Fault Ride Through Capability Analysis Of Wind Turbine With Doubly Fed Induction Generator

Abstract

The Doubly-fed induction generator (DFIG) based wind turbine is one of the most effective and frequently used wind power generation systems in the wind power industry. It offers several enticing benefits, including consistent output voltage, low cost, high performance, independent control of active and reactive power, and improved power quality. Despite any of the aforementioned advantages of DFIGs, it is precisely impacted by grid interruption because the stator winding of DFIG is directly connected to the grid and the rotor is connected to the grid via a fault-prone power converter. In early times, when a fault occurred, these generators were required to disconnect from the grid to secure the generator and power converters. However, due to the increased penetration of wind turbines into the power system, grid operators demanded that the wind turbines remain connected to the grid, as disconnecting them would further disrupt the grid and have a significant effect on the stability of the grid operation. The ability of a generator to remain connected to the grid under grid fault is known as fault ride-through (FRT) capability. Any sudden appearance of a fault, such as symmetrical or asymmetrical faults, can cause a reduction in stator voltage, oscillations in stator and rotor currents, DC-link overvoltage, and electromagnetic torque pulsations. Such a phenomenon can considerably affect the performance of the DFIG under a transient state if an appropriate protection system is not considered. Thus, in this thesis work, the crowbar protection system is employed for the improvement of the FRT capability of the wind turbine. The performance of the DFIG both under steady-state and transient state conditions is examined with and without this protection scheme. Furthermore, the analysis of the machine is rendered by integrating the crowbar protection system with the Battery Energy Storage System (BESS) for a much effective outcome in enhancing the ability of the machine to drive the fault. Moreover, the MATLAB/Simulink 2015a software is used for modeling and simulation and all system parameters are obtained from ADAMA-II Wind Farm.