Control Theory and Informatics www.iiste.org ISSN 2224-5774 (print) ISSN 2225-0492 (online) Vol 1, No.2, 2011 6 | Page www.iiste.org Investigation on D-STATCOM Operation for Power Quality Improvement in a Three Phase Three Wire Distribution System with a New Control Strategy S. SURESH (Corresponding author) Associate Professor/EEE, Kalaignar Karunanidhi Institute of Technology, Kannampalayam Post, Coimbatore, India Tel: +91 9500680004 Email: engrsuresh@gmail.com N.DEVARAJAN Professor/EEE, Government College of Technology, Coimbatore, India, Tel: +91 9443245163 Email: profdevarajan@ieee.org M.GEETHA Assistant Professor/ECE, Kalaignar Karunanidhi Institute of Technology, Kannampalayam Post, Coimbatore, India Tel: +91 9600680004 Email: engrsugeetha@gmail.com V. RAJASEKARAN UG Scholar / EEE, Kalaignar Karunanidhi Institute of Technology, Kannampalayam Post, Coimbatore, India Tel: +91 9789572582 Email: vrajasekaran@ieee.org Abstract This paper deals with the issue of modeling and analysis of power controllers, power electronic-based equipment aimed at improving the reliability, stability and quality of power flows in low voltage distribution networks. A new control scheme is proposed to generate the PWM signal based on the measurements of voltage, and no reactive power measurements are required. The operation of the proposed control method is presented for D-STATCOM. Simulations and analysis are carried out in MATLAB/PLECS with this control method for the proposed systems. The reliability of the control scheme in the system response to the voltage instabilities due to system faults or load variations is proved obviously in the simulation results. Keywords: D-STATCOM, PWM, VSC, MATLAB/PLECS. 1. INTRODUCTION The advancement in the technology, in the last decade has seen drastically increase in the electrical loads and multiplying in numbers of complexity of the equipment that is highly sensitive to poor quality of distribution. Several large industrial users are reported to have experienced huge financial losses as a result of even minor lapses in the quality of electricity supply. Mineski et al. (2004) reported that many efforts have been made to remedy the situation with solutions based on the use of the latest power electronic technology. The system developed by Reed & Giroux (1999) is implemented a number of flexible control strategies are developed to improve the efficiency and control of the emerging power system applications. Among this, the algorithm taken from Iravani & Crow (1994 & 2000) distribution Static Compensator (D-STATCOM) based on the VSC principle has been used in this paper to perform the modeling and analysis of such controllers for a wide range of operating conditions. MATLAB/PLECS' highly-developed simulation software with the graphical interface has been used for implementation of the PWM controller reported in this paper for the D-STATCOM. It relies only on voltage measurements for its operation. Effects of load variation, voltage sags and