Dynamic Parameters Tracking and Voltage Sag Source Location in the Distribution System with DG

Voltage sag is one of the most important power quality problems causing sensitive equipment to malfunction and many industrial process interruptions. The penetration of distributed generation (DG) into distribution networks make it is more difficult to locate the sag source reliably. The problem of sag source location in distribution system with DG is studied in this paper. First, an adaptive nonlinear filter (ANF) is proposed for processing non-stationary signal during sag. Later synchronized phasor measurement based ANF is realized to get phasor's phase and amplitude dynamicly during transient, and a time-varying dynamic phasor model is constructed. Then, system parameters tracking for upstream and downstream system model of the complex distribution system with DG is analyzed. Finally, the mechanism of source location is founded by studying the relation of parameters variation and voltage variation, and a quantitative criterion are derived for sag source location. To validate the proposed method, a simulation of 35 kV distributing system with DG is used. The result is significant for the customers and suppliers to solve the issue between them, and be helpful to compensate voltage sag and remove the disturbance source.