Energy curtailment analysis of offshore wind farms with DC series-parallel collection systems

Voltage balancing among the series connected wind turbines is one of the main technical challenges of offshore wind farms with DC series-parallel collection systems. Due to wake effect considerations, the power generated among the series connected wind turbines does not remain the same and the series connection causes the output voltages of the turbines to be distributed in proportion to their power output. Power curtailment is required in order to prevent the turbines being subjected to over-voltage and under-voltage conditions. In this paper, a voltage adjustment procedure is proposed to eliminate over-voltage and under-voltage of wind turbines. Based on the voltage adjustment procedure and the power generation model of wind turbines, the energy curtailment of a wind farm is analyzed with the consideration of wake effect due to series connection. A case study on several DC series-parallel collection configurations is presented to analyze the energy curtailment of wind farms using the voltage adjustment procedure.