In the vast, windswept expanses of the ocean, a silent revolution is underway. Offshore wind farms are becoming increasingly vital to the global energy mix, but transmitting that power back to shore efficiently and reliably is a complex challenge. A recent study published in Zhongguo dianli (China Electric Power) sheds new light on how to optimize these systems, with significant implications for the future of renewable energy.
At the heart of the research is Maoxin Chen, a specialist from State Grid Fujian Electric Power Co., Ltd., based in Fuzhou, China. Chen and his team have been delving into the intricacies of grid-forming control solutions for offshore wind farms connected via diode rectifier-based high voltage direct current (HVDC) transmission. Their findings could reshape how we think about integrating large-scale offshore wind power into the grid.
The crux of the issue lies in maintaining voltage and frequency stability in the offshore alternating current (AC) grid. This is where grid-forming control (GFM) comes into play. GFM enables wind turbines to support the grid by acting like conventional power plants, providing both active and reactive power control. However, not all GFM schemes are created equal.
Chen’s research compares two prominent GFM schemes: the widely studied Q/f droop-based control and the newer P/f droop-based control. The Q/f droop-based scheme, which adjusts reactive power (Q) based on frequency (f), has been the subject of extensive research. However, Chen’s analysis reveals a significant drawback: it exhibits coupling characteristics between active and reactive power control paths. This coupling can lead to power oscillations between multiple wind turbines, potentially destabilizing the system.
On the other hand, the P/f droop-based scheme, which adjusts active power (P) based on frequency, shows a natural power decoupling characteristic. This decoupling makes it more stable and robust under different load conditions, a crucial factor for the synchronous and stable operation of hundreds of wind turbines in large offshore wind farms.
“Our detailed analysis based on the small signal model shows that the P/f droop-based GFM control scheme has better stability robustness,” Chen explains. “This makes it more conducive to achieving the synchronous and stable operation of hundreds of wind turbines in offshore high-capacity wind farms.”
The commercial impacts of this research are substantial. As offshore wind farms grow in size and capacity, ensuring stable and efficient power transmission becomes increasingly critical. The P/f droop-based GFM control scheme offers a promising solution, potentially reducing operational costs and improving the reliability of offshore wind power integration.
Moreover, this research could influence the design and implementation of future offshore wind farms. By adopting the P/f droop-based GFM control scheme, developers can enhance system stability and efficiency, making offshore wind power a more attractive and viable option for energy providers.
As the energy sector continues to evolve, innovations like those highlighted in Chen’s research will play a pivotal role in shaping the future of renewable energy. By optimizing grid-forming control solutions, we can unlock the full potential of offshore wind power, paving the way for a more sustainable and resilient energy landscape. The study, published in Zhongguo dianli, which translates to China Electric Power, underscores the growing importance of advanced control strategies in the renewable energy sector. As offshore wind farms continue to expand, the insights from this research will be invaluable in ensuring their successful integration into the global energy mix.