In a significant advancement for the renewable energy sector, researchers have unveiled a novel strategy to mitigate transient overvoltage issues that arise during commutation failures in high voltage direct current (HVDC) transmission systems. This research, led by Shuyi Wang from the School of Electrical Engineering at Shandong University, offers new hope for enhancing the stability of wind power generation, particularly for virtual synchronous generator-based doubly fed induction generators (VSG-DFIGs).
As the global energy landscape shifts toward renewable sources, the integration of wind power has surged, presenting both opportunities and challenges. Traditional wind turbine generators often struggle to provide the inertia and reactive power support that synchronous generators naturally offer. Wang’s team has tackled this problem head-on, proposing an innovative control strategy that not only addresses transient overvoltage but also enhances the operational efficiency of wind farms connected to HVDC systems.
“Our research focuses on improving the response time of VSG-DFIGs during voltage faults,” Wang stated. “By adjusting the automatic voltage regulation (AVR) control parameters, we can better manage reactive power and significantly reduce the risk of wind turbine disconnections during commutation failures.”
The study highlights that during a commutation failure, the voltage at the sending end of an HVDC system can experience rapid fluctuations, leading to a critical need for wind turbines to respond effectively. The researchers found that by switching the time constant of the AVR control and adjusting the droop coefficient, the reactive power response lag could be minimized. This adjustment allows VSG-DFIGs to more effectively absorb excess reactive power, thereby stabilizing the grid and preventing disconnections of wind turbines—a scenario that could lead to a cascade of failures in the system.
Simulation results using the DIgSILENT/PowerFactory platform demonstrated the efficacy of the proposed method, revealing a marked decrease in transient overvoltage occurrences during continuous low and high voltage events. Wang emphasized the commercial implications of this research: “By enhancing the reliability of wind power systems, we can ensure that HVDC transmission systems operate closer to their rated capacity, ultimately leading to more efficient energy delivery and reduced operational costs for wind farm operators.”
As countries continue to expand their renewable energy portfolios, the findings from this research published in the journal ‘Energies’ (translated as ‘Energies’) could play a pivotal role in shaping future developments in wind power technology. The ability to effectively manage transient overvoltage not only enhances grid stability but also bolsters the overall reliability of renewable energy sources, making them more attractive for investment and integration into existing energy systems.
For more information about Shuyi Wang and his research team, visit School of Electrical Engineering, Shandong University.
