Why is harmonic mitigation crucial in the power electronics of a grid-connected WEC?

Harmonic mitigation is crucial in the power electronics of a grid-connected Wave Energy Converter (WEC) because the power converters used to interface the WEC with the grid can generate harmonic currents. Harmonics are sinusoidal currents or voltages with frequencies that are integer multiples of the fundamental grid frequency (e.g., 50 Hz or 60 Hz). These harmonic currents can cause several problems on the electrical grid. First, they can increase the total harmonic distortion (THD) of the grid voltage, which can negatively impact the performance and lifespan of other equipment connected to the grid. High THD can cause overheating of transformers and motors, misoperation of sensitive electronic devices, and interference with communication systems. Second, harmonic currents increase the RMS current flowing through the grid infrastructure, leading to increased losses in transmission lines and transformers. This reduces the overall efficiency of the grid and can potentially overload equipment. Third, some harmonic frequencies can resonate with the grid impedance, causing voltage amplification and potentially leading to equipment damage or grid instability. Therefore, harmonic mitigation techniques, such as using filters or advanced converter control strategies, are essential to ensure that the WEC meets grid code requirements and does not negatively impact the power quality and stability of the electrical grid.