Abstract
In this paper, we propose a universal control strategy of the advanced UPFC that joins shunt active filtering, flicker compensation and system balancing capabilities to real time power flow control into one device. To achieve optimal UPFC behavior in the different mode, the injected voltages and currents are determined on-line based on the local instantaneous measurements. The controller should monitor the system conditions and generate the appropriate injected voltages and currents for each phase and for each time step. The control algorithm compensates the oscillated part of the instantaneous active and reactive power components to achieve the harmonics and flicker compensations. This approach is based on the symmetrical components theory in instantaneous state. The implementation of the method is completely digital, thus, the number of acquired signals and the external analog circuitry are reduced to minimum. The UPFC and a typical unbalance and non-linear loads have been implemented in digital simulator to demonstrate the capabilities of the UPFC to compensate system disturbances. Copyright (C) 2008 Praise Worthy Prize S.r.l. - All rights reserved