Analyzing the Application of Crowbar And Statcom To Overcome Voltage Sags With Actual Field Data

Wind power generation is increasing rapidly in India and wind integration with the grid is considered as a promising source of energy, Double Fed Induction Generator (DFIG) being the most commonly used wind turbine generator, when integrated with the grid show challenges during grid faults. This paper focuses on the challenges faced by DFIG during the occurrence of voltage sags and the Low Voltage Ride Through (LVRT) methods to overcome it. The crowbar protection method is used to ride through voltage sags and FACTS device STATCOM is used to quickly sense the voltage sag and overcome it. Furthermore, simulation has done using MATLAB/ SIMULINK; analyses the performance of combined crowbar protection and STATCOM on DFIG during voltage sags. The results shows that crowbar protection method is a reliable method to ride through the fault and STATCOM helps to sense and overcome voltage sags quickly. Moreover, the grid code requirements are met. During the occurrence of grid faults grid codes prescribe that WT's must stay connected to the grid and should support the grid by generating reactive power to support the and restore the grid voltage quickly after the fault (3). Doubly Fed Induction Generator (DFIG) is dominant among the various wind turbine concepts due to its variable speed operation, its separately controllable active and reactive power and its partial rated power converter. The stator of the DFIG is directly connected with the grid and the rotor is connected to the grid through the power electronic converters. The back - to - back converters consists of two voltage source converters (ac-dc-ac) having a dc link capacitor connecting them. The generator side converter takes the variable frequency voltage and converts it into dc voltage. The grid side converter has the ac voltage from the dc link as input and voltage at grid parameters as output. The gearbox has the role of matching the speed between the blades and the rotor. The transformer couples the generator to the grid adjusts the voltage of the machine