SUMMARY
This paper deals with the voltage sag compensator in a system using flywheel energy storage system technology by using partial magnetic levitation. Voltage fluctuates in a generator from second to second and due to these fluctuations, it becomes difficult to meet the consumer demand since they account to high current losses. In such a case, Flywheels are used where energy is stored mechanically and transferred to and from the flywheel by an integrated motor/generator. Today flywheels are used as supplementary UPS storage at several industries world over. Future applications span a wide range including electric vehicles, intermediate storage for renewable energy generation and direct grid applications from power quality issues to offering an alternative to strengthening transmission. One of the key advantages of flywheel is that it compensates for the losses of the system by its storage mechanism and thus high overall efficiency is attained. When voltage is increased, current losses are reduced and transformer steps become redundant. Recent progress in semi-conductor technology enables faster switching and lower costs. Flywheel with magnetic bearings using magnetic levitation has been introduced for effectiveness of the system and to overcome frictional losses. The predominant parts of prior studies have been directed towards optimizing mechanical issues whereas the electro technical part now seems to show great potential for improvement. An overview of flywheel technology and previous projects are presented and moreover a 200kW flywheel using high voltage technology is simulated.