www.ijemr.net ISSN (ONLINE): 2250-0758, ISSN (PRINT): 2394-6962 240 Copyright © 2011-15. Vandana Publications. All Rights Reserved. Volume-5, Issue-2, April-2015 International Journal of Engineering and Management Research Page Number: 240-246 Transient Analysis of DFIG & Synchronous Generator Connected to Infinite Bus Dr. E.V.C.Sekhara Rao Assistant Professor, Department of EEE, CBIT, Hyderabad,. Telangana State, INDIA ABSTRACT The global electrical energy consumption is rising and there is a sudden increase in the demand of power generation. Large number of renewable energy units is now being integrated to power system for meeting and the rising demand of power generation. Slip ring induction machine in the variable speed wind turbine popularly known as double fed induction generator is mostly used in wind power generation. The main reason for the popularity of the doubly fed wind induction generators connected to the power network is their ability to supply power at constant voltage and frequency. Doubly Fed Induction generators are used commonly in wind generation purpose. When the slip of the induction motor is negative then it becomes Induction Generator. For a given speed by controlling the rotor voltage and phase angle the control of real and reactive power is obtained. This paper explains simulation study for d-q axis modeling of a DFIG for steady state and transient conditions. The simulation of wind electric generator system including wind turbine, the DFIG connected to a power system along with other wind mills will be simulated. MATLAB platform is used for Doubly Fed Induction Generator modeling. Keywords----- DFIG, PI Controller, Variable-Speed Wind Turbine, Grid interconnection I. INTRODUCTION Mainly energy sources can be divided into two categories as Renewable energy sources and Non- Renewable energy sources. Alternative energy sources include solar, wind, wave, tidal, hydroelectric and geothermal energy. Although they each have their own drawbacks, none of these energy sources produces significant air pollution, unlike conventional sources. Non-Renewable energy sources exist in a limited amount on earth. Thus all available material could eventually be completely used up. Coal, Oil and gas are considered as non-renewable energy sources because the rate of their formation is so slow on human time scales that they are using them without being replaced. Wind energy is available in abundance in our environment. When compared with the conventional sources of energy, wind energy is clean, efficient, and sustainable form of energy. The wind is a free, clean, and inexhaustible energy source. When the cost of supplying electricity to remote locations is expensive, wind energy provides a cost effective alternative. For conversion of this wind energy into electrical energy an induction generator is coupled with a wind mill offers an ideal solution. With increasing attention on renewable energy resources, wind energy conversion Systems (WECS) are today’s one of the most popular subject that the researches are intensively carried on. Due to the highly variable wind velocity, variable speed constant frequency wind generating system has distinct advantages than the traditional constant speed constant frequency wind generating system such as more effective power capture, lower mechanical stress and less power fluctuation. During last decades, an increasing interest has emerged on wind energy technology and it is considered to be one of the most important renewable energy resources. Today, it is one of the rapidly growing technologies and markets. By the end of 2010 the total installed capacity of wind energy is more than 160 GW all around the world. Wind turbines can either operate at fixed speed or variable speed. For a fixed-speed wind turbine the generator is directly connected to the electrical grid. For a variable speed wind turbine the generator is controlled by power electronic equipment. There are several reasons for using variable-speed operation of wind turbines; among those are possibilities to reduce stresses of the mechanical structure, acoustic noise reduction and the possibility to control active and reactive power. Most of the major wind turbine manufactures are developing new larger wind turbines in the 3-6 MW range. These large wind turbines are all based on variable-speed operation with pitch control using a direct-driven synchronous generator (without gear box) or a doubly- fed induction generator. Doubly-fed induction generators are most commonly used by the wind turbine industry (year 2002) for larger wind turbines. Both basic wind turbine concepts have proved their reliability and efficiency in energy production wind farms. But, this paper is emphasized on wound rotor induction machine, which can be used as a Doubly-Fed Induction Generator (DFIG).