The increase in electricity demand places its focus on renewable energies as sustainable energy resources. Wind energy is one of the most important green energy sources. The doubly fed induction generator (DFIG)-based wind farm has now gained prominence due to its many advantages, such as variable speed operation and autonomous control of active and reactive power. When the DFIG stator windings are directly connected to the power grid, when a grid fault occurs, some unwanted high current may be produced in the rotor windings, and the protection system will prevent the rotor side converter (RSC) from operating. Therefore, voltage stability is a significant factor in maintaining the DFIG-based wind farm in operation during grid faults and disturbances. This paper applies a static synchronous compensator (STATCOM) to restore the voltage levels of the Egyptian power grid connected to Al Zafarana-5th stage wind farm, which is made of 100 Gamesa G52/850 kW DFIG machines. In this paper, the STATCOM is controlled by a proportional integral (PI) and is compared with a STATCOM controlled by fuzzy logic control (FLC). For simulation, the MATLAB/SIMULINK environment is used. Moreover, the simulation results show that STATCOM devices with fuzzy logic controllers improve the effects of grid faults and disturbances such as a single line to ground fault, a line to line fault, voltage sag, and voltage swell as compared with STATCOM with PI controllers. Also, STATCOM devices based on FLC improve the stability and power quality of the system and the power system restoration procedures for the existing and futureplanned wind farms.
As a key portion of renewable energy resources (RESs), wind energy penetration is rapidly deployed. The effects of grid faults on grid-connected wind turbines (WTs) are causing problems for wind energy producers. To meet the necessary requirements, additional resources and technical interventions are needed. One of these requirements is low voltage ride-through (LVRT) of doubly fed induction generator (DFIG)-based WTs. This means that DFIG-WTs must stay connected to the grid during transient grid faults and supply active and reactive power after the fault is cleared. Many techniques for improving the LVRT capability of DFIG-WTs have been developed and this paper examines them. The paper also evaluates how well they align with grid codes, and offers case studies and simulations of the selected key techniques. Lastly, this paper provides guidelines and suggested designs for the LVRT techniques for DFIG-WTs to ensure they meet local grid codes.
Wind energy currently represents a very important source of renewable energy sources (RESs). Among other RESs, Wind Energy Conversion Systems (WECS) with Doubly Fed Induction Generators (DFIG) have become more competitive globally. Due to their improved dynamic performance, flexible regulation of active and reactive power, superior power quality, variable speed operation, and four-quadrant converter operation. Grid-connected DFIG-based WECS are vulnerable to disruptions in the grid because of the direct connection of stator windings to the grid. The ability of the wind turbine (WT) to maintain connectivity during grid faults refers to the low-voltage ride-through (LVRT). When DFIG-based WTs are used to power networks, the grid codes require that they stay connected and support the stability of the system in a range of transient grid fault scenarios. As a result, DFIG-WTs are subjected to various protective measures to improve LVRT capacity. To increase DFIG's LVRT capabilities, a lot of good research has taken place in the literature. So, this study centers on exploring the recently emerging LVRT techniques for DFIG-WTs to help wind energy producers/operators select the appropriate technique through critical analysis. According to a wide range of articles, LVRT techniques can be classified into two groups: exterior and interior techniques; each group has its merits and demerits. Also, a thorough discussion has been made to assess the performance. Different case studies using
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