A multifunctional DSTATCOM for power quality improvement

Abstract

The distribution static compensator (DSTATCOM) is used for various purposes such as load balancing, harmonic rejection, and power factor correction (PFC) in power distribution networks. In unbalanced and polluted power systems, the classic definition of power factor cannot be used for PFC due to the existence of harmonics and negative sequence components in voltage and current waveforms. In this paper, PFC is performed using the IEEE power factor definition for harmonic and unbalanced environments. Moreover, the application of a proportional-resonant (PR) controller is proposed as an effective controller in the stationary frame for DSTATCOM performance improvement. The PR controller is used in the abc-frame for load balancing and is then compared theoretically and by simulation with the conventional PI controller, which has the main drawback of steady-state error when used in the stationary frame. To improve the DSTATCOM structure, an LCL harmonic filter is used as it is advantageous over the L/LC filter in terms of the size of the filter. The proposed DSTATCOM compensates for the disturbances in the source current imposed by nonlinear, unbalanced, and low power factor loads. Simulation results show the capability of the DSTATCOM including the proposed PR controller in improving the power quality of distribution systems. © 2017 TÜBITAK.