D-statcom effetcs to voltage sags in medium voltage networks

Keywords: Power Quality, Voltage Sag, Voltage Swell, D-STATCOM Power electronics based devices have been getting increasingly important with the considering the consequences of power quality problems, for their effect of the power systems quality and performance, also capability to make reactive power compansation. With the FACTS (flexible alternative current transmission systems) devices, controlling of power systems more quickly and effectively, increasing of power systems transmission capabilitly, current, voltage control with the reactive power compansation can be done. D-STATCOM is the most improved FACTS devices to minimize power quality problems in distribution systems. D-STATCOM connected in shunt to the network, plays an effective role to regulate voltage changes from the power quality problems by making reactive power exchange with the network. In this thesis, D-STATCOM effects to voltage sags in medium voltage networks analysed, usage of D-STATCOM and its effects were observed for the mitigating voltage sags. D-STATCOM model was designed with the MATLAB Simulink Toolbox. With the different scenarios D-STATCOM's behaivor observed and control in the network was analysed at the state of voltage sag, swell. D-STATCOM based on the voltage source converter (VSC) prensiple. Sinusodial Pulsed With Modulation (SPWM) tecnique which offers simplicity and good responce was used for the switching strategy of two level voltage source converter (VSC). D-STATCOM injects current to the system for the mitigating of voltage sags. In this thesis, 6-pulse D-STATCOM configuration with IGBT was designed. Consequences show that, with the effective voltage regulation capability, D-STATCOM responded very effectively for the mitigation of voltage sag or voltage swells from power quality problems in medium voltage networks. The percantage of voltage sag of the load point was mitigated substantially while D-STATCOM connected in network.