California Electricity Market Crisis: Causes, Remedies, and Prevention

Voltage sag produced by an induction motor starting current is a main cause of sensitive equipment dropout. The use of a motor starter reduces the voltage sag depth but increases its duration. The subsequent connection to full voltage produces a new sag separated from the first one by a few seconds. A simple method is presented that allows us to transform the information of starting current/time characteristics to voltage sag depth/time characteristics that are directly comparable with the sensitive equipment susceptibility curves (CBEMA and other curves). The method also allows one to consider motor repetitive starts and different starting cycles.