IMPROVEMENT OF POWER QUALITY USING CURRENT CONTROLLED 3&5 LEVEL MULTILEVEL BASED STATCOM

Abstract

Solid state power converters are widely used in applications such as adjustable speed drives (ASD), static power supplies and asynchronous AC - DC links in wind and wave generating systems. These power converters behave as non-linear loads to ac mains and inject harmonics and result in lower power -factor and Voltage dips, power losses increases, and then efficiency of the power system decreases. It is nothing but power quality problems occur at our micro grids. A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or disoperation of end user equipment’s. Utility distribution networks, sensitive industrial loads and critical commercial operations suffer from various types of outages and service interruptions which can cost significant financial losses. This dissertation is dedicated to a comprehensive study of static synchronous compensator (STATCOM) systems utilizing cascaded-multilevel converters (CMCs). Among flexible AC transmission system (FACTS) controllers, the STATCOM has shown feasibility in terms of cost effectiveness in a wide range of problem solving abilities from transmission to distribution levels. The control compensators were, therefore, randomly selected. Finally, simulations are shown the 3-level & 5-level MLI based STATCOM operation for sag mitigation. The proposed controller can effectively mitigate voltage sag during disturbances.