In the rapidly evolving energy sector, the integration of High-Voltage Direct Current (HVDC) transmission technology has been a game-changer, offering lower construction costs, reduced transmission losses, and minimal environmental impact. However, as power grids become increasingly interconnected, new challenges arise, particularly in maintaining frequency stability. A recent study led by Kai Ye from the Energy and Electricity Research Center at Jinan University, Zhuhai, China, delves into these challenges and proposes innovative solutions to enhance the stability and efficiency of asynchronous interconnected power systems.
The research, published in the journal Energies, focuses on the frequency stability of power grids connected by HVDC transmission lines. These lines, while efficient, can weaken the mutual support capabilities between grids, leading to independent frequency operations and potential instability. “The isolating characteristics of HVDC transmission to some extent weaken the mutual support power capabilities between grids,” Ye explains. “In asynchronous power grid systems connected solely by HVDC links, the frequency of the two grids is independent, presenting new challenges to the stability of the frequency and power support of the grid.”
To address these issues, Ye and his team developed a frequency dynamic analysis model for asynchronous interconnected power grids and introduced an HVDC frequency controller. The study analyzed the control effects of HVDC frequency under two scenarios: without Automatic Generation Control (AGC) and with AGC. The findings revealed that the HVDC frequency controller parameters, particularly the proportional coefficient (kp) and integral coefficient (ki), significantly impact system stability. When these parameters are too small, frequency control performance is poor; if they are too large, the effectiveness does not improve and may even slightly decrease. Optimized parameters enhance the system’s response speed and steady-state accuracy across different operating conditions.
The introduction of AGC demonstrated good adaptability, particularly under the TBC mode, which restored frequency modulation power. This coordinated control improves frequency support and resource sharing in asynchronous interconnected grids, addressing frequency stability challenges. “The HVDC controller demonstrates strong adaptability, especially under TBC mode, restoring frequency modulation power,” Ye notes. “This coordinated control improves frequency support and resource sharing in asynchronous interconnected grids, addressing frequency stability challenges.”
The commercial implications of this research are substantial. As power grids become more interconnected and reliant on HVDC technology, the ability to maintain frequency stability is crucial for ensuring reliable and efficient power distribution. The optimized control parameters and adaptive AGC strategies proposed by Ye and his team could lead to more stable and efficient power systems, reducing the risk of blackouts and improving overall grid performance.
Looking ahead, this research paves the way for future developments in the field. As the energy sector continues to evolve, with a growing emphasis on renewable energy sources and smart grid technologies, the need for advanced frequency control strategies will only increase. The insights gained from this study could inform the development of more sophisticated control systems, enhancing the stability and efficiency of power grids worldwide.
