Power quality and flicker performance of the tidal energy converter, SeaGen

Paper in proceeding, 2012

SeaGen is a 1.2MW tidal energy converter (TEC) under development by Marine Current Turbines (MCT) Ltd. It has been in regular production since May 2009 and is the world's largest grid-connected TEC which has produced over 3, 000MWhr to date. A research project was undertaken by ESB International, Chalmers University and MCT to measure, analyse and characterise the power quality performance of the SeaGen device with a particular emphasis on developing an understanding of the levels of flicker emissions during operations and the determination of the device's flicker co-efficients. As no standard exists for this work, the existing standard used for wind turbine power quality performance assessment was adapted and the deviations from it are outlined in the paper and the justifications for the different approaches used. This paper presents a summary of many of the results of this research project but has a particular emphasis on a comparative analysis of the SeaGen PQ performance against comparably sized wind turbines. The technical paper also outlines the characteristic features of the TEC itself and its power take-off system, followed by the electrical and marine environments of its location. The research work found that the power quality performance of the TEC was generally good and the results are conservative as a much larger array of devices connected to the transmission grid would be expected to have significantly better power quality performance due to diversification and cancellation between them. The flicker co-efficients were determined mainly following the procedure in IEC61400-21 (adapted as outlined) and were found to be comparable to wind turbines with very good power quality performance. The harmonic performance of the device (both voltage and current) was also very good.