A novel power quality conditioner applied to high voltage power systems

A novel principle of parallel hybrid active power filter based on controllable impedance is proposed for high voltage alternate power systems application. The linear parallel transformer can exhibit controllable impedance under the control of power electronic inverters. On the one hand, the transformer can exhibit nearly zero impedance to harmonic current and thus lead harmonic current to flow into the transformer circuit. On the other hand, the transformer can also exhibit continuously adjustable reactance to fundamental current and thus together with the passive power filter compensate reactive power. To increase the capacity of the active power filter, a special transformer structure with multiple secondary compensation windings is adopted. In the mean time, a new reference current operation method is put forward. The simulated results show that the performance in harmonic suppression and reactive power compensation of the proposed scheme is satisfactory.