International Journal of Advanced Scientific Technologies in Engineering and Management Sciences (IJASTEMS-ISSN: 2454-356X) Volume.1,Issue.6,November.2015 www.ijastems.org Page20 Renewable Energy Source Integrated at Distribution Level for Power Quality Improvement P. Srikanth 1 , Dr.N.Sambasiva Rao 2 , I.Prasanna Kumar 3 PG Scholar, Dept. of EEE, NRI Institute of Technology, Agiripalli (M), Vijayawada, India 1 Professor, Dept. of EEE, NRI Institute of Technology, Agiripalli (M), Vijayawada, India 2 Assistant Professor, Dept. of EEE, NRI Institute of Technology, Agiripalli (M), Vijayawada, India 3 ABSTRACT: Today, Increase the demand of Renewable energy resources (RES) in distribution systems because total energy demand is supplied by the burning of fossil fuels and it is limited. In this paper presents a control strategy of three phase four wire grid interfacing inverter to effectively utilize the renewable energy Source with grid. Controlling of inverter in such a way that to utilize the following function 1)compensate load current (i.e. reduce harmonics), 2compensate load voltage (i.e. reduce harmonics), 3)compensate load reactive power and load neutral Current. The Renewable Energy Source may be Solar or Wind depends on distribution system voltage level. All these works of the inverter is done either individually or combined to over come the unbalanced effects of all types of linear, nonlinear ,balance or unbalance loads at distribution level. This new control concept is demonstrated with extensive. KEYWORDS: Fuels, Renewable energy resources, Reduce harmonics I.INTRODUCTION Electric utilities and end users of electric power are becoming increasingly concerned about meeting the growing energy demand. Seventy five percent of total global energy demand is supplied by the burning of fossil fuels. But increasing air pollution, global warming concerns, diminishing fossil fuels and their increasing cost have made it necessary to look towards renewable sources as a future energy solution. Since the past decade, there has been an enormous interest in many countries on renewable energy for power generation. The market liberalization and government’s incentives have further accelerated the renewable energy sector growth. (Renewable energy source (RES) integrated at distribution level is termed as distributed generation DG). The utility is concerned due to the high penetration level of intermittent RES in distribution systems as it may pose a threat to network in terms of stability, voltage regulation and power-quality (PQ) issues. Therefore, the DG systems are required to comply with strict technical and regulatory frameworks to ensure safe, reliable and efficient operation of overall network. With the advancement in power electronics and digital control technology, the DG systems can now be actively controlled to enhance the system operation with improved PQ at PCC. However, the extensive use of power electronics based equipment and non-linear loads at PCC generate harmonic currents, which may deteriorate the quality of power. Generally, current controlled voltage source inverters are used to interface the intermittent RES in distributed system. Recently, a few control strategies for grid connected inverters incorporating PQ solution have been proposed. In an inverter operates as active inductor at a certain frequency to absorb the harmonic current. But the exact calculation of network inductance in real-time is difficult and may deteriorate the control performance. A similar approach in which a shunt active filter acts as active conductance to damp out the harmonics in distribution network is proposed. A control strategy for renewable interfacing inverter based on – theory is proposed. In this strategy both load and inverter current sensing is required to compensate the load current harmonics. The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in the power system network. Active power filters (APF) are extensively used to compensate the load current harmonics and load unbalance at distribution level. This results in an additional hardware cost. However, in this paper authors have incorporated the features of APF in the, conventional inverter interfacing renewable with the grid, without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is most of the time underutilized due to intermittent nature of RES. II.DISTRIBUTED GENERATION Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy generates electricity from many small energy sources. Currently, industrial countries generate most of their electricity in large centralized facilities, such as fossil fuel (coal, gas powered) nuclear or hydropower plants. These plants have excellent economies of scale, but usually transmit electricity long distances and negatively affect the environment.