In the heart of China’s power grid evolution, a groundbreaking study led by Wenjia Zhang from the State Grid Jiangsu Electric Power Co. Ltd. is reshaping how we think about integrating renewable energy into our power systems. Zhang’s research, published in the journal Energies, delves into the crucial role of control strategies in maintaining the stability of power grids that rely heavily on modular multilevel converters (MMCs) to interface with AC power grids.
The Jiangsu Power Grid, one of the most developed regional AC systems in China, serves as the backdrop for this study. This grid, known for its extensive load requirements and intricate network, is a microcosm of the challenges faced by modern power systems worldwide. With a significant portion of its electricity imported and an uneven load distribution, the grid is a testament to the complexities of managing power flow, system stability, and voltage regulation in an era of rapid renewable energy integration.
Zhang’s work focuses on the transient stability of MMCs, comparing grid-forming and grid-following control strategies. The study employs electromagnetic transient simulation tools on an adapted IEEE three-machine, nine-bus system, replacing traditional synchronous generators with MMCs configured under different control modes. The results are clear: grid-forming control enhances the receiving-end grid’s transient stability by providing superior phase support and extended fault-clearing times compared to grid-following control.
“This study underscores the importance of converter control selection in achieving robust dynamic operation in modern power systems with a high penetration of renewable energy,” Zhang explains. The findings suggest that grid-forming control, with its self-synchronizing capability and virtual inertia, offers a more stable and resilient grid operation, especially under fault conditions.
The implications for the energy sector are profound. As grids become increasingly decentralized and renewable-rich, the choice of control strategy for MMCs will be pivotal. Grid-forming control, by mimicking the inertia and damping characteristics of conventional synchronous generators, can provide the stability needed for grids with a high proportion of DC feed-in or for offshore isolated substations.
“Future research should further dissect the underlying physical mechanisms and extend the analysis to more diverse network topologies and operating conditions,” Zhang adds. This call to action highlights the need for continued innovation and adaptation in the energy sector.
The study, published in the journal Energies, translates to “Energies” in English, provides a roadmap for future developments in the field. As we move towards a more sustainable energy future, understanding and implementing the right control strategies for MMCs will be crucial. This research not only advances our technical capabilities but also paves the way for more reliable and resilient power systems, ensuring a stable energy supply for generations to come.
