Abstract:

Calculating the increments of the voltage and current caused by disturbance can get the defined impedance. The sign of the real part of the defined impedance can reveal if the disturbance is from upstream or downstream. A positive sign showed that the source of sag was upstream, and the negativesign showed that the source of sag was downstream. A new and effective detecting method for the voltage sag source was proposed based on the defined impedance. In order to solve the problem that using a single during an event cycle could yieldunreliable results,the data of multiple cycles were processed by using the least squares method. Simulation results showed that this method was effective.

Key words: power quality; voltage sag; voltage sag source detection; leastsquares method; defined impedance