Resonance damping in array cable systems by wind turbine active filtering in large offshore wind power plants

The application of active filtering in large offshore wind power plants (WPPs) is presented in this study. The harmonic challenges such as sources of harmonic emission and resonances are identified and briefly explained. Also modern remedial harmonic mitigation methods as of active filtering are described and their application in real-life WPP systems demonstrated. It is underlined that WPP components such as widespread medium-voltage cable system and offshore grid transformers can introduce significant low-frequency parallel resonances which can cause a significant harmonic voltage distortion at the point of common coupling. Active filtering in modern grid-side converters used in wind turbines is applied simultaneously keeping sufficient harmonic/noise rejection. Extensive harmonic stability studies are also shown to prove the overall system robustness.