AUTHOR=Wen Xichang , Wu Ting , Jiang Hui , Peng Jianchun , Wang Huaizhi 

TITLE=Hierarchical Adaptive Control of the Cyber–Physical Power System With MMC-MTDC for Transient Stability Improvement

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.929568

DOI=10.3389/fenrg.2022.929568

ISSN=2296-598X

ABSTRACT=Large-scale wind power integration into the power system has promoted the development of multi-terminal DC transmission grid (MTDC) with modular multilevel converter (MMC). Basically, MTDC with MMC is a typical cyber physical system with continuous coupling interactions between cyber assets and power systems. However, cyber events may introduce many internet-based vulnerabilities and even result in loss of transient stability of power system. Therefore, a voltage compensation based two-level hierarchical adaptive control strategy is proposed in this paper. At the higher level, a modified MMC output current reference calculation method is developed in αβ framework to guarantee the transient stability of power system. Whereas a feedback adjustment method in MMC control framework is proposed, at the bottom level to contain the controller from deviating from its output reference while eliminating the impact of cyber communication delay on transient stability. The paper shows that the proposed hierarchical control strategy can improve the transient stability of power grid in the case of simultaneous disturbances in physical and cyber layer. Finally, the simulation results of the modified IEEE 9-bus test system with MMC-MTDC used to demonstrate the effectiveness of the proposed scheme.