SUPERCAPACITORS ENERGY STORAGE BASED DSTATCOM

Abstract

There is an exponential increase in the number of non-linear loads in power distribution networks especially due to advances in power electronics technology. Loads such as variable speed drives, IT equipment; fluorescent lights, etc. form a major portion of non-linear loads. Domestic appliances such as TVs, computers, SMPS, UPS, etc. cause harmonic pollution which leads to increased harmonic distortion of current and voltages. Single-phase loads on a three-phase supply system result in an unbalance in the system voltage and supply current. Harmonic pollution resulting from these loads distributed in an unbalanced manner adversely affects proper functioning of utility equipments. Unbalance in the voltages affects the performance of other loads, mainly induction motors. DSTATCOM is a custom power device that is used to regulate the voltage sags/swells in the distribution system for maintaining the rated voltage level at the terminal of load/sensitive loads. The DSTATCOM can inject three-phase voltages at point of common coupling whose magnitude and phase angle can be regulated with PI controller, while the supercapacitors are used to meet the instantaneous power demand since they can store and quickly release significant amounts of energy. This paper explores the use of Supercapacitors in DSTATCOM in place of battery for control of load terminal voltage.