Study on Power Quality Phenomena of Grid-connected AC Micro-grid

In recent electrical power system, there is a greatest interest on operation, control and performance of AC micro-grid by research community throughout the world. In this context, this paper investigates power quality issues of grid-connected AC micro-grid. The micro-grid consists of two wind farms (one is fixed speed type and other is variable speed type), a solar power plant and a mini hydel plant at point of common coupling (PCC). The grid is modeled as AC voltage source in series with impedance. The voltage and frequency at PCC are 600V and 50 Hz respectively. All heterogeneous non-conventional energy sources are interfaced to the main grid through different types of power electronics converter(s) and a common transformer. In the study, PSCAD software is used to model the grid-connected AC micro-grid. Various responses of individual entities and at grid-side variables are observed. Here, various power quality problems have been monitored from the model of AC micro-grid under dynamic operating conditions like switching of non-linear load and power factor improving capacitor. This study will be helpful to develop strategy in future for mitigating or suppressing power quality problems in the AC micro-grid.