US EPA

460396 

Journal Article 

Evaluation of performance of a novel voltage compensation strategy for an ac contactor during voltage sags 

Chi, CT 

2008 

4 

11 

2809-2822 

English 

This study concentrates on developing a novel voltage compensation strategy based on feedback control approach that allows contactors to ride through power line disturbances such as voltage sags and dropouts. Voltage sags are widely reported as being one of the worst power quality problems in many continuous process industries. Since the momentary voltage sag event, the electrical contacts of contactor abnormally open and lead to an uncontrollable and possibly resulting in expensive process shutdown results. In this paper, an ac contactor model is analyzed when sags event is ensured occurrence as well as a novel voltage compensation strategy is designed for timely offsetting the coil voltage; therefore, the critical equipment in continuous process industries are safely protected and prevents the loss caused by downtime. A dynamic performance evaluation was conducted on an ac contactor governing model for analyzing the system performance when the proposed compensation strategy is introduced. The simulation results clearly depicted that contactors are critical component as it was unable to ride through 20% sag and longer than 48 milliseconds. The effectiveness and feasibility of the proposed coil voltage compensation strategy during voltage sag events occur is validated by using simulation approach. Moreover, the shading rings have the effect of the contactor's transient performance when voltage sags event occur is studied and discussed as well. 

Voltage sags; Voltage compensation strategy; Feedback control; Ride; through; Contactor; Shading rings; Power quality; design; system