Effect of short-circuit in stator windings on the operation of doubly-fed induction generators operating in a wind power system

Introduction. Wind energy has been a clean and renewable source of electricity in recent decades, making a significant addition to overall generation, and wind power is one of the most popular sources of renewable energy. Problem. Accurate modeling of wind turbine generators is critical to improve the efficiency of power systems. Doubly-fed induction generator (DFIG) stands out for its economic advantages associated with the use of frequency converters and induction machines. Increasing operating and maintenance costs of wind turbines highlight the need for early fault identification to optimize costs and ensure reliable operation. The goal of this work is to develop a simplified yet effective model for analyzing stator winding short-circuits in DFIGs operating in wind turbines. The model uses line-to-line voltages as inputs and explicitly considers the neutral-point voltage variation under fault conditions. Methodology. The problem was solved using spectral analysis, the model was implemented for 4 kW DFIG wind turbine in MATLAB to validate its effectiveness. Results. The simulation results confirm the effectiveness of the proposed approach for timely fault detection and analysis. It demonstrates computational simplicity by accurately capturing the main fault characteristics, which is preferable to traditional methods such as symmetrical components and FEM. The scientific novelty of the work lies in a methodology for modeling DFIG during stator short-circuits, integrating the effect of elevated neutral voltage during faults using line-to-line voltages in the base model. It also takes into account phenomena such as magnetic saturation, gap effects, and skin effects. The simplicity of the model makes it suitable for condition monitoring and validation of fault-tolerant control algorithms, which distinguishes it from more complex methods such as symmetrical components or the FEM. Practical value. The proposed model offers a pragmatic and reliable approach for monitoring and analyzing defects in DFIG wind turbines. Its versatility and efficiency improve the optimization of maintenance costs and reliability of renewable energy systems. References 27, tables 2, figures 8.