In the vast, windswept expanses of the ocean, offshore wind farms are becoming the new frontier of renewable energy. However, as these farms grow in size and capacity, so too do the challenges they face, particularly in maintaining stable power transmission. A recent study published in the Chinese Society for Electrical Engineering Journal of Power and Energy Systems, led by Yiming Rao from Shanghai Jiao Tong University, tackles one of the most pressing issues: wideband oscillations that can threaten the stability of power systems connected to offshore wind farms.
Offshore wind farms, particularly those using modular multilevel converter-based high-voltage DC (MMC-HVDC) transmission technology, are becoming increasingly common. This technology is ideal for integrating offshore wind power into the grid, but it’s not without its challenges. Wideband oscillations—rapid fluctuations in power that can span a wide range of frequencies—pose a significant threat to the stability of these systems. Existing methods to mitigate these oscillations are often designed for specific cases and fall short when it comes to handling the wideband variety.
Rao and his team set out to address this gap. “Existing oscillation mitigation methods are usually designed for specific oscillation cases and are not capable of mitigating wideband oscillations,” Rao explains. “We needed a more adaptive solution.”
The researchers developed an adaptive wideband oscillation mitigation control for MMC-HVDC systems connected to offshore wind farms. They began by deriving analytical wideband impedance models of the wind farm side MMC (WFMMC) and offshore wind farm composed of permanent-magnetic synchronous generator-based wind turbine generators (PMSG-WTGs). These models were then verified through time-domain simulations, providing a solid foundation for their work.
The team revealed a wideband oscillation mechanism through impedance-frequency characteristics, which allowed them to propose their adaptive control method. The working principle and implementation process were elaborated, and case studies were conducted to verify the effectiveness of the proposed control. These included a sub-/super-synchronous oscillation (SSO) event and a high-frequency oscillation (HFO) event, both of which are critical for understanding and mitigating wideband oscillations.
The implications of this research are significant for the energy sector. As offshore wind farms continue to grow, the ability to adaptively mitigate wideband oscillations will be crucial for maintaining stable and reliable power transmission. This could lead to more efficient and cost-effective operations, reducing downtime and maintenance costs, and ultimately making offshore wind power a more viable and attractive option for energy providers.
Rao’s work, published in the Chinese Society for Electrical Engineering Journal of Power and Energy Systems, represents a significant step forward in addressing one of the key challenges in offshore wind power integration. As the demand for renewable energy continues to rise, innovations like this will be essential in shaping the future of the energy sector.