Posters

Abstract

Nowadays, the search for new renewable energy sources and the increase in efficiency of the existing ones is one of the main goals of the European Union policies. In this sense, wind energy sources have experienced a notable growth of new installed power, which has taken place both in onshore and offshore locations. Among both, most of the capacity is being installed onshore. Since best onshore sites are already used, some of the challenges that new wind farm (WF) installations are facing are, on one side, the more and more demanding grid codes and, on the other side, the weaker grids at the point of common coupling (PCC). The combined effect of these conditions typically leads to an increasing need of static synchronous compensator (STATCOM) installations in new WFs where doubly-fed induction generators (DFIGs) or full converter (FC) based wind turbines (WTs) are commissioned, thus increasing the overall WF cost. One alternative to STATCOMs for compensating the aforementioned issues are fast on-load tap changer (OLTC) transformers integrated at WT level. The use of fast OLTC WT transformers (electromechanical or novel electronic tap changer based) can provide huge benefits in cost reduction by allowing the WT to operate at optimum voltage levels. The benefits of the novel electronic OLTC transformers under development over their electromechanical counterparts are their fast tap change velocity and flexibility that will provide better response to the grid codes. In this research work, the benefits of the use of fast OLTC WT transformers are analysed and evaluated. Two different WF configurations are evaluated under various grid conditions to determine the benefits in terms of reactive power capabilities and cost that these OLTC transformers provide to the overall WF.