A power quality combined compensation system and its application on three-phase large-power and impulse loads

On account of the capacity of active power filter (APF) is limited, a novel structure of combined compensation system is proposed to solve the question of Jerky loadpsilas power quality, including voltage flicker, harmonic pollution, and power factor low. This combined compensation system is composed of static var compensator (SVC) and active power filter (APF). In this system, the SVC is used for compensating reactive power quickly, as well as for improving three-phase unbalanced degree and negative phase-sequence current caused by impulse load. The APF is used for mitigating harmonics caused by Jerky load and thyristor controlled reactor(TCR). In order to realize decentralized control of SVC and APF, a reasonable topological structure is adopted. The operational principle of system, a new reactive power calculation method and control strategy is presented in detail. The feasibility and validity of the combined compensation system is verified by the waves and data of practical operation.