103 International Journal for Modern Trends in Science and Technology Volume: 2 | Issue: 05 | May 2016 | ISSN: 2455-3778 IJMTST An Improved UPQC Controller to Provide Grid-Voltage Regulation Vijayraj Patel 1 | Mr. Amit Agrawal 2 | Dr. Dharmendra Kumar Singh 3 1 M.Tech. Scholar (Power Systems), Dept. of EEE, Dr. CVRU, Bilaspur, Chhattisgarh, India 2 Assistant Professor, Dept. of EEE, Dr. CVRU, Bilaspur, Chhattisgarh, India 3 HOD, Dept. of EEE, Dr. CVRU, Bilaspur, Chhattisgarh, India In this paper presents an improved controller for the dual topology of the Unified Power Quality Conditioner (UPQC) extending its capability in power quality compensation, as well as in micro-grid applications. By the use of this controller, beyond the conventional UPQC power quality features including voltage sag/swell compensation, the iUPQC will also compensate reactive power support to regulate not only the load-bus voltage, but also the voltage at the grid-side bus. We can say, the iUPQC will work as a STATCOM at the grid side, while providing also the conventional UPQC compensations at the load terminal or micro-grid side. Experimental results are provided to verify the new functionality of the equipment. KEYWORDS: UPQC, Micro-grid, Power quality, STATCOM, Unified Power Quality Conditioner Copyright © 2015 International Journal for Modern Trends in Science and Technology All rights reserved. I. INTRODUCTION Certainly, the devices which are used in power-electronics have brought about great technological improvements. However, the increasing number of load which are driven by power-electronic devices generally in the industry has brought about uncommon power quality problems. In contrast, the loads which are driven by power-electronic devices generally require ideal sinusoidal supply voltage for function properly, whereas they are the most responsible ones for abnormal harmonic currents level in the distribution system. In this scenario, the devices can mitigate these drawbacks have been developed over the years. the solutions which is involve in this flexible compensator, known as the Unified Power Quality Conditioner (UPQC) [1] [2] [3] [4] [5] [6] [7] and the Static Synchronous Compensator (STATCOM) [8] [9] [10] [11] [12] [13].In the power circuit of a UPQC consists of a combination of a shunt active filter and a series active filter connected in a back-to-back configuration. This combination allows the simultaneous compensation of the load current and the supply voltage, so that the compensated current drawn from the grid and supply voltage delivered to the load are compensated to keep balanced and sinusoidal. The topology of the Unified Power Quality Conditioner – the iUPQC – was presented in[14] [15] [16] [17] [18] [19],where the shunt active filter behaves as an ac-voltage source and the series one as an ac-current source, both at the fundamental frequency This is a key point to design a better control gains, as well as to optimize the LCL filter of the power converters, which allows improving significantly the overall performance of the compensator [20]. The Static Synchronous Compensator (STATCOM) has been used widely in transmission networks to regulate the voltage with the help of dynamic reactive-power compensation. Nowadays, the STATCOM is largely used for voltage regulation [9], while the UPQC and the iUPQC have been selected as solution for more specific applications [21]. Moreover, these last ones are used only in specific cases, where their relatively high costs are justified by the power quality improvement it can provide, which would be not possible by using conventional solutions. By joining the extra functionality like a STATCOM in the iUPQC device, then the applications of this can be used in wide scenario, particularly in case of distributed generation in smart grids and as the coupling ABSTRACT