Advanced Fault Ride Through Techniques for Double Fed Induction Generator Wind Turbines Integrated with Modular Multilevel Converter based HVDC systems: A Comprehensive Review

Abstract

Faults in electrical networks pose significant challenges and can lead to disruptions in the system's operation. Control and automation strategies play a crucial role in ensuring the safety and stability of the network. The constraints such as slow dynamic response, inability to remote network switching, high fault clearing time, and loss minimization issues, are critical concerns that impact the effectiveness of fault clearing techniques. Resolving these limitations is essential for ensuring the reliability and efficiency of the system. In the context of wind energy technologies, the perturbation of power flow from a wind turbine during a fault can cause the intermediate circuit voltage between the machine side converter and line side converter to rise significantly. This elevation in voltage occurs due to the accumulation of energy in the DC link capacitor [1]. This paper deals with low voltage ride through (LVRT) capability of wind turbines (WTs) and in particular those driven by Doubly Fed Induction Generator (DFIG). The Low Voltage Ride through (LVRT) capability of wind turbines, particularly those employing Doubly Fed Induction Generators (DFIGs), is indeed a critical concern for widespread wind farm deployment. As the penetration of wind turbines into grids increases, grid connection codes often mandate that these turbines remain connected during and after short-term faults to uphold grid reliability. This necessity leads to the requirement of maintaining LVRT, where wind turbines must continue operating with as little as 15% (or even less) remaining voltage at the point of common coupling (PCC). In addition, it is required for Wind Turbine’s to contribute to system stability during and after fault clearance. Meeting LVRT standards for DFIG-based wind turbines involves addressing two main challenges: namely rotor inrush current that may exceed the converter limit and the dc link overvoltage [3]. Indeed, Fault Ride-Through (FRT) capability is a crucial aspect for offshore wind farms (OWFs), especially when they are connected to onshore AC grids through Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) transmission systems [2].