Enhancing the Grid Support From DFIG-Based Wind Farms During Voltage Events

Abstract

With the increasing penetration of renewable energy generators, the world is positively progressing toward the goal of sustainable development. However, the grid strength and inertia are decreasing due to the associated technological limitations. To this end, this research paper proposes a novel approach to enhance the support from DFIG-based wind farms with their existing capacity during critical events like voltage-ride-through. The effectiveness of the method is tested with a reactive power-prioritizing grid code of India. The proposed optimization framework achieves this objective in three stages. The first stage maximizes the wind farm's reactive power reserve in maximum power and de-loaded modes. The second stage uniquely distributes the control references to achieve minimal transitional pitch action between these modes for reduced wear and tear while honoring the maximum reactive power capability. The third stage generates lookup tables of control limits for maximal active power support within the grid code and the system constraints. The optimization is a one-time process for a specified farm geometry. Since the method is lookup table-based, the mode transitions are real-time feasible. The simulation test cases with the benchmark model demonstrate the efficacy of the proposed strategy, especially when the Wake Effect is prominent.