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Abstract This thesies classifies three types of protections for the DFIG :the conventional crowbar protection the series crowbar protection and a new proposed crowbar protection the thesis illustrates the dynamic behavior of the DFIGs under different studies.Enhancement protection and operation of the doubly fed induction generator (DFIG) during the grid fault are investigated in this thesisWind power growth with a 20% annual rate has been experienced the fastest growth among all renewable energy sources since five years ago. It is predicted that by 2020 up to 12% of the world’s electricity will have been supplied by wind power so Wind generation is becoming the most development. During 2011, 40 GW of wind generation capacity was added to power networks around the world. Worldwide wind capacity has reached 254 GW, by the end of June 2012, 273 GW expected for full year, indicating a 25% annual average growth rate in wind energy capacity.DFIG has recently received much attention as one of preferred technology for wind power generation. Compared to a full rated converter system, the use of DFIG in a wind turbine offers many advantages, such as reduction of inverter cost, the potential to control torque and a slight increase in efficiency of wind energy extraction.The DFIG is very sensitive to any grid disturbances, if a severe voltage dip occurred due to grid fault, high currents will pass through stator and rotor windings and also a very high DC voltage would be induced in converter circuit, it may lead to damage the converter circuit and the DFIG windings. Protection systems are essential to avoid the disconnection of the DFIGs from the network during fault.This thesis classifies three types of protections for the DFIG: the conventional crowbar protection, the series crowbar protection and a new proposed crowbar protection (the outer crowbar protection). This thesis illustrates the dynamic behavior of the DFIGs under different studies: Without protection With conventional crowbar protection With series crowbar protection With outer crowbar protection This thesis produces strategy of determining the suitable protection method for the doubly fed induction generators to be applied during the grid fault.In the last decade the renewable energy sources, especially wind generation, have gained significant interest throughout the world due to the phasing out of conventional electrical power generation, this is caused by the global goals for the reduction of greenhouse gas emissions [1].Wind is a form of solar energy, winds are caused by the uneven heating of the atmosphere, the irregularities of the earth’s surface, and rotation of the earth. Wind flow patterns are modified by the earth’s terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing and even generating electricity. The terms wind energy or wind power describes the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical powerTo meet the growing energy demands in the future by taking advantage of the abundant energy in wind so as to protect the environment from CO2 released through some of the more conventional ways of generating power. The worldwide wind capacity reached 254 GW by the end of June 2012, out of which 16.546 GW were added in the first six months of 2012. This increase represents 10 % less than in the first half of 2011, when 18.405 GW were added. The global wind capacity grew by 7% within six months (2% less than the same period in 2011) and by 16.4 % on an annual basis (mid-2012 compared with mid-2011). In comparison, the annual growth rate in 2011 was 20. 3 %. [2], Figure 1-1 shows the expected annual and cumulative wind installations by 2020.Wind power growth with a 20% annual rate has been experienced the fastest growth among all renewable energy sources since five years ago. It is predicted that by 2020 up to 12% of the world’s electricity will have been supplied by wind power so Wind generation is becoming the most development. During 2011, 40 GW of wind generation capacity was added to power networks around the world. Worldwide wind capacity has reached 254 GW, by the end of June 2012, 273 GW expected for full year, indicating a 25% annual average growth rate in wind energy capacity.DFIG has recently received much attention as one of preferred technology for wind power generation. Compared to a full rated converter system, the use of DFIG in a wind turbine offers many advantages, such as reduction of inverter cost, the potential to control torque and a slight increase in efficiency of wind energy extraction.The DFIG is very sensitive to any grid disturbances, if a severe voltage dip occurred due to grid fault, high currents will pass through stator and rotor windings and also a very high DC voltage would be induced in converter circuit, it may lead to damage the converter circuit and the DFIG windings. Protection systems are essential to avoid the disconnection of the DFIGs from the network during fault. |