193 International Journal for Modern Trends in Science and Technology Voltage Sag and Support in Power Control on Distributed Generation Inverters M.A.Nabi 1 | S. Anusha 2 1 Associate Professor, Department of EEE, SVR Engineering College, Nandyal, Andhra Pradesh, India 2 PG Scholar, Department of ECE, SVR Engineering College, Nandyal, Andhra Pradesh, India To Cite this Article M.A.Nabi, S.Anusha, DzVoltage Sag and Support in Power Control on Distributed Generation Invertersdz, International Journal for Modern Trends in Science and Technology, Vol. 02, Issue 11, 2016, pp. 193-198. During voltage sags, continuous power delivery from distributed generation systems to the grid is desirable for the purpose of grid support. Ancillary services for distributed generation (DG) systems become a challenging issue to integrate renewable-energy sources into the grid. Voltage control is one of these ancillary services which can ride through and support the voltage under grid faults. In order to facilitate the control of distributed generation systems adapted to the expected change of grid requirements, flexible voltage support control scheme is proposed for inverter based distributed generation, aiming at regulating voltage limits and reactive power injection to remain connected and supports the grid under fault. In three-phase balanced voltage sags, the inverter should inject reactive power in order to raise the voltage in all phases. In one- or two-phase faults, the main concern of the DG inverter is to equalize voltages by reducing the negative symmetric sequence and clear the phase jump. Thus, over and under voltage can be avoided, and the proposed control scheme prevents disconnection while achieving the desired voltage support service which can be analyzed and simulated by using Matlab/Simulink environment. The main contribution of this work is the introduction of a control algorithm for reference current generation that provides flexible voltage support under grid faults. KEYWORDS: Distributed Generation Inverters Reactive power control, voltage sag, voltage support Copyright © 2016 International Journal for Modern Trends in Science and Technology All rights reserved. I. INTRODUCTION The recent trends in small scale power generation using the with the increased concerns on environment and cost of energy, the power industry is experiencing fundamental changes with more renewable energy sources (RESs) or micro sources such as photovoltaic cells, small wind turbines, and micro turbines being integrated into the power grid in the form of distributed generation (DG). These RES-based DG systems are normally interfaced to the grid through power electronics and energy storage systems[1] One of the most critical sections of the control system for a distributed generation (DG) unit’s interconnection to the utility grid lies within the grid-connected converter’s control and protection system; specifically the islanding detection algorithms. Through this controller subsection, the system is able to determine whether or not it is safe to remain connected to the grid. These islanding detection algorithms, which are integrated into the control system, are mainly present to prevent the undesirable feeding of loads during fault conditions and disconnections from the grid, whether or not the disconnection as intentional[2] This is required by standards since the creation of such “power islands” is forbidden. Thus, in effect, ABSTRACT International Journal for Modern Trends in Science and Technology Volume: 02, Issue No: 11, November 2016 ISSN: 2455-3778 http://www.ijmtst.com