D. Prasad et al Int. Journal of Engineering Research and Application www.ijera.com ISSN : 2248-9622, Vol. 3, Issue 6, Nov-Dec 2013, pp.398-403 www.ijera.com 398 | Page Fuzzy Logic Control of D-Statcom for Power Quality Improvement D. Prasad* T. Sandeep Kumar** Dr.B.Venkata Prasanth*** Dr.K.S.G.Sankar**** *Department of Electrical and Electronics Engineering, QISCET, ONGOLE **Department of Electrical and Electronics Engineering, QISCET, ONGOLE ***Department of Electrical and Electronics Engineering, QISCET, ONGOLE ****Department of Electrical and Electronics Engineering, QISCET, ONGOLE ABSTRACT A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a mis-operation of end user equipments. 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. With the restructuring of power systems and with shifting trend towards distributed and dispersed generation, the issue of power quality is going to take newer dimensions. This paper presents the Fuzzy Logic control of D-statcom to enhancement of voltage sags, harmonic distortion and low power factor using Distribution Static Compensator (D-STATCOM) with LCL Passive Filter in distribution system. The model is based on the Voltage Source Converter (VSC) principle. The D-STATCOM injects a current into the system to mitigate the voltage sags.LCL Passive Filter was then added to D-STATCOM to improve harmonic distortion and low power factor. Time domain simulations are used to verify the operation of the D-statcom with various faults and fault resistance. Keywords- D-STATCOM, Voltage Sags, Voltage Source Converter (VSC), LCL Passive Filter, Total harmonics Distortion (THD) I. INTRODUCTION Power quality is certainly a major concern in the present era. It becomes especially important with the insertion of sophisticated devices, whose performance is very sensitive to the quality of power supply. A Power quality problem is an occurrence manifested as a nonstandard voltage, current or frequency that results in a failure or a mis-operation of end user equipments. Modern industrial processes are mainly based on electronic devices such as PLC’s, power electronic devices, drives etc., and since their controls are sensitive to disturbances such as voltage sag , swell and harmonics , voltage sag is most important power quality problems It contributes more than 80% of power quality (PQ) problems that exist in power systems, and more concern problems faced by many industries and utilities. By definition, a voltage sag is an rms (root mean square) reduction in the AC voltage at the power frequency, for duration from a half-cycle to a few seconds. Voltage sag is caused by a fault in the utility system, a fault within the customer’s facility or a large increase of the load current, like starting a motor or transformer energizing. Typical faults are single-phase or multiple-phase short circuits, which leads to high currents. The high current results in a voltage drop over the network impedance. Voltage sags are not tolerated by sensitive equipments used in modern industrial plants such as process controllers; programmable logic controllers (PLC), adjustable speed drive (ASD) and robotics. Various methods have been applied to reduce or mitigate voltage sags. The conventional methods are by using capacitor banks, introduction of new parallel feeders and by installing uninterruptible power supplies (UPS). However, the PQ problems are not solved completely due to uncontrollable reactive power compensation and high costs of new feeders and UPS. The D-STATCOM has emerged as a promising device to provide not only for voltage sags mitigation but a host of other power quality solutions such as voltage stabilization, flicker suppression, power factor correction and harmonic control. In this paper, the configuration and design of the DSTATCOM with LCL Passive Filter are analyzed. It is connected in shunt or parallel to the 11 kV test distribution System. It also is design to enhance the power quality such as voltage sags, harmonic distortion and low power factor in distribution system . This paper is divided into several sections. Section II describes about the voltage sag and swell. Section III indicates the Modeling and Controlling of D-statcom. Fuzzy logic controller is discussed in section IV and System Implementation and Simulation results are discussed in sections V and VI respectively. RESEARCH ARTICLE OPEN ACCESS