AUTHOR=Liang Jifeng , Rong Shiyang , Yu Tengkai , Li Tiecheng , Qu Hanzhang , Cao Ye 

TITLE=On-line strength assessment of distribution systems with distributed energy resources

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 12 - 2024

YEAR=2025

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2024.1514705

DOI=10.3389/fenrg.2024.1514705

ISSN=2296-598X

ABSTRACT=To enable the online strength assessment of distribution systems integrated with Distributed Energy Resources (DERs), a novel hybrid model and data-driven approach is proposed. Based on the IEC-60909 standard, a new short-circuit calculation method is developed, allowing inverter-based DERs (IBDERs) to be represented as either voltage or current sources with controllable internal impedance. This method also accounts for the impact of distant generators by introducing a site-dependent Short Circuit Ratio (SCR) index to evaluate system strength. An adaptive sampling strategy is employed to generate synthetic data for real-time assessment. To predict the strength of distribution systems under various conditions, a rectified linear unit (ReLU) neural network is trained and further reformulated as a mixed-integer linear programming (MILP) problem to verify its robustness and input stability. The proposed method is validated through case studies on modified IEEE-33 and IEEE-69 bus systems, demonstrating its effectiveness regarding the varying operating conditions within the system.