Examenspresentation av Gabriel Hassellof

Master Thesis conducted at Hitachi Energy, under the supervision of Emil Eriksson

Opponents: Erik Johansson and Mattias Fransson

Abstract
With offshore wind power plants becoming more prevalent in quantity and size, there has been a heightened emphasis on the connection requirements for offshore wind power plants. The wind farms often utilize converters which produce harmonics, and reactive components such as long high voltage AC submarine cables for power export, further impacting the harmonics.

This thesis explores the voltage harmonics up to the 63:rd order seen at connection point between the offshore wind power plant and the main grid. It does so by describing the fundamentals of offshore wind power plant generation and simulating different cases of grid strength, cable length and harmonic injection from the main grid. It confirms the importance of studying low order harmonics and that the biggest impact on total harmonic distortion is grid strength. Longer cables result in greater total harmonic distortion for weak grids, and the opposite is found for stronger grids, which can have different causes. It also demonstrates that longer cables have greater lower harmonics compared to shorter cables.

Welcome!

Gabriel, Emil & Massimo