Investigation the Effects of Utility Unbalance Voltage on Adjustable Speed Drives and Induction Motors

M.Nafar; B.Azadbakht; K.Adinehvand

Volume : III, Issue : VIII, August - 2014

Investigation the Effects of Utility Unbalance Voltage on Adjustable Speed Drives and Induction Motors

M. Nafar , B. Azadbakht , K. Adinehvand

Abstract :

This paper endeavors to present a comprehensive summary of the causes and effects of voltage unbalance and to discuss related standards, definitions. Several causes of voltage unbalance on the power system and in industrial facilities are presented as well as the resulting adverse effects on the system and on equipment such as induction motors and power electronic converters and drives. Power electronic converters serve as the interface for many large electronic loads ranging from three-phase uninterruptible power supplies (UPSs) to motors operating at variable speeds through the use of adjustable speed drives (ASDs). Most of these converters contain diode rectifier front-end. Under the conditions of utility voltage unbalance, the input current harmonics are not restricted to the converter characteristic harmonics, and uncharacteristic triple harmonics can appear such as the 3rd and 9th harmonics. The more details of effects of unbalanced voltages on ASD are investigated follows.