems with Limited Monitoring Points

This paper presents a new method to obtain voltage sag indices in radial distribution systems. Since it is impossible to measure the sag level at every node of a distribution feeder, estimation of sag characteristics at unmetered nodes becomes necessary. This method estimates the voltage sages in unmetered buses and feeders by using the information of limited monitoring points of radial distribution systems (final points +1). The method is applicable and conforms to available instrumentation technology.