AUTHOR=Huang Kun , Chi Fuhai , Dou Zhenlan , Yang Zhongguang , Fu Ming , Liu Cheng 

TITLE=Stability Assessment of the PET-Based Distributed Grid

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.930708

DOI=10.3389/fenrg.2022.930708

ISSN=2296-598X

ABSTRACT=The penetration of renewables is getting higher nowadays. The traditional transformer can no longer meet the requirements of utilities. For this reason, power electronic transformer (PET) is proposed as one of the promising alternatives. However, there are coupling issues between PET and the connected converters in the low-voltage grid. To well study the issues, this paper develops impedance models of the PQ node, PV node and PET. Based on the models, the system stability under different scenarios is assessed by the generalized Nyquist criterion. The effects of the line impedance and control parameters on system stability are studied. Moreover, a comprehensive parameter sensitivity analysis is carried out to reveal the coupling mechanism between converters. Simulations are given to validate the effectiveness of the theoretical analyses.