Transformer Inrush Mitigation and Sequential Load Restoration in a Hybrid PV–BESS Microgrid Using Grid-Forming Black-Start Control—Case Study of a 31.59 MWp Photovoltaic Plant

Hybrid PV–BESS microgrids represent a promising solution for enhancing energy resilience; however, the implementation of black-start functions in such architectures remains a complex challenge, particularly in the presence of medium-voltage transformers and grid-following photovoltaic sources. This paper proposes and evaluates, through MATLAB/Simulink simulation, a black-start strategy for a hybrid microgrid derived from the architecture of a real 31.59 MWp photovoltaic power plant connected through a 20 kV collector network. The strategy is based on a BESS operated in grid-forming mode, responsible for voltage and frequency formation, controlled energization of the internal infrastructure, and support of the initial restoration stages, while the photovoltaic groups are synchronized at a later stage in order to reduce the energy burden imposed on the storage system. The methodology combines controlled voltage ramping for transformer inrush current mitigation, hybrid PV–BESS restoration, robustness evaluation under irradiance variation, sequential load restoration, and staged energization of the internal stations TS1–TS5. The results show that the soft-start strategy reduces the maximum instantaneous current of transformer TS2 from 188.3620 A to 0.3515 A and the maximum current of the BESS source from 4729.2 A to 57.7929 A. In the hybrid scenario, after photovoltaic source synchronization at 7 s, PV power rises to 2.75 MW, while the power supplied by the BESS decreases from 3.00 MW to 0.25 MW. The analysis of irradiance variation confirms the increased energy dependence on the BESS under reduced solar resource conditions, while sequential load restoration demonstrates the feasibility of controlled reconnection up to 30.25 MW. Overall, the study confirms that the proposed architecture and staged control logic provide a feasible and transferable framework for enhancing the resilience of large-scale photovoltaic power plants based on hybrid PV–BESS microgrids.